Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis...Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis,and milk fatty acid(FA)output is sparse in sows.This study aimed to evaluate impacts of dietary fat levels and FA composition on these traits in sows.Forty second-parity sows(Danish Landrace×Yorkshire)were assigned to 1 of 5 dietary treatments from d 108 of gestation until weaning(d 28 of lactation):low-fat control diet(3%added animal fat);or 1 of 4 high-fat diets with 8%added fat:coconut oil(CO),fish oil(FO),sunflower oil(SO),or 4%octanoic acid plus 4%FO(OFO).Three approaches were taken to estimate de novo milk fat synthesis from glucose and body fat.Results Daily intake of FA was lowest in low-fat sows within fat levels(P<0.01)and in OFO and FO sows within highfat diets(P<0.01).Daily milk outputs of fat,FA,energy,and FA-derived carbon reflected to a large extent the intake of those.On average,estimates for de novo fat synthesis were 82 or 194 g/d from glucose according to method 1 or 2 and 255 g de novo+mobilized FA/d according to method 3.The low-fat diet increased mammary FAS expression(P<0.05)and de novo fat synthesis(method 1;P=0.13)within fat levels.The OFO diet increased de novo fat synthesis(method 1;P<0.05)and numerically upregulated mammary FAS expression compared to the other high-fat diets.Across diets,a daily intake of 440 g digestible FA minimized milk fat originating from glucose and mobilized body fat.Conclusions Sows fed diets with low-fat or octanoic acid,through upregulating FAS expression,increased mammary de novo fat synthesis whereas the milk FA output remained low in sows fed the low-fat diet or high-fat OFO or FO diets,indicating that dietary FA intake,dietary fat level,and body fat mobilization in concert determine de novo fat synthesis,amount and profiles of FA in milk.展开更多
Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called "cultured" or "synthetic" or "in vitro" meat coul...Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called "cultured" or "synthetic" or "in vitro" meat could in theory be constructed with different characteristics and be produced faster and more efficiently than traditional meat. The technique to generate cultured muscle tissues from stem cells was described long ago, but has not yet been developed for the commercial production of cultured meat products. The technology is at an early stage and prerequisites of implementation include a reasonably high level of consumer acceptance, and the development of commercially-viable means of large scale production. Recent advancements in tissue culture techniques suggest that production may be economically feasible, provided it has physical properties in terms of colour, flavour, aroma, texture and palatability that are comparable to conventional meat. Although considerable progress has been made during recent years, important issues remain to be resolved, including the characterization of social and ethical constraints, the fine-tuning of culture conditions, and the development of culture media that are cost-effective and free of animal products. Consumer acceptance and confidence in in vitro produced cultured meat might be a significant impediment that hinders the marketing process.展开更多
Background: Extensive degradation of amino acids in the rumen via microbial deamination decreases the postruminal availability of dietary indispensable amino acids. Together with the normal decrease in voluntary dry m...Background: Extensive degradation of amino acids in the rumen via microbial deamination decreases the postruminal availability of dietary indispensable amino acids. Together with the normal decrease in voluntary dry matter intake(DMI) around parturition in dairy cows, microbial metabolism contributes to a markedly negative balance of indispensable amino acids, including methionine which may be the first-limiting for milk production. The main objective of the current study was to profile changes in major bacterial species with key functions in cel ulose and hemicel ulose digestion, xylan breakdown, proteolytic action, propionic acid production, lactate utilization and ruminal biohydrogenation in cows supplemented with rumen-protected Methionine(SM; Smartamine M, Adisseo NA, Alpharetta,GA, USA) from-23 through 30 d relative to parturition. Because ~90% of the methionine in SM bypasses the rumen,~10% of the methionine is released into the rumen and can be utilized by microbes.Results: As expected, there was an increase in overall DMI after parturition(Day, P < 0.05) during which cows consumed on average 19.6 kg/d versus 13.9 kg/d in the prepartum period. The postpartum diet contained greater concentrations of lipid and highly-fermentable carbohydrate from corn grain, which likely explains the increases in the relative abundance of Anaerovibrio lipolytica, Megasphaera elsdenii, Prevotella bryantii, Selenomonas ruminantium,Streptococcus bovis, and Succinimonas amylolytica. Despite similar DMI prepartum, cows fed SM had greater(Treatment × Day, P < 0.05) abundance prepartum of Fibrobacter succinogenes, Succinimonas amylolytica, and Succinivibrio dextrinosolvens. However, the greater DMI in cows fed SM after parturition(19.6 kg/d versus 13.9 kg/d) was associated with lower abundance of Fibrobacter succinogenes(2.13 × 10-3 versus 2.25 × 10-4) and Selenomonas ruminantium(2.98 × 10-1 versus 4.10 × 10-1). A lower abundance(Day, P < 0.05) was detected on d 20 compared with d-10 for Fibrobacter succinogenes and Succinivibrio dextrinosolvens. The relative abundance of Butyrivibrio proteoclasticus and Eubacterium ruminantium was stable across treatment and time.(Continued from previous page)Conclusions: In diets with proper balance of rumen-degradable protein and fermentable carbohydrate, the smal fraction of Methionine released from the rumen-protected supplement did not seem to compromise growth of major bacterial species in the rumen. In fact, it had a positive effect on 3 major species prepartum when DMI was similar between groups. Because the actual requirements of Methionine(and Lysine, for example) by the cow during the transition period are unknown, it appears warranted to study the rumen microbiome as it relates to supply of rumen-protected amino acids.展开更多
Background: Pregnancy and early life are critical periods of plasticity during which the fetus and neonate may be influenced by environmental factors such as nutrition.Maternal methionine(Met) supply in non-ruminants ...Background: Pregnancy and early life are critical periods of plasticity during which the fetus and neonate may be influenced by environmental factors such as nutrition.Maternal methionine(Met) supply in non-ruminants during pregnancy can affect offspring development and growth.Thus,the objective of this study was to investigate if increasing Met supply during late-pregnancy affects developmental parameters of the calf at birth and if either maternal Met or colostrum from Met-fed cows alters calf growth.Calves born to Holstein cows individually-fed a basal control [CON; 1.47 Mcal/kg dry matter(DM) and 15.3% crude protein] diet with no added Met or CON plus ethylcellulose rumen-protected Met(MET; Mepron? at 0.09% of diet DM; Evonik Nutrition & Care GmbH,Germany)during the last 28 ± 2 d of pregnancy were used.A total of 39 calves were in CON(n = 22 bulls,17 heifers) and 42 in MET(n = 20 bulls,22 heifers).At birth,calves were randomly allocated considering dam treatment and colostrum as fol ows: 1) calves from CON cows and colostrum from CON cows(n = 21); 2) calves from CON cows and colostrum from MET cows(n = 18); 3) calves from MET cows and colostrum from MET cows(n = 22); and 4) calves from MET cows and colostrum from CON cows(n = 20).Al calves were housed,managed,and fed individual y during the first 9 wk of life.Results: Despite greater daily DM intake pre-partum in cows fed MET(15.7 vs.14.4 ± 0.12 kg/d,P < 0.05),colostrum quality and quantity were not affected by maternal diet.At birth,MET calves had greater(P ≤ 0.05) body weight(BW,44.1 vs.42.1 ± 0.70 kg),hip height(HH,81.3 vs.79.6 ± 0.53 cm) and wither height(WH,77.8 vs.75.9 ± 0.47 cm).In contrast,concentrations of His,Lys,and Asn in plasma were lower(P ≤ 0.05) in MET calves.Regardless of colostrum source,the greater BW,HH,and WH in MET calves at birth persisted through 9 wk of age resulting in average responses of + 3.1 kg BW,+ 1.9 cm HH,and + 1.8 cm WH compared with CON.Average daily gain during the 9 wk was(P < 0.05) 0.72 ± 0.02 kg/d in MET compared with 0.67 ± 0.02 kg/d in CON calves.Respiratory scores were normal and did not differ(P > 0.05) due to maternal Met supply or colostrum source.However,fecal scores tended to be lower(P ≤ 0.10) in MET calves regardless of colostrum source.Conclusions: Increasing the maternal supply of MET during late-pregnancy enhanced growth in utero as wel as during the pre-weaning and early post-weaning periods.Although the ～ 1 kg/d greater DM intake during the last 2–3 wk prior to parturition could explain a portion of the 2 kg extra body mass of MET calves at birth,other mechanisms potential y encompassing nutrient assimilation efficiency likely played a role.Assessing the exact mechanisms sensitive to supply of Met or total amino acid supply during the latter stages of growth in utero merit further research.展开更多
The rapid growth of dairy sectors in the Middle East, particularly in Lebanon, led to extensive use of antibiotics to enhance the health and productivity of animals. Prolonged usage may lead to antibiotic residues in ...The rapid growth of dairy sectors in the Middle East, particularly in Lebanon, led to extensive use of antibiotics to enhance the health and productivity of animals. Prolonged usage may lead to antibiotic residues in foods of animal origin;hence, the emergence of antimicrobial resistant microorganisms. Accurate data on the antibiotic usage in livestock treatment, antibiotic residues and antimicrobial resistances in raw milk in Lebanon are lacking. This study aimed to investigate the types and usages of antibiotics in cattle, their residual levels and the potential microbial resistances in raw milk samples. A questionnaire-based survey identified Gentamicin and Streptomycin as the most frequently used antibiotics. Selected raw milk samples from main dairy farms were then analyzed in duplicate by quantitative ELISA for the antibiotics residual levels. The mean residual levels of Gentamicin and Streptomycin were 90 and 80 μg/L, respectively;which are below the allowable maximum residue limit of 200 μg/L as set by the FAO/WHO. Staphylococcus aureus, Listeria monocytogenes, E. coli and total aerobic microorganisms isolated from the milk samples were then tested for resistance against Gentamicin and Streptomycin by the disc agar diffusion method. All the S. aureus, E. coli, and L. monocytogenes isolates showed high resistance to Gentamicin. However, 95% of S. aureus, 60% of E. coli and 58% of L. monocytogenes isolates were resistant to Streptomycin. The obtained results provide evidence that antimicrobial resistant strains of the above pathogens have become remarkably widespread in raw milk. This requires better management for antibiotic usages among livestock farmers to control sources of food contamination and reduce the health risks associated with the development of resistant microbial strains.展开更多
Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral pass...Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral passaging in broilers and its relatedness to pathogenicity and amino acid (a.a) sequences of the hemagglutinin (HA) cleavage site and neuraminidase (NA) stalk. The original H9N2 AI virus (P0) was used to challenge ten-21 days old broilers. Individual recovery of H9N2 virus from homogenates of trachea, lungs and airsacs was attempted in 9 days old chicken embryos, as a conclusion of the first passage (P1). Tracheal isolates of H9N2 were passaged for a second (P2) and a third (P3) time in broilers, followed by a similar embryonic recovery procedure. The a.a. sequence of a part of HA1 cleavage site and Neuraminidase stalk were compared among the differently passaged viruses;an assessement of the relatedness of the determined a.a. sequences to the pathogenicity in broilers, based on frequency of mortality, morbidity signs, gross and microscopic lesions at 3 days post challenge with the P1, P2, and P3-H9N2, is concluded. An increase in certain morbidity signs and specific lesions was observed in P2- and P3-H9N2 challenged broilers compared to birds challenged with P1-H9N2. A conserved R-S-S-R amino acid sequence at the HA1 cleavage site was observed in the differently passaged H9N2, associated with a variability in the NA stalk-a.a sequences. The passaging of the low pathogenic H9N2 virus in broilers leads to a trend of increase in pathogenicity, manifested in higher frequency of morbidity signs, and of specific gross and microscopic lesions of the examined organs. This passaging was associated with a conserved a.a. sequence of the hemaglutinin cleavage site and a variability in the sequence of the neuraminidase stalk. A detailed study of the potential of the detected variability in the neuraminidase stalk of H9N2 in induction of a higher pathogenicity in broilers will be the subject of future investigations.展开更多
Growth hormone (GH) and estrogen are essential stimulators of mammary cell proliferation and mammary development as mammals near puberty. Mammary ductal growth requires modifications of the extracellular matrix (ECM) ...Growth hormone (GH) and estrogen are essential stimulators of mammary cell proliferation and mammary development as mammals near puberty. Mammary ductal growth requires modifications of the extracellular matrix (ECM) for this tissue expansion to occur. Our purpose was to evaluate the effects of exogenous GH and ovariectomy (known to impact estrogen production) on gene expression of selected ECM proteins in the mammary parenchyma (PAR) and mammary fat pad (MFP) of prepubertal calves. Our hypothesis was that both GH and ovariectomy would alter the mRNA expression of multiple mammary ECM proteins. However, treatment with GH significantly reduced the expression of only fibronectin in PAR. However, the mRNA expression of all of the ECM proteins tested was numerically lower in PAR from GH treated calves. In contrast, staged ovariectomy decreased expression of fibronectin and heat shock protein 90 but increased expression of epimorphin in mammary PAR. In the MFP expression of Rac-1 and fascin were increased. These findings suggest that effects of exogenous GH on mammary gland composition are only marginally dependent on alterations in ECM proteins but the more pronounced effects of ovariectomy (reduced PAR mass and altered myoepithelial ontogeny) are more likely linked to changes in expression of ECM proteins.展开更多
The DNA of duck plague virus (DPV) thymidine kinase (TK) gene was cloned and sequenced from a vaccine virus in the study. Degenerate oligonucleotide primers for the consensus site of herpesvirus UL24, TK, and glycopro...The DNA of duck plague virus (DPV) thymidine kinase (TK) gene was cloned and sequenced from a vaccine virus in the study. Degenerate oligonucleotide primers for the consensus site of herpesvirus UL24, TK, and glycoprotein H(gH) gene were used in the polymerase chain reaction (PCR) to amplify DNA product with 3 741-base-pairs (bp) in size. DNA sequence analysis revealed a 1 077-base-pairs (bp) open reading frame (ORF) encoding a 358 amino acid polypeptide homologous to herpesvirus TK proteins. The predicted TK protein shared 31.2, 41.3, 35.7, 37.4, and 28.4% identity with herpes simplex virus type1, equine herpesvirus type 4, Marek’s disease virus 2, herpesvirus turkey, and infectious laryngotracheitis virus, respectively. Comparison of the amino acid sequences of other herpesvirus TK proteins showed that these proteins were not conserved on the whole, otherwise the portion of the TK proteins corresponding to the nucleotide binding domain and the nucleoside binding site were highly conserved among herpesvirus. Comparison with the amino acid sequences of the conserved nucleotide and nucleoside binding domains of other eleven herpesvirus TK proteins to the predicted DPV peptide confirmed its identity as the DPV TK protein.展开更多
Background:Branched chain amino acids(BCAAs)are important substrates for milk protein synthesis in the mammary gland,and are tightly related to lipid metabolism.No study has been performed examining the role of BCAAs ...Background:Branched chain amino acids(BCAAs)are important substrates for milk protein synthesis in the mammary gland,and are tightly related to lipid metabolism.No study has been performed examining the role of BCAAs with high fat diets on milk fat synthesis.This study was designed to investigate the effect of dietary BCAAs on growth performance of piglets,progeny body weight,and milk fat composition in sows fed a high fat diet.Four diets(CON=control diet;HF=high fat diet with 8%soybean oil;HF-MB=HF plus 0.39%BCAAs;HF-HB=HF plus 0.78%BCAAs)were fed to sows from late gestation to weaning.Results:Compared to HF,BCAAs(HF-MB and HF-HB)increased the litter weight(P<0.05)and overall litter weight gain(P<0.05)at weaning and increased colostrum fat content by 27.3–35.8%(P<0.01).Fatty acid profiles between the two doses of BCAAs were similar.Compared with HF,HF-MB tended to decrease the percentage of C18:3n3(P=0.063)and increased the percentage of C18:1n9c(P=0.03).In addition,BCAAs in HF-MB increased the concentration of total fatty acid by 22.1%in colostrum(P=0.03)but decreased that in serum at parturition by 53.2%(P=0.027).The fatty acids in colostrum that increased with BCAAs were C15:0,C17:0,C20:3n6,C20:4n6,C20:5n3 and C22:6n3(P=0.00~0.04).Colostrum fatty acids of C20:0,C21:0,C22:0,C16:1,C20:1,C18:1n9c also tended to be increased(0.05<P<0.1)with BCAAs.The change in sow serum fatty acid profile due to BCAAs was different from that in colostrum.Conclusions:BCAAs in high fat diet of sows altered the fatty acid composition in colostrum and enhanced litter growth.Our study indicated that BCAAs supplementation can enhance mammary fatty acid uptake and mammary fat synthesis and that supplemental BCAAs and fat in late gestation and lactation diets for sows can improve reproductive performance.展开更多
Background: It is wel known that peptides play a vital role in the nutrition and health of dairy cows. Bovine oligopeptide transporter 1(bP epT 1) is involved in the peptide transport process in the gastrointestinal t...Background: It is wel known that peptides play a vital role in the nutrition and health of dairy cows. Bovine oligopeptide transporter 1(bP epT 1) is involved in the peptide transport process in the gastrointestinal tracts of dairy cows. However,little information is known in the characteristics of bP epT 1. Therefore, the purpose of this study was to characterize bP epT 1 functional y using a mammalian cel expression system. The uptake of radiolabeled dipeptide glycyl-sarcosine([3 H]-Gly-Sar)into the bP epT 1-transfected Chinese hamster ovary cel s was measured at various pH and substrate concentrations and with or without 15 other smal peptides that contained Met or Lys.Results: Western blot results showed that the abundance of bP epT 1 protein in the jejunum and ileum are the highest in the gastrointestinal tract of dairy cows. The uptake of [3 H]-Gly-Sar by b Pep T1-Chinese hamster ovary cells was dependent on time, p H, and substrate concentration, with a low Kmvalue of 0.94 ± 0.06 mmol/L and a maximum velocity of 20.80 ± 1.74 nmol/(mg protein · 5 min). Most of the di-and tripeptides were the substrates of b Pep T1,based on substrate-competitive studies. However, bP epT 1 has a higher affinity to the peptides with shorter chains, greater hydrophobicity, and negative or neutral charges.Conclusions: These results demonstrated for the first time the functional characteristics of bP epT 1, and they provide a new insight and better understanding into its vital role in absorbing a wide range of peptides from the digestive tract of dairy cows.展开更多
Background:The milk fat globule membrane(MFGM)proteomes of colostrum and transition milk are rich sources of proteins that are likely important for neonatal calf health.In addition,characterization of these proteomes ...Background:The milk fat globule membrane(MFGM)proteomes of colostrum and transition milk are rich sources of proteins that are likely important for neonatal calf health.In addition,characterization of these proteomes could also yield valuable information regarding mammary gland physiology of the early postpartum lactating cow.The objectives of this research were to characterize the MFGM proteomes of colostrum and transition milk through sample collections at four timepoints postpartum,including the first milking(M1,colostrum),second milking(M2,transition milk),fourth milking(M4,transition milk),and fourteenth milking(M14,mature milk),and compare these proteomes between multiparous(MP;n=10)and primiparous(PP;n=10)Holstein dairy cows.Isolated MFGM proteins were labeled using Tandem Mass tagging and analyzed using liquid chromatography-tandem mass spectrometry(LC-MS/MS).Protein identification was completed using MASCOT and Sequest in Proteome Discoverer 2.2.The scaled abundance values were analyzed using PROC MIXED in SAS to determine the effects of milking(MIL),parity(PAR),and MIL×PAR.The adaptive false-discovery rate(FDR)-adjusted P values were determined using PROC MULTTEST.Protein characterization and bioinformatic analysis were completed using a combination of PANTHER,Blast,and Uniprot.Results:A total of 104 common proteins were identified in each of the MFGM samples.Statistical analysis revealed that 70.2%of identified proteins were affected by MIL.Of these,78.1%were lower in M14 compared with M1,including immune-related proteins lactotransferrin,lactadherin and hemopexin.Parity affected 44.2%of proteins.Of the proteins affected by PAR,84.8%were higher in MP cows compared with PP cows,including apolipoprotein E and histones 2A,2B,3,and 4 b.Butyrophilin subfamily 1 member 1A and annexin 5 were higher in samples from PP cows.Milking×parity affected 32.7%of identified proteins,including lactotransferrin,gelsolin,vitamin D binding protein,and S100 proteins.Conclusions:This research supports previous findings that the Holstein MFGM proteome changes rapidly during the first week of lactation.In addition,this research identifies the impact of parity on the colostrum and transition milk MFGM proteomes,which may be important for milk-fed calf health or for the identification of protein biomarkers for mammary functionality.展开更多
Tocopherol sources in diets are often a combination of all-rac-a-tocopheryl acetate(synthetic a-tocopherol)from vitamin supplements and natural tocopherols and 2R-(4’R,8’R)-5,7,8-trimethyltocotrienol(a-tocotrienols)...Tocopherol sources in diets are often a combination of all-rac-a-tocopheryl acetate(synthetic a-tocopherol)from vitamin supplements and natural tocopherols and 2R-(4’R,8’R)-5,7,8-trimethyltocotrienol(a-tocotrienols)from the feed sources.Synthetic a-tocopherol consists of 8 different stereoisomers including 2R-(4’R,8’R)-5,7,8-trimethyltocol(RRR-a-tocopherol),2R-(4’S,8’R)-5,7,8-trimethyltocol(RSR-a-tocopherol),2R-(4’R,8’S)-5,7,8-trimethyltocol(RRS-a-tocopherol),2R-(4’S,8’S)-5,7,8-trimethyltocol(RSS-a-tocopherol),2S-(4’S,8’S)-5,7,8-trimethyltocol(SSS-a-tocopherol),2S-(4’R,8’S)-5,7,8-trimethyltocol(SRS-a-tocopherol),2S-(4’S,8’R)-5,7,8-trimethyltocol(SSR-a-tocopherol),and2S-(4’R,8’R)-5,7,8-trimethyltocol(SRR-a-tocopherol).The pre-absorption metabolism of tocopherols and tocotrienols in ruminants differs from monogastric animals due to the extensive microbial fermentation in the anaerobic rumen.The current study investigated the impact of toasting and decortication of oats on metabolism in the digestive tract(synthesis,digestion),and intestinal digestibility of tocopherols in dairy cows by using 4 ruminal and intestinal cannulated Danish Holstein cows in a 4×4 Latin square design for 4 periods.Cows were fed a total mixed ration ad libitum containing different forms of oats:whole oat,decorticated oat,toasted oat,and decorticated toasted oat,all rolled before mixed ration.Overall means across 4 treatments were statistically analyzed,testing whether overall means were different from zero.Decortication or toasting did not affect the balance or digestibility of a-tocopherols in rumen.Average across treatments showed the ruminal degradation of synthetic a-tocopherol(279 mg/d,P=0.02;P-value shows that average across treatments is different from zero),synthetic 2R-a-tocopherol(133 mg/d,P<0.01;summation of RRS-,RSR-and RSS-a-tocopherol),and 2S-a-tocopherol(190 mg/d;P<0.01,summation of SSS-,SRS-,SSR,and SRR-a-tocopherol),while RRR-a-tocopherol was formed in the rumen(221 mg/d,P=0.10).The average across treatments showed that small intestinal digestibility of tocopherols ranked in the following order:a-tocotrienol>natural a-tocopherol>synthetic a-tocopherols>2R-(4’R,8’R)-,7,8-dimethyltocol(γ-tocopherol).The average across treatments for small intestinal and feed-ileum digestibility ranked in the following order:RRR-a-tocopherol>synthetic 2R-a-tocopherol>2S-a-tocopherol.Results showed the first evidence for RRR-a-tocopherol formation under anaerobic conditions in the rumen.In addition,synthetic a-tocopherol stereoisomers,γ-tocopherol and a-tocotrienol were degraded in the rumen.There was a discrimination against absorption of synthetic 2R-and 2S-a-tocopherol in the small intestine.展开更多
Transposable elements are capable of switching their positions on the genome thereby causing gene arrangements and contributing to genome evolution. The aim of this review is to specifically discuss the role of transp...Transposable elements are capable of switching their positions on the genome thereby causing gene arrangements and contributing to genome evolution. The aim of this review is to specifically discuss the role of transposable elements in transferring antimicrobial resistance genes in E. coli, thus contributing to increase in virulence and conferring the possibility of multidrug resistance. Different types of transposable elements such as transposons and integrons and their profound influence on E. coli antimicrobial resistance are the focus of this review.展开更多
The objective of this study was to investigate whether supplementation with N-carbamoylglutamate(NCG)to cows during late gestation alters uteroplacental tissue nutrient transporters,calf metabolism and newborn weight....The objective of this study was to investigate whether supplementation with N-carbamoylglutamate(NCG)to cows during late gestation alters uteroplacental tissue nutrient transporters,calf metabolism and newborn weight.Thirty multiparous Chinese Holstein cows were used in a randomized complete block design experiment.During the last 28 d of pregnancy,cows were fed a diet without(CON)or with NCG(20 g/d per cow).The body weight of calves was weighed immediately after birth.Placentome samples were collected at parturition and used to assess mRNA expression of genes involved in transport of arginine,glucose,fatty acid and angiogenesis factors,as well as the mammalian target of rapamycin(mTOR)pathway.Blood samples of calves before colostrum consumption were also collected for the detection of plasma parameters,amino acids(AA)and metabolomics analysis.The newborn weight(P=0.02)and plasma Arg concentration of NCG-calves was significantly higher(P=0.05)than that of CON-calves,and the plasma concentrations of urea nitrogen tended to be lower(P=0.10)in the NCG group.The mRNA abundance of genes involved in glucose transport(solute carrier family 2 member 3[SLC2 A3],P<0.01),angiogenesis(nitric oxide synthase 3[NOS3],P=0.02),and mTOR pathway(serine/threonine-protein kinase 1[ACT1],P=0.10;euka ryotic translation initiation factor 4 B pseudogene 1[EIF4 BP1],P=0.08;EIF4 EBP2,P=0.04;and E74-like factor 2[ELF2],P=0.03)was upregulated in the placentome of NCG-supplemented cows.In addition,17 metabolites were significantly different in the placentome of NCG-supplemented cows compared to non-supplemented cows,and these metabolites are mainly involved in arginine and proline metabolism,alanine,aspartate and glutamate metabolism,and citrate cycle.In summary,the increased body weight of newborn calves from the NCG supplemented dairy cows maybe attributed to the increased angiogenesis and uteroplacental nutrient transport and to the activated mTOR signal pathway,which may result in the increased nutrient supply to the fetus,and improved AA metabolism and urea cycle of the fetus.展开更多
The continuous battle between humans and the multitude of pathogenic microorganisms in the environment has sought relief in the form of antimicrobials. But the counter attack by pathogenic organisms in the form of mul...The continuous battle between humans and the multitude of pathogenic microorganisms in the environment has sought relief in the form of antimicrobials. But the counter attack by pathogenic organisms in the form of multidrug resistance, acquired by various mechanisms such as transformation, transposition, conjugation and transduction is a major reason for concern. Bacteriophages have contributed in a significant way to dissemination of genes encoding antimicrobial resistance, heavy metal resistance and virulence factors through the phenomenon of transduction. This review aims at compiling information about the different mechanisms by which bacteriophages aid in transferring genes involved in antimicrobial resistance to Escherischia coli in various environments.展开更多
Background:Native warm-season grass(NWSG)mixtures may provide a lownitrogen(N)-input summer perennial forage option to extensively managed forage-livestock systems.Methods:Mixed pastures of big bluestem(Andropogon ger...Background:Native warm-season grass(NWSG)mixtures may provide a lownitrogen(N)-input summer perennial forage option to extensively managed forage-livestock systems.Methods:Mixed pastures of big bluestem(Andropogon gerardii Vitman),little bluestem(Schizachyrium scoparium Michx.),and indiangrass(Sorghastrum nutans L.)fertilized with 0 or 67 kgNha−1 were continuously stocked with beef heifers and cows.Forage mass,nutritive value,and canopy heights were determined every 2 weeks during the grazing season.Stand persistence measures included the canopy cover and leaf area index(LAI)and plant crown density at spring emergence following 3 years of grazing management.Results:Forage mass,canopy height,and stocking densities were greater for N-fertilized NWSG than unfertilized NWSG for the first 30 days of the growing season across the 3-year study.Forage NWSG fertilized with N had a greater decrease in LAI during the growing season(51%decrease)than unfertilized NWSG.Spring NWSG plant density estimates following 3 years of grazing did not differ across N management strategies.Conclusions:Forage NWSG mixtures supported superior forage attributes and greater stocking densities early in the grazing season under low-level N than zero-N-input systems and may provide a low-N-input alternative for improved species use in southeastern US forage-livestock systems.展开更多
Peptide transporter 2(PepT2)transports short peptides from the blood into bovine mammary epithelial cells(BMEC)to stimulate milk protein synthesis.Despite the fact that the effect of PepT2 is acknowledged in BMEC,litt...Peptide transporter 2(PepT2)transports short peptides from the blood into bovine mammary epithelial cells(BMEC)to stimulate milk protein synthesis.Despite the fact that the effect of PepT2 is acknowledged in BMEC,little is known about its regulation.This study was completed to investigate the role of mammalian target of the rapamycin(mTOR)signaling in regulating the expression and function of PepT2 in BMEC.The regulation of PepT2 by mTOR in BMEC was studied in vitro using peptide transport assay,gene silencing,Western blot.The membrane expression of PepT2 and the uptake of b-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid(b-Ala-Lys-AMCA),a model dipeptide,in BMEC were reduced by rapamycin(a mTOR inhibitor)and silencing of either mTOR complex 1(mTORC1)or mTOR complex 2(mTORC2),stimulated by DEP domain-containing mTOR-interacting protein(DEPTOR,endogenous inhibitor of mTORC1 and mTORC2)silencing.The trafficking of PepT2 to the membrane and the uptake of b-Ala-Lys-AMCA was promoted by neuronal precursor cell-expressed developmentally down-regulated 4 isoform 2(Nedd4-2)silencing.The effects of knockdown of mTORC1,but not mTORC2,on cell membrane expression and transport activity of PepT2 was abolished by Nedd4-2 silencing.With immunofluorescence staining,PepT2 was identified to be interacting with Nedd4-2.The Nedd4-2 expression and the interaction between PepT2 and Nedd4-2 was increased through mTORC1 knockdown,indicating an increased ubiquitination of PepT2.The results revealed that mTORC1 can regulate the expression and function of PepT2 through Nedd4-2 in BMEC.展开更多
Feed formulation is essential in the dairy production chain from economic,nutritional,and environmental perspectives.Optimizing the feed formulation across those three domains–given uncertainty of input prices,input ...Feed formulation is essential in the dairy production chain from economic,nutritional,and environmental perspectives.Optimizing the feed formulation across those three domains–given uncertainty of input prices,input availability,and regional climatic conditions–is a challenge for those in the industry.The diet formulation method that is widely used by trading firms and feed production facilities employs a static linear programming(LP)approach.This approach does not allow for intertemporal feed formulations and switches between dietary feed commodities under feed availability conditions,which result in foregone economic gains for feed producers.The current study develops a multi-period LP feed model that uses historical data to capture ration switch opportunities between available feed resources for dairy cows and demonstrates the potential use of the method in different commodity feed availability situations.We apply 14 diet formulations,each covering 150 months,representing a total of 2100 diets.The diet formulation considers a specific milk production level for a“model cow”,alternative feed formulations available,and volatility in feed prices.The results demonstrate that there is an opportunity for efficiency gains in the dairy industry with respect to feed formulation.Based on dietary feed inclusion and price spreads,barley can be an important dairy feed grain which completely replaces wheat,corn,and sorghum at price spreads of less than 94%,less than 78%,and less than 67%,respectively.Grain-based feed scenarios represent the lowest nutrient variation while multiple meal feeds had the lowest costs.Furthermore,and on average,multiple meal feed scenarios provided 10%higher dietary crude protein contents compared to grain based feed scenarios(i.e.163 vs 179 g/kg DM formulated feed).Meanwhile,multiple meal feeding cost was 11%lower than that in the grain based feeding scenarios.Additionally,the use of multiple meals reduces alfalfa dietary inclusion by 7%on dry matter basis.Our analysis shows a strong reduction in feed cost associated with dietary crude protein reduction equivalent to 7.6 USD/tonne per 1%reduction in dietary crude protein level.The modeling approach allows for the interaction between feed components over time taking into consideration volatile global feed prices,thereby improving feed availability and feed formulation.Overall,the model provides a decision making tool to improve the use of feed resources in the dairy sector.展开更多
基金Financially supported by the Danish Council for Independent Research,Technology and Production Sciences (Copenhagen K,Denmark)。
文摘Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis,and milk fatty acid(FA)output is sparse in sows.This study aimed to evaluate impacts of dietary fat levels and FA composition on these traits in sows.Forty second-parity sows(Danish Landrace×Yorkshire)were assigned to 1 of 5 dietary treatments from d 108 of gestation until weaning(d 28 of lactation):low-fat control diet(3%added animal fat);or 1 of 4 high-fat diets with 8%added fat:coconut oil(CO),fish oil(FO),sunflower oil(SO),or 4%octanoic acid plus 4%FO(OFO).Three approaches were taken to estimate de novo milk fat synthesis from glucose and body fat.Results Daily intake of FA was lowest in low-fat sows within fat levels(P<0.01)and in OFO and FO sows within highfat diets(P<0.01).Daily milk outputs of fat,FA,energy,and FA-derived carbon reflected to a large extent the intake of those.On average,estimates for de novo fat synthesis were 82 or 194 g/d from glucose according to method 1 or 2 and 255 g de novo+mobilized FA/d according to method 3.The low-fat diet increased mammary FAS expression(P<0.05)and de novo fat synthesis(method 1;P=0.13)within fat levels.The OFO diet increased de novo fat synthesis(method 1;P<0.05)and numerically upregulated mammary FAS expression compared to the other high-fat diets.Across diets,a daily intake of 440 g digestible FA minimized milk fat originating from glucose and mobilized body fat.Conclusions Sows fed diets with low-fat or octanoic acid,through upregulating FAS expression,increased mammary de novo fat synthesis whereas the milk FA output remained low in sows fed the low-fat diet or high-fat OFO or FO diets,indicating that dietary FA intake,dietary fat level,and body fat mobilization in concert determine de novo fat synthesis,amount and profiles of FA in milk.
文摘Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called "cultured" or "synthetic" or "in vitro" meat could in theory be constructed with different characteristics and be produced faster and more efficiently than traditional meat. The technique to generate cultured muscle tissues from stem cells was described long ago, but has not yet been developed for the commercial production of cultured meat products. The technology is at an early stage and prerequisites of implementation include a reasonably high level of consumer acceptance, and the development of commercially-viable means of large scale production. Recent advancements in tissue culture techniques suggest that production may be economically feasible, provided it has physical properties in terms of colour, flavour, aroma, texture and palatability that are comparable to conventional meat. Although considerable progress has been made during recent years, important issues remain to be resolved, including the characterization of social and ethical constraints, the fine-tuning of culture conditions, and the development of culture media that are cost-effective and free of animal products. Consumer acceptance and confidence in in vitro produced cultured meat might be a significant impediment that hinders the marketing process.
文摘Background: Extensive degradation of amino acids in the rumen via microbial deamination decreases the postruminal availability of dietary indispensable amino acids. Together with the normal decrease in voluntary dry matter intake(DMI) around parturition in dairy cows, microbial metabolism contributes to a markedly negative balance of indispensable amino acids, including methionine which may be the first-limiting for milk production. The main objective of the current study was to profile changes in major bacterial species with key functions in cel ulose and hemicel ulose digestion, xylan breakdown, proteolytic action, propionic acid production, lactate utilization and ruminal biohydrogenation in cows supplemented with rumen-protected Methionine(SM; Smartamine M, Adisseo NA, Alpharetta,GA, USA) from-23 through 30 d relative to parturition. Because ~90% of the methionine in SM bypasses the rumen,~10% of the methionine is released into the rumen and can be utilized by microbes.Results: As expected, there was an increase in overall DMI after parturition(Day, P < 0.05) during which cows consumed on average 19.6 kg/d versus 13.9 kg/d in the prepartum period. The postpartum diet contained greater concentrations of lipid and highly-fermentable carbohydrate from corn grain, which likely explains the increases in the relative abundance of Anaerovibrio lipolytica, Megasphaera elsdenii, Prevotella bryantii, Selenomonas ruminantium,Streptococcus bovis, and Succinimonas amylolytica. Despite similar DMI prepartum, cows fed SM had greater(Treatment × Day, P < 0.05) abundance prepartum of Fibrobacter succinogenes, Succinimonas amylolytica, and Succinivibrio dextrinosolvens. However, the greater DMI in cows fed SM after parturition(19.6 kg/d versus 13.9 kg/d) was associated with lower abundance of Fibrobacter succinogenes(2.13 × 10-3 versus 2.25 × 10-4) and Selenomonas ruminantium(2.98 × 10-1 versus 4.10 × 10-1). A lower abundance(Day, P < 0.05) was detected on d 20 compared with d-10 for Fibrobacter succinogenes and Succinivibrio dextrinosolvens. The relative abundance of Butyrivibrio proteoclasticus and Eubacterium ruminantium was stable across treatment and time.(Continued from previous page)Conclusions: In diets with proper balance of rumen-degradable protein and fermentable carbohydrate, the smal fraction of Methionine released from the rumen-protected supplement did not seem to compromise growth of major bacterial species in the rumen. In fact, it had a positive effect on 3 major species prepartum when DMI was similar between groups. Because the actual requirements of Methionine(and Lysine, for example) by the cow during the transition period are unknown, it appears warranted to study the rumen microbiome as it relates to supply of rumen-protected amino acids.
基金supported by a postdoctoral fellowship from the government of the Arab Republic of Egypt
文摘Background: Pregnancy and early life are critical periods of plasticity during which the fetus and neonate may be influenced by environmental factors such as nutrition.Maternal methionine(Met) supply in non-ruminants during pregnancy can affect offspring development and growth.Thus,the objective of this study was to investigate if increasing Met supply during late-pregnancy affects developmental parameters of the calf at birth and if either maternal Met or colostrum from Met-fed cows alters calf growth.Calves born to Holstein cows individually-fed a basal control [CON; 1.47 Mcal/kg dry matter(DM) and 15.3% crude protein] diet with no added Met or CON plus ethylcellulose rumen-protected Met(MET; Mepron? at 0.09% of diet DM; Evonik Nutrition & Care GmbH,Germany)during the last 28 ± 2 d of pregnancy were used.A total of 39 calves were in CON(n = 22 bulls,17 heifers) and 42 in MET(n = 20 bulls,22 heifers).At birth,calves were randomly allocated considering dam treatment and colostrum as fol ows: 1) calves from CON cows and colostrum from CON cows(n = 21); 2) calves from CON cows and colostrum from MET cows(n = 18); 3) calves from MET cows and colostrum from MET cows(n = 22); and 4) calves from MET cows and colostrum from CON cows(n = 20).Al calves were housed,managed,and fed individual y during the first 9 wk of life.Results: Despite greater daily DM intake pre-partum in cows fed MET(15.7 vs.14.4 ± 0.12 kg/d,P < 0.05),colostrum quality and quantity were not affected by maternal diet.At birth,MET calves had greater(P ≤ 0.05) body weight(BW,44.1 vs.42.1 ± 0.70 kg),hip height(HH,81.3 vs.79.6 ± 0.53 cm) and wither height(WH,77.8 vs.75.9 ± 0.47 cm).In contrast,concentrations of His,Lys,and Asn in plasma were lower(P ≤ 0.05) in MET calves.Regardless of colostrum source,the greater BW,HH,and WH in MET calves at birth persisted through 9 wk of age resulting in average responses of + 3.1 kg BW,+ 1.9 cm HH,and + 1.8 cm WH compared with CON.Average daily gain during the 9 wk was(P < 0.05) 0.72 ± 0.02 kg/d in MET compared with 0.67 ± 0.02 kg/d in CON calves.Respiratory scores were normal and did not differ(P > 0.05) due to maternal Met supply or colostrum source.However,fecal scores tended to be lower(P ≤ 0.10) in MET calves regardless of colostrum source.Conclusions: Increasing the maternal supply of MET during late-pregnancy enhanced growth in utero as wel as during the pre-weaning and early post-weaning periods.Although the ～ 1 kg/d greater DM intake during the last 2–3 wk prior to parturition could explain a portion of the 2 kg extra body mass of MET calves at birth,other mechanisms potential y encompassing nutrient assimilation efficiency likely played a role.Assessing the exact mechanisms sensitive to supply of Met or total amino acid supply during the latter stages of growth in utero merit further research.
文摘The rapid growth of dairy sectors in the Middle East, particularly in Lebanon, led to extensive use of antibiotics to enhance the health and productivity of animals. Prolonged usage may lead to antibiotic residues in foods of animal origin;hence, the emergence of antimicrobial resistant microorganisms. Accurate data on the antibiotic usage in livestock treatment, antibiotic residues and antimicrobial resistances in raw milk in Lebanon are lacking. This study aimed to investigate the types and usages of antibiotics in cattle, their residual levels and the potential microbial resistances in raw milk samples. A questionnaire-based survey identified Gentamicin and Streptomycin as the most frequently used antibiotics. Selected raw milk samples from main dairy farms were then analyzed in duplicate by quantitative ELISA for the antibiotics residual levels. The mean residual levels of Gentamicin and Streptomycin were 90 and 80 μg/L, respectively;which are below the allowable maximum residue limit of 200 μg/L as set by the FAO/WHO. Staphylococcus aureus, Listeria monocytogenes, E. coli and total aerobic microorganisms isolated from the milk samples were then tested for resistance against Gentamicin and Streptomycin by the disc agar diffusion method. All the S. aureus, E. coli, and L. monocytogenes isolates showed high resistance to Gentamicin. However, 95% of S. aureus, 60% of E. coli and 58% of L. monocytogenes isolates were resistant to Streptomycin. The obtained results provide evidence that antimicrobial resistant strains of the above pathogens have become remarkably widespread in raw milk. This requires better management for antibiotic usages among livestock farmers to control sources of food contamination and reduce the health risks associated with the development of resistant microbial strains.
文摘Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral passaging in broilers and its relatedness to pathogenicity and amino acid (a.a) sequences of the hemagglutinin (HA) cleavage site and neuraminidase (NA) stalk. The original H9N2 AI virus (P0) was used to challenge ten-21 days old broilers. Individual recovery of H9N2 virus from homogenates of trachea, lungs and airsacs was attempted in 9 days old chicken embryos, as a conclusion of the first passage (P1). Tracheal isolates of H9N2 were passaged for a second (P2) and a third (P3) time in broilers, followed by a similar embryonic recovery procedure. The a.a. sequence of a part of HA1 cleavage site and Neuraminidase stalk were compared among the differently passaged viruses;an assessement of the relatedness of the determined a.a. sequences to the pathogenicity in broilers, based on frequency of mortality, morbidity signs, gross and microscopic lesions at 3 days post challenge with the P1, P2, and P3-H9N2, is concluded. An increase in certain morbidity signs and specific lesions was observed in P2- and P3-H9N2 challenged broilers compared to birds challenged with P1-H9N2. A conserved R-S-S-R amino acid sequence at the HA1 cleavage site was observed in the differently passaged H9N2, associated with a variability in the NA stalk-a.a sequences. The passaging of the low pathogenic H9N2 virus in broilers leads to a trend of increase in pathogenicity, manifested in higher frequency of morbidity signs, and of specific gross and microscopic lesions of the examined organs. This passaging was associated with a conserved a.a. sequence of the hemaglutinin cleavage site and a variability in the sequence of the neuraminidase stalk. A detailed study of the potential of the detected variability in the neuraminidase stalk of H9N2 in induction of a higher pathogenicity in broilers will be the subject of future investigations.
文摘Growth hormone (GH) and estrogen are essential stimulators of mammary cell proliferation and mammary development as mammals near puberty. Mammary ductal growth requires modifications of the extracellular matrix (ECM) for this tissue expansion to occur. Our purpose was to evaluate the effects of exogenous GH and ovariectomy (known to impact estrogen production) on gene expression of selected ECM proteins in the mammary parenchyma (PAR) and mammary fat pad (MFP) of prepubertal calves. Our hypothesis was that both GH and ovariectomy would alter the mRNA expression of multiple mammary ECM proteins. However, treatment with GH significantly reduced the expression of only fibronectin in PAR. However, the mRNA expression of all of the ECM proteins tested was numerically lower in PAR from GH treated calves. In contrast, staged ovariectomy decreased expression of fibronectin and heat shock protein 90 but increased expression of epimorphin in mammary PAR. In the MFP expression of Rac-1 and fascin were increased. These findings suggest that effects of exogenous GH on mammary gland composition are only marginally dependent on alterations in ECM proteins but the more pronounced effects of ovariectomy (reduced PAR mass and altered myoepithelial ontogeny) are more likely linked to changes in expression of ECM proteins.
文摘The DNA of duck plague virus (DPV) thymidine kinase (TK) gene was cloned and sequenced from a vaccine virus in the study. Degenerate oligonucleotide primers for the consensus site of herpesvirus UL24, TK, and glycoprotein H(gH) gene were used in the polymerase chain reaction (PCR) to amplify DNA product with 3 741-base-pairs (bp) in size. DNA sequence analysis revealed a 1 077-base-pairs (bp) open reading frame (ORF) encoding a 358 amino acid polypeptide homologous to herpesvirus TK proteins. The predicted TK protein shared 31.2, 41.3, 35.7, 37.4, and 28.4% identity with herpes simplex virus type1, equine herpesvirus type 4, Marek’s disease virus 2, herpesvirus turkey, and infectious laryngotracheitis virus, respectively. Comparison of the amino acid sequences of other herpesvirus TK proteins showed that these proteins were not conserved on the whole, otherwise the portion of the TK proteins corresponding to the nucleotide binding domain and the nucleoside binding site were highly conserved among herpesvirus. Comparison with the amino acid sequences of the conserved nucleotide and nucleoside binding domains of other eleven herpesvirus TK proteins to the predicted DPV peptide confirmed its identity as the DPV TK protein.
基金This study is funded by The National Key Research and Development Program of China(2018YFD0500402).
文摘Background:Branched chain amino acids(BCAAs)are important substrates for milk protein synthesis in the mammary gland,and are tightly related to lipid metabolism.No study has been performed examining the role of BCAAs with high fat diets on milk fat synthesis.This study was designed to investigate the effect of dietary BCAAs on growth performance of piglets,progeny body weight,and milk fat composition in sows fed a high fat diet.Four diets(CON=control diet;HF=high fat diet with 8%soybean oil;HF-MB=HF plus 0.39%BCAAs;HF-HB=HF plus 0.78%BCAAs)were fed to sows from late gestation to weaning.Results:Compared to HF,BCAAs(HF-MB and HF-HB)increased the litter weight(P<0.05)and overall litter weight gain(P<0.05)at weaning and increased colostrum fat content by 27.3–35.8%(P<0.01).Fatty acid profiles between the two doses of BCAAs were similar.Compared with HF,HF-MB tended to decrease the percentage of C18:3n3(P=0.063)and increased the percentage of C18:1n9c(P=0.03).In addition,BCAAs in HF-MB increased the concentration of total fatty acid by 22.1%in colostrum(P=0.03)but decreased that in serum at parturition by 53.2%(P=0.027).The fatty acids in colostrum that increased with BCAAs were C15:0,C17:0,C20:3n6,C20:4n6,C20:5n3 and C22:6n3(P=0.00~0.04).Colostrum fatty acids of C20:0,C21:0,C22:0,C16:1,C20:1,C18:1n9c also tended to be increased(0.05<P<0.1)with BCAAs.The change in sow serum fatty acid profile due to BCAAs was different from that in colostrum.Conclusions:BCAAs in high fat diet of sows altered the fatty acid composition in colostrum and enhanced litter growth.Our study indicated that BCAAs supplementation can enhance mammary fatty acid uptake and mammary fat synthesis and that supplemental BCAAs and fat in late gestation and lactation diets for sows can improve reproductive performance.
基金supported by the grants from the National Key Basic Research Program of China Ministry of Science and Technology(Grant No.2011CB100801)Funds for Distinguished Young Scientists of Zhejiang Province(R16C170002)
文摘Background: It is wel known that peptides play a vital role in the nutrition and health of dairy cows. Bovine oligopeptide transporter 1(bP epT 1) is involved in the peptide transport process in the gastrointestinal tracts of dairy cows. However,little information is known in the characteristics of bP epT 1. Therefore, the purpose of this study was to characterize bP epT 1 functional y using a mammalian cel expression system. The uptake of radiolabeled dipeptide glycyl-sarcosine([3 H]-Gly-Sar)into the bP epT 1-transfected Chinese hamster ovary cel s was measured at various pH and substrate concentrations and with or without 15 other smal peptides that contained Met or Lys.Results: Western blot results showed that the abundance of bP epT 1 protein in the jejunum and ileum are the highest in the gastrointestinal tract of dairy cows. The uptake of [3 H]-Gly-Sar by b Pep T1-Chinese hamster ovary cells was dependent on time, p H, and substrate concentration, with a low Kmvalue of 0.94 ± 0.06 mmol/L and a maximum velocity of 20.80 ± 1.74 nmol/(mg protein · 5 min). Most of the di-and tripeptides were the substrates of b Pep T1,based on substrate-competitive studies. However, bP epT 1 has a higher affinity to the peptides with shorter chains, greater hydrophobicity, and negative or neutral charges.Conclusions: These results demonstrated for the first time the functional characteristics of bP epT 1, and they provide a new insight and better understanding into its vital role in absorbing a wide range of peptides from the digestive tract of dairy cows.
基金This research was funded by USDA HATCH(VT-H02310)the Alberta Livestock Industry Development Fund.Additional funding support included use of equipment funded by NIH Grant Numbers 5 P30 RR032135 from the COBRE Program of the National Center for Research Resources and 8 P30 GM 103498 from the National Institute of General Medical Sciences.The Vermont Genetics Network Proteomics Facility is supported through the Institutional Development Award(IdeA)from the National Institute of General Medical Sciences of the National Institutes of Health Grant number P20GM103449.
文摘Background:The milk fat globule membrane(MFGM)proteomes of colostrum and transition milk are rich sources of proteins that are likely important for neonatal calf health.In addition,characterization of these proteomes could also yield valuable information regarding mammary gland physiology of the early postpartum lactating cow.The objectives of this research were to characterize the MFGM proteomes of colostrum and transition milk through sample collections at four timepoints postpartum,including the first milking(M1,colostrum),second milking(M2,transition milk),fourth milking(M4,transition milk),and fourteenth milking(M14,mature milk),and compare these proteomes between multiparous(MP;n=10)and primiparous(PP;n=10)Holstein dairy cows.Isolated MFGM proteins were labeled using Tandem Mass tagging and analyzed using liquid chromatography-tandem mass spectrometry(LC-MS/MS).Protein identification was completed using MASCOT and Sequest in Proteome Discoverer 2.2.The scaled abundance values were analyzed using PROC MIXED in SAS to determine the effects of milking(MIL),parity(PAR),and MIL×PAR.The adaptive false-discovery rate(FDR)-adjusted P values were determined using PROC MULTTEST.Protein characterization and bioinformatic analysis were completed using a combination of PANTHER,Blast,and Uniprot.Results:A total of 104 common proteins were identified in each of the MFGM samples.Statistical analysis revealed that 70.2%of identified proteins were affected by MIL.Of these,78.1%were lower in M14 compared with M1,including immune-related proteins lactotransferrin,lactadherin and hemopexin.Parity affected 44.2%of proteins.Of the proteins affected by PAR,84.8%were higher in MP cows compared with PP cows,including apolipoprotein E and histones 2A,2B,3,and 4 b.Butyrophilin subfamily 1 member 1A and annexin 5 were higher in samples from PP cows.Milking×parity affected 32.7%of identified proteins,including lactotransferrin,gelsolin,vitamin D binding protein,and S100 proteins.Conclusions:This research supports previous findings that the Holstein MFGM proteome changes rapidly during the first week of lactation.In addition,this research identifies the impact of parity on the colostrum and transition milk MFGM proteomes,which may be important for milk-fed calf health or for the identification of protein biomarkers for mammary functionality.
基金the Danish Milk Levy Fund (M■lkeafgiftsfonden, Aarhus, Denmark) for its financial support
文摘Tocopherol sources in diets are often a combination of all-rac-a-tocopheryl acetate(synthetic a-tocopherol)from vitamin supplements and natural tocopherols and 2R-(4’R,8’R)-5,7,8-trimethyltocotrienol(a-tocotrienols)from the feed sources.Synthetic a-tocopherol consists of 8 different stereoisomers including 2R-(4’R,8’R)-5,7,8-trimethyltocol(RRR-a-tocopherol),2R-(4’S,8’R)-5,7,8-trimethyltocol(RSR-a-tocopherol),2R-(4’R,8’S)-5,7,8-trimethyltocol(RRS-a-tocopherol),2R-(4’S,8’S)-5,7,8-trimethyltocol(RSS-a-tocopherol),2S-(4’S,8’S)-5,7,8-trimethyltocol(SSS-a-tocopherol),2S-(4’R,8’S)-5,7,8-trimethyltocol(SRS-a-tocopherol),2S-(4’S,8’R)-5,7,8-trimethyltocol(SSR-a-tocopherol),and2S-(4’R,8’R)-5,7,8-trimethyltocol(SRR-a-tocopherol).The pre-absorption metabolism of tocopherols and tocotrienols in ruminants differs from monogastric animals due to the extensive microbial fermentation in the anaerobic rumen.The current study investigated the impact of toasting and decortication of oats on metabolism in the digestive tract(synthesis,digestion),and intestinal digestibility of tocopherols in dairy cows by using 4 ruminal and intestinal cannulated Danish Holstein cows in a 4×4 Latin square design for 4 periods.Cows were fed a total mixed ration ad libitum containing different forms of oats:whole oat,decorticated oat,toasted oat,and decorticated toasted oat,all rolled before mixed ration.Overall means across 4 treatments were statistically analyzed,testing whether overall means were different from zero.Decortication or toasting did not affect the balance or digestibility of a-tocopherols in rumen.Average across treatments showed the ruminal degradation of synthetic a-tocopherol(279 mg/d,P=0.02;P-value shows that average across treatments is different from zero),synthetic 2R-a-tocopherol(133 mg/d,P<0.01;summation of RRS-,RSR-and RSS-a-tocopherol),and 2S-a-tocopherol(190 mg/d;P<0.01,summation of SSS-,SRS-,SSR,and SRR-a-tocopherol),while RRR-a-tocopherol was formed in the rumen(221 mg/d,P=0.10).The average across treatments showed that small intestinal digestibility of tocopherols ranked in the following order:a-tocotrienol>natural a-tocopherol>synthetic a-tocopherols>2R-(4’R,8’R)-,7,8-dimethyltocol(γ-tocopherol).The average across treatments for small intestinal and feed-ileum digestibility ranked in the following order:RRR-a-tocopherol>synthetic 2R-a-tocopherol>2S-a-tocopherol.Results showed the first evidence for RRR-a-tocopherol formation under anaerobic conditions in the rumen.In addition,synthetic a-tocopherol stereoisomers,γ-tocopherol and a-tocotrienol were degraded in the rumen.There was a discrimination against absorption of synthetic 2R-and 2S-a-tocopherol in the small intestine.
文摘Transposable elements are capable of switching their positions on the genome thereby causing gene arrangements and contributing to genome evolution. The aim of this review is to specifically discuss the role of transposable elements in transferring antimicrobial resistance genes in E. coli, thus contributing to increase in virulence and conferring the possibility of multidrug resistance. Different types of transposable elements such as transposons and integrons and their profound influence on E. coli antimicrobial resistance are the focus of this review.
基金financially supported by grants from the ChinaUSA Intergovernmental Collaborative Project in S&T Innovation under the National Key R&D Program(Grant No.2018YFE0111700)the China Agricultural Research System(Grant No.CARS-36)。
文摘The objective of this study was to investigate whether supplementation with N-carbamoylglutamate(NCG)to cows during late gestation alters uteroplacental tissue nutrient transporters,calf metabolism and newborn weight.Thirty multiparous Chinese Holstein cows were used in a randomized complete block design experiment.During the last 28 d of pregnancy,cows were fed a diet without(CON)or with NCG(20 g/d per cow).The body weight of calves was weighed immediately after birth.Placentome samples were collected at parturition and used to assess mRNA expression of genes involved in transport of arginine,glucose,fatty acid and angiogenesis factors,as well as the mammalian target of rapamycin(mTOR)pathway.Blood samples of calves before colostrum consumption were also collected for the detection of plasma parameters,amino acids(AA)and metabolomics analysis.The newborn weight(P=0.02)and plasma Arg concentration of NCG-calves was significantly higher(P=0.05)than that of CON-calves,and the plasma concentrations of urea nitrogen tended to be lower(P=0.10)in the NCG group.The mRNA abundance of genes involved in glucose transport(solute carrier family 2 member 3[SLC2 A3],P<0.01),angiogenesis(nitric oxide synthase 3[NOS3],P=0.02),and mTOR pathway(serine/threonine-protein kinase 1[ACT1],P=0.10;euka ryotic translation initiation factor 4 B pseudogene 1[EIF4 BP1],P=0.08;EIF4 EBP2,P=0.04;and E74-like factor 2[ELF2],P=0.03)was upregulated in the placentome of NCG-supplemented cows.In addition,17 metabolites were significantly different in the placentome of NCG-supplemented cows compared to non-supplemented cows,and these metabolites are mainly involved in arginine and proline metabolism,alanine,aspartate and glutamate metabolism,and citrate cycle.In summary,the increased body weight of newborn calves from the NCG supplemented dairy cows maybe attributed to the increased angiogenesis and uteroplacental nutrient transport and to the activated mTOR signal pathway,which may result in the increased nutrient supply to the fetus,and improved AA metabolism and urea cycle of the fetus.
文摘The continuous battle between humans and the multitude of pathogenic microorganisms in the environment has sought relief in the form of antimicrobials. But the counter attack by pathogenic organisms in the form of multidrug resistance, acquired by various mechanisms such as transformation, transposition, conjugation and transduction is a major reason for concern. Bacteriophages have contributed in a significant way to dissemination of genes encoding antimicrobial resistance, heavy metal resistance and virulence factors through the phenomenon of transduction. This review aims at compiling information about the different mechanisms by which bacteriophages aid in transferring genes involved in antimicrobial resistance to Escherischia coli in various environments.
文摘Background:Native warm-season grass(NWSG)mixtures may provide a lownitrogen(N)-input summer perennial forage option to extensively managed forage-livestock systems.Methods:Mixed pastures of big bluestem(Andropogon gerardii Vitman),little bluestem(Schizachyrium scoparium Michx.),and indiangrass(Sorghastrum nutans L.)fertilized with 0 or 67 kgNha−1 were continuously stocked with beef heifers and cows.Forage mass,nutritive value,and canopy heights were determined every 2 weeks during the grazing season.Stand persistence measures included the canopy cover and leaf area index(LAI)and plant crown density at spring emergence following 3 years of grazing management.Results:Forage mass,canopy height,and stocking densities were greater for N-fertilized NWSG than unfertilized NWSG for the first 30 days of the growing season across the 3-year study.Forage NWSG fertilized with N had a greater decrease in LAI during the growing season(51%decrease)than unfertilized NWSG.Spring NWSG plant density estimates following 3 years of grazing did not differ across N management strategies.Conclusions:Forage NWSG mixtures supported superior forage attributes and greater stocking densities early in the grazing season under low-level N than zero-N-input systems and may provide a low-N-input alternative for improved species use in southeastern US forage-livestock systems.
基金the National Natural Science Foundation of China 32072756 and 31872989.
文摘Peptide transporter 2(PepT2)transports short peptides from the blood into bovine mammary epithelial cells(BMEC)to stimulate milk protein synthesis.Despite the fact that the effect of PepT2 is acknowledged in BMEC,little is known about its regulation.This study was completed to investigate the role of mammalian target of the rapamycin(mTOR)signaling in regulating the expression and function of PepT2 in BMEC.The regulation of PepT2 by mTOR in BMEC was studied in vitro using peptide transport assay,gene silencing,Western blot.The membrane expression of PepT2 and the uptake of b-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid(b-Ala-Lys-AMCA),a model dipeptide,in BMEC were reduced by rapamycin(a mTOR inhibitor)and silencing of either mTOR complex 1(mTORC1)or mTOR complex 2(mTORC2),stimulated by DEP domain-containing mTOR-interacting protein(DEPTOR,endogenous inhibitor of mTORC1 and mTORC2)silencing.The trafficking of PepT2 to the membrane and the uptake of b-Ala-Lys-AMCA was promoted by neuronal precursor cell-expressed developmentally down-regulated 4 isoform 2(Nedd4-2)silencing.The effects of knockdown of mTORC1,but not mTORC2,on cell membrane expression and transport activity of PepT2 was abolished by Nedd4-2 silencing.With immunofluorescence staining,PepT2 was identified to be interacting with Nedd4-2.The Nedd4-2 expression and the interaction between PepT2 and Nedd4-2 was increased through mTORC1 knockdown,indicating an increased ubiquitination of PepT2.The results revealed that mTORC1 can regulate the expression and function of PepT2 through Nedd4-2 in BMEC.
文摘Feed formulation is essential in the dairy production chain from economic,nutritional,and environmental perspectives.Optimizing the feed formulation across those three domains–given uncertainty of input prices,input availability,and regional climatic conditions–is a challenge for those in the industry.The diet formulation method that is widely used by trading firms and feed production facilities employs a static linear programming(LP)approach.This approach does not allow for intertemporal feed formulations and switches between dietary feed commodities under feed availability conditions,which result in foregone economic gains for feed producers.The current study develops a multi-period LP feed model that uses historical data to capture ration switch opportunities between available feed resources for dairy cows and demonstrates the potential use of the method in different commodity feed availability situations.We apply 14 diet formulations,each covering 150 months,representing a total of 2100 diets.The diet formulation considers a specific milk production level for a“model cow”,alternative feed formulations available,and volatility in feed prices.The results demonstrate that there is an opportunity for efficiency gains in the dairy industry with respect to feed formulation.Based on dietary feed inclusion and price spreads,barley can be an important dairy feed grain which completely replaces wheat,corn,and sorghum at price spreads of less than 94%,less than 78%,and less than 67%,respectively.Grain-based feed scenarios represent the lowest nutrient variation while multiple meal feeds had the lowest costs.Furthermore,and on average,multiple meal feed scenarios provided 10%higher dietary crude protein contents compared to grain based feed scenarios(i.e.163 vs 179 g/kg DM formulated feed).Meanwhile,multiple meal feeding cost was 11%lower than that in the grain based feeding scenarios.Additionally,the use of multiple meals reduces alfalfa dietary inclusion by 7%on dry matter basis.Our analysis shows a strong reduction in feed cost associated with dietary crude protein reduction equivalent to 7.6 USD/tonne per 1%reduction in dietary crude protein level.The modeling approach allows for the interaction between feed components over time taking into consideration volatile global feed prices,thereby improving feed availability and feed formulation.Overall,the model provides a decision making tool to improve the use of feed resources in the dairy sector.
