饲料添加γ-氨基丁酸对黄颡鱼幼鱼生长、消化酶活性、lpl和tor基因表达的影响

Effects of dietary γ-aminobutyric acid on growth, digestive enzyme activities, lpl and tor gene expressions of juvenile yellow catfish (Pelteobagrus fulvidraco)

摘要:

目的 为研究饲料中添加γ-氨基丁酸(GABA)对黄颡鱼生长性能、血清生化、体组成、消化酶活性、脂蛋白脂肪酶(lpl)和雷帕霉素靶蛋白(tor)基因表达的影响。方法 实验以初始体重为(1.26±0.01) g的黄颡鱼幼鱼为研究对象，共选取480尾，随机分为4组，每组3个重复，分别投喂添加0（对照组）、50、100、200 mg/kg γ-氨基丁酸的4种等氮等脂饲料，实验周期为56 d。结果 ① 100 mg/kg组终末体重、增重率、特定生长率显著高于对照组和200 mg/kg组。100 mg/kg组的蛋白沉积率、脂肪沉积率、钙沉积率、磷沉积率显著高于对照组，饲料系数显著低于对照组。② 50 mg/kg组和100 mg/kg组肝体比显著高于对照组。200 mg/kg组灰分显著高于对照组。③各组间的血清总蛋白、甘油三酯、胆固醇、葡萄糖、尿素、谷草转氨酶、谷丙转氨酶无显著差异。④100 mg/kg组胃中脂肪酶显著高于其他组。100 mg/kg组肝胰腺中胰蛋白酶显著高于对照组。100 mg/kg组肠道中脂肪酶显著高于对照组和50 mg/kg组。⑤ 100 mg/kg组肝胰腺中tor基因表达量显著高于其他组。200 mg/kg组肠道中tor基因表达量显著高于其他组。100 mg/kg组肠道中lpl基因表达量显著高于其他组。结论 饲料中添加50~100 mg/kg γ-氨基丁酸显著提高了黄颡鱼的生长性能、营养沉积，添加100 mg/kg显著提高了消化酶活性、lpl和tor基因表达水平，结合生长、体组成、消化酶活性、lpl和tor基因表达水平综合评价，黄颡鱼饲料中GABA的适宜添加量为100 mg/kg。综上所述，饲料添加GABA改善了黄颡鱼生长性能、消化酶活性、体组成和营养保留，对黄颡鱼生长起到积极作用。

Abstract:

This experiment was conducted to investigate the effects of dietary γ-aminobutyric acid (GABA) on growth performance, serum biochemistry, body composition, digestive enzyme activity, lpl and tor gene expression of yellow catfish (Pelteobagrus fulvidraco). Four isonitrogenous and isolipidic diets were formulated to contain graded levels of GABA (0, 50, 100 and 200 mg/kg of diet) by adding GABA. A total of 480 fish with an initial average body weight of (1.26±0.01) g were randomly divided into four groups with three replicates of 40 fish each, and each group was fed with one of the diets for 56 d. The results showed that: (1) The final body weight, weight gain rate and specific growth rate of the 100 mg/kg group were significantly higher than those of the control group and 200 mg/kg group. The protein deposition rate, fat deposition rate, calcium deposition rate, and phosphorus deposition rate of the 100 mg/kg group were significantly higher than those of the control group, and the feed ratio was significantly lower than that of the control group. (2) The liver-body ratio of the 50 mg/kg group and 100 mg/kg group was significantly higher than that of the control group. Ash in the 200 mg/kg group was significantly higher than in the control group. (3) There were no significant differences in total protein, triglyceride, cholesterol, glucan, urea, aspartate aminotransferase and alanine aminotransferase among the three groups. (4) The gastric lipase in the 100 mg/kg group was significantly higher than in other groups. Trypsin in the hepatopancreas of the 100 mg/kg group was significantly higher than that of the control group. The 100 mg/kg group had a significantly higher level of intestinal lipase than the control and 50 mg/kg groups (P<0.05). (5) The tor gene expression in the hepatopancreas of the 100 mg/kg group was significantly higher than that of other groups. The tor gene expression in the intestine was significantly higher in the 200 mg/kg group than in the other groups. The intestinal lpl gene expression was significantly higher in the 100 mg/kg group than in the other groups. The study showed that the dietary addition of 50-100 mg/kg γ-aminobutyric acid significantly improved the growth performance and body composition of P. fulvidraco , and the dietary addition of 100 mg/kg significantly increased the digestive enzyme activity, lpl and tor gene expression levels. Combined with the comprehensive evaluation of growth, body composition, digestive enzyme activity, lpl and tor gene expression levels, the dietary addition of 50-100 mg/kg γ-aminobutyric acid significantly increased the digestive enzyme activity of P. fulvidraco. The optimal amount of GABA added to the diet of yellow catfish was 100 mg/kg. In summary, adding GABA to feed improved the growth performance, digestive enzyme activity, body composition and nutrient retention of P. fulvidraco, and played a positive role in the growth of P. fulvidraco.