Background Ochratoxin A(OTA),a globally abundant and extremely hazardous pollutant,is a significant source of contamination in aquafeeds and is responsible for severe food pollution.The developmental toxicity of OTA a...Background Ochratoxin A(OTA),a globally abundant and extremely hazardous pollutant,is a significant source of contamination in aquafeeds and is responsible for severe food pollution.The developmental toxicity of OTA and the potential relieving strategy of natural products remain unclear.This study screened the substance curcumin(Cur),which had the best effect in alleviating OTA inhibition of myoblast proliferation,from 96 natural products and investigated its effect and mechanism in reducing OTA myotoxicity in vivo and in vitro.Methods A total of 720 healthy juvenile grass carp,with an initial average body weight of 11.06±0.05 g,were randomly assigned into 4 groups:the control group(without OTA and Cur),1.2 mg/kg OTA group,400 mg/kg Cur group,and 1.2 mg/kg OTA+400 mg/kg Cur group.Each treatment consisted of 3 replicates(180 fish)for 60 d.Results Firstly,we cultured,purified,and identified myoblasts using the tissue block culture method.Through preliminary screening and re-screening of 96 substances,we examined cell proliferation-related indicators such as cell viability and ultimately found that Cur had the best effect.Secondly,Cur could alleviate OTA-inhibited myoblast differentiation and myofibrillar development-related proteins(Myo G and MYHC)in vivo and in vitro and improve the growth performance of grass carp.Then,Cur could also promote the expression of OTA-inhibited protein synthesis-related proteins(S6K1 and TOR),which was related to the activation of the AKT/TOR signaling pathway.Finally,Cur could downregulate the expression of OTA-enhanced protein degradation-related genes(murf1,foxo3a,and ub),which was related to the inhibition of the Fox O3a signaling pathway.Conclusions In summary,our data demonstrated the effectiveness of Cur in alleviating OTA myotoxicity in vivo and in vitro.This study confirms the rapidity,feasibility,and effectiveness of establishing a natural product screening method targeting myoblasts to alleviate fungal toxin toxicity.展开更多
Background:Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish.As a necessary nutrient for fish growth,protein accounts for the highest proportion in the fish diet and is ex...Background:Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish.As a necessary nutrient for fish growth,protein accounts for the highest proportion in the fish diet and is expensive.Although our team found that the effect of protein on the muscle hardness of grass carp was probably related to an increased collagen content,the mechanism for this effect has not been deeply explored.Moreover,few studies have explored the protein requirements of sub-adult grass crap(Ctenopharyngodon idella).Therefore,the effects of different dietary protein levels on the growth performance,nutritional value,muscle hardness,muscle fiber growth,collagen metabolism and related molecule expression in grass carp were investigated.Methods:A total of 450 healthy grass carp(721.16±1.98 g)were selected and assigned randomly to six experimen-tal groups with three replicates each(n=25/replicate),and were fed six diets with 15.91%,19.39%,22.10%,25.59%,28.53%and 31.42%protein for 60 d.Results:Appropriate levels of dietary protein increased the feed intake,percentage weight gain,specific growth rate,body composition,unsaturated fatty acid content in muscle,partial free amino acid content in muscle,and muscle hardness of grass carp.These protein levels also increased the muscle fiber density,the frequency of new muscle fibers,the contents of collagen and IGF-1,and the enzyme activities of prolyl 4-hydroxylases and lysyloxidase,and decreased the activity of matrix metalloproteinase-2.At the molecular level,the optimal dietary protein increased col-lagen type Iα1(Colα1),Colα2,PI3K,Akt,S6K1,La ribonucleoprotein domain family member 6a(LARP6a),TGF-β1,Smad2,Smad4,Smad3,tissue inhibitor of metalloproteinase-2,MyoD,Myf5,MyoG and MyHC relative mRNA levels.The levels of the myostatin-1 and myostatin-2 genes were downregulated,and the protein expression levels of p-Smad2,Smad2,Smad4,p-Akt,Akt,LARP6 and Smad3 were increased.Conclusions:The appropriate levels of dietary protein promoted the growth of sub-adult grass carp and improved muscle hardness by promoting the growth of muscle fibers,improving collagen synthesis and depressing collagen degradation.In addition,the dietary protein requirements of sub-adult grass carp were 26.21%and 24.85%according to the quadratic regression analysis of growth performance(SGR)and the muscle hardness(collagen content),respectively.展开更多
Background Mannan oligosaccharides(MOS)are recommended as aquaculture additives owing to their excellent antioxidant properties.In the present study,we examined the effects of dietary MOS on the head kidney and spleen...Background Mannan oligosaccharides(MOS)are recommended as aquaculture additives owing to their excellent antioxidant properties.In the present study,we examined the effects of dietary MOS on the head kidney and spleen of grass carp(Ctenopharyngodon idella)with Aeromonas hydrophila infection.Methods A total of 540 grass carp were used for the study.They were administered six gradient dosages of the MOS diet(0,200,400,600,800,and 1,000 mg/kg)for 60 d.Subsequently,we performed a 14-day Aeromonas hydrophila challenge experiment.The antioxidant capacity of the head kidney and spleen were examined using spectrophotometry,DNA fragmentation,qRT-PCR,and Western blotting.Results After infection with Aeromonas hydrophila,400-600 mg/kg MOS supplementation decreased the levels of reactive oxygen species,protein carbonyl,and malonaldehyde and increased the levels of anti-superoxide anion,antihydroxyl radical,and glutathione in the head kidney and spleen of grass carp.The activities of copper-zinc superoxide dismutase,manganese superoxide dismutase,catalase,glutathione S-transferase,glutathione reductase,and glutathione peroxidase were also enhanced by supplementation with 400-600 mg/kg MOS.Furthermore,the expression of most antioxidant enzymes and their corresponding genes increased significantly with supplementation of 200-800 mg/kg MOS.mRNA and protein levels of nuclear factor erythroid 2-related factor 2 also increased following supplementation with 400-600 mg/kg MOS.In addition,supplementation with 400-600 mg/kg MOS reduced excessive apoptosis by inhibiting the death receptor pathway and mitochondrial pathway processes.Conclusions Based on the quadratic regression analysis of the above biomarkers(reactive oxygen species,malondialdehyde,and protein carbonyl)of oxidative damage in the head kidney and spleen of on-growing grass carp,the recommended MOS supplementation is 575.21,557.58,531.86,597.35,570.16,and 553.80 mg/kg,respectively.Collectively,MOS supplementation could alleviate oxidative injury in the head kidney and spleen of grass carp infected with Aeromonas hydrophila.展开更多
Background Muscle represents a unique and complex system with many components and comprises the major edible part of animals.Vitamin D is a critical nutrient for animals and is known to enhance calcium absorption and ...Background Muscle represents a unique and complex system with many components and comprises the major edible part of animals.Vitamin D is a critical nutrient for animals and is known to enhance calcium absorption and immune response.In recent years,dietary vitamin D supplementation in livestock has received increased attention due to biological responses including improving shear force in mammalian meat.However,the vitamin D acquisition and myofiber development processes in fish differ from those in mammals,and the effect of vitamin D on fish flesh quality is poorly understood.Here,the influence of dietary vitamin D on fillet quality,antioxidant ability,and myofiber development was examined in grass carp(Ctenopharyngodon idella).Methods A total of 540 healthy grass carp,with an initial average body weight of 257.24±0.63 g,were allotted in 6 experimental groups with 3 replicates each,and respectively fed corresponding diets with 15.2,364.3,782.5,1,167.9,1,573.8,and 1,980.1 IU/kg vitamin D for 70 d.Results Supplementation with 1,167.9 IU/kg vitamin D significantly improved nutritional value and sensory quality of fillets,enhancing crude protein,free amino acid,lipid,and collagen contents;maintaining an ideal pH;and reduc-ing lactate content,shear force,and cooking loss relative to respective values in the control(15.2 IU/kg)group.Average myofiber diameter and the frequency of myofibers>50μm in diameter increased under supplementation with 782.5–1,167.9 IU/kg vitamin D.Levels of oxidative damage biomarkers decreased,and the expression of antioxi-dant enzymes and nuclear factor erythroid 2-related factor 2 signaling molecules was upregulated in the 1,167.9 IU/kg vitamin D treatment compared to respective values in the control group.Furthermore,vitamin D supplementation activated cell differentiation by enhancing the expression of myogenic regulatory factors and myocyte enhancer factors compared to that in the control group.In addition,supplementation with 1,167.9 IU/kg vitamin D improved protein deposition associated with protein synthesis molecule(target of rapamycin)signaling and vitamin D receptor paralogs,along with inhibition of protein degradation(forkhead box protein 1)signaling.Conclusions Overall,the results demonstrated that vitamin D strengthened antioxidant ability and myofiber devel-opment,thereby enhancing nutritional value and sensory quality of fish flesh.These findings suggest that dietary vitamin D supplementation is conducive to the production of nutrient-rich,high quality aquaculture products.展开更多
Background: Methionine is an essential amino acid for fish. The present study was conducted to investigate the effects of dietary methionine on growth performance, digestive and absorptive ability, as well as antioxid...Background: Methionine is an essential amino acid for fish. The present study was conducted to investigate the effects of dietary methionine on growth performance, digestive and absorptive ability, as well as antioxidant capacity in the intestine and hepatopancreas of sub-adult grass carp(Ctenopharyngodon idella).Results: Dietary methionine deficiency significantly decreased percentage weight gain(PWG), feed intake, feed efficiency and protein efficiency ratio, as well as activities of hepatopancreatic glutamate-oxaloacetate transaminase and muscle glutamate-pyruvate transaminase in sub-adult grass carp(P < 0.05). Furthermore, methionine deficiency significantly reduced activities of trypsin, lipase and amylase in the intestine, Na^+/K^+-ATPase, alkaline phosphatase and γ-glutamyl transpeptidase in three intestinal segments, and creatine kinase(CK) in the proximal intestine(P < 0.05). However, an unexplained and significant increase in CK activity in the mid intestine was associated with dietary methionine deficiency. Malondialdehyde and protein carbonyl contents in the intestine and hepatopancreas were significantly increased by methionine deficiency(P < 0.05), whereas anti-hydroxyl radical capacity in the hepatopancreas and intestine, and anti-superoxide anion capacity in the intestine, were significantly decreased by methionine deficiency(P < 0.05). Moreover, methionine deficiency significantly decreased superoxide dismutase and glutathione reductase activities, glutathione contents in the hepatopancreas and intestine, as well as glutathione peroxidase activity in the intestine(P < 0.05), whereas it significantly increased activities of catalase in the hepatopancreas and glutathione-S-transferase in the hepatopancreas and intestine(P < 0.05).(Continued on next page)(Continued from previous page)Conclusions: The present results demonstrated that dietary methionine deficiency induced poor growth, and decreased digestive and absorptive function and antioxidant capacity in the hepatopancreas and intestine of sub-adult grass carp. Methionine requirements for sub-adult grass carp(450-1, 170 g) based on PWG, intestinal trypsin, and hepatopancreatic anti-hydroxyl radical activities were estimated to be 6.12 g/kg diet(21.80 g/kg protein),6.99 g/kg diet(24.90 g/kg protein) and 5.42 g/kg diet(19.31 g/kg protein), respectively, in the presence of 1.50 g cysteine/kg(5.35 g/kg protein).展开更多
Background:Muscle is the complex and heterogeneous tissue,which comprises the primary edible part of the trunk of fish and mammals.Previous studies have shown that dietary isoleucine(Ile)exerts beneficial effects on g...Background:Muscle is the complex and heterogeneous tissue,which comprises the primary edible part of the trunk of fish and mammals.Previous studies have shown that dietary isoleucine(Ile)exerts beneficial effects on growth in aquatic animals.However,there were limited studies regarding the benefits of Ile on fish muscle and their effects on flesh quality and muscle growth.Thus,this study was conducted to explore whether dietary Ile had affected flesh quality and muscle growth in hybrid bagrid catfish(Pelteobagrus vachelli♀×Leiocassis longirostris♂).Methods:A total of 630 hybrid fish,with an initial average body weight of 33.11±0.09 g,were randomly allotted into seven experimental groups with three replicates each,and respectively fed seven diets with 5.0,7.5,10.0,12.5,15.0,17.5,and 20.0 g Ile/kg diets for 8 weeks.Results:In the present study,we demonstrated that Ile significantly:(1)increased muscle protein and lipid contents and the frequency distribution of myofibers with≤20μm and≥50μm of diameter;(2)improved pH value,shear force,cathepsin B and L activities,hydroxyproline content,resilience,cohesiveness,and decreased cooking loss,lactate content,hardness,springiness,gumminess,and chewiness;(3)decreased reactive oxygen species(ROS),malondialdehyde(MDA),and protein carbonyl(PC)contents,GCLC and Keap1 mRNA levels,and up-regulated CuZnSOD,CAT,GPX1a,GST,and Nrf2 mRNA levels;(4)up-regulated the insulin-like growth factor 1,2(IGF-1,IGF-2),insulin-like growth factor 1 receptor(IGF-1R),proliferating cell nuclear antigen(PCNA),Myf5,Myod,Myog,Mrf4,and MyHC mRNA levels,and decreased MSTN mRNAlevel;(5)increased muscle protein deposition by activating AKT-TOR-S6K1 and AKT-FOXO3a signaling pathways.Conclusion:These results revealed that dietary Ile improved flesh quality,which might be due to increasing nutritional content,physicochemical,texture parameters,and antioxidant ability;promoting muscle growth by affecting myocytes hyperplasia and hypertrophy,and muscle protein deposition associated with protein synthesis and degradation signaling pathways.Finally,the quadratic regression analysis of chewiness,ROS,and protein contents against dietary Ile levels suggested that the optimal dietary Ile levels for hybrid bagrid catfish was estimated to be 14.19,12.36,and 12.78 g/kg diet,corresponding to 36.59,31.87,and 32.96 g/kg dietary protein,respectively.展开更多
Background： This study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp （ Ctenoph...Background： This study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp （ Ctenopharyngodonidella）. Results： Weight gain, specific growth rate, feed intake and feed efficiency were significantly improved by dietary threonine （P 〈 0.05）. Intestinal activities of trypsin, chymotrypsin, alpha-amylase, lipase, alkaline phosphatase, y-glutamyl transpeptidase and creatine kinase took the similar trends. Contents of malondialdehyde and protein carbonyl in intestine and hepatopancreas were significantly decreased by dietary optimal threonine supplementation （P 〈 0.05）. Anti-superoxide anion capacity, anti-hydroxyl radical capacity, glutathione content and activities of superoxide dismutase, catalase and glutathione-S-transferase in intestine and hepatopancreas were enhanced by dietary threonine （P 〈 0.05）. Conclusions： Dietary threonine could improve growth, enhance digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp. The dietary threonine requirement of sub-adult grass carp （441.9-1,013.4 g） based on weight gain was 11.6 g/kg diet or 41.5 g/kg of dietary protein by quadratic regression analysis.展开更多
D-mannose,essential for protein glycosylation,has been reported to have immunomodulatory effects and to maintain intestinal flora homeostasis.In addition to evaluating growth performance,we examined the impact of D-ma...D-mannose,essential for protein glycosylation,has been reported to have immunomodulatory effects and to maintain intestinal flora homeostasis.In addition to evaluating growth performance,we examined the impact of D-mannose on the structure of epithelial cells and apical junction complexes in the animal intestine.All 1800 grass carp(16.20±0.01 g)were randomly divided into six treatments with six replicates of 50 fish each and fed with six different levels of D-mannose(0.52,1.75,3.02,4.28,5.50 and 6.78 g/kg diet)for 70 d.The study revealed that D-mannose increased feed intake(P 0.05).D-mannose supplementation at 1.75 g/kg increased crude protein content in fish and lipid production value(P<0.05).D-mannose supplementation at 4.28 g/kg increased intestinal length,intestinal weight and fold height of grass carp compared to the control group(P<0.05).This improvement may be attributed to the phosphomannose isomerase(PMI)-mediated enhancement of glycolysis.This study found that D-mannose supplementation at 4.28 or 3.02 g/kg reduced serum diamine oxidase activity or D-lactate content(P<0.05)and improved cellular and intercellular structures for the first time.The improvement of cellular redox homeostasis involves alleviating endoplasmic reticulum(ER)stress through the inositol-requiring enzyme 1(IRE1),RNA-dependent protein kinase-like ER kinase(PERK),and activating transcription factor 6(ATF6)signaling pathways.The alleviation of ER stress may be linked to the phosphomannomutase(PMM)-mediated enhancement of protein glycosylation.In addition,ubiquitin-dependent[PTEN-induced putative kinase 1(PINK1)/Parkin]and ubiquitin-independent[BCL2-interacting protein 3-like(BNIP3L),BCL2-interacting protein 3(BNIP3),and FUN14 domain containing 1(FUNDC1)]mitophagy may play a role in maintaining cellular redox homeostasis.The enhancement of intercellular structures includes enhancing tight junction and adherent junction structures,which may be closely associated with the small Rho GTPase protein(RhoA)/the Rho-associated protein kinase(ROCK)signaling pathway.In conclusion,D-mannose improved intestinal cellular redox homeostasis associated with ER stress and mitophagy pathways,and enhanced intercellular structures related to tight junctions and adherent junctions.Furthermore,quadratic regression analysis of the PWG and intestinal reactive oxygen species content indicated that the optimal addition level of D-mannose for juvenile grass carp was 4.61 and 4.59 g/kg,respectively.展开更多
Arecoline is an alkaloid with important pharmacological effects in the plant areca nut,which has been demonstrated to be an agonist of muscarinic receptors(M receptor).This study explored the influences of dietary are...Arecoline is an alkaloid with important pharmacological effects in the plant areca nut,which has been demonstrated to be an agonist of muscarinic receptors(M receptor).This study explored the influences of dietary arecoline on growth performance,intestinal digestion and absorption abilities,antioxidant capacity,and the apical junction complex(AJC)of adult grass carp(Ctenopharyngodon idella).Adult grass carp(608to 1512 g)were fed at 6 graded levels of dietary arecoline(0,0.5,1.0,1.5,2.0,and 2.5 mg/kg diet)for 9weeks.The results suggested that appropriate dietary supplementation of arecoline(1.0 mg/kg)increased growth parameters and intestinal growth in adult grass carp(P<0.05),enhanced digestion and absorption capacities(P<0.05),up-regulated muscarinic receptor 3(M3)mRNA level(P<0.05),increased the content of neuropeptide fish substance P(P<0.05),improved antioxidant capacity by activating the Keap1a/Nrf2signaling pathway(P<0.05),reduced intestinal mucosal permeability(P<0.05),and increased m RNA levels of tight junction(TJ)and adherent junction AJ-related proteins in fish by inhibiting the RhoA/ROCK signaling pathway(RhoA/ROCK/MLCK/NMII)(P<0.05).In addition,the appropriate arecoline supplementation for adult grass carp was determined to be 1.20,1.21,1.07,and 1.19 mg/kg based on percentage weight gain,lipase activity,serum diamine oxidase,and protein carbonyl,respectively.Overall,to the best of our knowledge,we investigated for the first time the effects and possible mechanisms of dietary arecoline on intestinal digestive and absorptive capacities and structural integrity in fish and evaluated the appropriate level of supplementation.展开更多
Growth, muscle composition, meat quality characteristics and antioxidant capacity in muscle of young grass carp(Ctenopharyngodon idella)(initial weight 282.9 ± 3.3 g) fed graded levels of phosphorus(1.0,2.5, 3.8,...Growth, muscle composition, meat quality characteristics and antioxidant capacity in muscle of young grass carp(Ctenopharyngodon idella)(initial weight 282.9 ± 3.3 g) fed graded levels of phosphorus(1.0,2.5, 3.8, 5.6, 7.8 and 9.5 g/kg diet) for 8 wk were investigated. Results indicated that percentage weight gain, feed intake, feed efficiency, serum phosphorus and alkaline phosphatase were improved with optimal phosphorus supplementations(P < 0.05). Muscle protein content and water holding capacity were significantly elevated, while moisture, lipid and ash contents were significantly decreased with dietary phosphorus to a certain level(P < 0.05). The meat shear force value and hydroxyproline content were not influenced by different levels of phosphorus. Muscle anti-hydroxyl radical, superoxide dismutase, catalase, glutathione S-transferase activities and glutathione content were significantly improved(P < 0.05). Conversely, anti-superoxide anion, glutathione reducase and glutathione peroxidase activities were decreased(P < 0.05) with dietary phosphorus to a certain level. These results indicated that suitable dietary phosphorus improved growth performance, meat quality and muscle antioxidant capacity. Dietary available phosphorus requirement of young grass carp for percentage weight gain was4.0 g/kg diet.展开更多
This dissertation was primarily focused on the immune response,inflammatory response and molecular mechanisms in the skin,head kidney and spleen of grown-up grass carp(Ctenopharyngodon idella).Six iso-nitrogen diets d...This dissertation was primarily focused on the immune response,inflammatory response and molecular mechanisms in the skin,head kidney and spleen of grown-up grass carp(Ctenopharyngodon idella).Six iso-nitrogen diets differing in lysine concentrations(5.6,8.5,11.6,14.4,17.5 and 20.7 g/kg)were fed to 540 grass carp(164.85±0.79 g)for 60 d.After that,grass carp were challenged by Aeromonas hydrophila for 6 d.This study revealed that lysine deficiency(1)suppressed the growth performa,nce of the fish and decreased their ability to resist skin lesion morbidity,(2)impaired the immune organ s immune response by decreasing the gene expressions of mucin,liver-expressed antimicrobial peptide(LEAP)-2B,β-defensin-1 and LEAP-2A and the production of antibacterial compounds of grown-up grass carp,and(3)aggravated the inflammatory response of immune organs in the fish by increasing the gene expressions of pro-inflammatory cytokines(interferon y2[IFN-γ2],tumor necrosis factorα[TNF-α],interleukin[IL]-15,IL-17D,IL-12p40,IL-6 and IL-8)and down-regulating anti-inflammatory cytokines(IL-11,transforming growth factorβ1[TGF-β1],IL-10 and IL-4/13A),which were tightly correlated with signal transducer and activator of transcription(STAT)1 and STAT3 signaling pathway,respectively.The different phenomenon in the skin,spleen and head kidney of fish may be correlated with the difference in gene subtype.In addition,using quadratic regression analysis of percent weight gain(PWG),skin lesion morbidity,and the lysozyme activities in the spleen and head kidney,the dietary lysine requirements for grown-up grass carp were estimated to be 13.58,13.51,14.56 and 14.18 g/kg,respectively.展开更多
The present study investigated the effect of body weight on body composition, digestive and absorptive capacity, transaminase activities in hepatopancreas and muscle, and plasma ammonia concentration of Jian carp(Cypr...The present study investigated the effect of body weight on body composition, digestive and absorptive capacity, transaminase activities in hepatopancreas and muscle, and plasma ammonia concentration of Jian carp(Cyprinus carpio var.Jian). A total of 750 Jian carps(18.0 ± 0.2 g) were randomly distributed into five groups with three replicates and fed the same diet for 56 days. Tissue and plasma samples were collected on days 14, 28,42, and 56. The results were used to develop a mathematical model for specific growth rate, body moisture and fat content, aspartate transaminase activity and alanine aminotransferase activity in hepatopancreas and muscle, plasma ammonia concentration, and trypsin, chymotrypsin, lipase, and amylase activities in hepatopancreas and intestine, activities of creatine kinase, Na^+/K^+-ATPase, alkaline phosphatase, and γ-glutamyl transpeptidase in intestine in Jian carp. There were linear relationships between natural logarithms of above indexes and body weight. The body moisture and fat content, digestive and absorptive enzymes activities, and transaminase activities showed negative allometry against body weight of Jian carp which were partial reasons to explain fish growth rate decreasing.展开更多
基金financially supported by the earmarked fund for CARS(CARS-45)National Natural Science Foundation of China for Outstanding Youth Science Foundation(31922086)+1 种基金the Young Top-Notch Talent Support Programthe 111 project(D17015)。
文摘Background Ochratoxin A(OTA),a globally abundant and extremely hazardous pollutant,is a significant source of contamination in aquafeeds and is responsible for severe food pollution.The developmental toxicity of OTA and the potential relieving strategy of natural products remain unclear.This study screened the substance curcumin(Cur),which had the best effect in alleviating OTA inhibition of myoblast proliferation,from 96 natural products and investigated its effect and mechanism in reducing OTA myotoxicity in vivo and in vitro.Methods A total of 720 healthy juvenile grass carp,with an initial average body weight of 11.06±0.05 g,were randomly assigned into 4 groups:the control group(without OTA and Cur),1.2 mg/kg OTA group,400 mg/kg Cur group,and 1.2 mg/kg OTA+400 mg/kg Cur group.Each treatment consisted of 3 replicates(180 fish)for 60 d.Results Firstly,we cultured,purified,and identified myoblasts using the tissue block culture method.Through preliminary screening and re-screening of 96 substances,we examined cell proliferation-related indicators such as cell viability and ultimately found that Cur had the best effect.Secondly,Cur could alleviate OTA-inhibited myoblast differentiation and myofibrillar development-related proteins(Myo G and MYHC)in vivo and in vitro and improve the growth performance of grass carp.Then,Cur could also promote the expression of OTA-inhibited protein synthesis-related proteins(S6K1 and TOR),which was related to the activation of the AKT/TOR signaling pathway.Finally,Cur could downregulate the expression of OTA-enhanced protein degradation-related genes(murf1,foxo3a,and ub),which was related to the inhibition of the Fox O3a signaling pathway.Conclusions In summary,our data demonstrated the effectiveness of Cur in alleviating OTA myotoxicity in vivo and in vitro.This study confirms the rapidity,feasibility,and effectiveness of establishing a natural product screening method targeting myoblasts to alleviate fungal toxin toxicity.
基金supported by National Key R&D Program of China(2018YFD0900400,2019YFD0900200)National Natural Science Foundation of China for Outstanding Youth Science Foundation(31922086)+3 种基金National Nature Science Foundation of China(32172988)the Young Top-Notch Talent Support Program of National Ten-Thousand Talents Program,the Earmarked Fund for China Agriculture Research System(CARS-45)Outstanding Talents and Innovative Team of Agricultural Scientific Research(Ministry of Agriculture)Supported by Sichuan Science and Technology Program(2019YFN0036).
文摘Background:Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish.As a necessary nutrient for fish growth,protein accounts for the highest proportion in the fish diet and is expensive.Although our team found that the effect of protein on the muscle hardness of grass carp was probably related to an increased collagen content,the mechanism for this effect has not been deeply explored.Moreover,few studies have explored the protein requirements of sub-adult grass crap(Ctenopharyngodon idella).Therefore,the effects of different dietary protein levels on the growth performance,nutritional value,muscle hardness,muscle fiber growth,collagen metabolism and related molecule expression in grass carp were investigated.Methods:A total of 450 healthy grass carp(721.16±1.98 g)were selected and assigned randomly to six experimen-tal groups with three replicates each(n=25/replicate),and were fed six diets with 15.91%,19.39%,22.10%,25.59%,28.53%and 31.42%protein for 60 d.Results:Appropriate levels of dietary protein increased the feed intake,percentage weight gain,specific growth rate,body composition,unsaturated fatty acid content in muscle,partial free amino acid content in muscle,and muscle hardness of grass carp.These protein levels also increased the muscle fiber density,the frequency of new muscle fibers,the contents of collagen and IGF-1,and the enzyme activities of prolyl 4-hydroxylases and lysyloxidase,and decreased the activity of matrix metalloproteinase-2.At the molecular level,the optimal dietary protein increased col-lagen type Iα1(Colα1),Colα2,PI3K,Akt,S6K1,La ribonucleoprotein domain family member 6a(LARP6a),TGF-β1,Smad2,Smad4,Smad3,tissue inhibitor of metalloproteinase-2,MyoD,Myf5,MyoG and MyHC relative mRNA levels.The levels of the myostatin-1 and myostatin-2 genes were downregulated,and the protein expression levels of p-Smad2,Smad2,Smad4,p-Akt,Akt,LARP6 and Smad3 were increased.Conclusions:The appropriate levels of dietary protein promoted the growth of sub-adult grass carp and improved muscle hardness by promoting the growth of muscle fibers,improving collagen synthesis and depressing collagen degradation.In addition,the dietary protein requirements of sub-adult grass carp were 26.21%and 24.85%according to the quadratic regression analysis of growth performance(SGR)and the muscle hardness(collagen content),respectively.
基金financially supported by the National Key R&D Program of China(2019YFD0900200,2018YFD0900400)Supported by the earmarked fund for CARS(CARS-45)+2 种基金National Natural Science Foundation of China for Outstanding Youth Science Foundation(31922086)the Young Top-Notch Talent Support ProgramSichuan Science and Technology Program(2019YFN0036)。
文摘Background Mannan oligosaccharides(MOS)are recommended as aquaculture additives owing to their excellent antioxidant properties.In the present study,we examined the effects of dietary MOS on the head kidney and spleen of grass carp(Ctenopharyngodon idella)with Aeromonas hydrophila infection.Methods A total of 540 grass carp were used for the study.They were administered six gradient dosages of the MOS diet(0,200,400,600,800,and 1,000 mg/kg)for 60 d.Subsequently,we performed a 14-day Aeromonas hydrophila challenge experiment.The antioxidant capacity of the head kidney and spleen were examined using spectrophotometry,DNA fragmentation,qRT-PCR,and Western blotting.Results After infection with Aeromonas hydrophila,400-600 mg/kg MOS supplementation decreased the levels of reactive oxygen species,protein carbonyl,and malonaldehyde and increased the levels of anti-superoxide anion,antihydroxyl radical,and glutathione in the head kidney and spleen of grass carp.The activities of copper-zinc superoxide dismutase,manganese superoxide dismutase,catalase,glutathione S-transferase,glutathione reductase,and glutathione peroxidase were also enhanced by supplementation with 400-600 mg/kg MOS.Furthermore,the expression of most antioxidant enzymes and their corresponding genes increased significantly with supplementation of 200-800 mg/kg MOS.mRNA and protein levels of nuclear factor erythroid 2-related factor 2 also increased following supplementation with 400-600 mg/kg MOS.In addition,supplementation with 400-600 mg/kg MOS reduced excessive apoptosis by inhibiting the death receptor pathway and mitochondrial pathway processes.Conclusions Based on the quadratic regression analysis of the above biomarkers(reactive oxygen species,malondialdehyde,and protein carbonyl)of oxidative damage in the head kidney and spleen of on-growing grass carp,the recommended MOS supplementation is 575.21,557.58,531.86,597.35,570.16,and 553.80 mg/kg,respectively.Collectively,MOS supplementation could alleviate oxidative injury in the head kidney and spleen of grass carp infected with Aeromonas hydrophila.
基金National Key R&D Program of China(2018YFD0900400 and 2019YFD0900200)National Natural Science Foundation of China for Outstanding Youth Science Foundation(31922086)+1 种基金the earmarked fund for CARS(CARS-45)Sichuan Science and Technology Program(2019YFN0036).
文摘Background Muscle represents a unique and complex system with many components and comprises the major edible part of animals.Vitamin D is a critical nutrient for animals and is known to enhance calcium absorption and immune response.In recent years,dietary vitamin D supplementation in livestock has received increased attention due to biological responses including improving shear force in mammalian meat.However,the vitamin D acquisition and myofiber development processes in fish differ from those in mammals,and the effect of vitamin D on fish flesh quality is poorly understood.Here,the influence of dietary vitamin D on fillet quality,antioxidant ability,and myofiber development was examined in grass carp(Ctenopharyngodon idella).Methods A total of 540 healthy grass carp,with an initial average body weight of 257.24±0.63 g,were allotted in 6 experimental groups with 3 replicates each,and respectively fed corresponding diets with 15.2,364.3,782.5,1,167.9,1,573.8,and 1,980.1 IU/kg vitamin D for 70 d.Results Supplementation with 1,167.9 IU/kg vitamin D significantly improved nutritional value and sensory quality of fillets,enhancing crude protein,free amino acid,lipid,and collagen contents;maintaining an ideal pH;and reduc-ing lactate content,shear force,and cooking loss relative to respective values in the control(15.2 IU/kg)group.Average myofiber diameter and the frequency of myofibers>50μm in diameter increased under supplementation with 782.5–1,167.9 IU/kg vitamin D.Levels of oxidative damage biomarkers decreased,and the expression of antioxi-dant enzymes and nuclear factor erythroid 2-related factor 2 signaling molecules was upregulated in the 1,167.9 IU/kg vitamin D treatment compared to respective values in the control group.Furthermore,vitamin D supplementation activated cell differentiation by enhancing the expression of myogenic regulatory factors and myocyte enhancer factors compared to that in the control group.In addition,supplementation with 1,167.9 IU/kg vitamin D improved protein deposition associated with protein synthesis molecule(target of rapamycin)signaling and vitamin D receptor paralogs,along with inhibition of protein degradation(forkhead box protein 1)signaling.Conclusions Overall,the results demonstrated that vitamin D strengthened antioxidant ability and myofiber devel-opment,thereby enhancing nutritional value and sensory quality of fish flesh.These findings suggest that dietary vitamin D supplementation is conducive to the production of nutrient-rich,high quality aquaculture products.
基金supported by the National Basic Research Program of China(973 Program)(2014CB138600)National Science Foundation of China(31502184)+7 种基金Outstanding Talents and Innovative Team of Agricultural Scientific Research(Ministry of Agriculture)the National Department Public Benefit Research Foundation(Agriculture)of China(201003020)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20135103110001)Science and Technology Support Program of Sichuan Province of China(2014NZ0003)Major Scientific and Technological Achievement Transformation Project of Sichuan Province of China(2012NC00072013NC0045)the Demonstration of Major Scientific and Technological Achievement Transformation Project of Sichuan Province of China(2015CC0011)Natural Science Foundation for Young Scientists of Sichuan Province(2014JQ0007)
文摘Background: Methionine is an essential amino acid for fish. The present study was conducted to investigate the effects of dietary methionine on growth performance, digestive and absorptive ability, as well as antioxidant capacity in the intestine and hepatopancreas of sub-adult grass carp(Ctenopharyngodon idella).Results: Dietary methionine deficiency significantly decreased percentage weight gain(PWG), feed intake, feed efficiency and protein efficiency ratio, as well as activities of hepatopancreatic glutamate-oxaloacetate transaminase and muscle glutamate-pyruvate transaminase in sub-adult grass carp(P < 0.05). Furthermore, methionine deficiency significantly reduced activities of trypsin, lipase and amylase in the intestine, Na^+/K^+-ATPase, alkaline phosphatase and γ-glutamyl transpeptidase in three intestinal segments, and creatine kinase(CK) in the proximal intestine(P < 0.05). However, an unexplained and significant increase in CK activity in the mid intestine was associated with dietary methionine deficiency. Malondialdehyde and protein carbonyl contents in the intestine and hepatopancreas were significantly increased by methionine deficiency(P < 0.05), whereas anti-hydroxyl radical capacity in the hepatopancreas and intestine, and anti-superoxide anion capacity in the intestine, were significantly decreased by methionine deficiency(P < 0.05). Moreover, methionine deficiency significantly decreased superoxide dismutase and glutathione reductase activities, glutathione contents in the hepatopancreas and intestine, as well as glutathione peroxidase activity in the intestine(P < 0.05), whereas it significantly increased activities of catalase in the hepatopancreas and glutathione-S-transferase in the hepatopancreas and intestine(P < 0.05).(Continued on next page)(Continued from previous page)Conclusions: The present results demonstrated that dietary methionine deficiency induced poor growth, and decreased digestive and absorptive function and antioxidant capacity in the hepatopancreas and intestine of sub-adult grass carp. Methionine requirements for sub-adult grass carp(450-1, 170 g) based on PWG, intestinal trypsin, and hepatopancreatic anti-hydroxyl radical activities were estimated to be 6.12 g/kg diet(21.80 g/kg protein),6.99 g/kg diet(24.90 g/kg protein) and 5.42 g/kg diet(19.31 g/kg protein), respectively, in the presence of 1.50 g cysteine/kg(5.35 g/kg protein).
基金supported by National Key R&D Program of China(2019YFD0900200)the Applied Basic Research Programs of ScienceTechnology Commission Foundation of Sichuan Province,China(2015JY0067).
文摘Background:Muscle is the complex and heterogeneous tissue,which comprises the primary edible part of the trunk of fish and mammals.Previous studies have shown that dietary isoleucine(Ile)exerts beneficial effects on growth in aquatic animals.However,there were limited studies regarding the benefits of Ile on fish muscle and their effects on flesh quality and muscle growth.Thus,this study was conducted to explore whether dietary Ile had affected flesh quality and muscle growth in hybrid bagrid catfish(Pelteobagrus vachelli♀×Leiocassis longirostris♂).Methods:A total of 630 hybrid fish,with an initial average body weight of 33.11±0.09 g,were randomly allotted into seven experimental groups with three replicates each,and respectively fed seven diets with 5.0,7.5,10.0,12.5,15.0,17.5,and 20.0 g Ile/kg diets for 8 weeks.Results:In the present study,we demonstrated that Ile significantly:(1)increased muscle protein and lipid contents and the frequency distribution of myofibers with≤20μm and≥50μm of diameter;(2)improved pH value,shear force,cathepsin B and L activities,hydroxyproline content,resilience,cohesiveness,and decreased cooking loss,lactate content,hardness,springiness,gumminess,and chewiness;(3)decreased reactive oxygen species(ROS),malondialdehyde(MDA),and protein carbonyl(PC)contents,GCLC and Keap1 mRNA levels,and up-regulated CuZnSOD,CAT,GPX1a,GST,and Nrf2 mRNA levels;(4)up-regulated the insulin-like growth factor 1,2(IGF-1,IGF-2),insulin-like growth factor 1 receptor(IGF-1R),proliferating cell nuclear antigen(PCNA),Myf5,Myod,Myog,Mrf4,and MyHC mRNA levels,and decreased MSTN mRNAlevel;(5)increased muscle protein deposition by activating AKT-TOR-S6K1 and AKT-FOXO3a signaling pathways.Conclusion:These results revealed that dietary Ile improved flesh quality,which might be due to increasing nutritional content,physicochemical,texture parameters,and antioxidant ability;promoting muscle growth by affecting myocytes hyperplasia and hypertrophy,and muscle protein deposition associated with protein synthesis and degradation signaling pathways.Finally,the quadratic regression analysis of chewiness,ROS,and protein contents against dietary Ile levels suggested that the optimal dietary Ile levels for hybrid bagrid catfish was estimated to be 14.19,12.36,and 12.78 g/kg diet,corresponding to 36.59,31.87,and 32.96 g/kg dietary protein,respectively.
基金National 973 Project of China(2014CB138600)National Department Public Benefit Research Foundation(Agriculture) of China (201003020)+1 种基金Science and Technology Support Programme of Sichuan Province of China(2014NZ0003)Major Scientific and Technological Achievement Transformation Project of Sichuan Province of China(2012NC0007 and 2013NC0045) for their financial support
文摘Background： This study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp （ Ctenopharyngodonidella）. Results： Weight gain, specific growth rate, feed intake and feed efficiency were significantly improved by dietary threonine （P 〈 0.05）. Intestinal activities of trypsin, chymotrypsin, alpha-amylase, lipase, alkaline phosphatase, y-glutamyl transpeptidase and creatine kinase took the similar trends. Contents of malondialdehyde and protein carbonyl in intestine and hepatopancreas were significantly decreased by dietary optimal threonine supplementation （P 〈 0.05）. Anti-superoxide anion capacity, anti-hydroxyl radical capacity, glutathione content and activities of superoxide dismutase, catalase and glutathione-S-transferase in intestine and hepatopancreas were enhanced by dietary threonine （P 〈 0.05）. Conclusions： Dietary threonine could improve growth, enhance digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp. The dietary threonine requirement of sub-adult grass carp （441.9-1,013.4 g） based on weight gain was 11.6 g/kg diet or 41.5 g/kg of dietary protein by quadratic regression analysis.
基金supported by the earmarked fund for CARS (CARS-45),and the National Key R&D Program of China (2019YFD0900200).
文摘D-mannose,essential for protein glycosylation,has been reported to have immunomodulatory effects and to maintain intestinal flora homeostasis.In addition to evaluating growth performance,we examined the impact of D-mannose on the structure of epithelial cells and apical junction complexes in the animal intestine.All 1800 grass carp(16.20±0.01 g)were randomly divided into six treatments with six replicates of 50 fish each and fed with six different levels of D-mannose(0.52,1.75,3.02,4.28,5.50 and 6.78 g/kg diet)for 70 d.The study revealed that D-mannose increased feed intake(P 0.05).D-mannose supplementation at 1.75 g/kg increased crude protein content in fish and lipid production value(P<0.05).D-mannose supplementation at 4.28 g/kg increased intestinal length,intestinal weight and fold height of grass carp compared to the control group(P<0.05).This improvement may be attributed to the phosphomannose isomerase(PMI)-mediated enhancement of glycolysis.This study found that D-mannose supplementation at 4.28 or 3.02 g/kg reduced serum diamine oxidase activity or D-lactate content(P<0.05)and improved cellular and intercellular structures for the first time.The improvement of cellular redox homeostasis involves alleviating endoplasmic reticulum(ER)stress through the inositol-requiring enzyme 1(IRE1),RNA-dependent protein kinase-like ER kinase(PERK),and activating transcription factor 6(ATF6)signaling pathways.The alleviation of ER stress may be linked to the phosphomannomutase(PMM)-mediated enhancement of protein glycosylation.In addition,ubiquitin-dependent[PTEN-induced putative kinase 1(PINK1)/Parkin]and ubiquitin-independent[BCL2-interacting protein 3-like(BNIP3L),BCL2-interacting protein 3(BNIP3),and FUN14 domain containing 1(FUNDC1)]mitophagy may play a role in maintaining cellular redox homeostasis.The enhancement of intercellular structures includes enhancing tight junction and adherent junction structures,which may be closely associated with the small Rho GTPase protein(RhoA)/the Rho-associated protein kinase(ROCK)signaling pathway.In conclusion,D-mannose improved intestinal cellular redox homeostasis associated with ER stress and mitophagy pathways,and enhanced intercellular structures related to tight junctions and adherent junctions.Furthermore,quadratic regression analysis of the PWG and intestinal reactive oxygen species content indicated that the optimal addition level of D-mannose for juvenile grass carp was 4.61 and 4.59 g/kg,respectively.
基金This research was financially supported by the National Key R&D Program of China(2019YFD0900200,2018YFD0900400)National Natural Science Foundation of China for Outstanding Youth Science Foundation(31922086)supported by the earmarked fund for CARS(CARS-45).
文摘Arecoline is an alkaloid with important pharmacological effects in the plant areca nut,which has been demonstrated to be an agonist of muscarinic receptors(M receptor).This study explored the influences of dietary arecoline on growth performance,intestinal digestion and absorption abilities,antioxidant capacity,and the apical junction complex(AJC)of adult grass carp(Ctenopharyngodon idella).Adult grass carp(608to 1512 g)were fed at 6 graded levels of dietary arecoline(0,0.5,1.0,1.5,2.0,and 2.5 mg/kg diet)for 9weeks.The results suggested that appropriate dietary supplementation of arecoline(1.0 mg/kg)increased growth parameters and intestinal growth in adult grass carp(P<0.05),enhanced digestion and absorption capacities(P<0.05),up-regulated muscarinic receptor 3(M3)mRNA level(P<0.05),increased the content of neuropeptide fish substance P(P<0.05),improved antioxidant capacity by activating the Keap1a/Nrf2signaling pathway(P<0.05),reduced intestinal mucosal permeability(P<0.05),and increased m RNA levels of tight junction(TJ)and adherent junction AJ-related proteins in fish by inhibiting the RhoA/ROCK signaling pathway(RhoA/ROCK/MLCK/NMII)(P<0.05).In addition,the appropriate arecoline supplementation for adult grass carp was determined to be 1.20,1.21,1.07,and 1.19 mg/kg based on percentage weight gain,lipase activity,serum diamine oxidase,and protein carbonyl,respectively.Overall,to the best of our knowledge,we investigated for the first time the effects and possible mechanisms of dietary arecoline on intestinal digestive and absorptive capacities and structural integrity in fish and evaluated the appropriate level of supplementation.
基金supported by the National Department Public Benefit Research Foundation(Agriculture)of China(201003020)Science and Technology Support Programme of Sichuan Province of China(2011NZ0071)Major Scientific and Technological Achievement Transformation Project of Sichuan Province of China(2012NC0007)
文摘Growth, muscle composition, meat quality characteristics and antioxidant capacity in muscle of young grass carp(Ctenopharyngodon idella)(initial weight 282.9 ± 3.3 g) fed graded levels of phosphorus(1.0,2.5, 3.8, 5.6, 7.8 and 9.5 g/kg diet) for 8 wk were investigated. Results indicated that percentage weight gain, feed intake, feed efficiency, serum phosphorus and alkaline phosphatase were improved with optimal phosphorus supplementations(P < 0.05). Muscle protein content and water holding capacity were significantly elevated, while moisture, lipid and ash contents were significantly decreased with dietary phosphorus to a certain level(P < 0.05). The meat shear force value and hydroxyproline content were not influenced by different levels of phosphorus. Muscle anti-hydroxyl radical, superoxide dismutase, catalase, glutathione S-transferase activities and glutathione content were significantly improved(P < 0.05). Conversely, anti-superoxide anion, glutathione reducase and glutathione peroxidase activities were decreased(P < 0.05) with dietary phosphorus to a certain level. These results indicated that suitable dietary phosphorus improved growth performance, meat quality and muscle antioxidant capacity. Dietary available phosphorus requirement of young grass carp for percentage weight gain was4.0 g/kg diet.
基金National Key R&D Program of China(2019YFD0900200,2018YFD0900400)National Natural Science Foundation of China for Outstanding Youth Science Foundation(31922086)+4 种基金the Young Top-Notch Talent Support Program of National Ten-Thousand Talents Program,the Earmarked Fund for China Agricultural Research System(CARS-45)Outstanding Talents and Innovative Team of Agricultural Scientific Research(Ministry of Agriculture)Foundation of Sichuan Youth Science and Technology Innovation Research Team(2017TD0002)Key Research and Development Plan in Sichuan Province(2018NZ0007)Supported by Sichuan Science and Technology Program(2019YFN0036).
文摘This dissertation was primarily focused on the immune response,inflammatory response and molecular mechanisms in the skin,head kidney and spleen of grown-up grass carp(Ctenopharyngodon idella).Six iso-nitrogen diets differing in lysine concentrations(5.6,8.5,11.6,14.4,17.5 and 20.7 g/kg)were fed to 540 grass carp(164.85±0.79 g)for 60 d.After that,grass carp were challenged by Aeromonas hydrophila for 6 d.This study revealed that lysine deficiency(1)suppressed the growth performa,nce of the fish and decreased their ability to resist skin lesion morbidity,(2)impaired the immune organ s immune response by decreasing the gene expressions of mucin,liver-expressed antimicrobial peptide(LEAP)-2B,β-defensin-1 and LEAP-2A and the production of antibacterial compounds of grown-up grass carp,and(3)aggravated the inflammatory response of immune organs in the fish by increasing the gene expressions of pro-inflammatory cytokines(interferon y2[IFN-γ2],tumor necrosis factorα[TNF-α],interleukin[IL]-15,IL-17D,IL-12p40,IL-6 and IL-8)and down-regulating anti-inflammatory cytokines(IL-11,transforming growth factorβ1[TGF-β1],IL-10 and IL-4/13A),which were tightly correlated with signal transducer and activator of transcription(STAT)1 and STAT3 signaling pathway,respectively.The different phenomenon in the skin,spleen and head kidney of fish may be correlated with the difference in gene subtype.In addition,using quadratic regression analysis of percent weight gain(PWG),skin lesion morbidity,and the lysozyme activities in the spleen and head kidney,the dietary lysine requirements for grown-up grass carp were estimated to be 13.58,13.51,14.56 and 14.18 g/kg,respectively.
基金financially supported by the National Department Public Benefit Research Foundation(Agriculture)of China(2010003020)
文摘The present study investigated the effect of body weight on body composition, digestive and absorptive capacity, transaminase activities in hepatopancreas and muscle, and plasma ammonia concentration of Jian carp(Cyprinus carpio var.Jian). A total of 750 Jian carps(18.0 ± 0.2 g) were randomly distributed into five groups with three replicates and fed the same diet for 56 days. Tissue and plasma samples were collected on days 14, 28,42, and 56. The results were used to develop a mathematical model for specific growth rate, body moisture and fat content, aspartate transaminase activity and alanine aminotransferase activity in hepatopancreas and muscle, plasma ammonia concentration, and trypsin, chymotrypsin, lipase, and amylase activities in hepatopancreas and intestine, activities of creatine kinase, Na^+/K^+-ATPase, alkaline phosphatase, and γ-glutamyl transpeptidase in intestine in Jian carp. There were linear relationships between natural logarithms of above indexes and body weight. The body moisture and fat content, digestive and absorptive enzymes activities, and transaminase activities showed negative allometry against body weight of Jian carp which were partial reasons to explain fish growth rate decreasing.
