饲料中蛋白质含量对花生长和消化的影响

Effects of dietary protein levels on growth and digestibility in fish Hemibarbus maculatus

在水温（22±3）℃下，将体重5．90g的花[鱼骨]Hemibarbus maculatus放养在网箱（60cm×60cm×120cm）中，投喂蛋白质含量分别为25．0％、31．0％、37．0％、43．0％、49．0％（质量分数，下同）的5种饲料，饲养100d。结果表明：饲料中蛋白质含量为33．42％-38．79％时，鱼的特定生长率和蛋白质效率最高，饲料系数最低（P〈0．05）；蛋白质的含量从25．0％升到37．0％时，鱼肌肉中蛋白质含量（53．18％升到57．97％）达最大值；当饲料中蛋白质含量从25．0％升到31．0％时，鱼肌肉中脂肪含量（14．36％升至17．10％）达最大值；当饲料蛋白质含量为49．0％时，鱼肌肉中蛋白质（54．14％）和脂肪（15．37％）含量降低。当饲料中蛋白质含量由25．0％升到37．0％和43．0％时，肠道中脂肪酶和蛋白酶的活性先升高，后降低；而饲料中蛋白质含量对肠道淀粉酶活性的影响不显著（P〉0．05）。花[鱼骨]由鱼种至食用鱼阶段，饲料中蛋白质含量为38．79％-33．42％较适宜。

Juvenile Hemibarbus maculatus weighting 5.90 g were stocked into 15 net cages of each 60 cm × 60 cm × 120 cm and fed diets containing 25.0%, 31.0%, 37.0%, 43.0% and 49. 0% crude protein at （22 ± 3） ℃ for 100 days. The results showed that the fish fed the diets containing 33.42% -38.79% protein had the maximal special growth rate （SGR）, and protein efficiency ratio （PER） and the minimal food conversion ratio（FCR） （P 〈 0. 05）. There were the maximal protein levels （from 53. 18% to 57.97% ） in the muscles in the fish fed the diets containing the protein levels varying from 25.0% to 37.0%. There were the maximal lipid levels （ from 14. 36% to 17.10% ） in the muscles in the fish fed the diets containing the protein rangingfrom 25.0% to 31.0%. However, the fish fed the diet containing 49. 0% protein had decrease in protein （54. 14% ） and lipid （ 15.37% ） levels in the muscles. The first increase and then decrease in activities of protease and lipase were observed in the fish fed the diets containing protein varying from 25.0% to 37.0% and 43.0%, respectively. There were no significant differences in the activities of amylase in the digestive tracts in the fish fed the diets containing different protein levels. It is recommended that 38.79% - 33.42% dietary protein be of optimum for juvenile and marketable Hemibarbus maculates.