饲料中精氨酸水平对杂交鲟幼鱼肠道消化酶活性及形态结构的影响

为研究饲料中不同水平精氨酸(arginine,Arg)对杂交鲟Acipenser schrenckii♀×Acipenser baeri♂幼鱼肠道消化酶活性及形态结构的影响,以0.3%为梯度,配制精氨酸水平为1.74%~3.54%(干物质)的7种等氮、等能饲料,实际精氨酸水平分别为1.76%、2.05%、2.36%、2.64%、2.93%、3.24%和3.53%。选取初始体质量为(3.63±0.08)g的健康杂交鲟幼鱼630尾,随机分成7组,每组设3个平行,每缸30尾鱼,养殖周期为8周。结果表明:与1.76%精氨酸对照组相比,2.64%和2.93%精氨酸组杂交鲟前肠蛋白酶活力显著提高(P0.05),2.36%、2.64%、2.93%和3.24%精氨酸组前肠淀粉酶活力显著提高(P0.05),2.36%、2.64%和2.93%精氨酸组中肠蛋白酶活力显著提高(P0.05),各肠段中脂肪酶活力随饲料中精氨酸水平的增加均表现出升高趋势,但无显著性差异(P0.05);与1.76%精氨酸组相比,2.36%、2.64%和2.93%精氨酸组前肠皱襞高度和肌层厚度显著增加(P0.05),2.93%精氨酸组前肠绒毛高度显著增加(P0.05),2.64%、2.93%和3.24%精氨酸组中肠皱襞高度显著增加(P0.05)。研究表明,饲料中添加适宜水平的精氨酸,对提高杂交鲟幼鱼肠道内消化酶活性和促进肠道形态结构发育均具有积极作用,可提高营养物质在杂交鲟幼鱼肠道内的消化和吸收,并促进其生长。

Effects of dietary arginine levels on intestinal digestive enzyme activity and morphology in juvenile hybrid sturgeon

A total of 630 juvenile hybrid sturgeon Acipenser schrrenckii♀× A. baeri♂with an average initial body weight of (3. 63±0. 08)g were randomly divided into 7 groups with 3 replicates per group and 30 fish per replicate and fed seven isonitrogenous and isolipidic diets containing arginine levels ranging from 1 . 74% to 3 . 54% ( dry matter) in approximately 0. 3% increments, and actual dietary arginine levels of 1. 76%, 2. 05%, 2. 36%, 2 . 64%, 2 . 93%, 3 . 24% and 3 . 53% for 8 weeks to study the effects of dietary arginine levels on intestinal diges-tive enzyme activities and morphology of juvenile hybrid sturgeon. The results showed that there was significantly higher activity of foregut protease in 2 . 64% and 2 . 93% groups than that in 1 . 76% group ( P<0 . 05 ) , and that significantly higher activity of foregut amylase in 2 . 36%, 2 . 64%, 2 . 93% and 3 . 24% groups than that in 1 . 76%group ( P<0 . 05 ) . The activity of midgut protease in 2 . 36%, 2 . 64% and 2 . 93% groups was shown to be in-creased with increase in dietary arginine levels, without significant difference (P>0. 05). The hybrid sturgeon in 2 . 36%, 2 . 64% and 2 . 93% groups had significantly higher fold height and muscular thickness of foregut than the hybrid sturgeon in 1 . 76% group ( P< 0 . 05 ) , with significantly higher villus width in foregut of the juveniles in 2 . 93% group ( P<0 . 05 ) . The hybrid sturgeon in 2 . 64%, 2 . 93% and 3 . 24% groups had significantly higher fold height in midgut than the juveniles in 1. 76% group did (P<0. 05). In conclusion, appropriate dietary arginine level leads to improve the digestion and absorption of intestinal nutrients due to increase in intestinal digestive ene-my activity and to improvement of intestinal morphology.