团头鲂两个生长阶段适宜蛋白/脂肪比的需要量

为了在相同配方体系下研究团头鲂两个生长阶段对饲料中蛋白/脂肪比的需要量,以初均重为(35.07±0.45)g(幼鱼)、(101.65±1.82)g(育成鱼)两个阶段的团头鲂为实验鱼,以秘鲁鱼粉、酪蛋白、大豆磷脂、豆油等原料配制半纯化饲料,在蛋白质26.93%~35.63%、脂肪10.24%~3.35%范围内,设置蛋白/脂肪比浓度分别为2.63、3.20、4.07、5.33、7.25和10.64共6组饲料。分别在池塘网箱养殖85和56 d,每组实验鱼设置4个平行。结果发现,随着饲料蛋白/脂肪比水平的增加,两个阶段的团头鲂体质量特定生长率(SGR)、蛋白质沉积率(PDR)、能量保留率(ERR)总体均呈现先上升后下降的趋势,均在饲料蛋白/脂肪比为5.33组达到最高;饲料系数(FCR)则呈先下降后上升的趋势,且均在饲料蛋白/脂肪比为5.33组达到最低。分别以实验鱼特定生长率(SGR)、饲料系数(FCR)、蛋白质沉积率(PDR)及能量保留率(ERR)作为评价指标,经过回归分析可知,幼鱼阶段团头鲂对饲料中蛋白/脂肪比需要量为6.09~7.58,适宜蛋白质水平为32.83%~33.98%、脂肪水平为4.48%~5.39%;在日均摄食量为5.06 g/100 g体质量的条件下,团头鲂幼鱼对饲料蛋白质每日需要量为1.66~1.72 g/100 g体质量,对饲料脂肪每日需要量为0.23~0.27 g/100 g体质量。育成鱼阶段团头鲂对饲料中蛋白/脂肪比需要量为4.03~4.34,适宜蛋白质水平为30.19%~30.72%、脂肪水平为7.07%~7.49%。在日均摄食量为3.61 g/100 g体质量的条件下,团头鲂育成鱼对饲料蛋白质每日需要量为1.09~1.11 g/100 g体质量,对饲料脂肪每日需要量为0.26~0.27 g/100 g体质量。

Research on the optimal protein to lipid(energy)ratio of blunt snout bream(Megalobrama amblycephala)in two growth stages

In order to estimate the appropriate protein to lipid(P/L)ratio of blunt snout bream(Megalobrama amblycephala)for semi-purified diet in different growth stages,2 feeding trials including diets with different P/L levels were conducted in the same formula system.Casein and Peruvian fish meal were used as the source of protein,while soybean oil and soy lecithin were used as lipid source.Dietary protein concentration ranged from 26.93% to 35.65%,and the lipid concentration range was correspondingly between 10.24% and 3.35%.The experimental diets contained 6 gradients,and P/L ratios were 2.63,3.20,4.07,5.33,7.25,10.64,respectively.Test one,two respectively used blunt snout bream with initial average weight of (35.07±0.45) g(juvenile stage),(101.65±1.82) g(premature stage),and were divided into 6 groups,each with 4 replicates.Experiments on the two tests were conducted in pond cages.Both the two tests were fed with the above-mentioned feed,precisely and on schedule.The feeding time were respectively 85 d,and 56 d.The results of 2 experiments showed that:with the feed P/L ratio gradually increased,the evaluation indexes such as the specific growth rate(SGR),the rate of protein deposition(PDR)and energy retention(ERR)increased first and then decreased.The feed conversion ratio(FCR)was the first decline after rising trend.The best growth appeared in the group of P/L 5.33.SGR,FCR,PDR and ERR were used as sensitive criterions for regression analysis,and it showed that different growth stages of blunt snout bream need different optimal P/L ratios:Appropriate P/L ratio of juvenile stage was 6.09-7.58,the optimal protein concentration was 32.83%-33.98% and lipid concentration was 4.48%-5.39%;In the conditions of the average daily intake of 5.06 g/100 g body weight,protein requirement was 1.66-1.72 g/100 g body weight,and lipid requirement was 0.23-0.27 g/100 g body weight for juvenile stage.Appropriate P/L ratio of premature stage was 4.03-4.34,the optimal protein concentration was 30.19%-30.72% and lipid concentration was 7.07%-7.49%.In the conditions of the average daily intake of 3.61 g/100 g body weight,protein requirement was 1.09-1.11 g/100 g body weight,and lipid requirement was 0.26-0.27 g/100 g body weight for premature stage.