Although,dietary proteins play a crucial role in poultry profit maximization,through the sustenance of birds`welfare,growth and development,yet metabolic excesses from crude protein(CP)degradation is detrimental to br...Although,dietary proteins play a crucial role in poultry profit maximization,through the sustenance of birds`welfare,growth and development,yet metabolic excesses from crude protein(CP)degradation is detrimental to broiler chickens(BC)affected by heat stress.This study evaluated the effect of dietary protein levels on blood profile of heat-stressed BC at starter phase(SP)and finisher phase(FP).Arbor Acre BC(n=288)were randomly allotted to four dietary treatments(T1-23%CP;T2-21%CP;T3-19%CP;and T4-17%CP)with six replicate groups in a completely randomized design.Data were subjected to descriptive analysis,analysis of variance(p=0.05)and correlation statistics.Protein intake(PI)was not significantly affected by varying CP in diets at SP,but not at FP,where PI significantly increased with increasing dietary CP.PER had a negative correlation with PCV(r=-0.89,p<0.01),Hb(r=-0.88,p<0.01),RBC(r=-0.93,p<0.01)and PI(r=-0.78,p<0.01).Metabolic excesses including heat dissipation from dietary proteins influenced PCV,Hb,platelets and glucose of heat-stressed broilers.展开更多
Grazing exclusion (GE) is the most effective rangeland restoration technique which facilitates species diversity and forage quality. This study aimed at assessing short-term impact of GE and continuously grazed rangel...Grazing exclusion (GE) is the most effective rangeland restoration technique which facilitates species diversity and forage quality. This study aimed at assessing short-term impact of GE and continuously grazed rangeland on relative frequency, dry matter yield and nutritive value of dominant grasses in an area invaded by Euryops floribundus. A plot of 2.5 ha was measured and the boundaries demarcated using tape measure and steal pins, the plot was further divided into two subplots of 1ha each which were 5 m apart. One subplot was fenced and protected from grazing livestock, while one subplot was grazed continuously and not fenced. Three parallel belt transects of 100 m × 2 m with 3 m apart were laid out in both subplots. Woody plants occurring within the transects were identified and recorded to determine density. In each subplot, a 0.25 m<sup>2</sup> quadrant measuring was thrown randomly to take detailed records on plant species, relative frequency of species and herbage biomass. Four dominant species at the two sites were harvested to determine the nutritive value. Results indicate that grazing exclusion (GE) facilitates grass species diversity, subsequently sixteen and thirteen grasses species were recorded in the GE and uncontrolled grazed (UG) sites, respectively. Eragrostis chloromelas (21.7%), and Themeda triandra (13.2%) had high relative frequencies in the GE site. Highest biomass production was recorded in the GE site (1400 kg·ha<sup>-1</sup>) compared to UG site (1102 kg·ha<sup>-1</sup>). Crude protein content was relatively lower at UG site (5.4% - 5.8%) as compared to GE site (7.2% - 7.8%). It was concluded that, GE showed a positive impact on a relative frequency (%), dry matter yield and crude protein content. UG creates a conducive environment for Euryops recruitment. Further studies are required to examine the impact of GE in long-term trial setup.展开更多
Background:Valine and isoleucine are similar in chemical structure and their limitation in broiler chicken diets.To evaluate their limitation and interactive effects,multivariate assessment nutrition studies for the b...Background:Valine and isoleucine are similar in chemical structure and their limitation in broiler chicken diets.To evaluate their limitation and interactive effects,multivariate assessment nutrition studies for the branched-chain amino acids(BCAA)are needed.A three level(−1,0,+1),three-factor Box-Behnken design study was conducted to assess dietary BCAA ratios to lysine of 65,75,and 85 for valine,58,66,and 74 for isoleucine,and 110,130,and 150 for leucine in male and female Lohman Indian River broilers from 22 to 35 d of age.Results:Live performance of male broilers was not affected by BCAA level.However,male broilers fed increasing isoleucine had improved(P=0.07)carcass yield as leucine and valine were reduced.Female broilers had improved body weight gain(P=0.05)and feed conversion(P=0.003)when leucine and isoleucine were at their lowest levels,independent of valine,but increasing leucine impaired live performance and warranted concomitant increases in isoleucine to restore responses.Increasing dietary isoleucine and valine in female broilers increased breast meat yield(P=0.05),but increasing leucine tended to diminish the response.Conclusion:The female Lohman Indian River broiler is more sensitive to BCAA diet manipulation than males.Specifically,as dietary leucine is increased in female broilers,dietary isoleucine increases were needed to offset the negative effects.Both increases in dietary valine and isoleucine improved breast meat yield in female broilers,but only when birds were fed the lowest dietary leucine.展开更多
Southeastern wildrye (Elymus glabriflorus, Vasey ex L.H. Dewey) is a cool-season, perennial grass native to southeastern United States. Recently, there is a growing interest in its development as a grazing and haying ...Southeastern wildrye (Elymus glabriflorus, Vasey ex L.H. Dewey) is a cool-season, perennial grass native to southeastern United States. Recently, there is a growing interest in its development as a grazing and haying forage crop due to its wide area of adaptation across this region. Consequently, there is a great need for the evaluation of its forage quality by rapid, but accurate analytical methods like Near-Infrared Reflectance Spectroscopy (NIRS). In this study, acceptable NIRS calibration models were developed for: dry matter, DM (n = 113, R<sup>2</sup> = 0.904, RSCD = 2.54, RSCIQ = 4.65);crude protein, CP (n = 113, R<sup>2</sup> = 0.974, RSCD = 5.16, RSCIQ = 5.92);acid detergent fiber, ADF (n = 116, R<sup>2</sup> = 0.896, RSCD = 2.35, RSCIQ = 1.28);neutral detergent fiber, NDF (n = 118, R<sup>2</sup> = 0.934, RSCD = 2.53, RSCIQ = 3.38);digestible dry matter, DDM (n = 116, R<sup>2</sup> = 0.895, RSCD = 2.36, RSCIQ = 1.35);dry matter intake, DMI (n = 115, R<sup>2</sup> = 0.924, RSCD = 2.40, RSCIQ = 2.53);and relative feed value, RFV (n = 114, R<sup>2</sup> = 0.932, RSCD = 2.94, RSCIQ = 2.81). Prediction of independent validation sets yielded good agreement between the NIRS predicted values and the laboratory reference values for each of: DM (n = 53, R<sup>2</sup> = 0.831, RPD = 2.45, RPIQ = 4.24);CP (n = 57, R<sup>2</sup> = 0.967, RPD = 5.37, RPIQ = 7.16);ADF (n = 49, R<sup>2</sup> = 0.895, RPD = 2.97, RPIQ = 1.51);NDF (n = 53, R<sup>2</sup> = 0.928, RPD = 3.75, RPIQ = 4.22);digestible dry matter, DDM (n = 55, R<sup>2</sup> = 0.860, RSCD = 265, RSCIQ = 1.15);dry matter intake, DMI (n = 156, R<sup>2</sup> = 0.845, RSCD = 2.48, RSCIQ = 2.11);and relative feed value, RFV (n = 55, R<sup>2</sup> = 0.916, RSCD = 3.45, RSCIQ = 3.04) contents, indicating that all seven calibration models had good quantitative information. Therefore, precise, accurate, and rapid analysis of these important forage quality attributes of southeastern wildrye can be routinely done using the developed NIRS calibration models.展开更多
Alpine meadows,comprising the main ecosystem of the Three-River Source Region,play an important role in the economic development of western pastoral areas.To determine whether the grazing level was too intense or the ...Alpine meadows,comprising the main ecosystem of the Three-River Source Region,play an important role in the economic development of western pastoral areas.To determine whether the grazing level was too intense or the nutrient-carrying capacity of the meadows was overloaded,and to offer solutions in Maqin County,Qinghai Province,China,the meadows carrying capacity was determined by combining grass-yield and nutrients data for different seasons across different meadows.The results showed that the levels of crude protein(CP),ether extract(EE),ash,soluble sugars(SS),gas production,and energy value of forage in the summer–autumn grazing meadows were higher than those of the winter–spring meadows.Neutral detergent fiber(NDF)and acid detergent fiber(ADF)of forage in the summer–autumn grazing meadows were lower than those of the winter–spring meadows.We found that no pastures were overloaded with metabolizable energy(ME)for the whole year but digestible crude protein(DCP)was overloaded in winter–spring.And there were differences in the amount carrying capacity(forage yield)of seasonal grazing meadows for the different herds,the overload types were annual overloading(herd A),overloaded in summer–autumn(herd B),overloaded in winter–spring(herd C),and not overloaded(herd D).Compared with the previous grazing mode,theoretical carrying capacity,DCP carrying capacity,and ME carrying capacity of herd A increased by 20,19,and 27 sheep units,respectively,after optimization;herd B:36,31,and 45 sheep units,respectively;herd C:28,23,and 44 sheep units,respectively;and herd D:43,40,and 61 sheep units,respectively.In the Three-River Source Region and similar alpine pastoral areas,the grassland-livestock structure should be optimized to improve grassland vegetation status and increase the theoretical carrying capacity.展开更多
In order to improve the comprehensive utilization value of water chestnut peel and the income of farmers. Contents of crude protein( CP),total sugar and reducing sugar were taken as indicators. Effects of initial p H,...In order to improve the comprehensive utilization value of water chestnut peel and the income of farmers. Contents of crude protein( CP),total sugar and reducing sugar were taken as indicators. Effects of initial p H,ratio of yeast to fungi species,incubation time and liquid volume on production of single cell protein( SCP) feed was studied,and technological conditions on production of SCP feed by water chestnut peel were optimized by orthogonal test. Results showed that the production of SCP feed by water chestnut peel was optimal when p H was 5. 0,ratio of yeast to fungi species was 2:1,fermentation time was 2 d and the liquid volume was 70 m L/250 m L. Under the optimum conditions,content of fermentation CP was 64. 25%,content of total sugar was 19. 8%,content of reducing sugar was 5. 0%,content of coarse fibre was 0. 0% and content of ash was 8. 04%.展开更多
[Objectives]This study was conducted to investigate the effects of magnesium on the yield of Blumea balsamifera(L.)DC.and the accumulation of primary metabolites that affect yield of the medicinal material.[Methods]Th...[Objectives]This study was conducted to investigate the effects of magnesium on the yield of Blumea balsamifera(L.)DC.and the accumulation of primary metabolites that affect yield of the medicinal material.[Methods]The annual seedlings of B.balsamifera were selected as experimental materials.The treatment concentrations of magnesium(Mg)were set as 0,1.5,15 and 150 mg/ml supplied by MgSO4·7H2O.The yield of the medicinal material was measured dynamically.And the content of total sugar was determined by 3,5-dinitrosalicylic acid colorimetry;the content of crude protein was determined by the Kjeldahl method;the ash content was determined by the high-temperature burning method;the crude fat content was determined with a crude fat instrument;and the crude fiber content was determined by the acid-base washing and weighing method.[Results]Mg significantly increased the yield of B.balsamifera medicinal material,especially 15 mg/ml Mg.It was found that in September,October and November,1.5 mg/ml and 15 mg/ml Mg significantly increased the contents of primary metabolites including total sugar,ash,crude protein,crude fat and crude fiber,and 150 mg/ml of Mg increased the accumulation of total sugar,ash,crude protein and crude fiber to different degrees,but had certain inhibitory effect on the accumulation of crude fat.In December,the application of Mg inhibited the accumulation of total sugar,ash and crude protein to different degrees,but significantly promoted the accumulation of crude fat and fiber.[Conclusions]This study provides a theoretical basis for clarifying the effects of different concentrations of magnesium on plant growth.展开更多
In order to study the feeding effect of fine division of feeding stages on the growing-finishing pigs,96 healthy Duroc × Landrace ×Yorkshire hybrid commercial pigs with similar age in days,size,and body weig...In order to study the feeding effect of fine division of feeding stages on the growing-finishing pigs,96 healthy Duroc × Landrace ×Yorkshire hybrid commercial pigs with similar age in days,size,and body weight about 15 kg,half boars and half sows,randomly divided into3 treatments( each treatment repeated 4 times,and each repetition 8 pigs). According to the body weight division standard,three stages,four stages,and five stages of feeding were adopted separately. The daily ration of with different nutrition levels was used,body weight and feed consumption were measured,and effects of different feeding methods on body weight increase,feed utilization,and economic benefits of growing-finishing pigs. The results showed that compared with the three-stage feeding,the body weight of five-stage and four-stage feeding increased by 4. 18%( P < 0. 01) and 2. 41%( P < 0. 05),respectively,and the body weight of five-stage feeding increased by 1. 74%( P < 0. 05) compared with that of four-stage feeding; the daily feed consumption of five-stage and four-stage feeding increased 3. 10%( P < 0. 01) and 1. 70%(P <0. 01),respectively,and the daily feed consumption of five-stage feeding was 1. 37% higher than that of four-stage feeding. The feed cost of five-stage feeding and four-stage feeding increased 3. 32%( P < 0. 01) and 1. 61%( P < 0. 05) separately,and the feed cost of five-stage feeding was 1. 69% higher than that of four-stage feeding( P < 0. 01). The income from average body weight increase of five-stage and fourstage feeding increased by 5. 47%( P < 0. 01) and 3. 59%( P < 0. 01) respectively,and the benefit of average body weight increase of fivestage feeding was 1. 81% higher than that of four-stage feeding( P > 0. 05). The crude protein consumption from average body weight increase of five-stage and four-stage feeding decreased by 2. 28%( P < 0. 01) and 1. 68%( P < 0. 01),respectively; the crude protein consumption from average body weight increase of five-stage feeding was 0. 67% lower than that of four-stage feeding; the feed conversion ratio of five-stage feeding,four-stage feeding,and three-stage feeding was 2. 92,2. 93,and 2. 95 respectively. The results showed that compared with the threestage feeding,the four-stage and five-stage feeding could significantly increase the body weight of the growing-finishing pigs,improve the feed utilization level and improve the economic benefits,and the effect of five-stage feeding was better than the four-stage feeding.展开更多
The present study aimed to evaluate the effects of daily feeding pattern on growth performance, blood biochemistry, and antioxidant indexes in pigs. One hundred and eighty female Duroc x Landrace x Yorkshire(DLY) pigs...The present study aimed to evaluate the effects of daily feeding pattern on growth performance, blood biochemistry, and antioxidant indexes in pigs. One hundred and eighty female Duroc x Landrace x Yorkshire(DLY) pigs with similar body weight(11.00 ± 0.12 kg) were randomly assigned to 3 groups: the control group(fed 17.01% CP diet, twice daily); high-low group(H-L group, fed18.33% CP diet in the morning, followed by 15.70% CP diet in the afternoon); and low-high group(L-H group, fed 15.70% CP diet in the morning, followed by 18.33% CP diet in the afternoon)(n = 6). Comparable amounts of their respective diets were given at 05:30 and 15:00 throughout the experimental periods to make all the treatments consumed the same type of food and the same amount of calories on a daily basis. On day 30, one pig was randomly selected per litter for blood samples. Compared with the control group, ADG in the H-L and L-H groups increased by 8.11% and 16.23%, but not significant(P > 0.05); and blood urea nitrogen(BUN) in the H-L and L-H groups decreased by 26.76% and 41.04%(P < 0.05), respectively. The H-L group feeding pattern could significantly improve levels of serum superoxide dismutase(SOD), when compared with the control group. These findings suggest that the twomeal daily feeding pattern with varied levels of CP affects serum levels of BUN and SOD. These changes could effectively silightly improve growth performance and antioxidant capacity in pigs without incurring increased feeding costs.展开更多
Inclusions of non-bound amino acids particularly methionine,lysine and threonine,together with the"ideal protein"concept have allowed nutritionists to formulate broiler diets with reduced crude protein(CP)an...Inclusions of non-bound amino acids particularly methionine,lysine and threonine,together with the"ideal protein"concept have allowed nutritionists to formulate broiler diets with reduced crude protein(CP)and increased nutrient density of notionally"essential"amino acids and energy content in recent decades,However,chicken-meat production has been projected to double between now and 2050,providing incentives to reduce dietary soybean meal inclusions further by tangibly reducing dietary CP and utilising a larger array of non-bound amino acids.Whilst relatively conservative decreases in dietary CP,in the order of 20 to 30 g/kg,do not negatively impact broiler performance,further decreases in CP typically compromise broiler performance with associated increases in carcass lipid deposition.Increases in carcass lipid deposition suggest changes occur in dietary energy balance,the mechanisms of which are still not fully understood but discourage the acceptance of diets with reductions in CP,Nevertheless,the groundwork has been laid to investigate both amino acid and non-amino acid limitations and propose facilitative strategies for adoption of tangible dietary CP reductions;consequently,these aspects are considered in detail in this review.Unsurprisingly,investigations into reduced dietary CP are epitomised by variability broiler performance due to the wide range of dietary specifications used and the many variables that should,or could,be considered in formulation of experimental diets.Thus,a holistic approach encompassing many factors influencing limitations to the adoption of tangibly reduced CP diets must be considered if they are to be successful in maintaining broiler performance without increasing carcass lipid deposition.展开更多
To reduce nitrogen excretion and lower feeding costs,low crude protein(CP)diets are sometimes pro-posed,however,a great reduction of dietary CP concentration(>4%reduction vs.recommended con-centration),even supplem...To reduce nitrogen excretion and lower feeding costs,low crude protein(CP)diets are sometimes pro-posed,however,a great reduction of dietary CP concentration(>4%reduction vs.recommended con-centration),even supplemented with essential and nonessential amino acids(AA)can detrimentally affect small intestinal barrier function and immunity,possibly due to the excessive lack of peptides.Here we hypothesize that with an extremely low CP concentration diet,protein-derived peptides,rather than AA supplementation,can improve intestinal barrier development and health.To test this hypothesis,21 growing pigs(19.90±1.00 kg body weight)were randomly assigned to 3 treatments with control diet(16%CP),or low CP diets(13%CP)supplemented with AA(LCPA)or casein hydrolysate(LCPC)for 28 days.In comparison with the control diet,the LCPA diet decreased the protein expression level of jejunal barrier factor zonula occludens-1(ZO-1)and stem cell proliferation factor leucine-rich repeat-containing G-protein-coupled receptor-5,whereas the LCPC diet enhanced intestinal barrier function by increasing the protein expression level of jejunal occludin and ZO-1 and ileal mucin-2.The LCPA diet reduced Lactobacillus counts,whereas the LCPC diet increased Lactobacillus counts and reduced Escherichia coli counts in the ileum.The LCPA diet also increased protein expression levels of pro-inflammatory cytokine interleukin-6(IL-6)and IL-22,whereas the LCPC diet decreased protein expression levels of pro-inflammatory IL-1β,IL-17A and tumor necrosis factor-αin the ileum.Collectively,the casein hydroly-sate supplementation of low CP diets showed beneficial effects on the small intestinal barrier,bacterial community,and immunity in pigs,pointing to the important role of protein-derived peptides in small intestinal health in cases of low crude protein diets.展开更多
The hypothesis that capping dietary starch:protein ratios would enhance the performance of broiler chickens offered reduced-crude protein(CP)diets was tested in this experiment.A total of 432 off-sex,male Ross 308 chi...The hypothesis that capping dietary starch:protein ratios would enhance the performance of broiler chickens offered reduced-crude protein(CP)diets was tested in this experiment.A total of 432 off-sex,male Ross 308 chicks were allocated to 7 dietary treatments from 7 to 35 d post-hatch.The experimental design consisted of a 3×2 factorial array of treatments with the seventh treatment serving as a positive control.Three levels of dietary CP(197.5,180.0 and 162.5 g/kg)with either uncapped or capped dietary starch:protein ratios constituted the factorial array of treatments,whilst the positive control diet contained 215.0 g/kg CP.The positive control diet had an analysed dietary starch:protein ratio of 1.50 as opposed to a ratio of 1.68 in the uncapped 197.5 g/kg CP diet and 1.41 in the corresponding capped diet and the capped 197.5 g/kg CP diet displayed promise.The growth performance this diet matched the positive control but outperformed the uncapped 197.5 g/kg CP diet by 10.4%(2,161 vs.1,958 g/bird;P=0.009)in weight gain,by 3.10%(3,492 vs.3,387 g/bird;P=0.019)in feed intake on the basis of pairwise comparisons and numerically improved FCR by 4.04%(1.616 vs.12684).However,the growth performance of birds offered the 180.0 and 162.5 g/kg CP dietary treatments was remarkably inferior,irrespective of dietary starch:protein ratios.This inferior growth performance was associated with poor feathering and even feather-pecking and significant linear relationships between feather scores and parameters of growth performance were observed.The amino acid profile of feathers was determined where cysteine,glutamic acid,glycine,proline and serine were dominant in a crude protein content of 931 g/kg.Presumably,the feathering issues observed were manifestations of amino acid inadequacies or imbalances in the more reduced-CP diets and consideration is given to the implications of these outcomes.展开更多
Nitrogen(N)excreted by poultry is converted to ammonia(NH3),presenting an environmental risk and a health risk to the farmer and animals.A study was performed to investigate the effect of reduced CP and feed form on b...Nitrogen(N)excreted by poultry is converted to ammonia(NH3),presenting an environmental risk and a health risk to the farmer and animals.A study was performed to investigate the effect of reduced CP and feed form on broiler performance and welfare,meat and litter quality,N utilization,and NH3 concentrations at litter level.A total of 2,232 Ross 308 male broilers was divided into 6 treatments and 6 replicates,which was fed diets in both pellet and mash forms with different CP levels of 205.0 g/kg(H,high),187.5 g/kg(M,intermediate)and 175.0 g/kg(L,low)in the grower phase and 195.0 g/kg(H),180.0 g/kg(M)and 165.6 g/kg(L)in the finisher phase.Individual amino acids(AA)were supplemented to maintain digestible AA-to-digestible lysine ratios.Decreasing dietary CP content to 187.5 g/kg in the grower phase and 180.0 g/kg in the finisher phase reduced NH3 concentrations at litter level(P<0.001),but a further reduction in dietary CP had no additional effect.Mash treatments had better litter qualities and lower incidences of foot and hock lesions than pellet treatments at d 38(P<0.001).In addition,treatments with reduced CP had lower incidence of foot lesions at d 38(P<0.001).Broilers fed pelleted diets had higher ADFI,ADG,and final BW,improved feed conversion ratio(FCR),and heavier carcasses(P<0.001)than those fed mash diets over a production period of 39 d.Performance could not be maintained when birds were fed L CP pelleted diets.This study demonstrated that,with the supplementation of AA to meet requirements,the concentration of dietary CP can be reduced to 187.5 and 180.0 g/kg in the grower and finisher phases respectively,without impairing broiler performance,meat yield and quality.Mash diets were favorable when considering the overall litter quality and welfare of the birds.However,they could not maintain the same broiler performance and slaughter yield as pelleted diets.Results from the present study may assist the poultry sector towards a socially acceptable lowemission farming system.展开更多
In a previous experiment,male Ross 308 broiler chickens were offered dietary treatments with 3 levels of crude protein(222,193,165 g/kg)and 3 feed grains(ground maize,ground wheat,whole wheat)from 7 to 35 d post-hatch...In a previous experiment,male Ross 308 broiler chickens were offered dietary treatments with 3 levels of crude protein(222,193,165 g/kg)and 3 feed grains(ground maize,ground wheat,whole wheat)from 7 to 35 d post-hatch.Maize-based diets supported superior growth performance in comparison to wheatbased diets.Uric acid concentrations in excreta were retrospectively determined and related to total nitrogen(N)excreta concentrations.Uric acid concentrations ranged from 28.5 to 69.4 mg/g and proportions of uric acid-N to total excreta-N ranged from 27.4%to 42.6%in broiler chickens offered the 3×3 factorial array of dietary treatments.Proportions of uric acid-N to total N in excreta in birds offered the165 g/kg CP,maize-based diet were significantly lower by 10.6 percentage units(27.4%versus 38.0%;P=0.00057)than their wheat-based counterparts.Total excreta analysed had been collected from 35 to37 d post-hatch when feed intakes and excreta outputs were monitored.There were linear relationships between proportions of uric acid-N to total N in excreta in birds offered the three 165 g/kg CP diets with weight gain(r=-0.587;P=0.010),feed intake(r=-0.526;P=0.025)and feed conversion ratios(r=0.635;P=0.005).The possibility that increasing uric acid-N proportions in excreta is indicative of excessive ammonia accumulations compromising growth performance is discussed.The mean proportion of dietary glycine involved in uric acid excretion was 49.2%across all dietary treatments but ranged from 25.0%to 80.9%.Thus,the appropriate amount of dietary glycine is variable and largely dependent on the volume of uric acid synthesised and excreted.展开更多
As lowering crude protein(CP)in poultry diets continues to minimize amino acid excess,it is important to understand the limiting order of amino acids and the impact of their deficiencies.Therefore,a pair of experiment...As lowering crude protein(CP)in poultry diets continues to minimize amino acid excess,it is important to understand the limiting order of amino acids and the impact of their deficiencies.Therefore,a pair of experiments were conducted to observe the effects of individual amino acid deletions on growth performance,carcass traits,and nutrient utilization.Both experiments involved 3 control diets based on wheat and soybean meal,including a 210.0 g/kg CP industry control(IC),186.7 g/kg CP positive control(PC)supplemented with feed-grade amino acids to match the IC amino acid profile,186.7 g/kg CP negative control(NC)with reducing N corrected apparent metabolizable energy(AMEN)by 0.5 MJ/kg and removing feed-grade amino acids beyond L-Lys-HCl,DL-Met,and L-Thr from PC.Ten deletion diets where the following supplemented amino acids were individually removed from the PC:Val,Ile,Leu,Trp,Arg,His,Phe t Tyr,glycine equivalence(Glyequi),Pro,and Energy(0.5 MJ/kg reduction in AMEN of the PC).All diets were formulated to contain similar concentrations of digestible Lys,total sulfur amino acid(TSAA)and Thr.Experimental diets were offered to broiler chickens from 15 to 22 d postehatch in a cage study(Exp.1)to gain digestibility and nutrient utilization data;whereas they were offered from 15 to 35 d post ehatch in a floor-pen study(Exp.2)to gain performance and carcass yield data.The removal of supplemented Val,Arg,and Ile resulted in reduction on broiler performance(P<0.05),and the removal of Val,Arg,Ile,and Glyequi negatively influenced carcass traits(P<0.05).Results from both experiments indicate that Val and Arg are co-limiting in wheat-soybean meal diets,but that Ile and Glyequi may potentially limit breast and thigh development.展开更多
We compared a 3-and 5-phase feeding program in terms of ammonia concentrations measured at litter level,litter composition and quality,nitrogen(N)utilization,performance,welfare,and meat deposition in broilers.A total...We compared a 3-and 5-phase feeding program in terms of ammonia concentrations measured at litter level,litter composition and quality,nitrogen(N)utilization,performance,welfare,and meat deposition in broilers.A total of 744 Ross 308 male broilers was divided into 2 treatments,each with 6 replicates.The 3-phase diets were formulated to CP and digestible lysine contents of 205 and 11.5 g/kg(0 to 9 d),195 and 10.8 g/kg(9 to 24 d),and 183.3 and 10.15 g/kg(24 to 39 d),respectively.The 5-phase diets had additional phases from 17 to 24 d and 32 to 39 d with CP and digestible lysine contents of 188 and 10.4 g/kg and 177 and 9.8 g/kg,respectively.Feeding 5 phases reduced the NH3concentrations at litter level by37.95%and 20.81%at 23(P<0.05)and 37 d of age(P<0.05),respectively.There was a tendency for a lower litter total ammoniacal nitrogen concentration for the 5-phase treatment than the 3-phase treatment at 24 and 39 d of age(P<0.1 for both).Total N concentration of the litter also tended to be lower for the 5-phase treatment at 39 d of age(P<0.1).The lower NH3coincided with a lower average litter pH at 24 and 32 d of age(P<0.05 for both).Birds fed the 5-phase treatments had a lower incidence of foot lesions at 24 d of age(P<0.001).Performance as well as carcass yield could be maintained,except for FCR,which was higher for the 5-phase treatment between 17 and 24 d of age and the overall period(P<0.05 and<0.001,respectively).The impact of the 5-phase treatment regarding the utilization of N(digestibility,excretion,and retention)was less clear,however the NH3volatilized from the litter was significantly reduced.Feeding 5 phases may therefore potentially reduce the NH3emitted from broiler houses which has several environmental and health benefits.Although the 5-phase treatment resulted in a significant decrease in feed efficiency,growth performance and meat deposition were maintained.展开更多
The current study was carried out to detect the effect of dietary guanidinoacetic acid(GAA)supplementation on carcass characteristics and meat quality in finishing pigs fed different dietary crude protein(CP)levels.Si...The current study was carried out to detect the effect of dietary guanidinoacetic acid(GAA)supplementation on carcass characteristics and meat quality in finishing pigs fed different dietary crude protein(CP)levels.Sixty-four barrows with an initial body weight of 73.05±2.34 kg were randomly allocated into 1 of 4 dietary treatments in a 2(100%vs.125%NRC CP level)×2(0 vs.300 mg/kg GAA)factorial arrangement(n=7).The feeding trial lasted for 49 d.GAA supplementation significantly reduced drip loss(P=0.01),free water distribution(T23peak area ratio)(P=0.05)and the concentrations of free alanine,threonine,methionine and isoleucine(P<0.05);but increased total glycine content(P=0.03)in the longissimus dorsi muscle of finishing pigs regardless of the dietary CP levels.Furthermore,primary myogenic cell differentiation system was employed to investigate the influence of inclusion of GAA on free amino acid concentrations in myotubes(n=4)and validate the finding in the animal feeding trial.We found that GAA inclusion in culture medium also decreased intracellular concentrations of free alanine,threonine,methionine,isoleucine,valine and proline in differentiated primary myogenic cells in vitro(P<0.05).Meanwhile,relative to diets with 100%NRC CP level,the intake of diets with 125%NRC CP level improved sarcoplasmic protein solubility,increased the contents of carnosine and total free amino acids as well as flavor amino acids in the longissimus dorsi muscle and decreased backfat thickness at the 6-7th ribs in pigs(P<0.05).In addition,we observed that the impact of dietary GAA supplementation on the last rib fat thickness,shear force,and free lysine content in the longissimus dorsi muscle was dependent on dietary CP levels(P<0.05).Collectively,dietary GAA supplementation can reduce drip loss,decrease the concentrations of free amino acids and flavor amino acids of fresh meat independent of dietary CP levels.展开更多
Background:Despite high nutritional and economic value,alfalfa yield has not been improved in the United States.Soil moisture critically influences alfalfa's yield and quality,affecting its physiological processes...Background:Despite high nutritional and economic value,alfalfa yield has not been improved in the United States.Soil moisture critically influences alfalfa's yield and quality,affecting its physiological processes,nutrient uptake,and stand growth.Additionally,the maturity stage at harvest can significantly impact both hay yield and quality.Thus,this study aimed to assess the effect of different soil moisture levels and harvesting times on forage yield,nutritive value,and the overall profitability of commercially cultivated alfalfa.Methods:Two conventional and three lower-lignin alfalfa varieties were planted in a randomized complete block with split plot design under drought,rainfed,and irrigation conditions in 2020 in Manhattan,Kansas,USA.The dry matter yield(DMY)and forage nutritive value were evaluated at late bud,early flowering,and 7 days after early flowering stages,respectively.Results:DMY varied with production year,soil water availability,and growth stages,with drought conditions causing a decline in DMY of 5%to 38%in the second production year.Water conditions and maturity stages influenced crude protein(CP)and in vitro dry matter digestibility(IVDMD).Higher soil moisture and advancing maturity stages negatively impacted CP,IVDMD,and relative forage quality.The study revealed net profit margins of 62%,64%,and 52%for drought-prone,rainfed,and irrigated production,respectively.Conclusions:Harvest timing and irrigation practices were found to have substantial implications for forage yield and nutritive value of alfalfa.The yield-quality trade-off differed under drought and irrigation,with early harvesting leading to lower yields but higher protein content and digestibility.The study findings provide potential guidance for improving alfalfa hay yield,quality,and profitability.展开更多
文摘Although,dietary proteins play a crucial role in poultry profit maximization,through the sustenance of birds`welfare,growth and development,yet metabolic excesses from crude protein(CP)degradation is detrimental to broiler chickens(BC)affected by heat stress.This study evaluated the effect of dietary protein levels on blood profile of heat-stressed BC at starter phase(SP)and finisher phase(FP).Arbor Acre BC(n=288)were randomly allotted to four dietary treatments(T1-23%CP;T2-21%CP;T3-19%CP;and T4-17%CP)with six replicate groups in a completely randomized design.Data were subjected to descriptive analysis,analysis of variance(p=0.05)and correlation statistics.Protein intake(PI)was not significantly affected by varying CP in diets at SP,but not at FP,where PI significantly increased with increasing dietary CP.PER had a negative correlation with PCV(r=-0.89,p<0.01),Hb(r=-0.88,p<0.01),RBC(r=-0.93,p<0.01)and PI(r=-0.78,p<0.01).Metabolic excesses including heat dissipation from dietary proteins influenced PCV,Hb,platelets and glucose of heat-stressed broilers.
文摘Grazing exclusion (GE) is the most effective rangeland restoration technique which facilitates species diversity and forage quality. This study aimed at assessing short-term impact of GE and continuously grazed rangeland on relative frequency, dry matter yield and nutritive value of dominant grasses in an area invaded by Euryops floribundus. A plot of 2.5 ha was measured and the boundaries demarcated using tape measure and steal pins, the plot was further divided into two subplots of 1ha each which were 5 m apart. One subplot was fenced and protected from grazing livestock, while one subplot was grazed continuously and not fenced. Three parallel belt transects of 100 m × 2 m with 3 m apart were laid out in both subplots. Woody plants occurring within the transects were identified and recorded to determine density. In each subplot, a 0.25 m<sup>2</sup> quadrant measuring was thrown randomly to take detailed records on plant species, relative frequency of species and herbage biomass. Four dominant species at the two sites were harvested to determine the nutritive value. Results indicate that grazing exclusion (GE) facilitates grass species diversity, subsequently sixteen and thirteen grasses species were recorded in the GE and uncontrolled grazed (UG) sites, respectively. Eragrostis chloromelas (21.7%), and Themeda triandra (13.2%) had high relative frequencies in the GE site. Highest biomass production was recorded in the GE site (1400 kg·ha<sup>-1</sup>) compared to UG site (1102 kg·ha<sup>-1</sup>). Crude protein content was relatively lower at UG site (5.4% - 5.8%) as compared to GE site (7.2% - 7.8%). It was concluded that, GE showed a positive impact on a relative frequency (%), dry matter yield and crude protein content. UG creates a conducive environment for Euryops recruitment. Further studies are required to examine the impact of GE in long-term trial setup.
文摘Background:Valine and isoleucine are similar in chemical structure and their limitation in broiler chicken diets.To evaluate their limitation and interactive effects,multivariate assessment nutrition studies for the branched-chain amino acids(BCAA)are needed.A three level(−1,0,+1),three-factor Box-Behnken design study was conducted to assess dietary BCAA ratios to lysine of 65,75,and 85 for valine,58,66,and 74 for isoleucine,and 110,130,and 150 for leucine in male and female Lohman Indian River broilers from 22 to 35 d of age.Results:Live performance of male broilers was not affected by BCAA level.However,male broilers fed increasing isoleucine had improved(P=0.07)carcass yield as leucine and valine were reduced.Female broilers had improved body weight gain(P=0.05)and feed conversion(P=0.003)when leucine and isoleucine were at their lowest levels,independent of valine,but increasing leucine impaired live performance and warranted concomitant increases in isoleucine to restore responses.Increasing dietary isoleucine and valine in female broilers increased breast meat yield(P=0.05),but increasing leucine tended to diminish the response.Conclusion:The female Lohman Indian River broiler is more sensitive to BCAA diet manipulation than males.Specifically,as dietary leucine is increased in female broilers,dietary isoleucine increases were needed to offset the negative effects.Both increases in dietary valine and isoleucine improved breast meat yield in female broilers,but only when birds were fed the lowest dietary leucine.
基金supported by the National Key Project of Research and Development(2016YFC0501904-03)Key Laboratory of Superior Forage Germplasm in the Qinghai-Tibetan Plateau(2017-ZJY12)。
文摘Alpine meadows,comprising the main ecosystem of the Three-River Source Region,play an important role in the economic development of western pastoral areas.To determine whether the grazing level was too intense or the nutrient-carrying capacity of the meadows was overloaded,and to offer solutions in Maqin County,Qinghai Province,China,the meadows carrying capacity was determined by combining grass-yield and nutrients data for different seasons across different meadows.The results showed that the levels of crude protein(CP),ether extract(EE),ash,soluble sugars(SS),gas production,and energy value of forage in the summer–autumn grazing meadows were higher than those of the winter–spring meadows.Neutral detergent fiber(NDF)and acid detergent fiber(ADF)of forage in the summer–autumn grazing meadows were lower than those of the winter–spring meadows.We found that no pastures were overloaded with metabolizable energy(ME)for the whole year but digestible crude protein(DCP)was overloaded in winter–spring.And there were differences in the amount carrying capacity(forage yield)of seasonal grazing meadows for the different herds,the overload types were annual overloading(herd A),overloaded in summer–autumn(herd B),overloaded in winter–spring(herd C),and not overloaded(herd D).Compared with the previous grazing mode,theoretical carrying capacity,DCP carrying capacity,and ME carrying capacity of herd A increased by 20,19,and 27 sheep units,respectively,after optimization;herd B:36,31,and 45 sheep units,respectively;herd C:28,23,and 44 sheep units,respectively;and herd D:43,40,and 61 sheep units,respectively.In the Three-River Source Region and similar alpine pastoral areas,the grassland-livestock structure should be optimized to improve grassland vegetation status and increase the theoretical carrying capacity.
基金Supported by Guangxi Science and Technology Development Project:Construction of Technology Services Platform of Hezhou Agricultural Science and Technology Park(14258003)Guangxi Higher Education Teaching Reform Project:Research on Regional Academic Specialty Biological Experiment Teaching Mode Innovation and Service of Local Economy(2014JGZ145)
文摘In order to improve the comprehensive utilization value of water chestnut peel and the income of farmers. Contents of crude protein( CP),total sugar and reducing sugar were taken as indicators. Effects of initial p H,ratio of yeast to fungi species,incubation time and liquid volume on production of single cell protein( SCP) feed was studied,and technological conditions on production of SCP feed by water chestnut peel were optimized by orthogonal test. Results showed that the production of SCP feed by water chestnut peel was optimal when p H was 5. 0,ratio of yeast to fungi species was 2:1,fermentation time was 2 d and the liquid volume was 70 m L/250 m L. Under the optimum conditions,content of fermentation CP was 64. 25%,content of total sugar was 19. 8%,content of reducing sugar was 5. 0%,content of coarse fibre was 0. 0% and content of ash was 8. 04%.
基金Supported by National Natural Science Foundation of China(81403035)Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences(1630032019004)Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences(1630032020002).
文摘[Objectives]This study was conducted to investigate the effects of magnesium on the yield of Blumea balsamifera(L.)DC.and the accumulation of primary metabolites that affect yield of the medicinal material.[Methods]The annual seedlings of B.balsamifera were selected as experimental materials.The treatment concentrations of magnesium(Mg)were set as 0,1.5,15 and 150 mg/ml supplied by MgSO4·7H2O.The yield of the medicinal material was measured dynamically.And the content of total sugar was determined by 3,5-dinitrosalicylic acid colorimetry;the content of crude protein was determined by the Kjeldahl method;the ash content was determined by the high-temperature burning method;the crude fat content was determined with a crude fat instrument;and the crude fiber content was determined by the acid-base washing and weighing method.[Results]Mg significantly increased the yield of B.balsamifera medicinal material,especially 15 mg/ml Mg.It was found that in September,October and November,1.5 mg/ml and 15 mg/ml Mg significantly increased the contents of primary metabolites including total sugar,ash,crude protein,crude fat and crude fiber,and 150 mg/ml of Mg increased the accumulation of total sugar,ash,crude protein and crude fiber to different degrees,but had certain inhibitory effect on the accumulation of crude fat.In December,the application of Mg inhibited the accumulation of total sugar,ash and crude protein to different degrees,but significantly promoted the accumulation of crude fat and fiber.[Conclusions]This study provides a theoretical basis for clarifying the effects of different concentrations of magnesium on plant growth.
基金Supported by Key Scientific and Technological Planning Project of Shanxi Province(20120311022-5)Project of Scientific and Technological Innovation Team for Safe and Efficient Swine Production in Shanxi Province
文摘In order to study the feeding effect of fine division of feeding stages on the growing-finishing pigs,96 healthy Duroc × Landrace ×Yorkshire hybrid commercial pigs with similar age in days,size,and body weight about 15 kg,half boars and half sows,randomly divided into3 treatments( each treatment repeated 4 times,and each repetition 8 pigs). According to the body weight division standard,three stages,four stages,and five stages of feeding were adopted separately. The daily ration of with different nutrition levels was used,body weight and feed consumption were measured,and effects of different feeding methods on body weight increase,feed utilization,and economic benefits of growing-finishing pigs. The results showed that compared with the three-stage feeding,the body weight of five-stage and four-stage feeding increased by 4. 18%( P < 0. 01) and 2. 41%( P < 0. 05),respectively,and the body weight of five-stage feeding increased by 1. 74%( P < 0. 05) compared with that of four-stage feeding; the daily feed consumption of five-stage and four-stage feeding increased 3. 10%( P < 0. 01) and 1. 70%(P <0. 01),respectively,and the daily feed consumption of five-stage feeding was 1. 37% higher than that of four-stage feeding. The feed cost of five-stage feeding and four-stage feeding increased 3. 32%( P < 0. 01) and 1. 61%( P < 0. 05) separately,and the feed cost of five-stage feeding was 1. 69% higher than that of four-stage feeding( P < 0. 01). The income from average body weight increase of five-stage and fourstage feeding increased by 5. 47%( P < 0. 01) and 3. 59%( P < 0. 01) respectively,and the benefit of average body weight increase of fivestage feeding was 1. 81% higher than that of four-stage feeding( P > 0. 05). The crude protein consumption from average body weight increase of five-stage and four-stage feeding decreased by 2. 28%( P < 0. 01) and 1. 68%( P < 0. 01),respectively; the crude protein consumption from average body weight increase of five-stage feeding was 0. 67% lower than that of four-stage feeding; the feed conversion ratio of five-stage feeding,four-stage feeding,and three-stage feeding was 2. 92,2. 93,and 2. 95 respectively. The results showed that compared with the threestage feeding,the four-stage and five-stage feeding could significantly increase the body weight of the growing-finishing pigs,improve the feed utilization level and improve the economic benefits,and the effect of five-stage feeding was better than the four-stage feeding.
基金supported by grants from the National key research and development program of China (2016YFD0500504)National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2012BAD39B03)Major Project of Hunan Province (2015NK1002)
文摘The present study aimed to evaluate the effects of daily feeding pattern on growth performance, blood biochemistry, and antioxidant indexes in pigs. One hundred and eighty female Duroc x Landrace x Yorkshire(DLY) pigs with similar body weight(11.00 ± 0.12 kg) were randomly assigned to 3 groups: the control group(fed 17.01% CP diet, twice daily); high-low group(H-L group, fed18.33% CP diet in the morning, followed by 15.70% CP diet in the afternoon); and low-high group(L-H group, fed 15.70% CP diet in the morning, followed by 18.33% CP diet in the afternoon)(n = 6). Comparable amounts of their respective diets were given at 05:30 and 15:00 throughout the experimental periods to make all the treatments consumed the same type of food and the same amount of calories on a daily basis. On day 30, one pig was randomly selected per litter for blood samples. Compared with the control group, ADG in the H-L and L-H groups increased by 8.11% and 16.23%, but not significant(P > 0.05); and blood urea nitrogen(BUN) in the H-L and L-H groups decreased by 26.76% and 41.04%(P < 0.05), respectively. The H-L group feeding pattern could significantly improve levels of serum superoxide dismutase(SOD), when compared with the control group. These findings suggest that the twomeal daily feeding pattern with varied levels of CP affects serum levels of BUN and SOD. These changes could effectively silightly improve growth performance and antioxidant capacity in pigs without incurring increased feeding costs.
文摘Inclusions of non-bound amino acids particularly methionine,lysine and threonine,together with the"ideal protein"concept have allowed nutritionists to formulate broiler diets with reduced crude protein(CP)and increased nutrient density of notionally"essential"amino acids and energy content in recent decades,However,chicken-meat production has been projected to double between now and 2050,providing incentives to reduce dietary soybean meal inclusions further by tangibly reducing dietary CP and utilising a larger array of non-bound amino acids.Whilst relatively conservative decreases in dietary CP,in the order of 20 to 30 g/kg,do not negatively impact broiler performance,further decreases in CP typically compromise broiler performance with associated increases in carcass lipid deposition.Increases in carcass lipid deposition suggest changes occur in dietary energy balance,the mechanisms of which are still not fully understood but discourage the acceptance of diets with reductions in CP,Nevertheless,the groundwork has been laid to investigate both amino acid and non-amino acid limitations and propose facilitative strategies for adoption of tangible dietary CP reductions;consequently,these aspects are considered in detail in this review.Unsurprisingly,investigations into reduced dietary CP are epitomised by variability broiler performance due to the wide range of dietary specifications used and the many variables that should,or could,be considered in formulation of experimental diets.Thus,a holistic approach encompassing many factors influencing limitations to the adoption of tangibly reduced CP diets must be considered if they are to be successful in maintaining broiler performance without increasing carcass lipid deposition.
基金supported by Natural Science Foundation of China(31430082)National Key Basic Research Program of China,973 Program(2013CB127300)
文摘To reduce nitrogen excretion and lower feeding costs,low crude protein(CP)diets are sometimes pro-posed,however,a great reduction of dietary CP concentration(>4%reduction vs.recommended con-centration),even supplemented with essential and nonessential amino acids(AA)can detrimentally affect small intestinal barrier function and immunity,possibly due to the excessive lack of peptides.Here we hypothesize that with an extremely low CP concentration diet,protein-derived peptides,rather than AA supplementation,can improve intestinal barrier development and health.To test this hypothesis,21 growing pigs(19.90±1.00 kg body weight)were randomly assigned to 3 treatments with control diet(16%CP),or low CP diets(13%CP)supplemented with AA(LCPA)or casein hydrolysate(LCPC)for 28 days.In comparison with the control diet,the LCPA diet decreased the protein expression level of jejunal barrier factor zonula occludens-1(ZO-1)and stem cell proliferation factor leucine-rich repeat-containing G-protein-coupled receptor-5,whereas the LCPC diet enhanced intestinal barrier function by increasing the protein expression level of jejunal occludin and ZO-1 and ileal mucin-2.The LCPA diet reduced Lactobacillus counts,whereas the LCPC diet increased Lactobacillus counts and reduced Escherichia coli counts in the ileum.The LCPA diet also increased protein expression levels of pro-inflammatory cytokine interleukin-6(IL-6)and IL-22,whereas the LCPC diet decreased protein expression levels of pro-inflammatory IL-1β,IL-17A and tumor necrosis factor-αin the ileum.Collectively,the casein hydroly-sate supplementation of low CP diets showed beneficial effects on the small intestinal barrier,bacterial community,and immunity in pigs,pointing to the important role of protein-derived peptides in small intestinal health in cases of low crude protein diets.
基金the guidance and financial support provided by AgriFutures Chicken-meatpart of project PRJ-010623 entitled"Utilisation of synthetic amino acids by poultry"
文摘The hypothesis that capping dietary starch:protein ratios would enhance the performance of broiler chickens offered reduced-crude protein(CP)diets was tested in this experiment.A total of 432 off-sex,male Ross 308 chicks were allocated to 7 dietary treatments from 7 to 35 d post-hatch.The experimental design consisted of a 3×2 factorial array of treatments with the seventh treatment serving as a positive control.Three levels of dietary CP(197.5,180.0 and 162.5 g/kg)with either uncapped or capped dietary starch:protein ratios constituted the factorial array of treatments,whilst the positive control diet contained 215.0 g/kg CP.The positive control diet had an analysed dietary starch:protein ratio of 1.50 as opposed to a ratio of 1.68 in the uncapped 197.5 g/kg CP diet and 1.41 in the corresponding capped diet and the capped 197.5 g/kg CP diet displayed promise.The growth performance this diet matched the positive control but outperformed the uncapped 197.5 g/kg CP diet by 10.4%(2,161 vs.1,958 g/bird;P=0.009)in weight gain,by 3.10%(3,492 vs.3,387 g/bird;P=0.019)in feed intake on the basis of pairwise comparisons and numerically improved FCR by 4.04%(1.616 vs.12684).However,the growth performance of birds offered the 180.0 and 162.5 g/kg CP dietary treatments was remarkably inferior,irrespective of dietary starch:protein ratios.This inferior growth performance was associated with poor feathering and even feather-pecking and significant linear relationships between feather scores and parameters of growth performance were observed.The amino acid profile of feathers was determined where cysteine,glutamic acid,glycine,proline and serine were dominant in a crude protein content of 931 g/kg.Presumably,the feathering issues observed were manifestations of amino acid inadequacies or imbalances in the more reduced-CP diets and consideration is given to the implications of these outcomes.
基金This study wasfinancially supported by Flanders Innovation and Entrepreneurship(VLAIO)(project number 160778)and ILVO.
文摘Nitrogen(N)excreted by poultry is converted to ammonia(NH3),presenting an environmental risk and a health risk to the farmer and animals.A study was performed to investigate the effect of reduced CP and feed form on broiler performance and welfare,meat and litter quality,N utilization,and NH3 concentrations at litter level.A total of 2,232 Ross 308 male broilers was divided into 6 treatments and 6 replicates,which was fed diets in both pellet and mash forms with different CP levels of 205.0 g/kg(H,high),187.5 g/kg(M,intermediate)and 175.0 g/kg(L,low)in the grower phase and 195.0 g/kg(H),180.0 g/kg(M)and 165.6 g/kg(L)in the finisher phase.Individual amino acids(AA)were supplemented to maintain digestible AA-to-digestible lysine ratios.Decreasing dietary CP content to 187.5 g/kg in the grower phase and 180.0 g/kg in the finisher phase reduced NH3 concentrations at litter level(P<0.001),but a further reduction in dietary CP had no additional effect.Mash treatments had better litter qualities and lower incidences of foot and hock lesions than pellet treatments at d 38(P<0.001).In addition,treatments with reduced CP had lower incidence of foot lesions at d 38(P<0.001).Broilers fed pelleted diets had higher ADFI,ADG,and final BW,improved feed conversion ratio(FCR),and heavier carcasses(P<0.001)than those fed mash diets over a production period of 39 d.Performance could not be maintained when birds were fed L CP pelleted diets.This study demonstrated that,with the supplementation of AA to meet requirements,the concentration of dietary CP can be reduced to 187.5 and 180.0 g/kg in the grower and finisher phases respectively,without impairing broiler performance,meat yield and quality.Mash diets were favorable when considering the overall litter quality and welfare of the birds.However,they could not maintain the same broiler performance and slaughter yield as pelleted diets.Results from the present study may assist the poultry sector towards a socially acceptable lowemission farming system.
文摘In a previous experiment,male Ross 308 broiler chickens were offered dietary treatments with 3 levels of crude protein(222,193,165 g/kg)and 3 feed grains(ground maize,ground wheat,whole wheat)from 7 to 35 d post-hatch.Maize-based diets supported superior growth performance in comparison to wheatbased diets.Uric acid concentrations in excreta were retrospectively determined and related to total nitrogen(N)excreta concentrations.Uric acid concentrations ranged from 28.5 to 69.4 mg/g and proportions of uric acid-N to total excreta-N ranged from 27.4%to 42.6%in broiler chickens offered the 3×3 factorial array of dietary treatments.Proportions of uric acid-N to total N in excreta in birds offered the165 g/kg CP,maize-based diet were significantly lower by 10.6 percentage units(27.4%versus 38.0%;P=0.00057)than their wheat-based counterparts.Total excreta analysed had been collected from 35 to37 d post-hatch when feed intakes and excreta outputs were monitored.There were linear relationships between proportions of uric acid-N to total N in excreta in birds offered the three 165 g/kg CP diets with weight gain(r=-0.587;P=0.010),feed intake(r=-0.526;P=0.025)and feed conversion ratios(r=0.635;P=0.005).The possibility that increasing uric acid-N proportions in excreta is indicative of excessive ammonia accumulations compromising growth performance is discussed.The mean proportion of dietary glycine involved in uric acid excretion was 49.2%across all dietary treatments but ranged from 25.0%to 80.9%.Thus,the appropriate amount of dietary glycine is variable and largely dependent on the volume of uric acid synthesised and excreted.
基金AgriFutures Chicken-meat for funding the'Optimising amino acid profiles and energy in reduced-protein diets'project(PRJ010520)。
文摘As lowering crude protein(CP)in poultry diets continues to minimize amino acid excess,it is important to understand the limiting order of amino acids and the impact of their deficiencies.Therefore,a pair of experiments were conducted to observe the effects of individual amino acid deletions on growth performance,carcass traits,and nutrient utilization.Both experiments involved 3 control diets based on wheat and soybean meal,including a 210.0 g/kg CP industry control(IC),186.7 g/kg CP positive control(PC)supplemented with feed-grade amino acids to match the IC amino acid profile,186.7 g/kg CP negative control(NC)with reducing N corrected apparent metabolizable energy(AMEN)by 0.5 MJ/kg and removing feed-grade amino acids beyond L-Lys-HCl,DL-Met,and L-Thr from PC.Ten deletion diets where the following supplemented amino acids were individually removed from the PC:Val,Ile,Leu,Trp,Arg,His,Phe t Tyr,glycine equivalence(Glyequi),Pro,and Energy(0.5 MJ/kg reduction in AMEN of the PC).All diets were formulated to contain similar concentrations of digestible Lys,total sulfur amino acid(TSAA)and Thr.Experimental diets were offered to broiler chickens from 15 to 22 d postehatch in a cage study(Exp.1)to gain digestibility and nutrient utilization data;whereas they were offered from 15 to 35 d post ehatch in a floor-pen study(Exp.2)to gain performance and carcass yield data.The removal of supplemented Val,Arg,and Ile resulted in reduction on broiler performance(P<0.05),and the removal of Val,Arg,Ile,and Glyequi negatively influenced carcass traits(P<0.05).Results from both experiments indicate that Val and Arg are co-limiting in wheat-soybean meal diets,but that Ile and Glyequi may potentially limit breast and thigh development.
基金Flanders Innovation and Entrepreneurship(VLAIO)(project number 160778)and ILVO。
文摘We compared a 3-and 5-phase feeding program in terms of ammonia concentrations measured at litter level,litter composition and quality,nitrogen(N)utilization,performance,welfare,and meat deposition in broilers.A total of 744 Ross 308 male broilers was divided into 2 treatments,each with 6 replicates.The 3-phase diets were formulated to CP and digestible lysine contents of 205 and 11.5 g/kg(0 to 9 d),195 and 10.8 g/kg(9 to 24 d),and 183.3 and 10.15 g/kg(24 to 39 d),respectively.The 5-phase diets had additional phases from 17 to 24 d and 32 to 39 d with CP and digestible lysine contents of 188 and 10.4 g/kg and 177 and 9.8 g/kg,respectively.Feeding 5 phases reduced the NH3concentrations at litter level by37.95%and 20.81%at 23(P<0.05)and 37 d of age(P<0.05),respectively.There was a tendency for a lower litter total ammoniacal nitrogen concentration for the 5-phase treatment than the 3-phase treatment at 24 and 39 d of age(P<0.1 for both).Total N concentration of the litter also tended to be lower for the 5-phase treatment at 39 d of age(P<0.1).The lower NH3coincided with a lower average litter pH at 24 and 32 d of age(P<0.05 for both).Birds fed the 5-phase treatments had a lower incidence of foot lesions at 24 d of age(P<0.001).Performance as well as carcass yield could be maintained,except for FCR,which was higher for the 5-phase treatment between 17 and 24 d of age and the overall period(P<0.05 and<0.001,respectively).The impact of the 5-phase treatment regarding the utilization of N(digestibility,excretion,and retention)was less clear,however the NH3volatilized from the litter was significantly reduced.Feeding 5 phases may therefore potentially reduce the NH3emitted from broiler houses which has several environmental and health benefits.Although the 5-phase treatment resulted in a significant decrease in feed efficiency,growth performance and meat deposition were maintained.
基金financially supported by the National Key R&D Program of China(Grant no.2018YFD0500402)S&T Program of Hebei(199A7310H)。
文摘The current study was carried out to detect the effect of dietary guanidinoacetic acid(GAA)supplementation on carcass characteristics and meat quality in finishing pigs fed different dietary crude protein(CP)levels.Sixty-four barrows with an initial body weight of 73.05±2.34 kg were randomly allocated into 1 of 4 dietary treatments in a 2(100%vs.125%NRC CP level)×2(0 vs.300 mg/kg GAA)factorial arrangement(n=7).The feeding trial lasted for 49 d.GAA supplementation significantly reduced drip loss(P=0.01),free water distribution(T23peak area ratio)(P=0.05)and the concentrations of free alanine,threonine,methionine and isoleucine(P<0.05);but increased total glycine content(P=0.03)in the longissimus dorsi muscle of finishing pigs regardless of the dietary CP levels.Furthermore,primary myogenic cell differentiation system was employed to investigate the influence of inclusion of GAA on free amino acid concentrations in myotubes(n=4)and validate the finding in the animal feeding trial.We found that GAA inclusion in culture medium also decreased intracellular concentrations of free alanine,threonine,methionine,isoleucine,valine and proline in differentiated primary myogenic cells in vitro(P<0.05).Meanwhile,relative to diets with 100%NRC CP level,the intake of diets with 125%NRC CP level improved sarcoplasmic protein solubility,increased the contents of carnosine and total free amino acids as well as flavor amino acids in the longissimus dorsi muscle and decreased backfat thickness at the 6-7th ribs in pigs(P<0.05).In addition,we observed that the impact of dietary GAA supplementation on the last rib fat thickness,shear force,and free lysine content in the longissimus dorsi muscle was dependent on dietary CP levels(P<0.05).Collectively,dietary GAA supplementation can reduce drip loss,decrease the concentrations of free amino acids and flavor amino acids of fresh meat independent of dietary CP levels.
基金US Department of Agriculture,National Institute of Food and Agriculture,Grant/Award Number:2019-70005-30238。
文摘Background:Despite high nutritional and economic value,alfalfa yield has not been improved in the United States.Soil moisture critically influences alfalfa's yield and quality,affecting its physiological processes,nutrient uptake,and stand growth.Additionally,the maturity stage at harvest can significantly impact both hay yield and quality.Thus,this study aimed to assess the effect of different soil moisture levels and harvesting times on forage yield,nutritive value,and the overall profitability of commercially cultivated alfalfa.Methods:Two conventional and three lower-lignin alfalfa varieties were planted in a randomized complete block with split plot design under drought,rainfed,and irrigation conditions in 2020 in Manhattan,Kansas,USA.The dry matter yield(DMY)and forage nutritive value were evaluated at late bud,early flowering,and 7 days after early flowering stages,respectively.Results:DMY varied with production year,soil water availability,and growth stages,with drought conditions causing a decline in DMY of 5%to 38%in the second production year.Water conditions and maturity stages influenced crude protein(CP)and in vitro dry matter digestibility(IVDMD).Higher soil moisture and advancing maturity stages negatively impacted CP,IVDMD,and relative forage quality.The study revealed net profit margins of 62%,64%,and 52%for drought-prone,rainfed,and irrigated production,respectively.Conclusions:Harvest timing and irrigation practices were found to have substantial implications for forage yield and nutritive value of alfalfa.The yield-quality trade-off differed under drought and irrigation,with early harvesting leading to lower yields but higher protein content and digestibility.The study findings provide potential guidance for improving alfalfa hay yield,quality,and profitability.
