摘要
为探讨酵母硒和茶多酚对团头鲂幼鱼生长、肌肉营养品质和抗病力的影响,以初始体质量为(1.75±0.01)g的团头鲂为研究对象,采用二因素三水平实验设计在基础饲料(Se含量为0.08 mg/kg)中分别添加酵母硒(按硒计)3个水平(分别为0、0.25和0.50 mg/kg),茶多酚3个水平(分别为0、50和100 mg/kg),进行排列组合后得到9组饲料。连续投喂60 d后,检测团头鲂生长、肌肉营养成分、血液和肝脏生化指标以及生长相关基因的表达水平,并统计团头鲂感染嗜水气单胞菌后的成活率,以综合评价酵母硒和茶多酚对团头鲂的作用效果。结果表明:饲料中添加酵母硒和茶多酚均显著提高了团头鲂幼鱼的增重率、特定生长率以及肌肉中粗蛋白含量,降低了饵料系数(P<0.05),酵母硒和茶多酚交互作用也显著提高增重率和特定生长率,显著降低饵料系数(P<0.05),表现出协同增效作用。酵母硒和茶多酚均可以通过诱导下丘脑—垂体—生长轴相关基因表达来提高生长性能,不同的是,酵母硒主要上调脑垂体Ma GH和肝脏Ma IGF-I基因的mRNA表达,茶多酚主要上调脑垂体Ma GHR2基因而显著下调肝脏Ma IGF-I基因的mRNA表达(P<0.05),结果表明,饲料中添加酵母硒显著提高团头鲂血清中GH和IGF-Ⅰ的含量(P<0.05),而茶多酚显著降低血清中IGF-Ⅰ的含量(P<0.05)。攻毒实验表明,酵母硒和茶多酚均能提高攻毒后鱼的成活率,且两者交互作用明显。综合生长性能和抗病力分析,团头鲂幼鱼饲料中酵母硒和茶多酚配伍的适宜添加量为0.50 mg/kg酵母硒和50 mg/kg茶多酚。
Selenium yeast（SY） and tea polyphenols （TP）belong to high-quality natural antioxidants. As an organic selenium source, SY has the effects on both promoting growth and improving product quality. TP is a term for polyphenols in tea, which is helpful to induce growth, improve product quality and enhance immunity. In the present study, a two-factorial and three-level experiment was designed to evaluate the effects of dietary SY, TP and their combination on the growth performance, the nutritional composition in muscle and the ability to resist Aeromonas hydrophila in juvenile Wuchang bream, Megalobrama amblycephala[ mean weight（ 1.75 ～ 0.01 ）g]. Totally nine semi-purified diets were formulated to provide graded levels of SY 0,0. 25,0. 50 mg/kg and TP 0,50,100 mg/kg. After 60 days＇ feeding, the growth performance, muscle composition, biochemical parameters of serum and liver, related gene transcription in the hypothalamus-pituitary-growth axis as well as survival rates after being infected with A. hydrophila were investigated. The results showed that dietary SY and TP significantly improved the weight gain rate（WGR）, specific growth rate （SGR） and the content of protein in muscle （ P 〈 0. 05 ）, while reduced the food conversion ratio（FCR）significantly（P 〈 0.05 ）. Both dietary SY and TP significantly enhanced the growth performance by upregulating the mRNA expression of growth related genes in the hypothalamus-pituitary- growth axis. The difference is that SY mainly upregulated the mRNA expression of MaGH and MalGF-I significantly （ P 〈 0.05 ）, whereas TP enhanced the transcription of MaGHR2 and decreased the mRNA level of MalGF-I significantly（ P 〈 0.05 ）. Consequently, dietary SY significantly enhanced the contents of GH and IGF- I in the serum,whereas TP decreased serum IGF- I levels significantly（P 〈 0.05）. No significant interaction effect of dietary SY and TP on serum GH and IGF- I was observed in juvenile Wuchang bream （P 〉 0.05）. Both dietary SY and TP significantly enhanced the crude protein content in the muscle （ P 〈 0.05）. And there was no significant interaction effect of dietary SY and TP on the content of the crude protein in the muscle（P 〉0.05）. Both dietary SY and TP could improve the ability to resist A. hydrophila. And there was an interaction effect of SY and TP on the ability to resist A. hydrophila. In light of the above, it could be concluded that a basal diet supplemented with 0.50 mg/kg of SY and 50 mg/kg of TP could help keep better growth performance and disease resistance in juvenile Wuchang bream.
出处
《水产学报》
CAS
CSCD
北大核心
2015年第1期97-107,共11页
Journal of Fisheries of China
基金
湖北省自然科学基金(2014CFB938)
国家自然科学基金(31100378,51179134)
华中农业大学大学生科技创新基金(SRF2014177)
关键词
团头鲂
酵母硒
茶多酚
生长
基因表达
嗜水气单胞菌
Megalobrama amblycephala
selenium yeast
tea polyphenols
growth
gene expression
Aeromonas hydrophila
