不同蛋白质和脂肪水平饲料对拉氏幼鱼生长、体成分和免疫力的影响

为探讨不同蛋白质和脂肪水平饲料对拉氏幼鱼生长、体成分和免疫力的影响,以鱼粉和豆粕为蛋白质源,以豆油为脂肪源,配制蛋白质水平分别为23%、28%、33%、38%,脂肪水平分别为5%、8%、11%的12种半精制饲料,饲喂初始均重为(27.60±0.13)g的拉氏幼鱼。每种饲料投喂3个网箱(重复),每个网箱放养30尾试验鱼,进行60 d的养殖试验。结果表明:饲料蛋白质水平对拉氏幼鱼的增重率(WGR)、特定生长率(SGR)、蛋白质效率(PER)和饲料系数(FCR)有显著影响(P0.05),饲料脂肪水平对拉氏幼鱼的PER和FCR有显著影响(P0.05),但饲料蛋白质和脂肪水平对各生长性能指标无显著的交互作用(P0.05)。23%和28%蛋白质组的W GR和SGR显著高于33%和38%蛋白质组(P0.05),8%脂肪组的FCR显著低于11%脂肪组(P0.05),与5%脂肪组差异不显著(P0.05)。随着饲料中蛋白质水平的升高,全鱼粗蛋白质、粗脂肪和粗灰分含量都呈现出先升高后降低的趋势,在蛋白质水平为28%时达到最高值,而全鱼水分含量不受饲料蛋白质水平的影响(P0.05)。随着饲料中脂肪水平的升高,全鱼粗脂肪含量呈现升高的趋势,但8%和11%脂肪组差异不显著(P0.05)。嗜水气单胞菌攻毒48 h后,低、中蛋白质组(23%和28%蛋白质组)的存活率高于高蛋白质组(33%和38%蛋白质组),低脂肪组(5%脂肪组)的存活率高于其他2个脂肪组(8%和11%组)。综合以上研究结果得出,拉氏幼鱼饲料的适宜蛋能比为23.67~26.03 mg/k J,蛋白质水平为23%~28%,脂肪水平为5%~8%。

Effects of Different Protein and Lipid Level Diets on Growth,Body Composition and Immunity of Juvenile Phoxinus lagowskii

To evaluate the effects of different protein and lipid level diets on growth, body composition and im-munity of juvenile Phoxinus lagowskii, twelve practical diets were formulated to contain 23%, 28%, 33%, 38%of protein supplied with fish meal and soybean meal, and 5%, 8%, 11%of lipid supplied with soybean oil, respectively.Each diet was fed to 3 net cages for 60 d, and each net cage had 30 juvenile Phoxinus lagowskii with an initial average body weight of (27.60±0.13) g.The results showed that protein level signifi-cantly affected weight gain rate ( WGR) , special growth rate ( SGR) , protein efficiency ratio ( PER) and feed conversion rate ( FCR) ( P<0.05) , and lipid level significantly affected PER and FCR ( P<0.05) .No signifi-cant interactions between dietary protein and lipid levels existed for growth performance indices ( P>0.05). The WGR and SGR of fish in 23%and 28%protein groups were significantly higher than those in 33%and 38%groups ( P<0.05); whereas, the FCR of fish in 8%lipid group was significantly lower than that in 11%lipid group ( P<0.05) , but there was no significant difference between 8%and 5%lipid groups ( P>0.05) . With the increase of protein level, the crude protein, crude lipid and ash contents of whole body were firstly in-creased and then depressed, and the highest values of them were found when protein level was 28%.While moisture content of whole body was not significantly affected by dietary protein level ( P>0.05) .With the in-crease of lipid level, the crude lipid content of whole body showed an increasing trend, but no significant difference was found between 8%and 11%lipid groups ( P>0.05) .The survival rate in low and middle pro-tein groups ( 23%and 28%protein groups) was higher than that in high protein groups ( 33%and 38%protein groups) at 48 h after injecting Aeromonas hydrophila ( P<0.05) .The survival rate in low lipid group ( 5%lip-id group) was higher than that in other 2 groups ( 8%and 11%lipid groups) at 48 h after injecting Aeromonas hydrophila.In conclusion, the overall results in this study suggest that diet containing 23%to 28%protein and 5%to 8%lipid with a protein to energy ratio of 23.67 to 26.03 mg/kJ is suitable for juvenile Phoxinus lagowskii.