饲料脂肪水平和投喂频率对大黄鱼生长、体组成及脂肪沉积的影响

本实验以我国重要的海水养殖鱼类大黄鱼初始体质量(13.57±0.33)g]为研究对象,在浮式网箱中进行为期8周的摄食生长实验,探讨饲料脂肪水平和投喂频率对大黄鱼生长、体组成及脂肪沉积的影响。采用3×2双因子实验设计,其中饲料脂肪水平分别为9%、12%和15%,投喂频率分别为2次/天和1次/天。结果表明:投喂频率对大黄鱼特定生长率(SGR)和饲料效率(FER)均有显著影响(P<0.05),而饲料脂肪水平仅对FER有显著影响(P<0.05)。2次/天投喂组的大黄鱼末体质量和SGR均显著高于1次/天投喂组,而饲料效率显著低(P<0.05)。在2次/天投喂时,各个饲料脂肪水平对SGR和FER没有显著影响(P>0.05)。而在1次/天投喂时,随着饲料脂肪水平的提高,SGR和FER均显著提高(P<0.05)。2次/天投喂组的大黄鱼全鱼水分含量显著低于1次/天投喂组,而粗脂肪含量显著高(P<0.05)。大黄鱼全鱼粗脂肪含量随着饲料脂肪水平的增加而显著升高(P<0.05)。然而在1次/天投喂时,饲料脂肪水平未对全鱼体粗脂肪含量产生显著影响(P>0.05)。大黄鱼的肝脏和肌肉脂肪含量、肝体比(HSI)以及脏体比(VSI)受到了饲料脂肪水平的显著影响(P<0.05)。在2次/天投喂时,肝脏和肌肉脂肪含量、HSI以及VSI随饲料脂肪水平的升高而显著增加(P<0.05);而在1次/天投喂时,各个饲料脂肪组大黄鱼肝脏和肌肉脂肪含量、HSI以及VSI均无显著差异(P>0.05)。饲料脂肪水平和投喂频率仅对大黄鱼的生长、饲料效率的影响存在显著的交互作用(P<0.05),而对大黄鱼体组成、形态学指标以及肝脏和肌肉脂肪含量无显著的交互作用(P>0.05)。

Effects of dietary lipid level and feeding frequency on growth, body composition and lipid deposition in juvenile large yellow croaker(Larimichthys crocea)

An 8-week feeding trial in a 3×2 two-factorial design was conducted to study the effects of dietary lipid level(9%, 12% and 15%)and feeding frequency(one time or two times daily)on growth, body composition and lipid deposition in juvenile large yellow croakerinitial average weight(13.57±0.33)g].Compared with those fed once daily, fish fed two times daily had significantly higher final weight, specific growth rate(SGR), but lower feed efficiency ratio(FER)at each dietary lipid level(P < 0.05).When animals were fed two times daily, no significant difference was observed in the SGR and FER among dietary lipid levels(P > 0.05).However, SGR and FER of fish fed once daily increased significantly with the increase of dietary lipid contents(P < 0.05).Compared with that fed once daily, fish fed two times daily had significantly lower body moisture, but higher body crude lipid contents(P < 0.05), regardless of the dietary lipid levels.Body crude lipid contents of fish fed two times daily increased significantly with the increase of dietary lipid contents(P < 0.05).However, body crude lipid contents of fish fed once daily was not affected by dietary lipid contents(P > 0.05).Liver and muscle lipid contents, HSI and VSI were significantly affected by dietary lipid levels.When animals were fed two times daily, lipid contents in liver and muscle, HSI, and VSI increased significantly with the increase of dietary lipid level(P < 0.05).However, no significant difference was found in fish fed once daily(P > 0.05).Significant interactions of dietary lipid level and feeding frequency were only found in growth and FER(P < 0.05), but not in HSI, VSI, body composition and lipid contents in liver and muscle(P > 0.05).