In the current study, we investigated the effect of a probiotic bacterium (Lactobacillus rhamnosus ATCC 7469) microencapsulated with alginate and hi-maize starch and coated with chitosan on improving growth factors, body composition, blood chemistry, and the immune response of rainbow trout (initial weight: 18.41 ± 0.32 g). Four experimental diets were formulated to feed fish for 60 days. They were control diet without any additive (C), diet added with beads without probiotic (E), a probiotic sprayed to the diet (L.r), and encapsulated probiotic supplemented diet (E-L.r). The results indicated that feeding with E-Lr significantly improved weight gain (84.98 g) and feed conversion ratio (0.95) compared to the other groups (P < 0.05). Also, fish fed E-Lr diet had a significantly higher value of whole-body protein (17.51%), total protein in the blood (4.98 g/dL), lysozyme (30.66 U/mL), alternative complement pathway hemolytic activity (134 U/mL), superoxide dismutase (203 U/mg protein), and catalase (528.33 U/mg protein) (P < 0.05) as compared to those fed the control diet. Similarly, a higher relative expression of immune-related genes such as interleukin-1 (Il-1) and tumor necrosis factor-alpha (TNF-1α) were reported in those fed E-L.r and L.r diets respectively. Interestingly, the fish fed dietary E-L.r had a significantly lower value of lipid in the whole body (4.82%) and cholesterol in the blood (160.67%) in comparison with those fed the control diet (P < 0.05). At the end of the experiment, all groups were challenged by Yersinia ruckeri where the survival rate of rainbow trout fed dietary E-L.r (70.36%) was statistically higher than that of the others (P < 0.05). Overall, the results suggested that encapsulated probiotic Lact. rhamnosus ATCC 7469 acted better than unencapsulated probiotic and has a potential to improve growth performance, flesh quality, and the immune response of rainbow trout.

在本研究中，我们研究了用藻酸盐和高玉米淀粉微囊化并涂有壳聚糖的益生菌（鼠李糖乳杆菌ATCC 7469）对改善生长因子，人体成分，血液化学和虹鳟鱼免疫反应的影响（初始重量：18.41±0.32克）。配制了四种实验饮食来喂鱼60天。他们是没有任何添加剂的对照饮食（C），添加了不含益生菌的珠子的饮食（E），喷洒到饮食中的益生菌（Lr）和封装的益生菌补充饮食（EL.r）。结果表明，与其他组相比，用E-Lr喂养可显着改善体重增加（84.98 g）和饲料转化率（0.95）（P <0.05）。同样，以鱼的E-Lr饲料喂养的鱼的全身蛋白（17.51％），血液中的总蛋白（4.98 g / dL），溶菌酶（30.66 U / mL），替代补体途径的溶血活性（134）显着更高U / mL），超氧化物歧化酶（203 U / mg蛋白质）和过氧化氢酶（528.33 U / mg蛋白质）（ 与对照饮食相比）（P <0.05）。同样，据报道，分别饲喂EL.r和Lr日粮的人的免疫相关基因，例如白介素-1（Il-1）和肿瘤坏死因子-α（TNF-1α）的相对表达较高。有趣的是，饲喂EL.r的鱼与饲喂对照的鱼相比，其体内的脂质（4.82％）和血液中的胆固醇（160.67％）的值明显较低（P <0.05）。在实验结束时，所有组均受到了鲁氏耶尔森氏菌的挑战，其中饲喂日粮EL.r的虹鳟鱼的存活率（70.36％）在统计学上高于其他组（P  <0.05）。总体而言，该结果表明包封的益生菌乳酸。鼠李糖ATCC 7469的表现优于未包囊的益生菌，并且具有改善生长性能，肉质和虹鳟鱼免疫反应的潜力。