Dietary available phosphorus requirement of juvenile grass carp (Ctenopharyngodon idella)

A growth trial was conducted to estimate the optimum concentration of dietary available phosphorus (P) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (5.59 ± 0.02 g) were fed diets containing graded levels (2.36, 4.27, 6.31, 8.36, 10.4 and 14.8 g kg^?1) of available P for 8 weeks. Grass carp fed with the P‐supplemented diets had significantly higher specific growth rate, weight gain, protein efficiency ratio and feed efficiency than fish fed with the basal diet. In whole‐body composition, protein content increased, while lipid content decreased with the increase in P level in diet (P < 0.05). Fish fed with the P‐supplemented diets had significantly higher whole body, vertebrae and scales mineralization (P < 0.05), but Ca/P ratios were not influenced. The blood chemistry analysis showed that dietary available P had distinct effects on P, Ca and Mg contents, as well as on the contents of triacylglycerol and total cholesterol. Broken‐line analysis indicated that 8.49 g kg^?1 dietary available P was required for maximal tissue storage and mineralization as well as optimal growth.     

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.     

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.     

草鱼肠系膜脂肪沉积量的测定与分析

为了精确且批量测定草鱼肠系膜脂肪（肠脂）沉积量，避免传统人工刮取称量方法耗时费力、量化粗糙等问题，本研究利用脂溶性染料油红O可特异性着色脂肪的特性，探索开发出一种便捷定量草鱼肠脂含量的新方法。测试发现，麻醉解剖200尾平均体质量约80 g的草鱼，取出整个内脏团简单处理并塞入PIT个体识别标记后，样品集中进行多聚甲醛固定、无水乙醇脱水、油红O染液定染，可在维持样品组织完整的基础上，实现肠脂组织的特异性、均一化批量染色处理。各染色样品再分别通过无水乙醇溶剂完全萃取，萃取液吸光度测定，并依据绘制的标准曲线（y = 0.0276x + 0.0403, R2 = 0.9997），即可精确获得个体肠脂沉积的相对含量，是以萃取出的油红O质量来表示。对比发现，样品肠脂组织染色-萃取量化结果与传统刮取称量数据保持了较高的相关性（n = 20，r = 0.80）。进一步的统计分析显示，对于同塘养殖体质量变异系数8.93%的草鱼群体（n = 200），萃取测定的肠脂沉积量变异系数达到24.49%，预示该性状具有丰富变异特征及遗传改良潜力。相关与聚类分析显示，肠脂沉积量与内脏质量相关性最高（r = 0.60），并且聚为一类，符合二者同属脏器关联指标的预期。多元线性回归分析显示，利用简单易测的形态指标只能解释肠脂沉积量的少量变异（R2 = 0.20），表明基于表型性状的拟合回归方程进行间接预测的效果不佳，直接测定是该性状精准量化的有效途径。本研究为草鱼体脂性状改良提供了一种性状精确测定方法。     

草鱼生长相关优势基因型的聚合效果分析

为研究草鱼(Ctenopharyngodon idella)生长性状相关分子标记聚合效果,本研究选择利用候选基因关联分析方法获得10个与生长性状相关SNP标记,分别位于草鱼载脂蛋白A-I-1基因(apoA-I-1)、丙酮酸激酶1型(PKL)、羧肽酶A1(CPA1)、柠檬酸合酶(CS)、醛缩酶B(Aldo-B)、生长催乳...     

Total aromatic amino acid requirement of juvenile grass carp (Ctenopharyngodon idella)

This experiment was conducted to investigate total aromatic amino acid requirement of juvenile grass carp Ctenopharyngodon idella. Six isonitrogenous and isoenergetic semipurified diets containing casein and gelatin with graded level of phenylalanine (7.8, 11.1, 14.4, 17.6, 21.7, 24.9 g kg^?1 DM) were formulated. Each diet was randomly assigned to triplicate group of 30 fish (3.58 ± 0.002 g, mean ± SEM) each tank for 8 weeks. The highest weight gain (WG, %), final body weight (g) and specific growth rate were recorded when phenylalanine level was 17.6 g kg^?1 of the diet. Fish muscle protein content, protein efficiency ratio (PER), feed conversion ratio and alanine aminotransferase were significantly affected by dietary phenylalanine level. The polynomial regression calculated using WG and PER indicated that the optimal dietary total aromatic amino acid (phenylalanine + tyrosine) requirement for juvenile grass carp was 24.4 g kg^?1 of the diet, corresponding to 65.9 g kg^?1 of dietary protein.     

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。     

膨化与非膨化饲料对大规格草鱼生长、体成分及部分生理生化指标影响

以商业配方为基础,配制膨化饲料和非膨化饲料饲喂初始体重（394.96±13.21g）草鱼（Ctenopharynodon idellus）120天,旨在对比这两种饲料对其生长、体成分及部分生理生化指标的影响。养殖试验在水库网箱（2m×2m×2m）中进行,每个处理组3个重复,每个重复30尾鱼。实验结果表明,与非膨化料组相比,膨化饲料组草鱼成活率和增重率显著提高（P＜0.05）,饵料系数显著降低（P＜0.05）,增重成本显著降低（P＜0.05）;肥满度、肝体比、脏体比和肠体比显著升高（P＜0.05）;鱼体血清血糖、甘油三酯、总固醇和过氧化氢酶显著升高（P＜0.05）;胰蛋白酶、淀粉酶和脂肪酶显著降低（P＜0.05）;肝脏谷丙转氨酶（GPT）显著升高,谷草转氨酶（GOT）显著降低（P＜0.05）;鱼体成分中水分和灰分无显著差异（P>0.05）,粗脂肪显著升高、粗蛋白显著降低（P＜0.05）。综上所述,与非膨化饲料相比,饲喂膨化饲料可使大规格草鱼生长性能和养殖效益提高,但会鱼体肥满度和粗脂肪含量提高。     

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.     

Effect of dietary lysine on growth,intestinal enzymes activities and antioxidant status of sub-adult grass carp (Ctenopharyngodon idella)

The dietary lysine requirement of sub-adult grass carp (460 ± 1.5 g) was assessed by feeding diets supplemented with grade levels of lysine (6.6, 8.5, 10.8, 12.9, 15.0 and 16.7 g kg^?1 diet) for 56 days. The test diets (28 % CP) contained fish meal, casein and gelatin as sources of intact protein, supplemented with crystalline amino acids. Weight gain (WG), feed intake and feed efficiency were significantly improved with increasing levels of lysine up to 12.9 g kg^?1 diet and thereafter declined (P < 0.05). Quadratic regression analysis of WG at 95 % maximum response indicated lysine requirement was 10.9 g kg^?1 diet. Activities of trypsin, chymotrypsin, lipase, Na⁺, K⁺-ATPase and alkaline phosphatase in intestine, creatine kinase activity in proximal and mid-intestine responded similar to WG (P < 0.05). In addition, lipid and protein oxidation decreased with increasing levels of lysine up to certain values and increased thereafter (P < 0.05); the anti-hydroxyl radical capacity, dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase (GST) activities and glutathione content were increased with increasing dietary lysine levels up to certain values in the detected tissues, except for hepatopancreatic GST. Requirement estimated on the basis of malondialdehyde content in intestine and hepatopancreas was 10.6 and 9.53 g lysine kg^?1 diet, respectively.     

南美白对虾和草金鱼、草鱼等池塘混养技术初探

为探索南美白对虾与鱼类的新型混养模式,于2020年5月—10月在上海市青浦区某合作社开展了南美白对虾和草金鱼、草鱼等的池塘混养试验.试验结果显示:0.33 hm2(5亩)试验池塘共收获南美白对虾2070 kg,平均规格83尾/kg,平均销售价格37.7元/kg,销售收入78040元;共收获草金鱼430 kg,平均规格2...     

Qualitative and quantitative strategies of thermal adaptation of grass carp (Ctenopharyngodon idella) cytoplasmic malate dehydrogenases

Malate dehydrogenase isozymes of grass carp,Ctenopharyngodon idella, were identified by mitochondrial preparation and thermal denaturation. The structural and kinetic characteristics of chromatographically separated thermostable and thermolabile cMDHs were different in (1) half-life at 42°C, 10 min and 24 h, respectively, (2) optimal substrate, oxaloacetate and malate, concentrations, and (3) the apparent Michaelis-Menten constants of NADH and oxaloacetate.Total MDH activity in white muscle of 11°C-acclimated fish was about twice that of the 30°C-acclimated group. In addition, the ratio of the thermostable to thermolabile cMDH activity in white muscle of 30°C-acclimated fish was significantly higher than that of 11°C-acclimated fish. These results suggest that temperature acclimation can induce temperature compensation in MDH activity and differential expression of thermostable and thermolabile cMDH isozymes in freshwater fish.     

草鱼Ⅱ型干扰素的单克隆抗体制备与鉴定

Ⅱ型干扰素,也称干扰素-γ（IFN-γ）,是参与辅助性T淋巴细胞1（Th1）免疫应答的关键细胞因子之一。研究表明,鱼类与哺乳类Ⅱ型干扰素同源,不同的是真骨鱼类（Teleost）有两种Ⅱ型干扰素,即IFN-γ和干扰素-γ相关因子（IFN-γrel）。迄今,对鱼类IFN-γ基因的表达规律和功能已有大量报道,而对IFN-γrel的研究尚不深入,产生IFN-γ和IFN-γrel的细胞来源不清楚,它们是否有功能差异也存在争议。为此,本研究构建原核表达质粒,在大肠杆菌DE3中表达草鱼（Ci）IFN-γ和CiIFN-γrel重组蛋白。实验结果显示,重组CiIFN-γ蛋白为可溶性蛋白,而CiIFN-γrel蛋白则不可溶。通过亲和层析和分子筛层析获得了高纯度CiIFN-γ和CiIFN-γrel重组蛋白,免疫小鼠制备了单克隆抗体。通过Western Blotting筛选获得4株特异性高、亲和力强的抗体,结果表明CiIFN-γ单克隆抗体与CiIFN-γrel没有交叉反应,反之亦然,其中FITC标记的两株抗体可用于免疫荧光和流式细胞术分析。此外,Western Blotting分析显示草鱼IFN-γ和IFN-γrel单克隆抗体不识别斑马鱼的同源Ⅱ型干扰素蛋白。本研究制备了首个IFN-γrel的单克隆抗体,为深入研究草鱼Ⅱ型干扰素的产生和生物学功能奠定基础。     

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.     

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.     

Comparisons of physiological and biochemical responses between milkfish (Chanos chanos) and grass carp (Ctenopharyngodon idella) to cold shock

Temporal changes in physiological parameters and enzyme activities related to carbohydrate metabolism in the milkfish (Chanos chanos) and the grass carp (Ctenopharyngodon idella) under cold shock at 15 °C were examined in order to better understand thermal compensation mechanisms of teleosts with different cold tolerances. The plasma glucose, lactate, and lipid contents as well as enzyme activities of citrate synthase, glucose-6-phosphate dehydrogenase, fructose-1,6-bisphosphatase, phosphorylase a, and lactate dehydrogenase at varying time intervals were monitored. The results show that changes in plasma glucose and lipid contents of the milkfish were more notable than those of the grass carp, but the elevation in plasma lactate contents in the grass carp occurred earlier and was much greater than that in the milkfish. Furthermore, changes in plasma glucose contents in the milkfish were correlated with the enzyme activities of phosphorylase a and fructose-1,6-bisphosphatase, but in the grass carp they were correlated with glucose-6-phosphate dehydrogenase and lactate dehydrogenase activities instead. In addition, the change in lactate dehydrogenase activity in the grass carp was more notable than those of other enzymes, but lactate dehydrogenase activities in the milkfish steadily decreased during cold compensation. The results demonstrate that the two species (milkfish and grass carp) respond quite differently to cold shock, and this may be related to their differences in cold tolerance.     

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.     

The feedback regulation of carbohydrates intake on food intake and appetite in grass carp (Ctenopharyngodon idella)

Fish Physiology and Biochemistry - Improving carbohydrate utilization can contribute to sustainability of aquaculture. In order to explore the feedback mechanism of glucose homeostasis in fish, one...