胆汁酸对草鱼(Ctenopharyngodon idellus)的生长性能、肌肉营养成分及消化酶活性的影响

Effects of Bile Acids on Growth Performance, Muscle Composition and Digestive Enzyme Activities of Ctenopharyngodon idellus

中文关键词: 草鱼  胆汁酸  生长性能  肌肉营养成分  消化酶活性

英文关键词: Ctenopharyngodon idellus  Bile acids  Growth performance  Muscle composition  Digestive enzyme activities

中文摘要:

      为研究胆汁酸对草鱼(Ctenopharyngodon idellus)生长性能、肌肉营养成分及消化酶活性的影响，选取初始体重为(13.11±0.58) g的草鱼540尾，随机分成6个实验组，分别饲喂胆汁酸添加量为0、75、150、225、300、375 mg/kg的等氮等能饲料(粗蛋白含量34.56%，总能13.54 kJ/g)，养殖时间为60 d。结果显示，随着胆汁酸浓度的增加，草鱼的增重率(WGR)、特定生长率(SGR)均呈先上升后下降的变化趋势，且均在胆汁酸添加量为300 mg/kg时达到最大值(分别为281.18%和2.23%/d)；饲料系数(FCR)则呈先下降后上升的趋势，且在胆汁酸添加水平为225 mg/kg时达最低值(1.26)。由二次回归方程可知，WGR、SGR、FCR等生产性能最优时，胆汁酸添加水平分别为222.15、265.00、242.86 mg/kg。实验鱼肌肉粗脂肪含量随胆汁酸添加量的增加而呈先下降后趋于稳定的变化趋势，粗蛋白质含量则呈先上升后降低的变化趋势。肠道各段及肝胰脏的消化酶活性均随胆汁酸添加量的增加呈先升高后下降的趋势。由此说明，适量的胆汁酸能提高草鱼生长性能，促进其脂肪代谢，降低机体脂肪沉积，改善其肌肉品质。本研究考虑到草鱼消化酶活性、肌肉品质及生长性能等因素，其饲料中胆汁酸适宜的添加量为222.15–265.00 mg/kg。

英文摘要:

      This experiment was conducted to study the effects of dietary bile acids levels on growth, muscle composition and digestive enzyme activities of juvenile Ctenopharyngodon idellus. Five hundred and forty healthy fish, mean body weight of (13.11±0.58) g, were randomly selected and divided into six groups, with three replicates in each group (30 fish/replicate). Each group was fed a diet containing bile acids level of either 0 (control group), 75 mg/kg, 150 mg/kg, 225 mg/kg, 300 mg/kg and 375 mg/kg for a period of 60 days. The results showed that the increase of dietary bile acids levels resulted in an initial elevation of weight gain rate (WGR), specific growth rate (SGR) and followed by a decrease in WGR and SGR when bile acids was 375 mg/kg in the diet. Furthermore, inclusion of 300 mg/kg dietary bile acids produced the highest WGR and SGR (281.18% and 2.23%/d respectively). By contrast, coupled with the increase of dietary bile acids, the feed conversion ratio (FCR) decreased initially and then increased. The FCR reached the lowest (1.26) level when the dietary bile acids level was 225 mg/kg. Based on square regression analysis, to optimize each growth parameter: WGR, SGR and FCR during C. idellus juvenile growth, the most appropriate inclusion levels of dietary bile acids were 222.15 mg/kg, 265.00 mg/kg and 242.86 mg/kg respectively. The crude lipid of muscle during the experiment decreased initially and then leveled out, while the crude protein of muscle increased with the increase of dietary bile acids levels (0–300 mg/kg) and then decreased. Similarly, digestive enzyme activities of segments intestinal and hepatopancreas had a tendency of increasing with the elevated bile acids inclusion and then leveled out at the end. Results indicated that certain range of dietary bile acids levels could promote growth, fat metabolism, reduce fat deposition in muscle and improve meat quality. In conclusion, the bile acids supplementary level of 222.15–265.00 mg/kg is recommended for growing juvenile C. idellus based on the consideration of digestive enzyme activities, meat quality and growth performance.