吉富罗非鱼对饲料中泛酸的需要量

Dietary pantothenic acid requirement of GIFT tilapia( Oreochromis niloticus)

选用初始体质量为（79.4±1.6）g吉富罗非鱼270尾,随机分成6组（每组3重复,每重复15尾）,养殖于500 L养殖桶中,分别饲喂泛酸含量为0.5、4.8、9.5、18.2、36.3和74.4 mg/kg纯化饲料12周,研究确定其对泛酸的需要量。结果表明,随着饲料泛酸含量增加,吉富罗非鱼增重率、肝脏和肌肉泛酸含量均呈先线性增加后稳定的趋势;肥满度和肝体比呈先增加后降低的趋势,均以4.8 mg/kg组最高。全鱼水分含量先降低后增加,全鱼脂肪含量呈现与水分含量相反的趋势。肝总脂含量显著降低,添加组显著低于未添加组（P〈0.05）。血清高密度脂蛋白含量随着饲料泛酸含量的增加而显著增加（P〈0.05）。折线回归分析结果表明,吉富罗非鱼（80～350 g）获得最佳生长时对饲料泛酸需要量为10.5 mg/kg,饲料中12.6和13.5mg/kg泛酸可以分别使肝脏和肌肉泛酸累积量达到最大。

A 12-week growth experiment was conducted to quantify the optimum dietary pantothenic acid（ PA） requirement of GIFT tilapia Oreochromis niloticus. Triplicate groups of experimental tilapia with initial body weight[（ 79. 4 ± 1. 6） g]were cultured in 500 L aquaria（ r = 0. 9 m,h = 0. 75 m; 15 fish each aquarium） and fed with the experimental diets at six levels（ 0. 5,4. 8,9. 5,18. 2,36. 3 and 74. 4 mg /kg diet,respectively） of PA（ supplied as Calcium d-PA）. The results showed that,with the increasing of dietary PA level,weight gain rate of tilapia first increased linearly,then remained nearly unchanged at high PA treatments. Hepatic and muscle PA contents presented the same tendency with weight gain rate. Condition factor and hepatosomatic index first increased,then decreased with the increase of dietary PA level,and they were highest in 4. 8 mg /kg PA supplement group. Whole body moisture content of tilapia first decreased,then increased as dietary PA increased,while whole body crude lipid content presented an opposite tendency.Hepatic total lipid concentration significantly decreased,the supplement groups showed significantly lower values than that in the un-supplemented group（ P〈0. 05）. The increase of dietary PA level also significantly increased serum high density lipoprotein cholesterol content（ P〈0. 05）. Broken-line regression analysis showed the optimum dietary PA requirement of GIFT tilapia was estimated to be 10. 5 mg /kg for maximum growth,12. 6 and 13. 5 mg /kg for maximum hepatic and muscle PA concentration,respectively.