云纹石斑鱼幼鱼对高能低氮饲料的适应性

Adaptation of Juvenile Epinephelus moara Fed Diets with High Energy and Low Nitrogen

为研究云纹石斑鱼幼鱼对高能低氮饲料的适应性,采用双因素试验设计,设蛋白质水平分别为35%(P35)、40%(P40)、45%(P45),脂肪水平分别为9%(L9)、12%(L12)、15%(L15),共配制9种试验饲料,依次标记为P35L9、P35L12、P35L15、P40L9、P40L12、P40L15、P45L9、P45L12、P45L15。选取初始平均体重为27.09 g的云纹石斑鱼幼鱼810尾,随机分为9组,每组设置3个重复,每个重复30尾,饲喂9周后测定其生长性能、肌肉营养组成和血清生化指标。结果表明:1)随着饲料蛋白质和脂肪水平的升高,云纹石斑鱼幼鱼的增重率和特定生长率先升高后降低,且饲料蛋白质和脂肪水平间有显著的交互作用(P<0.05),以P40L12组的增重率和特定生长率最高,分别为184.59%和1.49%/d;饲料系数、摄食率和蛋白质效率随着饲料蛋白质和脂肪水平的升高逐渐降低,且饲料蛋白质与脂肪水平对其有显著的交互作用(P<0.05);各组试验鱼成活率差异不显著(P>0.05)。2)饲料脂肪水平对肌肉粗脂肪含量的影响显著(P<0.05),最高值出现在L15组;饲料蛋白质、脂肪水平及其交互作用对肌肉粗蛋白质、水分和粗灰分的含量无显著影响(P>0.05)。3)血清中谷草转氨酶活性随饲料脂肪水平的升高而升高,L15组活性最高(121.98 U/L),与L9组存在显著差异(P<0.05);血清中谷丙转氨酶活性随饲料蛋白质水平的升高而升高,在P45组出现最高值(89.79 U/L);血清中总胆固醇含量和饲料脂肪水平呈显著的正相关(P<0.05),但不受饲料蛋白质水平的显著影响(P>0.05);血清中尿素氮和饲料蛋白质水平呈显著的负相关(P<0.05),P35组尿素氮含量为1.97 mmol/L,显著高于其他蛋白质水平组(P<0.05);饲料蛋白质、脂肪水平及其交互作用对血清中碱性磷酸酶活性及低密度脂蛋白胆固醇、高密度脂蛋白胆固醇及甘油三酯的含量无显著影响(P>0.05)。结果显示:在本试验条件下,饲料蛋白质水平为40%和脂肪水平为12%时云纹石斑鱼幼鱼的生长效果最好,饲料的利用率较高。

A 9-week trial was carried out to assess the adaptation of juvenile Epinephelus moara fed diets with high energy and low nitrogen.Nine practical diets were formulated to contain three protein levels[35%（P35）,40%（P40） and 45%（P45）]and three lipid levels[9%（L9）,12%（L12） and 15%（L15）]by two-factor experimental design,and in turn marked P35L9,P35L12,P35L15,P40L9,P40L12,P40L15,P45L9,P45L12 and P45L15.Eight hundred and ten juvenile Epinephelus moara with the average initial body weight of 27.09 g were randomly divided in 9 groups with 3 replicates,and each replicate had 30 fish.After feeding for 9 weeks,the growth performance,muscle nutritive composition and serum biochemical parameters of juvenile Epinephelus moara were measured.The results showed as follows：1） weight gain rate（WGR）and specific growth rate（SGR） were firstly increased and then decreased with the increase of dietary protein and lipid levels,and significant interactions between dietary protein and lipid levels were observed in WGR and SGR（P〈0.05）.The highest values of WGR and SGR were all found in P40L12 group which were 184.59%and 1.49%/d,respectively.Feed conversion ratio（FCR）,protein efficiency ratio（PER） and feed intake（FI） reduced gradually with the increase of dietary protein and lipid levels,and significant interactions between dietary protein and lipid levels were observed in them（P〈0.05）.Survival rate showed no significant difference among 9 groups（P〉0.05）.2） Muscle crude lipid content was significantly affected by dietary lipid level（P〈0.05）,and the highest value was observed in L15 group） dietary protein,lipid levels and their interaction had no significant effects on the contents of crude protein,moisture and ash of muscle（P〉0.05）.3） serum glutamic oxalacetic transaminase（GOT） activity was increased with increase dietary lipid level,and the highest value（121.98 U/L） appeared in L15 group,which had significant difference compared with L9 group（P〈0.05）;serum glutamic pyruvic transaminase（GPT） activity was increased with increase dietary protein level,and the highest value（89.79 U/L） appeared in P45 group;serum total cholesterol content was positively correlated with dietary lipid level（P〈0.05）,whereas it was not significantly affected by dietary protein level（P〈0.05）;serum urea nitrogen（UN） content was negatively correlated with dietary protein level（P〈0.05）,and it had the highest value（1.97 mmol/L） in P35 group,which significantly higher than that in other protein level groups（P〈0.05）;dietary protein,lipid levels and their interaction had no significant differences on serum alkaline phosphatase（AKP） activity and the contents of triglyceride（TG）,high-density lipoprotein（HDLC） and low-density lipoprotein（LDL-C）（P〉0.05）.According to these results,juvenile Epinephelus moara fed the diet with 40%protein level and 12%lipid level has the best growth effect,and the utilization ratio of feed is higher under the condition of this experiment.