以初始体重(1.6±0.18)mg的大黄鱼(Pseudosciaena crocea Richardson)稚鱼(12日龄)为实验对象,在室内水族箱中进行为期30d的摄食生长实验。以白鱼粉为主要蛋白源,通过双酶水解制得鱼肉水解蛋白(FPH,粗蛋白72%),分别以鱼肉水解蛋白替代0%、25%、50%和75%的鱼粉蛋白配制出4种等氮等能的实验微颗粒饲料,同时,以生物饵料(冷藏桡足类)为对照组,研究饲料中不同鱼肉水解蛋白对大黄鱼存活、生长以及体组成的影响。实验结果表明,当以FPH替代25%的鱼粉蛋白时,其存活率(32.6%)显著高于其余的各替代水平(P〈0.05),但与生物饵料组(33.2%)之间差异不显著(P〉0.05)。随着饲料中FPH替代水平的升高,实验鱼的特定生长率(SGR)逐渐下降,但当替代水平为25%时,其SGR(10.5%day^-1)与全鱼粉组(10.4%day^-1)和生物饵料组(10.3%day^-1)之间没有出现显著差异(P〉0.05)。体成分分析结果表明随着饲料中FPH替代水平的升高,鱼体干物质、粗蛋白和粗脂肪含量均有显著降低(P〈0.05)的趋势。脂肪酸的分析结果也表明随着饲料中FPH升高,鱼体的二十碳五烯酸(EPA)、二十二碳六烯酸(DHA)含量均有显著降低的趋势(P〈0.05)。本研究结果表明以适宜水平的鱼肉水解蛋白替代鱼粉蛋白,将显著提高大黄鱼稚鱼存活率,可能有利于其生长,而过高的替代水平则起到阻碍作用。在大黄鱼微颗粒饲料中FPH替代鱼粉蛋白在0%~25%之间是否能更有利于大黄鱼稚鱼的存活、生长和发育尚有待于进一步研究。
A 30-day feeding experiment was conducted in tanks to investigate the effects of dietary fish protein hydrolysate (FPH) levels on the growth, survival and body composition of large yellow croaker ( Pseudosciaena crocea Richardson) larvae [ 12 days after hatchery, with inidal average weight ( 1.6 ± 0.18) mg]. FPH was produced by hydrolyzing fish with two protease. Five practical diets were used in the present study. Four microdiets (MD), with FPH replacing 0%, 25%, 50% and 75% of fish meal protein, were formulated. The frozen copepods were used as a control diet. The results showed that dietary FPH levels significantly influenced the growth, survival and body composition of large yellow croaker larvae. With increasing dietary FPH, the specific growth rates (SGRs) and survival of large yellow croaker significantly decreased ( P 〈0.05). While the survival (32.6%) in fish fed the diet with 25 % FPH replacing fish meal protein was significantly higher than other groups ( P 〈 0.05), but was not significantly different from that of the control diet group ( P 〉 0.05). The SGR (9.0% day^-1) in fish fed the diet with 25% FPH replacing fish meal protein was not significantly different from the 0% FPH group. The body composition analysis showed that with increasing FPH, the whole body dry matter, crude protein and crude lipid significantly decreased ( P 〈 0.05). Analysis of whole body fatty acid showed that with increasing dietary FPH, DHA and EPA in fish body significantly decreased ( P 〈 0.05 ). Results from this study indicated that a proper replacement of fish meal with FPH in the microdiet of large yellow croaker larvae will improve survival, and excessive FPH will result in poor growth and low survival of the larvae.