Xu Qiyou

Effect of Dietary Alanyl-glutamine Supplementation on Growth Performance, Development of Intestinal Tract, Antioxidant Status and Plasma Non-specific Immunity of Young Mirror Carp (Cyprinus carpio L.)

Exogenous alanyl-glutamine (Aln-Gln) was evaluated for its effects on growth performance, intestinal structure and function, antioxidant status and non-specific immunity of young carp (Cyprinus carpio L.). Six diets supplemented with 0, 2.5, 5.0, 7.5, 10.0, or 15.0 g · kg−1 of Aln-Gln were fed to fish for 12 weeks. Supplementation with 7.5, 10.0, or 15.0 g · kg−1 of Aln-Gln significantly increased weight gain rate (WGR), protein efficiency ratio (PER), but feed conservation rate (FCR) and survival were not affected (P>0.05). The intestinal fold height and number, digestive enzyme, Na+, K+-ATPase activities was found to be significantly high (P<0.05) with increasing dietary Aln-Gln supplementation up to 7.5 g · kg−1, but there were no significant differences for Aln-Gln supplementation from 7.5 to 15.0 g · kg−1. The glutathione peroxidase (GPX) activity, glutathione (GSH), superoxide dismutase (SOD) activity increased and malondialdehyde (MDA) levels decreased significantly (P<0.05) in the intestine, hepatopancreas, plasma and muscles. The plasma complement-3 (C3) and complement-4 (C4) levels were significantly (P<0.05) improved at 5.0 g · kg−1 level and decreased when over 7.5 g · kg−1. The plasma lysozyme (LSZ) activity increased significantly (P<0.05) at 7.5, 10.0, or 15.0 g · kg−1 level. In summary, the results showed that Aln-Gln improved growth performance, development and function of the intestine, the activity of the antioxidant defense system and the plasma non-specific immunity of the carps. The optimal Aln-Gln level was 8.24 g · kg−1 diet for WGR based on broken-line regression model analysis.

Effects of Dietary Protein and Temperature on Growth and Flesh Quality of Songpu Mirror Carp

The study was conducted to demonstrate the effects of dietary protein and water temperature on growth and flesh quality of Songpu mirror carp (Cyprinus carpio) at an initial weight (165.24±5.08) g. Practical diets were formulated to contain five protein levels (29.12%, 31.46%, 34.49%, 38.17%, and 40.13%), and each diet was randomly assigned triplicate groups of 15 fishes at three temperatures (18°C, 22°C, and 26°C) in the recirculation system. Fishes were fed twice daily to apparent satiation for 56 days. Results indicated that fishes had higher weight gain rate at 22°C and 26°C than that at 18°C (P 0.05). Based on the weight gain rate, dietary protein level 29.12% could meet the requirement of the body at 18°C, 22°C, or 26°C. Crude protein, crude lipid, moisture and ash of muscle had no significant differences among those treatments (P>0.05). pH (after 24 h) of muscle was the highest at 18°C and the lowest at 22°C (P 0.05). No significant differences on shear force, water holding capacity, collagen, glycogen and lactate among all the treatments were found (P>0.05). It was concluded that when C. carpio fed to apparent satiation, the growth mainly depended upon temperature. Dietary protein could not significantly affect flesh quality, but temperature significantly affected pH of muscles. A dietary protein level 29.12% could meet the requirement of the body at 18°C, 22°C, or 26°C.

Requirement of essential amino acids for Hucho taimen juvenile.

Feeding experiments were conducted with protein diets(PD)and protein-free diets(FPD) for Hucho taimen(6.8-7.3 g),the diets(PD) was prepared by casein and gelatin as protein source with high biological values.The whole body amino acid composition was determined at the beginning and the end of the study.The requirements of Hucho taimen for essential amino acids(EAA) were determined based on the daily increment and daily maintenance requirement of each EAA in fish body.Fish were raised in tanks.There were 2 diets,each diet was randomly assigned to triplicate groups of 25 fish.During the experiment,the water temperature fluctuated from 23 ℃ to 25 ℃,and the dissolved oxygen was 6.4 mg/L to 7.5 mg/L.The experiment was conducted for 28 days.Compared with the FPD fish,the survival rate,the feed coefficient rate,the weight gain and crude lipid were increased significantly(P 0.05).The daily maintenance requirement of EAA(except trytophan) accounted for 20% to 30% of the sum of daily increment and daily maintenance requirement,and accounting for 54.52% of tryptophan.So the daily maintenance requirement of EAA can not be ignored.The minimum requirements of EAA needed to satisfy the requirements of Hucho taimen[g/(100 g body weight)/d]were:Threonine 0.040,Valine 0.041,Methionine 0.027,Isoleuline 0.034,Leucine 0.067,Phenylalanine 0.035,Lysine 0.068,Histidine 0.110,Arginine 0.050.When dietary protein level was 42%,the minimum contents of EAA in the dietary(g/kg diet) were as follows:Threonine 4.17,Valine 4.24,Methionine 2.84,Isoleuline 3.56,Leucine 6.99,Phenylalanine 3.64,Lysine 7.18,Histidine 11.53,Arginine 5.19 and Trytophan 0.76.

不同蛋白质源饲料中添加α-酮戊二酸对杂交鲟幼鱼肝脏谷氨酰胺含量、抗氧化能力及生长激素、胰岛素样生长因子-I基因表达的影响

本试验旨在研究不同蛋白质源饲料中添加α-酮戊二酸对杂交鲟（Acipenser schrenckii♀×Acipenser baeri♂）幼鱼肝脏谷氨酰胺（Gln）含量、抗氧化能力及生长激素（GH）、胰岛素样生长因子-Ⅰ（IGF-Ⅰ）基因表达的影响。分别以大豆浓缩蛋白和大豆浓缩蛋白+鱼粉为蛋白质源，设2个α-酮戊二酸（AKG）添加量（0和1%），配制4种试验饲料。选取平均体重为（7.65±0.04）g的杂交鲟幼鱼500尾，随机分为4组，每组5个重复，每个重复25尾，养殖周期为8周。结果表明：饲料中添加1% AKG显著提高肝脏Gln含量和谷氨酰氨合成酶（GS）活性（P＜0.05），对肝脏碱性磷酸酶（ALP）活性无显著影响（P>0.05）。蛋白质源对肝脏Gln含量、GS活性和ALP活性无显著影响（P>0.05），且蛋白质源和AKG添加量对肝脏Gln含量、GS活性和ALP活性无显著交互作用（P>0.05）。饲料中添加1% AKG显著降低肝脏丙二醛（MDA）含量，显著提高肝脏还原型谷胱甘肽（GSH）含量（P＜0.05）。与大豆浓缩蛋白+鱼粉作为蛋白质源相比，大豆浓缩蛋白作为蛋白质源显著提高肝脏GSH含量（P＜0.05）。蛋白质源和AKG添加量对肝脏超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性均无显著影响（P>0.05），且蛋白质源和AKG添加量对肝脏各抗氧化指标无显著交互作用（P>0.05）。饲料中添加1% AKG显著提高肝脏GH、IGF-Ⅰ基因的相对表达量（P＜0.05）。与大豆浓缩蛋白+鱼粉作为蛋白质源相比，大豆浓缩蛋白作为蛋白质源显著提高肝脏IGF-Ⅰ和GH基因的相对表达量（P＜0.05）。蛋白质源和AKG添加量对肝脏GH、IGF-Ⅰ基因的相对表达量无显著交互作用（P>0.05）。综上所述，杂交鲟幼鱼饲料中添加1% AKG可以通过提高肝脏中GS的活性进而提高Gln的含量，通过提高肝脏中GSH的含量进而降低MDA的含量，并可提高肝脏中生长相关基因GH、IGF-Ⅰ的表达。