许氏平鲉幼鱼对饲料中精氨酸需求量的研究

本实验旨在研究饲料中不同精氨酸含量对许氏平鲉(Sebastes schlegelii)幼鱼生长、体组成、血清生化指标及肝脏相关酶活力的影响，以确定其对精氨酸的最适需求量。在基础饲料中添加晶体L-精氨酸配制精氨酸含量分别为1.39%、1.83%、2.34%、2.80%、3.39%和4.08%的6组等氮等脂的实验饲料(D1、D2、D3、D4、D5和D6)。饲喂初始体重为(12.03±0.03) g的许氏平鲉幼鱼56 d。结果显示，随着饲料中精氨酸含量的升高，实验鱼的增重率(WGR)、特定生长率(SGR)和蛋白质效率(PER)均先升高后降低，在D3组达到最高值，显著高于D1、D2、D5和D6组(P<0.05)；饲料系数(FCR)先降低后升高，在D3组达到最低值，显著低于D1、D2、D5和D6组(P<0.05)；D3组肌肉粗蛋白含量最高且显著高于其他组(P<0.05)，肌肉水分、粗脂肪、粗灰分和全鱼水分、粗蛋白、粗脂肪和粗灰分无显著性差异；全鱼和肌肉总必需氨基酸(ΣEAA)和总氨基酸(ΣAA)含量均先升高后降低；血清谷丙转氨酶(ALT)活力先降低后升高，D3组显著小于其他组(P<0.05)，一氧化氮(NO)含量先升高后降低，D3和D4组显著高于其他组(P<0.05)，尿素氮(BUN)含量先升高后趋于平缓；肝脏超氧化物歧化酶(SOD)、溶菌酶(LZM)、总一氧化氮合酶(TNOS)和诱导型一氧化氮合酶(iNOS)活力均先升高后降低，丙二醛(MDA)含量先降低后升高，D2~D4组显著低于D1、D5和D6组(P<0.05)。在本研究条件下，以WGR为评价指标，经一元二次回归分析得出，许氏平鲉幼鱼(12.03±0.03) g]饲料中精氨酸适宜需求量为2.78% (占5.56%饲料粗蛋白)。

Dietary Arginine Requirement of Juvenile Rockfish (Sebastes schlegelii)

An eight week experiment was conducted to investigate the effects of dietary arginine on the growth performance, body composition, serum biochemical parameters, and liver enzyme activities of juvenile Korean rockfish (Sebastes schlegelii) and to determine the dietary arginine requirement. Six isonitrogenous and isolipidic diets were formulated to contain graded dietary arginine (1.5%, 1.0%, 2.0%, 2.5%, 3.5%, and 4.5% dry diet). The crystalline amino acid mixture was supplemented in the test diets to simulate the amino acid profile of the juvenile S. schlegelii muscle protein, except for arginine. The initial average body weight of the juvenile S. schlegelii was (12.03±0.03) g. The results showed that, with increasing dietary arginine, the weight gain rate (WGR), specific growth rate, and protein efficiency ratio significantly increased at first and then decreased; these were significantly higher in the 2.34% and 2.80% arginine diets than the 1.39% arginine diet, but the feed conversion ratio showed the opposite trend. The crude protein content of the muscle was significantly affected by dietary arginine levels and was significantly higher in the 2.34% arginine diet than the other groups. The concentrations of both total essential amino acids and total amino acids first increased and then decreased in the whole fish and muscle tissues. The levels of albumin and nitrogen oxide in the serum significantly increased first and then decreased (P<0.05), whereas the serum blood urea nitrogen content first increased and then plateaued. However, the glutamic pyruvic transaminase in the serum significantly decreased at first and then increased, and was significantly lower in the 2.34% arginine diet than in other groups. The activities of superoxide dismutase, lysozyme, aspartate aminotransferase, total antioxidant enzymes, alkaline phosphatase, total nitric oxide synthase, and inducible nitric oxide synthase in the liver first significantly increased and then decreased, whereas the content of malonaldehyde first significantly decreased and then increased. With WGR as an evaluation index, the optimal arginine requirement of juvenile S. schlegelii was 2.78% (5.56% dietary protein).