吉富罗非鱼对饲料中维生素B_1的需要量

Dietary thiamin requirement of GIFT Oreochromis niloticus

采用维生素B1（VB1）含量为0.08（对照组）、0.57、1.13、2.09、4.11和8.09 mg/kg的6种纯化饲料,分别饲养初始体质量为（64.4±1.5）g的吉富罗非鱼12周,研究VB1对其生长性能、部分血清生化指标、肝脏VB1蓄积量及转酮醇酶基因表达量的影响,以确定其对饲料VB1的需要量。结果显示,随着饲料中VB1含量增加,吉富罗非鱼增重率先呈线性增加后趋于稳定,当饲料中VB1含量为1.13、2.09、4.11、8.09 mg/kg时增重率达最大。吉富罗非鱼肝脏VB1含量随着饲料VB1含量增加不断增大,当增加到2.09 mg/kg后趋于稳定。饲料中缺乏VB1显著提高血清丙酮酸含量（P〈0.05）,但对全鱼水分、粗脂肪、粗蛋白、灰分无显著性影响（P〉0.05）。饲料中添加VB1显著提高血清高密度脂蛋白胆固醇和肝脏转酮醇酶基因表达量（P〈0.05）。饲料中VB1含量大于1.13 mg/kg各组的肝脏转酮醇酶活性显著高于VB1含量小于0.57 mg/kg组（P〈0.05）。折线回归分析表明,吉富罗非鱼（64-325 g）获得最佳生长时对饲料VB1需要量为1.16 mg/kg;肝脏VB1蓄积量达到最大时,对VB1的需要量为2.06mg/kg。

GIFT tilapia[ initial weight（ 64.4 ±1.5 ）g ] were fed purified diets containing six levels （0.08, 0.57,1.13,2.09,4. 11 and 8.09 mg/kg diet, respectively）of thiamin for 12 weeks. The experiment was used to determine the dietary thiamin requirement of GIFT tilapia on the basis of growth parameters,hepatic thiamin saturation and a thiamin-dependent biochemical function. The results showed that, with the increasing dietary thiamin level, weight gain rate of tilapia first increased linearly then remained nearly unchanged. Hepatic thiamin contents presented the same tendency with weight gain rate. Fish fed diets supplemented with VB1 showed significantly higher hepatic transketolase expression, serum high density lipoprotein cholesterol and lower serum pyruvate than fish fed diets without supplementation of VB1 （P 〈 0. 05 ）. Fish fed the control diet without supplementation of thiamin showed significantly higher serum pyruvate content than fish fed diets supplemented with thiamin （ P 〈 0.05 ）, while protein, moisture, ash, lipid ontent in whole body had no significant differences among various treatments（P 〉 0.05）. Based on broken method of the relationships between weight gain rate,hepatic thiamin contents and dietary VB1 concentrations,it can be concluded that the dietary VBI requirement for GIFT tilapia was considered to be 1.16 and 2.06 mg/kg diet respectively.