海洋红酵母H26对刺参幼参生长、免疫指标和肠道菌群的影响

Effects of dietary yeast Rhodotorula sp. H26 on growth, immunity and intestinal microbiota in sea cucumber Apostichopus japonicus

为探讨在饲料中添加海洋红酵母Rhodotorula sp.H26对刺参Apostichopus japonicas幼参生长、免疫指标和肠道菌群的影响,以体质量为(0.54±0.06)g幼参为试验对象,研究了饲喂基础饲料(对照组)和含H26为10^5、10^7 cells/g的饲料后,幼参生长、消化酶活力、体壁营养和脂肪酸组成,以及免疫指标和肠道菌群的变化。结果表明:在试验第4周时,饲喂含H26为10^7 cells/g饲料幼参特定生长率较对照组显著提高(P<0.05);在试验第4周和第8周时,饲喂含H26为10^5、10^7 cells/g饲料的幼参肠道胃蛋白酶、胰蛋白酶、淀粉酶和脂肪酶活力均显著增加(P<0.05);在试验第4周和第8周时,饲喂含H26为10^5和/或10^7 cells/g饲料的幼参具有较高的体壁粗蛋白质和糖分含量;在第8周时,饲喂含H26为10^7 cells/g饲料的幼参具有较低的体壁灰分含量;在试验第8周时,饲喂含H26为10^5 cells/g饲料的幼参体壁花生四烯酸(C20:4n-6)/二十四烯酸(C24:1)含量显著高于/低于饲喂基础饲料幼参(P<0.05),饲喂含H26为10^7 cells/g饲料的幼参比对照组具有较高/较低的体壁C20:4n-6、二高-γ-亚麻酸(C20:3n-6)、肾上腺酸(C22:4n-6)/油酸(C18:1)、亚油酸(C18:2n-6)、二十碳二烯酸(C20:2n-6)+二十碳三烯酸(C20:3n-6)和二十碳五烯酸(C20:5n-3)含量;试验第4周和/或第8周时,与对照组比较,饲喂含H26为10^5、10^7 cells/g饲料的幼参体腔细胞呼吸爆发、体腔细胞裂解液上清液(CLS)溶菌酶活力及体腔液上清液(CF)和CLS酚氧化酶活力显著增加(P<0.05),饲喂含H26为10^7 cells/g饲料的幼参体腔细胞吞噬活力及CF溶菌酶活力显著提高(P<0.05);变性梯度凝胶电泳图谱显示,H26对肠道菌群无显著影响(P>0.05)。研究表明,饲料中添加H26,可促进幼参生长、增强消化酶活性、增加营养价值,并刺激幼参先天免疫系统。

A 8-week feeding trial was conducted to evaluate the effects of marine yeast Rhodotorula sp.H26 on growth,digestive enzyme activity,body composition,immunity and intestinal microbiota in the juvenile sea cucumber,Apostichopus japonicus.Sea cucumber with body weight of(0.54±0.06)g were reared in a plastic bucket and fed diets containing H26 at 0(control),10 5 and 10 7 cells/g at water temperature of 16-24℃,and growth,digestive enzyme activity,body composition,immunity and intestinal microbiota were analyzed in the sea cucumber.There was significantly higher specific growth rate in the sea cucumber fed H26-supplemented diet at 10 7 cells/g for 4 weeks compared with the control group(P<0.05).The sea cucumber fed H26-containing diets at 10 5 and/or 10 7 cells/g for 4 and 8 weeks had significantly higher activities of pepsin,trypsin,amylase,and lipase and body wall crude protein and carbohydrate contents compared to those fed the control diet did(P<0.05).The ash content was shown to be significantly lower in the sea cucumber fed H26-containing diet at 10 7 cells/g for 8 weeks than that in the sea cucumber in the control group.In 8 week feeding trail,a significantly higher/lower contents of arachidonic acid(C 20:4n-6)/tetracosenoic acid were detected in the body wall of sea cucumber fed H26-containing diet at 10 5 cells/g than those fed the control diet.There were significantly higher/lower(C 20:4n-6),dihomo-gamma-linolenic acid and adrenic acid/oleic acid,linoleic acid,eicosadienoic acid plus eicosatrienoic acid and eicosapentaenoic acid contents in sea cucumber fed H26-containing diet at 10 7 cells/g than those in the control group(P<0.05).In the 4 and/or 8 weeks,sea cucumber fed H26-supplemented diets at 10 5 and 10 7 cells/g had significantly higher respiratory burst in the coelomocytes,lysozyme activity in the coelomocyte lysate supernatant(CLS)and phenoloxidase activity in coelomic fluid supernatant(CF)and coelomocyte lysate supernatant(CLS)than those fed the control diet did(P<0.05).The phagocytic activity of the coelomocytes and lysozyme activity of the CF in sea cucumber fed H26-containing diet at 10 7 cells/g were significantly higher than those in the control group(P<0.05).Denaturing gradient gel electrophoresis revealed that the H26 did not significantly affect the composition of intestinal microbiota.These findings suggest that a diet supplemented with H26 can lead to improve the growth,to enhance digestive enzyme activity,to increase nutritive value and to stimulate the innate immune system of juvenile sea cucumber.