【作者】 徐超； 李向飞； 田红艳； 徐维娜； 蒋广震； 刘文斌；

【Author】 Chao Xu;Xiang-Fei Li;Hong-Yan Tian;Wei-Na Xu;Guang-Zhen Jiang;Wen-Bin Liu;Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology,Nanjing Agricultural University;Wuxi Fisheries College,Nanjing Agricultural University;

【机构】 南京农业大学； 南京农业大学无锡渔业学院；

【摘要】 为了确定团头鲂(Megalobrama amblycephala)幼鱼的最适投喂量,选取初始体重为23.74±0.09g的团头鲂幼鱼840尾,随机分成6组,每组4个重复,每重复35尾鱼,分别投喂2%,3%,4%,5%,6%,7%(%为每日投喂量占试验鱼体重的比例)的商品饲料,饲养八周后测定其生长性能,肠道消化和吸收能力及内分泌功能。结果表明:当投喂量从2%升高到5%时,增重率显著增加(P<0.05)。蛋白效率比和氮、能保留显示出相似的变化趋势。除此之外,随投喂量的增加饲料转化率显著地升高(P<0.05)。投喂量对鱼体的水分、灰分和蛋白质含量无显著影响(P>0.05),但脂肪和能量在4%组显著高于其他实验组。同时,适中的投喂量水平(2.0%-4.0%BW/day)增强了肠道中脂肪酶、蛋白酶、Na+,K+-ATP酶、碱性磷酸酶和肌酸激酶的活性。此外,当投喂量从2%升高到5%和6%时,生长激素、胰岛素样生长因子-I、生长激素受体和神经肽的表达量水平显著增加(P<0.05);然而,瘦素和胆囊收缩素的表达量水平呈现出相反的变化趋势。根据对SGR折线回归的分析发现,团头鲂幼鱼的最适投喂量为4.57%BW/day。更多还原

【Abstract】 An 8-week feeding trial was conducted to investigate the optimal feeding rate for juvenile blunt snout bream(average initial weight: 23.74 ± 0.09 g) based on the results on growth performance, intestinal digestive and absorptive capabilities and endocrine functions. A total of 840 fish were randomly distributed into 24 cages and fed a commercial feed at six feeding rates ranging from 2.0% to 7.0% body weight(BW)/day. The results indicated that weight gain rate increased significantly(P<0.05) as feeding rates increased from 2.0% to 5.0% BW/day, but decreased with the further increasing feeding rates(P>0.05). Protein efficiency ratio and nitrogen and energy retention all showed a similar trend. However, feed conversion ratio increased significantly(P<0.05) with increasing feeding rates. Feeding rates have little effects(P>0.05) on whole-body moisture, ash and protein contents, but significantly(P<0.05) affect both lipid and energy contents with the highest values both observed in fish fed 4.0% BW/day. In addition, moderate ration sizes(2.0%-4.0% BW/day) resulted in the enhanced activities of intestinal enzymes, including lipase, protease, Na+, K+-ATPase, alkaline phosphatase and creatine kinase. Furthermore, the m RNA levels of growth hormone, insulin like growth factors-I, growth hormone receptor and neuropeptide all increased significantly(P<0.05) as feeding rates increased from 2.0% to 5.0% and 6.0% BW/day, but decreased significantly(P<0.05) with the further increasing feeding rates; whereas both leptin and cholecystokinin expressions showed an opposite trend. Based on the broken line regression analysis of SGR against feeding rates, the optimal feeding rate for juvenile blunt snout bream was estimated to be 4.57% BW/day.更多还原