卵形鲳鲹对饲料中硒的需求量

Dietary Selenium Requirement of Golden Pompano(Trachinotus ovatus)

为确定卵形鲳鲹(Trachinotus ovatus)对饲料中硒的需求量,选取初始体重为(15.04±0.20)g的卵形鲳鲹450尾,随机分成6组,每组3个重复,每个重复25尾。分别投喂以亚硒酸钠(Na2SeO3)为硒源,硒含量分别为0.41、0.60、0.73、0.80、0.90和1.12mg/kg的等氮等脂饲料50d。结果显示,随着饲料中硒含量的增加,卵形鲳鲹的增重率和特定生长率先升高后趋于稳定,饲料系数变化趋势与之相反。饲料中硒含量对全鱼体成分无显著影响(P>0.05)。血清白蛋白和高密度脂蛋白胆固醇含量随饲料中硒含量的增加呈先升高后降低的趋势,而血清碱性磷酸酶活性先升高后保持稳定。饲料中添加硒可以显著提高血清谷胱甘肽过氧化物酶、超氧化物歧化酶和肝脏谷胱甘肽过氧化物酶、谷胱甘肽硫转移酶、谷胱甘肽还原酶、过氧化氢酶活性(P<0.05),随着饲料中硒含量的增加,其谷胱甘肽过氧化物酶、谷胱甘肽硫转移酶和过氧化氢酶活性呈先升高后稳定的趋势,而超氧化物歧化酶和谷胱甘肽还原酶活性呈先上升后下降的趋势。饲料中不同硒水平显著影响了卵形鲳鲹全鱼中的硒含量(P<0.05),且随着饲料中硒含量的增加先上升后趋于稳定。折线回归分析表明,以增重率、血清谷胱甘肽过氧化物酶活性和全鱼中硒含量为评价指标,卵形鲳鲹对饲料中硒的需求量分别为0.66、0.82和0.76 mg/kg。

To determine the optimal dietary selenium requirement of golden pompano(Trachinotus ovatus),a total of 450 fish with an initial body weight of(15.04±0.20)g were randomly assigned into 6 groups with 3 replicates per group and 25 fish per replicate.The fish were fed isonitrogenous and isolipidic diets with sodium selenite(Na2SeO3)as the selenium source for 50 days,which the selenium contents were 0.41,0.60,0.73,0.80,0.90 and 1.12 mg/kg,respectively.The results showed that weight gain rate and specific growth rate firstly increased and then remained stable with the increased dietary selenium content,while the feed conversion ratio had an opposite trend.No significant difference was found in the whole body composition(P>0.05).In serum,with the dietary selenium levels increasing,the contents of albumin and high density lipoprotein cholesterol firstly increased and then decreased,while the activity of alkaline phosphatase increased and then remained stable.The selenium in the feed had significant effects on the activities of glutathione peroxidase and superoxide dismutase in the serum,and glutathione peroxidase,glutathione S-transferase,glutathione reductase,catalase in the liver(P<0.05).As the dietary selenium levels increased,the activities of glutathione peroxidase,glutathione S-transferase and catalase firstly increased and then remained stable,whereas the activities of superoxide dismutase and glutathione reductase increased and then decreased.The selenium levels in feed significantly affected the selenium concentration in the whole body(P<0.05),as the dietary selenium content increased,whole body selenium concentration increased and then remained stable.Broken-line regression analysis based on the weight gain rate,serum glutathione peroxidase activity and whole body selenium concentration indicate that the optimal dietary selenium requirements for golden pompano are 0.66,0.82 and 0.76 mg/kg,respectively.