本试验旨在研究逆流运动及饲料脂肪水平对吉富罗非鱼生长和肌肉营养成分的影响。对初始体重为(59.36±5.88) g的雄性吉富罗非鱼(GIFT,Oreochromis niloticus)分别投喂脂肪水平为0(A组)、3%(B组)、6%(C组)、9%(D组)、12%(E组)和15%(F组)的饲料,每种饲料分别设置3个逆流运动强度[水流速分别为0(静水组)、1.0(低强度运动组)、1.5 bl/s(高强度运动组)],共包含18个试验组(分别为0A、1A、1.5A、0B、1B、1.5B、0C、1C、1.5C、0D、1D、1.5D、0E、1E、1.5E、0F、1F和1.5F组)。每组分配10尾试验鱼,饲养42 d后测定试验鱼生长指标和肌肉营养成分。结果显示:各组试验鱼存活率均达90%以上。与静水组相比,投喂低脂肪水平(0、3%)和中脂肪水平(6%、9%)饲料时,运动组试验鱼终末体重增加1.72%~31.79%,而投喂高脂肪水平(12%、15%)饲料时,运动组终末体重下降2.07%~27.07%。在饲料脂肪水平为0~9%时,相同脂肪水平下特定生长率和增重率均随逆流运动强度增加而上升,但当饲料脂肪水平达到12%~15%时,特定生长率和增重率则均随逆流运动强度上升而出现下降趋势。相比静水组,逆流运动使得试验鱼白肌粗蛋白质含量增加0.83%~3.41%,红肌粗蛋白质含量增加0.06%~13.25%;同一逆流运动强度下,白肌粗蛋白质含量随饲料脂肪水平升高呈先降后升趋势,而红肌粗蛋白质含量则呈下降趋势。逆流运动对试验鱼肌肉饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸相对百分含量没有显著影响(P>0.05),但是,随饲料脂肪水平升高,肌肉多不饱和脂肪酸相对百分含量增加10.19%~52.67%。由此得出,逆流运动能够提高吉富罗非鱼肌肉粗蛋白质含量,适当增加饲料脂肪水平有利于生长,并增加肌肉多不饱和脂肪酸含量,且在较低饲料脂肪水平下适当强度的逆流运动的促生长效应更为明显。

This experiment was conducted to evaluate the effects of upstream-swimming exercise and dietary lipid level on growth and muscle nutritional components of genetic improvement of farmed tilapia (GIFT, Oreochromis niloticus). GIFT with the initial body weight of (59.36±5.88) g were fed 6 diets with different dietary lipid levels [0 (group A), 3% (group B), 6% (group C), 9% (group D), 12% (group E) and 15% (group F), respectively], and each diet group had 3 upstream-swimming exercise intensity [flow rate was 0 (still water group), 1.0 (low exercise intensity group) and 1.5 bl/s (high exercise intensity group), respectively]. There were totally 18 experimental groups, which were groups 0A, 1A, 1.5A, 0B, 1B, 1.5B, 0C, 1C, 1.5C, 0D, 1D, 1.5D, 0E, 1E, 1.5E, 0F, 1F and 1.5F, respectively. Each group had 10 fish, and the growth indices and muscle nutritional components were measured after feeding 42 days. The results showed as follows: tilapia's survival rate was over 90% in 18 experimental groups. Compared with still water group, the final body weight in exercise groups was increased by 1.72% to 31.79% when fed the diets with low (0 and 3%) or middle lipid levels (6% and 9%), but was decreased by 2.07% to 27.07% when fed the diets with high lipid levels (12% and 15%). In addition, the special gain rate (SGR) and weight gain rate (WGR) were increased with increasing exercise intensity where the lipid level range from 0 to 9%, however, these values were decreased with increasing exercise intensity where the lipid level range from 12% to 15%. Compared with still water group, Upstream-swimming exercise resulted to crude protein content of white muscle increased from 0.83% to 3.41% and that of red muscle increased from 0.06% to 13.25%. In the same exercise intensity and ascending dietary lipid level, the crude protein content of white muscle was firstly decreased and then increased, but that of red muscle was decreased. Upstream-swimming exercise had no significant effects on the relative percentage contents of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) in tilapia's muscle (P>0.05), but increased PUFA relative percentage content from 10.19% to 52.67% with the dietary lipid level increasing. Therefore, upstream-swimming exercise and suitable increased of dietary lipid level has a positive effect on the growth, muscle crude protein content, and muscle PUFA relative percentage content of GIFT. And the promoting growth effect is better in the conditions of low dietary lipid level and appropriate upstream-swimming exercise intensity.