饲料蛋白质水平对三倍体虹鳟生长和肠道组织形态的影响

Effect of Dietary Protein Levels on Growth and Intestinal Histological Morphology of Triploid Rainbow Trout

在水温8~16℃下,将初始体质量为(233.30±0.39)g的三倍体虹鳟Oncorhynchus mykiss饲养在规格为3m×3 m×6 m的网箱中,网箱放在青海省龙羊峡水库,每箱100尾,分别投喂蛋白质水平为35.4%(低蛋白质组)、43.3%(中蛋白质组)和52.4%(高蛋白质组)的等脂等能饲料,每种饲料4个网箱,探讨饲料蛋白质水平对三倍体虹鳟生长和肠道组织形态的影响。80 d的饲养结果表明:随着饲料蛋白质水平的增加,特定生长率、肠道皱襞高度和上皮细胞厚度呈显著上升的趋势(P<0.05);与低蛋白组相比,中蛋白组和高蛋白组特定生长率分别高出14.4%和22.1%;肠长指数(肠长/体长×100%)、Zihler指数(肠长(mm)/[10×(体质量(g)1/3)])、肠道微绒毛高度和肌层厚度呈显著下降的趋势(P<0.05);饲料蛋白质水平对三倍体虹鳟肠道中杯状细胞数量无显著影响(P>0.05)。综上所述:投喂高蛋白质水平饲料能促进三倍体虹鳟生长,其原因是投喂高水平蛋白质饲料(52.4%)增大了鱼肠道表面积,提高对饲料的消化吸收率;投喂低水平蛋白质饲料(35.4%)可能导致肠道炎症。

An 80-day feeding trial was conducted to investigate the effects of dietary protein levels on growth performance and intestinal histological morphology of triploid rainbow trout(Oncorhynchus mykiss).Triploid rainbow trout with initial body weight of(233.30±0.39)g were reared in a cage of 3 m×3 m×6 m disposed in Longyangxia Reservoir,Qinghai Province,at a stocking density of 100 individuals per cage and fed three isolipidic and isoenergetic diets containing 35.4%(low dietary protein group),43.3%(medium dietary protein group)and 52.4%(high dietary protein group)protein at water temperature of 8~16℃for 80 days.Results showed that the specific growth rate,intestinal villus height and epithelium thickness were shown to be significantly increased with the increase in dietary protein level(P<0.05);the specific growth rate of the medium dietary protein and high dietary protein group was respectively 14.4%and 22.1%higher than that of the low dietary protein group,with significant decrease in intestinal length inde x(ILI),Zihler’s index(ZI),intestinal microvillus height and muscular thickness(P<0.05),and without significant effect of dietary protein level on the number of goblet cells in the intestine of triploid rainbow trout(P>0.05).In short,high dietary protein(52.4%)level can lead to promote the growth of triploid rainbow trout,due to increase in the intestinal surface area of the fish by high dietary protein level,thus high digestion and absorption of the diet.However,the triploid rainbow trout fed low protein level(35.4%)diet had intestinal inflammation.