摘要
在基础饲料中添加不同梯度的蛋氨酸钴（Co Met）,制成钴含量分别为0.30 mg/kg、1.75 mg/kg、3.42 mg/kg、6.73 mg/kg、12.56 mg/kg、25.50 mg/kg的6组实验饲料（记作D1、D2、D3、D4、D5、D6组）,饲喂初始体重（60.02±0.42）g的珍珠龙胆石斑鱼（Epinephelus lanceolatu♂×E.fuscoguttatus♀）幼鱼8周,研究蛋氨酸钴对其生长、矿物元素沉积和肝脏酶活力的影响。结果表明,随饲料中蛋氨酸钴含量的增加,实验鱼增重率（WGR）和特定生长率（SGR）均先升后降,D3组显著高于其他组（P〈0.05）;饲料系数（FCR）先降后升,D3、D4组显著低于其他组（P〈0.05）。蛋氨酸钴对肌肉水分和灰分含量均无显著影响（P〉0.05）;粗蛋白含量呈降低的趋势,D5、D6组显著低于D1~D4组（P〈0.05）,但二者之间无显著差异（P〉0.05）;粗脂肪含量先降后升,D4组显著低于其他组（P〈0.05）,D6组显著高于其他组（P〈0.05）。肝脏、肠道、脊椎骨及肌肉钴含量均随饲料中蛋氨酸钴的增加而显著增加（P〈0.05）;全鱼钴沉积率呈先升高后平稳的趋势,D1组显著低于其他组（P〈0.05）。肝脏铁、铜和锌含量随饲料中蛋氨酸钴的增加呈先升后降的趋势;肝脏锰含量显著降低（P〈0.05）。随饲料中蛋氨酸钴的增加,肝脏谷胱甘肽过氧化物酶（GSH-PX）活力先升后降,D5组显著高于其他组（P〈0.05）;D5、D6组肝脏丙二醛（MDA）含量显著低于其他组（P〈0.05）;肝脏精氨酸酶（DArg）活力随饲料中蛋氨酸钴的增加显著升高（P〈0.05）;D4~D6组肝脏羧肽酶A（CPA）活力显著高于D1~D3组（P〈0.05）,但三组之间无显著差异（P〉0.05）。本实验条件下,以SGR为评价指标,经折线回归分析,珍珠龙胆石斑鱼幼鱼对钴的最适需求量为3.25 mg/kg,即53.28 mg（Co Met）/kg（饲料）。
Cobalt （Co） is one of the essential elements for fish, with various biological functions, including in growth promotion, blood production, reproduction, and immunity. In this study, we evaluated the effects of dietary cobalt methionine （CoMet） on growth performance, mineral deposition, and hepatic enzyme activities in the juvenile pearl gentian grouper （Epinephelus lanceolatus ♂× E. fuscoguttatus ♀）. Six extruded isonitrogenous and isoenergetic diets （51% crude protein and 13% crude lipid） were formulated by supplementing the basal diet with CoMet, providing actual Co contents of 0.30, 1.75, 3.42, 6.73, 12.56, or 25.50 mg/kg diet, which were fed to groups designated D1, D2, D3, D4, D5, and D6, respectively. Each diet was randomly assigned to triplicate groups of 20 juveniles （initial weight, 60.02±0.42 g）. The experiment was conducted for 8 weeks in plastic cylindrical tanks in an indoor recirculated feeding system. The weight gain rate （WGR） and specific growth rate （SGR） of the juveniles both increased and then decreased with higher CoMet levels, and both were significantly higher in the D3 group than in the other groups （P〈0.05）. The feed conversion rate declined with dietary CoMet level decrease but increased with dietatry CoMet increase, and the lowest feed conversion rate was observed in the D3 group. There were no significant differences in the moisture or ash contents of the muscle among the treatment groups （P〉0.05）. The crude protein content of the muscle was clearly reduced by dietary CoMet, and was significantly lower in the D5 and D6 groups than in the other groups （P〈0.05）, whereas it did not differ in groups D5 and D6 （P〉0.05）. The muscle of fish fed the D6 diet had the highest crude lipid content （P〈0.05）, and the muscle offish fed the D4 diet had the lowest crude lipid content （P〈0.05）. The Co contents of the liver, intestine, vertebrae, and muscle were significantly increased with CoMet supplementation （P〈0.05）. The Co d
出处
《中国水产科学》
CAS
CSCD
北大核心
2016年第3期574-583,共10页
Journal of Fishery Sciences of China
基金
国家海洋公益性行业专项(201205025
201205028)
国家海洋生物产业水生动物营养与饲料研发创新示范平台项目(201501005)
国家自然科学基金青年科学基金项目(31201973)
关键词
珍珠龙胆石斑鱼
蛋氨酸钴
生长
微量元素
酶活力
pearl gentian grouper
cobalt methionine
growth
trace element
enzyme activity
