Comparison study of three compounds in Eucommia ulmoides on growth,flesh quality of grass carp (Ctenopharyngodon idella)

This study was conducted to compare the growth‐promoting and flesh quality ‐improving effects of three active compounds in Eucommia ulmoides (EU) on grass carp (Ctenopharyngodon idella). Four iso‐nitrogenous diets supplemented with 400 mg/kg inclusion of geniposidic acid (GA), chlorogenic acid (CGA), geniposide (GP) and their combination (GA:CGA:GP = 1:1:1, the mixture) were prepared and fed to grass carp (47.1 ± 0.6 g) for 75 days. The results indicated that weight gain was increased by 5.22%, and feed conversion ratio decreased by 0.07 by dietary CGA (p < 0.05). In flesh quality, the four supplementations significantly increased muscle fibre density, total collagen and alkaline‐insoluble collagen in skin, and reduced steaming loss of flesh. In addition, dietary CGA, GP and the active compounds mixture further increased total collagen, alkaline‐insoluble collagen and amino acid in flesh. In collagen genes expression, the expression of COL1A1 in muscle and skin was significantly promoted by the supplementation of GA, CGA, GP and their combination (p < 0.05). In conclusion, the supplementation of GA, CGA, GP and their combination improved the flesh quality of grass carp, and the growth was increased by CGA. CGA played more important roles in growth‐promoting and flesh quality‐improving effects than GP and GA.     

Effects of dietary chlorogenic acid on growth,flesh quality and serum biochemical indices of grass carp (Ctenopharyngodon idella)

The study was to investigate effects of dietary chlorogenic acid (CGA) on growth performance, flesh quality and serum biochemical indices of grass carp (95.1 ± 0.3 g) (Ctenopharyngodon idella) fed seven different diets, including control diet, Eucommia ulmoides (EU)‐supplemented diet (20 g kg^–1) and CGA‐supplemented diets containing 100, 200, 400, 600 and 800 mg/kg CGA. Contents of collagen and alkaline‐insoluble collagen in muscle and skin were significantly increased by dietary CGA and EU (p < .05). Total essential amino acids (TEAA) and total amino acids (TAA) in muscle of grass carp fed EU diet or 400, 600 and 800 mg/kg CGA diet were significantly higher than those of fish fed control diet and 100 and 200 mg/kg CGA diet (p < .05). Fish fed 200–800 mg/kg CGA showed significantly lower muscle crude lipid content than EU, control and 100 mg/kg CGA groups (p < .05). Fish fed CGA‐supplemented diets (100–800 mg/kg) had significantly higher muscle fibre density and lower muscle fibre diameter than control group (p < .05). In conclusion, supplementation of CGA improved flesh quality of grass carp, and supplemental level of CGA for improving flesh quality and growth was estimated to be 400 mg/kg diet.     

Dietary quercetin improved the growth,antioxidation, and flesh quality of grass carp (Ctenopharyngodon idella)

To investigate the effects of dietary quercetin on growth, antioxidation, and flesh quality of grass carp, Ctenopharyngodon idella, six diets were prepared with quercetin inclusion rates of 0 (control diet), 0.1, 0.2, 0.4, 0.6, and 0.8 g/kg. Grass carp with a body weight of 13.3 ± 0.1 g were fed with one of the six diets for 60 days. The weight gain (WG) showed a quadratic relationship with dietary quercetin levels; the supplementation of 0.4 g/kg quercetin significantly improved WG (+4.73%) and decreased feed conversion ratio (?0.06) (p < .05) when compared to those of the control group. The intestinal fat ratio was reduced by the addition of 0.2 or 0.4 g/kg of quercetin (p < .05), and serum activities of alkaline phosphatase and superoxide dismutase were increased by the addition of 0.4 and 0.6 g/kg of quercetin (p < .05). The inclusion of 0.2–0.6 g/kg of quercetin increased the contents of delicious amino acids and decreased the cooking loss of flesh (p < .05). Flesh collagen content was increased by the addition of 0.4–0.8 g/kg of quercetin (p < .05). In conclusion, dietary quercetin could improve the growth and enhance the antioxidation and flesh quality of grass carp, with the recommended supplemental level of quercetin was 0.37 g/kg.     

不同饲料原料对草鱼生长和肌肉品质的影响

分别以专用配合饲料、浸泡蚕豆、浸泡豌豆喂养体质量为(1540.9±57.5)g的草鱼(Cteno-pharyngodon idellus)90d,以考察不同原料对草鱼生长和肌肉品质的影响。结果表明,配合饲料组、浸泡蚕豆组和浸泡豌豆组草鱼的增重率分别为17.3%、13.7%和12.2%,饵料系数分别为5.00、4.09和5.08,三种原料对草鱼的脏体比、肝体比没有显著影响;与普通草鱼相比,三种原料组草鱼肌肉粗脂肪含量和肌肉失水率显著降低(P0.05),胶原蛋白含量和肌原纤维长度显著增加(P0.05)。上述结果表明,三种原料均可显著改善草鱼肌肉品质;与浸泡蚕豆组相比,专用配合饲料组显著提高了草鱼的生长性能。     

投饲蚕豆对草鱼生长和肌肉品质的影响

分别以配合饲料、浸泡蚕豆、发芽蚕豆喂养体质量为(530±20)g的草鱼(Ctenopharyngodon idellus)77 d,以考察投饲蚕豆对草鱼生长和肌肉品质的影响.结果表明,配合饲料组、浸泡蚕豆组和发芽蚕豆组草鱼的增重率分别为83.08%、55.01%和62.82%,饵料系数分别为2.03、2.96和2.70,投饲浸泡蚕豆或发芽蚕豆显著降低了草鱼增重率(P<0.05),增加了饲料系数(P<0.05):与配合饲料组相比,浸泡蚕豆组和发芽蚕豆组草鱼肌肉粗脂肪含量和肌肉失水率显著降低(P<0.05),胶原蛋白含量和肌纤维直径显著增加(P<0.05);肌肉游离氨基酸中呈味氨基酸的含量显著下降(P<0.05),而必需氨基酸含量显著增加(P<0.05);肌肉的硬度和黏性也有了显著提高(P<0.05).上述结果表明,饲喂蚕豆可显著改善草鱼肌肉品质,但同时降低了草鱼生长性能.[中国水产科学,2008,15(6):1 042-1 049]     

投喂蚕豆对草鱼生长及肌肉营养特性分析

分别用配合饲料、浸泡蚕豆和发芽蚕豆喂养平均体重(1000±20)g草鱼70d,分析投喂蚕豆对草鱼生长及肌肉营养的影响。结果表明,配合饲料组、浸泡蚕豆组和发芽蚕豆组的草鱼增重率分别为79.5%、40.32%和50.10%,饵料系数分别为2.11、4.78和4.31,投喂蚕豆降低了草鱼增重率(P<0.05),显著增加了饵料系数(P<0.05)。与配合饲料组相比,浸泡蚕豆组和发芽蚕豆组肌肉中粗脂肪和粗蛋白含量显著降低(P<0.05)。浸泡蚕豆组和发芽蚕豆组的必需氨基酸含量、鲜味氨基酸含量、氨基酸总量比配合饲料组显著提高(P<0.05)。投喂蚕豆降低了草鱼的生长性能,但是显著提高了草鱼肌肉品质。投喂发芽蚕豆的效果要优于投喂浸泡蚕豆。     

Depuration and starvation improves flesh quality of grass carp (Ctenopharyngodon idella)

Farmed grass carp (Ctenopharyngodon idella) at commercial size were transported to a natural lake for long‐term depuration while being food deprived. The effect of depuration time on the quality of fish fillets was investigated based on proximate compositions, textural parameters and flavour characteristics. The results showed that protein and lipids, but not carbohydrates, were the major source of energy for grass carp during depuration and starvation. Textural parameters that included hardness, springiness, gumminess and cohesiveness increased significantly after depuration, as well as water‐holding capacity of fish muscle. Taste and odour characteristics of grass carp muscle were obviously changed by depuration based on tests by an electronic tongue and nose. Off‐flavour volatile compounds, such as nonanal and hexanal, were reduced after depuration. In conclusion, the quality of grass carp fillets was improved effectively by long‐term depuration and food deprivation. More than 20 days of depuration was appropriate for the enhancement of grass carp quality before marketing.     

Effects of Dietary Geniposide on Growth,Flesh Quality,and Lipid Metabolism of Grass Carp,Ctenopharyngodon idella

The aim of this study was to investigate effects of dietary geniposide (GP) on growth performance, flesh quality, and lipid metabolism of grass carp, Ctenopharyngodon idella (95.2 ± 0.6 g), fed seven different diets, including a control diet; Eucommia ulmoides (EU)–supplemented diet (20 g/kg); and GP‐supplemented diets containing 100, 200, 400, 600, and 800 mg/kg GP, respectively. Weight gain rate was significantly improved (P < 0.05) and feed conversation ratio was significantly decreased (P < 0.05) by supplementation of EU. Grass carp fed 100–800 mg/kg GP‐supplemented diets showed significantly higher total collagen and alkaline‐insoluble collagen content in muscle than control (P < 0.05). Contents of total collagen and the alkaline‐insoluble collagen content in the skin of grass carp were significantly increased by dietary 600–800 mg/kg GP and EU (P < 0.05). Fish fed diets containing 600–800 mg/kg GP showed significantly lower muscle crude lipid content than the EU, control, and 100–400 mg/kg GP groups (P < 0.05). Fish fed 400–800 mg/kg GP diets had significantly higher muscle fiber density and lower muscle fiber diameter and serum triglyceride level than the control (P < 0.05). In conclusion, supplementation of GP could improve flesh quality, but not growth of grass carp. The supplemental level of GP for improving flesh quality was estimated to be a 400–600 mg/kg diet.     

Effects of dietary glutamate supplementation on growth performance,digestive enzyme activities and antioxidant capacity in intestine of grass carp (Ctenopharyngodon idella)

A 56‐day feeding trial was carried out to investigate the effect of dietary glutamate (Glu) supplementation on growth performance, digestive enzyme activities and intestinal antioxidant capacity of grass carp (Ctenopharyngodon idella). A total of 540 grass carp with average initial weight of 370 ± 3.8 g were fed three diets supplemented with 0, 8 and 16 g kg^?1 Glu. The per cent weight gain, specific growth rate, feed conversion ratio, and protein and lipid productive value were significantly improved by dietary Glu supplementation. Feed intake, condition factor, visceral somatic index and perivisceral fat ratio were not significantly different between dietary groups. Hepatosomatic index, intestinal somatic index, intestine length index, intestine protein content, trypsin activity in hepatopancreas and intestine, lipase activity in proximal and mid‐intestine (MI) and hepatopancreas, alkaline phosphatase and gamma‐glutamyl transpeptidase activities in intestine, creatine kinase activities in the mid‐ and distal intestine, intestinal folds height in the proximal and MI were significantly increased with increased Glu. Malondialdehyde and protein carbonyl contents in the intestine decreased with increased Glu. Superoxide anion and hydroxyl radical scavenging ability, glutathione reducase, catalase and total superoxide dismutase activities, and glutathione content in the intestine were increased with increased Glu. These results suggested that dietary Glu supplementation increased intestinal antioxidant capacity, digestive and absorptive ability and improved fish growth.     

Effects of dietary phosphorus and starch levels on growth performance,body composition and nutrient utilization of grass carp (Ctenopharyngodon idella Val.)

Six iso‐nitrogenous (410 g kg^?1) diets with three levels of total phosphorus (P4, P10 and P18 g kg^?1) and two levels of starch (S200 and S350 g kg^?1) were fed to triplicate groups of 30 fish to evaluate whether the high level of dietary phosphorus could improve the utilization of starch. Over 8‐week‐growth trial, best weight gain (WG) and specific growth rate (SGR) (P < 0.05) were observed in fish fed the P10/S200 and P18/S200 diets. WG and SGR significantly decreased as starch levels increased whereas for P4, while lipid contents of liver and whole body, hepatosomatic index and intraperitoneal fat ratio (IPF) significantly increased. These results suggested that high dietary starch will depress the growth performance and cause lipid accumulation. Within both starch levels, fish fed diet with P4 tended to produce lower (P < 0.05) WG and SGR, and had higher (P < 0.05) values of IPF. The whole body lipid, ash, calcium, phosphorus and iron contents were significantly affected by dietary phosphorus levels. Supplied phosphorus could improve the growth and decrease the whole body lipid, but there is no more effect after the phosphorus requirement was met at 10 g kg^?1.     

Effects of dietary Bacillus natto supplementation on growth performance and the growth‐related gene/microRNA expression in the skeletal muscle of grass carp (Ctenopharyngodon idella)

In this study, Bacillus natto NT was evaluated for use as a probiotic supplement in the feeds on the growth performance and the growth‐related genes' and microRNAs' (miRNAs) expression in the skeletal muscle of grass carp (Ctenopharyngodon idella). Grass carps (ave. wt. 43.96 ± 0.27 g) were fed diets supplemented with 1.87 × 10⁹ (Bn1), 3.73 × 10⁹ (Bn2), 5.60 × 10⁹ (Bn3), 7.47 × 10⁹ (Bn4) and 9.33 × 10⁹ (Bn5) B. natto NT cells per 100 g feed for 56 days. The control group (BnC) was not supplemented with the B. natto NT. The fish of Bn3, Bn4 and Bn5 groups displayed better growth performance and lower feed conversion ratio (FCR) than the other groups (P < 0.05). Compared with the fish of BnC group, miR‐1a, miR‐181a, miR‐23a and miR‐206 expressions increased (P < 0.05), and the myostatin and myocyte enhancer factor C (MEF2C) mRNAs were down‐regulated (P < 0.05) in the fish of Bn4 and Bn5 groups. The specific growth rate analysis and apparent expressional regulation of the growth‐related miRNAs and genes stimulated by B. natto suggest the potential application of B. natto in improving the growth performance on the grass carps.     

Effects of dietary glutamine supplementation on growth performance,antioxidant status and intestinal function in juvenile grass carp (Ctenopharyngodon idella)

Glutamine (Gln) is a conditionally essential free amino acid that has been widely used in aquaculture. The present study showed that appropriate levels of dietary Gln could significantly improve growth performance and increase lipase and trypsin activity, mucosal thickness (MT) and the number of lymphocytes. The levels of glycine (Gly) in the 6 g/kg Gln group, threonine (Thr) in the 12 g/kg group and lysine (Lys) in the 6 and 9 g/kg group were increased significantly, while glutamate (Glu) and serine (Ser) concentrations decreased significantly with increasing dietary Gln levels from 3 to 12 g/kg. Moreover, the 12 g/kg dietary Gln level could improve the concentration of malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GSH‐PX) and the total antioxidant capacity (T‐AOC). In addition, 3 g/kg Gln upregulated the gene expression of aminopeptidase N (APN), caudal‐related homeobox gene (CDX2), L‐type amino acid transporter 2 (LAT2), oligopeptide transporter 1 (PEPT1), specificity proteins 1 (SP1) and 3 (SP3), and peroxisome proliferator‐activated receptor α (PPAR‐α) but downregulated PPAR‐γ gene expression compared to that in the control group. Taken together, these findings suggest that Gln could improve the growth performance, antioxidant status and intestinal function of grass carp.     

Influence of dietary zinc on muscle composition,flesh quality and muscle antioxidant status of young grass carp (Ctenopharyngodon idella Val.)

This study was conducted to investigate graded levels of dietary zinc on the growth, flesh quality, and the relationship between flesh quality and muscle antioxidant status in young grass carp (Ctenopharyngodon idella Val.). Per cent weight gain (PWG), special growth rate (SGR), feed intake (FI), feed conversion ratio (FCR), anti‐hydroxy radical (AHR), superoxide dismutase (SOD), catalase (CAT), glutathione reducase (GR) activities and glutathione (GSH) content were significantly increased with increasing levels of Zn up to a point, and thereafter declined (P < 0.05). Serum zinc, alkaline phosphatase (AKP), muscle anti‐superoxide anion (ASA), glutathione peroxidase (GPx), glutathione‐S‐transferase (GST) activities and collagen content were significantly enhanced with dietary zinc levels up to a point (P < 0.05), beyond which it plateaued. Cooking loss, shear force and malondialdehyde (MDA) were significantly reduced with increasing level of zinc up to a point, and thereafter increased (P < 0.05). The pH value significantly increased with the increasing zinc levels, whereas the trend of protein carbonyl content was opposite. Flesh quality was positively related to the antioxidant enzymes activities in muscle of young grass carp. These results indicated that optimum zinc could improve growth, and improve flesh quality partly through improving muscle antioxidant status of young grass carp.     

Dietary zinc requirement of juvenile grass carp (Ctenopharyngodon idella) based on growth and mineralization

A growth trial was conducted to estimate the optimum requirement of dietary zinc (Zn) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.97 ± 0.05 g) were fed diets containing graded levels (13, 25, 34, 53, 89 and 135 mg kg^?1) of Zn for 8 weeks. Grass carp fed with dietary Zn levels higher than 34 mg kg^?1 significantly increased final body weight, weight gain and specific growth rate (P < 0.05). For body composition, fish fed with dietary Zn levels higher than 53 mg kg^?1 significantly decreased the moisture contents but increased the lipid contents of whole body and liver. Whole body, scales, vertebrae and liver mineralization were all affected significantly (P < 0.05) by dietary Zn levels. Zn contents in whole body, scales, vertebrae and plasma were linearly increased up to the 53 mg kg^?1 dietary Zn and then remained stable beyond this level. Grass carp fed with dietary Zn levels higher than 53 mg kg^?1 significantly increased triacyglyceride and total cholesterol contents and plasma alkaline phosphatase activity in plasma (P < 0.05). Broken‐line analysis indicated that 55.1 mg kg^?1 dietary Zn was required for maximal tissue storage and mineralization as well as optimal growth of grass carp.     

Dietary arginine requirement of juvenile grass carp Ctenopharyngodon idella (Valenciennes in Cuvier & Valenciennes, 1844)

This experiment was conducted to estimate the optimum requirement of arginine for juvenile grass carp Ctenopharyngodon idella. Six isonitrogenous (38%) and isoenergetics (16 MJ kg^?1) semi‐purified diets containing casein and gelatine with graded level of arginine (0.93, 1.20, 1.51, 1.84, 2.10 and 2.41 g 100 g^?1 DM) were formulated. Each diet was randomly assigned to triplicate groups of 25 fish each tank (initial weight: 3.84 ± 0.01) for 10 weeks. The highest weight gain (WG, %) was recorded when arginine level was 2.10% of the diet. Dietary arginine level higher than 1.84% significantly increased the protein contents of whole body. Whole body amino acid composition of juvenile grass carp was not significantly affected by the dietary arginine level. Plasma‐free arginine level was increased linearly with increasing of arginine level in the diets, and the plasma‐free ornithine level was significantly higher when the dietary arginine level was 2.41% compared with other groups. Quadratic model analysis of SGR data indicated that the minimum recommended dietary arginine requirement for grass carp was 2.17% of the diet, corresponding to 5.71% of dietary protein.     

The effect of dietary folic acid on flesh quality and muscle antioxidant status referring to Nrf2 signalling pathway in young grass carp (Ctenopharyngodon idella)

To investigate the effect of dietary folic acid on fish flesh quality, muscle antioxidant status and the potential mechanism, young grass carp (Ctenopharyngodon idella) were fed diets containing 0.10–3.12 mg/kg diet of folic acid for 8 weeks. The results showed that optimum folic acid increased muscle contents of protein, lipid, pH, shear force, amino acids, unsaturated fatty acids, hydroxyproline and glutathione, whereas contents of moisture, cooking loss, lactate and saturated fatty acids and cathepsin L activity showed an opposite trend (p < .05). Moreover, optimum folic acid elevated antioxidant enzyme activities and mRNA levels, as well as NF‐E2‐related factor 2 and casein kinase 2 mRNA levels (p < .05). However, optimum folic acid decreased reactive oxygen species (ROS) content and Kelch‐like ECH‐associated protein 1a (Keap1a) and Keap1b mRNA levels (p < .05). Interestingly, excess folic acid induced negative effects on above‐mentioned parameters (p < .05). Summarily, this study indicated that optimum folic acid improved fish flesh quality and muscle antioxidant system associated with Nrf2‐Keap1 pathway. Based on muscle cathepsin L activity and ROS content, the folic acid requirements for young grass carp were 1.87 and 1.80 mg/kg diet, respectively, regarding to the flesh quality and antioxidant status.     

Effect of dietary lipid level on growth, feed utilization and body composition by juvenile grass carp (Ctenopharyngodon idella)

A study was undertaken to determine the effect of dietary lipid level on growth, feed efficiency and body chemical composition of juvenile grass carp. Seven isonitrogenous diets (400 g kg^?1 crude protein) containing seven dietary lipid level (0, 20, 40, 60, 80, 100 and 120 g kg^?1 dry matter) were fed to triplicate groups of 40 fish with initial weight 6.52 g, for 70 days. No obvious and assured essential fatty acid deficiency symptom appeared in fish fed the lipid‐free diet. Excess dietary lipid level (100 and 120 g kg^?1) resulted in decreased feed intake. The best growth performance and feed utilization was observed in fish fed 20–40 g kg^?1 dietary lipid. The fish fed a lipid‐free diet had the lowest protein efficiency and protein retention. Growth performance and feed utilization increased with the increasing dietary lipid levels up to 40 g kg^?1 dietary lipid. Higher dietary level (above 40 g kg^?1) made growth performance and feed utilization decrease and no protein sparing effect was observed. Lipid retention decreased as dietary lipid level increased. Mesenteric fat index (MFI) increased, hepatosomatic index (HSI) decreased with dietary lipid level. The increased MFI and simultaneous decrease lipid retention can be explained by differences in growth. The effect of dietary lipid levels on the chemical composition of tissues was significant only for whole body and muscle. The excess lipid content of liver in all groups was regarded as a slight symptom of fatty liver, which was partly identified by microscopic structural study and lower plasma lipid indexes, comparing to the initial plasma data. In conclusion, grass carp is a fish with low energy requirement and excess dietary lipid level should be avoided.     

金丝桃素、绿原酸和硬葡聚糖对草鱼幼鱼生长及免疫功能的影响

在水温（25±2）℃下,分别在基础饲料中添加不同剂量的硬葡聚糖（0．2％,G1组;0．4％,G2组）绿原酸（0．04％,G3组;0．08％,G4组）和金丝桃素（0．066％,G5组;0．132％,G6组）,连续投喂放在1．0m×0．5m×1．0m网箱内、体质量110±5g的草鱼（Ctenopharyngodon idellus）幼鱼35d,以未添加者为对照组,探讨三种添加剂对草鱼幼鱼生长和免疫功能的影响。结果表明,三种添加济对草鱼幼鱼增重率和特定生长率均影响不显著,当饲料中添加0．08％的绿原酸时,草鱼幼鱼末体质量和肝体比显著增加（P〈0．05）;三种添加剂都可显著提高碱性磷酸酶活性,其中以添加0．08％的绿原酸效果最好,添加剂各组间碱性磷酸酶活性差异不显著（P〉0．05）;0．132％金丝桃素组的草鱼血清超氧化物歧化酶活性显著高于对照组,其它试验组与对照组差异不显著;饲料中添加0．2％硬葡聚糖可显著提高草鱼幼鱼血清溶菌酶含量（P〈0．05）;三种添加剂对草鱼幼鱼血清中丙二醛的含量影响不显著（P〉0．05）。     

草鱼C1qC基因的克隆及表达分析

为了研究C1qC基因在草鱼(Ctenopharyngodon idella)免疫过程中所起的作用,利用RT-PCR和RACE方法克隆获得了C1qC基因cDNA全长序列,经序列分析表明,所克隆的C1qC cDNA全长为916 bp,包括开放阅读框(open reading frame,ORF)735 bp,5′端非编码区(untranslated region,UTR)89 bp和3′端非编码区(UTR)92 bp。735 bp的ORF共编码244个氨基酸,相对分子量为26 162.5 U。同源性分析表明,草鱼与斑马鱼(Danio rerio)的相似度最高,达到71%。经草鱼呼肠孤病毒(grass carp reovirus,GCRV)诱导后,草鱼C1qC基因在鳃、皮肤、肌肉、肝、中肾、心脏、头肾等组织中的mRNA表达水平均显著上调。在草鱼胚胎发育的各个阶段都能检测到C1qC mRNA的表达,说明该基因可能在草鱼胚胎和鱼苗的免疫反应和早期发育中起重要作用。本研究将为今后在草鱼免疫功能方面深入研究C1qC基因提供基础资料。