饲料脂肪水平对奥尼罗非鱼幼鱼生长和血浆生化指标的影响

Effects of different lipid levels on growth and haematological biochemistry in juvenile tilapia(Oreochromis niloticus×Oreochromis aureus)

研究了奥尼罗非鱼幼鱼的生长及血浆生化指标与不同脂肪含量饲料间的关系。饲料脂肪水平为0%、2%、4%、6%、8%5个梯度组。结果表明,5组不同脂肪水平的饲料对奥尼罗非鱼幼鱼的成活率无显著性影响。随着饲料脂肪水平升高,奥尼罗非鱼幼鱼的增重率、肥满度和摄食量先上升后下降,而饲料系数则先下降后上升;肝脏重量、肝体比、肝脏与肌肉脂肪含量等4个指标均呈现逐渐升高的趋势。饲料脂肪水平与奥尼罗非鱼幼鱼血浆中的胆固醇、甘油三脂、低密度脂蛋白、极低密度脂蛋白呈负相关,与高密度脂蛋白呈正相关。随着饲料中脂肪含量的增加,试验鱼血浆中谷丙转氨酶、谷草转氨酶、乳酸脱氢酶、淀粉酶、碱性磷酸酶等活性逐渐升高。本研究条件下饲料脂肪水平超过6%容易导致奥尼罗非鱼幼鱼形成脂肪肝,对其摄食、体形特征、生长指标、相关组织脂肪含量以及血清中酶的活性等都有明显影响。

Juvenile tilapia were fed by five diets for 70 days to study the relationship between diet lipid levels and fatty liver disease. Lipid content levels included 0%, 2%, 4%, 6%, 8%. The results showed that five different diets didn＇t affect survival rate of juvenile tilapia significantly. Fish fed with 6% and 8% lipid levels showed symptom of fatty liver disease, including anorexia, swimming impotence, skin color becoming dark, body becoming thin and abdomen tumefaction etc. The weight gain rate and condition factor increased first and decreased later with the growing lipid content level. The feed conversion ratio decreased first and increased later contrarily. Liver weight, liver weight / body weight ratio, liver fat content and muscle fat content all increased gradually. The relationship between diet lipid level and cholesterol, triglyceride, low density lipoprotein-cholesterol, very low density lipoprotein-cholesterol was negative correlation. And the relationship between diet lipid level and high density lipoprotein-cholesterol was positive correlation. The values of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, amylase and alkaline phosphatase increased with the growing lipid content level. The values of bile acid increased together.