额尔齐斯河银鲫对饲料蛋白质需要量的研究

Study on dietary protein requirement of carassius auratus gibelio bloch in the Irtysh river

为了解额尔齐斯河银鲫(Carassius auratus gibelio Bloch)对饲料蛋白质的适宜需要量,本试验配制了6种不同蛋白质水平(27%、31%、35%、39%、43%、47%)的实用配合饲料,饲养初始体质量(52.95±3.22)g额河银鲫8周,分析了饲料蛋白质水平对其生长性能、饲料利用、体成分及血清生化指标的影响。结果显示:饲料蛋白质水平未显著影响成活率、肥满度和脏体比,但肝体比随饲料蛋白质水平的升高而逐渐降低,至蛋白质水平为47%时肝体比下降至3.42%。随饲料蛋白质水平的升高,试验鱼的末体质量、增重率和特定增长率逐渐升高后稳定在较高水平,蛋白质水平27%组与31%组差异不显著,但显著低于其他组;饲料系数逐渐下降后稳定在较低水平,蛋白质水平27%组和31%组显著高于其余各组;蛋白质效率和蛋白质保留率均表现出先不显著的升高而后逐渐降低的趋势,蛋白质水平35%组最高且显著高于47%组。在鱼体成分中,全鱼水分、灰分含量和肌肉粗蛋白含量随饲料蛋白质水平的升高而升高,但全鱼粗脂肪和肌肉水分含量随饲料蛋白质水平的升高而降低。在血清生化指标中,仅谷草转氨酶活性随饲料蛋白质水平的升高表现出先升高后降低的趋势。以特定生长率和饲料系数为评价指标,通过折线回归分析,得出试验鱼的饲料蛋白质需要量为34.6%和35.4%。

A total of six practical diets were formulatedwith different protein levels(27%,31%,35%,39%,43%and 47%)to investigate the dietary protein requirement of gibel carp(carassius auratus gibelio Bloch)in the Irtysh river.The fish(initial body weight 52.95±3.22 g)were fed the experimental diets for 8 weeks,the effects of dietary protein level on growth performance,feed utilization,body composition and serum biochemical indexes were analyzed.The results showed that dietary protein levels did not affect the survival rate,condition factor and viscerosomatic index,the hepatosomatic index gradually decreased with the increase of dietary protein level.The hepatosomatic index decreased to 3.42%when dietary protein level reached 47%.With the increase of dietary protein levels,the final body weight,weight gain rateandspecific growth rateof experimental fish showed a trend of increasing at first and then stabilized at a higher level.There were no significant difference between 27%group and 31%group.However,the final body weight,weight gain rate and specific growth rate of 27%group and 31%group were significantly lower than other groups.The feed conversion rate decreased gradually and stabilized at a lower level.The protein level of 27%group and 31%group were significantly higher than other groups.With the increase of dietary protein level,protein efficiency and protein retention rate of experimental fish did not increase significantly at first and then gradually decreased.The protein level of 35%group was the highest and significantly higher than 47%group.The contents of whole body moisture and ash,and muscle crude protein were increased with the dietary protein levels increasing.However,the whole body crude lipid and muscle moisture were decreased with the dietary protein levels increasing.Among the serum biochemical indexes,only the activity of aspartate aminotransferase showed a trend of increasing at first and then decreasing with the dietary protein level increasing.Based on the specific growth rate and feed conversion ratio,the dietary protein requirements of fish were 34.6%and 35.4%by broken line regression analysis.