吉富罗非鱼成鱼对烟酸的需要量

The Dietary Niacin Requirement of Large GIFT Tilapia

选用初始体质量为(220.16±7.66)g的吉富罗非鱼Oreochromis niloticus 360尾,随机分成6组(每组3个重复,每重复20尾),分别饲喂烟酸质量分数为11.84(对照组)、37.78、64.70、89.44、157.15、335.36 mg.kg-1的半纯化饲料10周.研究烟酸对吉富罗非鱼成鱼生长、饲料利用、鱼体营养组成、部分血清指标及肝脏烟酸累积的影响,以确定其对烟酸的需要量.结果表明,经过10周的生长,饲料中添加烟酸显著提高了试验鱼的增质量率和饲料效率(P<0.05).157.15和335.36 mg.kg-1组全鱼粗蛋白含量显著高于其他组(P<0.05);粗脂肪含量在64.70mg.kg-1组最高,显著高于对照组(P<0.05);水分与粗灰分含量各组间无显著差异(P>0.05);试验鱼血清总胆固醇、高密度脂蛋白胆固醇和总蛋白含量先升后降,在烟酸质量分数为157.15 mg.kg-1组达到最高;三酰甘油含量显著降低(P<0.05);试验鱼肝脏烟酸含量先上升后稳定,各烟酸添加组显著高于对照组(P<0.05).对增质量率、肝脏烟酸和血清高密度脂蛋白胆固醇含量回归分析,确定吉富罗非鱼成鱼获得最大生长时对饲料中烟酸的最低需要量为63.62 mg.kg-1,维持正常生理功能的需要量为158.52～172.41 mg.kg-1.

Total 360 large GIFT tilapia,Oreochromis niloticus,with average initial body mass of(220.16±7.66) g were randomly divided into 6 groups consisting of 3 replicates(20 fish per net).Each group was fed a diet that mass fractions of niacin were 11.84(control group),37.78,64.70,89.44,157.15,335.36 mg·kg-1 for 10 weeks.Growth,feed utilization,body composition,some serum biochemical indices and liver niacin concentration were measured to detect the suitable requirement of niacin in diet of large GIFT tilapia.The results showed that the addition of niacin to diets significantly improved fish mass gain rate(MGR,%) and feed efficiency(FE);the crude protein content in whole-body of fish in the 157.15 and 335.36 mg·kg-1 groups was significantly higher than that of other groups.The crude lipid content of fish in the 64.70 mg·kg-1 group was the highest and significantly higher than that of the control group;there were no significant differences in carcase moisture and crude ash of the fish.The serum total cholesterol(T-CHO,mmol·L-1),high density lipoprotein cholesterol(HDL-C,mmol·L-1) and total protein(TP,mmol·L-1) content first increased then decreased as the level of dietary niacin increased,and they reached the peak when feeding the fish mass fraction of niacin 157.15 mg·kg-1.The addition of niacin to diets significantly reduced serum triglyceride(TG,mmol·L-1) content.The niacin content in liver first increased then plateaued with increasing dietary niacin levels and it was significantly higher in the niacin added groups than that of the control group.Regression analysis showed that large GIFT tilapia were estimated to need mass fraction of niacin 63.62,158.52-172.41 mg·kg-1 respectively to maintain their maximum growth and normal physiological function.