Effects of dietary non‐protein energy source levels on growth performance,body composition and lipid metabolism in herbivorous grass carp (Ctenopharyngodon idella Val.)

A study was conducted to determine the effects of dietary non‐protein energy sources on growth, tissue lipid accumulation and lipid metabolism‐related genes expression of grass carp. Triplicate groups of fish were fed for 9 weeks on four isonitrogenous (300 g kg^?1) experimental diets with four levels of non‐protein energy (6.52 kJ g^?1 control diet, 5.32 kJ g^?1 high‐CEL diet, 8.46 kJ g^?1 high‐CHO diet and 8.53 kJ g^?1 high‐LIP diet respectively). Increasing dietary non‐protein energy source levels did not improve the growth, and the high‐CEL diet reduced the growth of grass carp. The high‐CHO diet tended to induce high hepatosomatic index, with high fat and glycogen content of liver. However, the high‐LIP diet caused the high mesenteric fat index, but did not increase liver fat. The mRNA abundance and activities of hepatic lipogenic enzymes were significantly increased in the high‐CHO diet group, whereas the opposite tendencies were observed in the high‐LIP diet group. Peroxisome proliferator‐actived receptor‐α (PPARα) in liver and PPARγ in mesenteric adipose tissue were up‐regulated in the high‐CEL diet group. Lipoprotein lipase (LPL) gene expression was significantly increased both in liver and mesenteric adipose tissue of fish fed the high‐LIP diet, while the LPL gene expression was up‐regulated in liver but down‐regulated in mesenteric adipose tissue of fish fed the high‐CEL diet. These findings suggest that an increase in dietary non‐protein energy sources alters the genes expression of lipid metabolism and increased lipid deposition.     

Growth of grass carp,Ctenopharyngodon idella Val., fed on two terrestrial fodder plants*

Abstract. Studies on the growth rate of grass carp, Ctenopharyngodon idella Val., fed on the leaves of two terrestrial fodder plants, lucerne, Medicago saliva L., and drumstick, Moringa pterygosperma, were carried out in cement cisterns. The grass carp had gained an average net weight of 177g and 111 g with an overall specific growth rate of 3·17 and 2·78% per day when fed on lucerne and drumstick leaves respectively in a period of 120 days. Feed conversion ratios were 13·9:1 in lucerne as against 10·2:1 in drumstick leaves. The percentage acceptance of drumstick leaves as feed was lower than lucerne. However, superior feed conversion was observed in fish fed on drumstick leaves. The average net production of grass carp fed on lucerne was higher than the drumstick leaves. Fish fed on drumstick leaves, however, gave better economical returns.     

草鱼蛋白质和脂肪代谢对饥饿胁迫的响应

实验选取平均体质量(31.86±1.47) g的草鱼, 随机分为2个实验组, 对照组(CG)和饥饿组(SG), 每组3个平行, 饥饿处理15、30、45和60 d, 测定饥饿对鱼体的生长、肌肉生化组成、血液生化指标以及蛋白质代谢的影响。结果表明: 饥饿组肥满度、脏体比、肝体比显著低于对照组。随着饥饿时间的延长, 草鱼肌肉中的水分含量逐渐增加, 脂肪和蛋白质含量呈现降低趋势, 脂肪含量在4个时期没有明显的差异(P>0.05), 水分和蛋白质含量分别呈现差异性增加和降低的趋势。血清总蛋白在饥饿15 d时与对照组没有明显的差异(P>0.05), 其后3个时期对照组显著高于饥饿组(P<0.05), 但饥饿组后3个时期趋于稳定。随着饥饿时间的延长, 白蛋白、总胆固醇和甘油三脂含量在4个时期与对照组都有明显变化(P<0.05), 饥饿组呈现先降低后升高再降低的波浪形变化。丙氨酸氨基转移酶活性在15、60 d时与对照组没有明显的变化(P>0.05), 在30 d时先降低, 45 d时显著升高(P<0.05)。随着饥饿时间的延长, 与对照组相比RNA︰DNA在肌肉中没有明显的差异(P>0.05), 在肝胰脏中与对照组呈现显著性差异, 随着时间的延长饥饿组呈现先降低后增高的趋势。谷氨酸脱氢酶活性在肌肉中于饥饿15 d时与对照组没有明显差异(P<0.05), 其后比对照组显著增加, 随着时间的延长饥饿组谷氨酸脱氢酶活性呈现上升的趋势; 在15、45 d时与对照组没有明显的变化(P>0.05), 在30、45 d时显著升高(P<0.05)。肝胰脏中谷氨酸脱氢酶活性在4个时期比对照组有显著的增加; 与肌肉相比, 肝胰脏和血清中谷氨酸脱氢酶活性是一种有效的反应蛋白质代谢的指标。草鱼对体内贮能物质(蛋白质和脂肪)的动用并不是简单地与饥饿时间呈线性相关, 而是出现周期性和阶段性起伏的变化。     

Dietary manganese requirement of juvenile grass carp (Ctenopharyngodon idella Val.) based on growth and tissue manganese concentration

A growth trial was conducted to estimate the optimum concentration of dietary Manganese (Mn) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.97 ± 0.05 g) were fed diets containing graded levels (4.0, 8.9, 13.8, 18.7, 23.6 and 33.3 mg kg^?1) of Mn for 8 weeks. Weight gain, specific growth rate and feed efficiency were linearly increased up to the 18.7 mg kg^?1 dietary Mn and then levelled off beyond this level. For body composition, lipid contents in whole body, muscle and liver decreased significantly with increasing dietary Mn level. Grass carp fed with dietary Mn levels higher than 19.7 mg kg^?1 significantly decreased condition factor. Whole body, vertebrae and scales mineralization were all affected significantly by dietary Mn levels. Mn contents in whole body, vertebrae and scales were linearly increased up to the 18.7 mg kg^?1 dietary Mn and then levelled off beyond this level. Contrarily, Ca and P contents seem to be inversely related to dietary Mn. However, dietary Mn levels had no significant effect on body Fe contents. Broken‐line analysis indicated that 20.6 mg kg^?1 dietary Mn was required for maximal tissue Mn storage, as well as satisfied for the optimal growth of juvenile grass carp.     

Partial characterization and activity distribution of proteases along the intestine of grass carp, Ctenopharyngodon idella (Val.)

A series of studies based on biochemical assays and electrophoretical observations has been conducted in order to investigate activity distributions and partially characterize various types of proteinases in the digestive tract of grass carp, Ctenopharyngodon idella (Val.). The casein digestion assays revealed that the presence of acidic proteinase had the highest activity at pH 2.5–3.0 and the alkaline proteinases at pH 10.0. The acidic proteinase activity distribution was found to decrease gradually from the oesophagus to the anus. Pepstatin A and EDTA inhibited the acidic proteinases activity. The SDS‐substrate‐PAGE showed that crude extraction of grass carp intestine contained an acidic proteinase active component with molecular mass of 28.5 ku. The substrate‐PAGE at neutral pH condition showed the presence of two acidic proteinase active components. The activity distribution of alkaline proteinase was found to slightly fluctuate along the intestine. And the whole intestine had very high activity. The inhibition assays and substrate specificity assays showed that trypsin was the main active component of the alkaline proteinases. The SDS‐substrate‐PAGE further showed that the crude extraction of grass carp intestine had four types of alkaline proteinase with molecular mass of 26.4, 30.8, 43.0 and 105.0 ku respectively. They were characterized to be trypsin (26.4, 30.8 and 43.0 ku) and un‐serine proteinase (105.0 ku) respectively. No chymotrypsin was detected.     

Dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idella Val.) based on growth and tissue potassium content

A growth trial was conducted to estimate the optimum concentration of dietary potassium (K) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.96 ± 0.06 g) were fed diets containing graded levels (0.87, 2.90, 5.37, 7.54, 9.87 and 12.4 g kg^?1) of K for 8 weeks. Final body weight, weight gain and feed efficiency and gill Na⁺‐K⁺ ATPase activity were highest in fish fed with 9.87 g kg^?1 dietary K and lowest in fish fed the basal diet (P < 0.05). The K contents in whole body and muscle were linearly increased up to the 9.87 g kg^?1 dietary K and then levelled off beyond this level, whereas in scales and vertebrae up to the 7.54 g kg^?1 dietary K (P < 0.05). However, dietary K levels had no significant effect on ash, Ca, P and Mg contents in whole body, scales, vertebrae or muscle. Analysis using polynomial regression of weight gain and gill Na⁺‐K⁺ ATPase activity and using the broken‐line regression of whole body K concentrations indicated that the adequate dietary K concentration for grass carp is about 9.45–9.99 g kg^?1 diet.     

不同脂肪源饲料对草鱼稚鱼生长的影响

不同脂肪源饲料对草鱼稚鱼生长的影响刘玮，徐萍，任本根，龚纲明（江西省科学院生物资源研究所，南昌３３００２９）关键词草鱼，鱼饲料，必采脂肪酸ＥＦＦＥＣＴＳＯＦＤＩＥＴＳＣＯＮＴＡＩＮＩＮＧＤＩＦＦＥＲＥＮＴＬＩＰＩＤＳＯＮＧＲＯＷＴＨＯＦＪＵＶＥＮＩＬ...     

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.     

Biochemical investigations on the protein-calorie availability in grass carp (Ctenopharyngodon idella Val.) from an aquatic weed (Ceratophyllum demersum Linn.) in the tropics

The submerged aquatic weed, Ceratophyllum demersum (Linn.), offered ad libitum to grass carp, Ctenopharyngodon idella (Val.), in two stages of development provided an average dry matter (DM) intake of 120.8 and 457.7 mg, digestible dry matter of 61.6 and 224.2 mg and digestible energy (DE) of 174.04 and 631.73 cal per day in small and large fingerlings respectively. The supplies of digestible protein (DP) and total digestible nutrients (TDN) were recorded to be 12 and 48 mg in small fingerlings and 42 and 172 mg in large fingerling stages. The ratio of the precentages of DP and TDN was found to be approximately 1:4 in both size groups. The weed, as feed, supported growth, the feed efficiency (FE) being 4.10 and 4.05 and protein efficiency ratio (PER) 1.89 and 1.91 in small and large fingerlings. The ‘feed merit’ of the aquatic weed was poor, which might be due to the lesser supply of digestible dry matter and protein-calorie to grass carp on voluntary intake.     

Growth,digestive and absorptive abilities and antioxidative capacity in the hepatopancreas and intestine of young grass carp (Ctenopharyngodon idellus Val.) fed graded levels of dietary manganese

To study the effects of manganese on growth performance, digestive and absorptive abilities, as well as the antioxidative capacity in the hepatopancreas and intestine, young grass carp (Ctenopharyngodon idellus Val.) (264 ± 1 g) were fed diets containing graded levels of manganese at 3.65 (control), 8.62, 13.48, 18.24, 22.97 and 27.86 mg kg^?1 diet for 8 weeks. Per cent weight gain (PWG) and feed intake were the poorest in fish fed the basal diet (P < 0.05). The activities of trypsin, lipase and alkaline phosphatase in the intestine were significantly enhanced with dietary manganese level at 13.48 mg kg^?1 diet (P < 0.05). Additionally, in the hepatopancreas and intestine, the protein carbonyl and malondialdehyde contents were the lowest in fish fed the diet with dietary manganese level at 13.48 mg kg^?1 diet (P < 0.05), while the anti‐hydroxyl radical capacities, manganese superoxide dismutase (MnSOD), glutathione peroxidase and glutathione‐S‐transferase activities were significantly enhanced with dietary manganese level at 13.48 mg kg^?1 diet (P < 0.05). Moreover, the catalase activity and glutathione content in the intestine were the highest in fish fed the diet with dietary manganese level at 18.24 mg kg^?1 diet (P < 0.05). These results indicated that optimum dietary manganese promoted growth, enhanced the digestive and absorptive abilities, and improved the antioxidative capacity in young grass carp. Based on the quadratic regression analysis for PWG and intestinal MnSOD activity, the manganese requirements for young grass carp with the initial body weight of 264 g were 16.91 and 18.21 mg kg^?1 diet respectively.     

饲料中添加氯化胆碱对草鱼成鱼生长、脂肪沉积和脂肪代谢酶活性的影响

选用初始体质量为(314.7±9.9)g的草鱼(Ctenophary ngodon idella)240尾,随机分成4组,每组3个重复,每重复20尾鱼,分别饲喂氯化胆碱添加量为0%(对照组)、0.2%、0.4%和0.6%(占饲料的质量分数)的4组饲料(粗蛋白、粗脂肪含量分别为28.01%和4.54%),胆碱实测含量分别为1010mg/kg、2516mg/kg、4184mg/kg、5852mg/kg,养殖77d后,考察氯化胆碱对草鱼成鱼生长性能、脂肪沉积及脂肪代谢酶活性的影响。结果表明,与对照组相比较,添加0.4%和0.6%氯化胆碱可显著提高鱼体增重率(P0.05)、特定生长率(P0.05),降低饲料系数(P0.05);添加0.2%～0.6%氯化胆碱可显著降低肝胰脏和全鱼脂肪含量(P0.05);添加0.4%和0.6%氯化胆碱,肌肉脂肪含量显著下降(P0.05);添加0.2%～0.6%氯化胆碱可显著提高血清甘油三酯和总胆固醇含量(P0.05),添加0.4%和0.6%氯化胆碱可显著降低肝胰脏甘油三酯和总胆固醇含量(P0.05);在脂肪代谢酶方面,添加0.2%～0.6%氯化胆碱可显著提高前肠脂肪酶活性(P0.05),添加0.6%氯化胆碱显著提高脂蛋白脂酶活性(P0.05),添加0.4%～0.6%氯化胆碱可显著升高肝脂酶和总脂酶活性(P0.05)。综上所述,适量添加胆碱能改善草鱼成鱼生长性能,提高饲料利用率,降低肝胰脏、全鱼和肌肉的脂肪含量,提高脂肪代谢酶活性。建议草鱼实用饲料中氯化胆碱添加量为0.4%～0.6%。     

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.     

Effects of dietary lipid source on fatty acid composition,expression of genes involved in lipid metabolism and antioxidant status of grass carp (Ctenopharyngodon idellus)

This study determined the effect of different lipid sources on growth, feed use, lipid metabolism and antioxidant status of grass carp (Ctenopharyngodon idellus). Juvenile fish (56.9 ± 4.7 g) were divided into four triplicate groups and fed diets containing 30 g/Kg of fish oil (FO), olive oil (OO), peanut oil (PO) and linseed oil (LO), respectively, for 60 days. Weight gain and feed conversion ratio were not significantly different between the dietary groups, but we observed changes in the fatty acid composition of muscle and intraperitoneal fat reflecting the fatty acid profile of the dietary lipid source. In the hepatopancreas, the highest mRNA level of fatty acid translocase CD36 (FAT/CD36) and carnitine palmitoyl transferase (CPT‐1A) was both observed in the FO group. In muscle, the expression of FAT/CD36 and CPT‐1A in the LO group was significantly higher than that in other groups, except for CPT‐1A in the PO group. In addition, the lowest and highest content of malondialdehyde in serum was observed in OO and FO groups, respectively. In summary, dietary lipid source altered the fatty acid composition, potential uptake (FAT/CD36) and oxidation (CPT‐1A) of fatty acids, and antioxidant status of grass carp, which should be considered when selecting a lipid source.     

草鱼肾细胞中双氟沙星代谢酶的酶动学

细胞色素P450s(CYPs)主要参与动物体内药物代谢。水产养殖中不合理的联合用药常会导致治疗失败,这通常与CYP活性的诱导有关。然而,关于鱼类CYP的诱导却知之甚少。为获得有关CYP诱导的信息,实验采用反相高效液相色谱(RP-HPLC)的方法测定了草鱼肾细胞(CIK)中CYPs的特异性诱导剂对双氟沙星(DIF)的代谢作用及酶动学分析。对照组和β-萘黄酮(BNF)诱导组的酶动学方程分别为1/V=0.1375×1/[S]+0.003和1/V=0.0245×1/[S]+0.0013。DIF与经BNF处理的CIK共孵育后,其代谢量增加了1倍,酶动学参数Clint和Vmax值分别增加了7倍和2倍。BNF是CYP1A的特异性诱导剂,因此,CYP1A可能参与了DIF的代谢。     

Studies on the growth rate of the grass carp Ctenopharyngodon idella (Valenciennes) fed on two aquatic weeds and a terrestrial grass

The growth rate of grass carp fed with hybrid napier was found to be nearly three times the growth attained with Hydrilla and about five times the growth attained with Ceratophyllum. The gross conversion ratio on fresh weight basis with hybrid napier was on average 26.99 : 1, while with Hydrilla and Ceratophyllum it was 93.98 : 1 and 128.43 : 1 respectively. The average net production of grass carp fed on hybrid napier worked out to 1579.3 kg/ha in 182 days.     

Protein requirements of grass carp fry (Ctenopharyngodon idella Val.)

The study was aimed at determining the optimal level of protein in a casein diet for grass carp. There was a linear relationship between the percentage of protein in the diet and the increase in fish protein and weight up to optimal levels of 41 and 43%, respectively. No further increase in fish protein or weight was noted with diets containing up to 64% of protein. However, if the optimal level was defined by the parabolic curve with the formula y = 36.21 + 6.238x ? 0.0593x², it would equal 52.6 ± 1.93%. Net protein utilization (NPU) values for experimental diets were obtained using a formula which took the maintenance nitrogen metabolism on a non-protein diet into consideration. This NPU formula was related to the length of the experiment, difference in the weight of fish at the beginning of the experiment, and growth of fish fed protein diets. Both protein efficiency ratio (PER) and NPU decreased with the increase in protein content of the diets according to the formulae y = 1.966?0.018x and $\text{y = 40.8?0.327x +}\text{302.6}\text{x}$, respectively.     

Effect of dietary bile acids on growth,body composition,lipid metabolism and microbiota in grass carp (Ctenopharyngodon idella)

To investigate the effects of dietary bile acids (BA) on growth and metabolism of lipid in grass carp (Ctenopharyngodon idella, C. idella) at high dietary lipid level, a basal diet (50 g kg^–1 lipid, 5L group) was supplemented with 20 g kg^–1 soybean oil (70 g kg^–1 lipid, 7L group); then, 0.06 g/kg BA was added in 7L diet to form the third diet (7L+BA group). The 96 C. idella (69.86 ± 6.24 g) were divided into three groups (duplicate per group) and fed three diets, respectively, for 8 weeks, and then, growth and lipid metabolism were determined. Results showed that growth of fish in 7L+BA group was significantly higher than 5L and 7L groups. The lipid level in whole body, hepatopancreas and muscle of grass carp in 7L+BA group were significantly lower than 7L group. Relative expression of lipid catabolism genes in hepatopancreas and muscle of 7L+BA group was significantly higher than 5L group. The amount of microbiota in intestine of fish in 7L+BA group was significantly higher than the other two groups. The present results indicated that BA in 7L diet improved growth of fish by increasing protein synthesizing, decreasing lipid content in fish body and by regulating amount of microbiota in intestine of fish.