This experiment was conducted to evaluate the effects of a commercial dietary β‐mannanase enzyme on growth performance, immunity, gut integrity and salinity tolerance of spinefoot rabbitfish (Siganus rivulatus) juveniles fed soybean‐based diets. A basal diet (protein, 400 g/kg; gross energy, 20 MJ/kg) was supplemented with 0.0 (control), 0.2, 0.5 or 0.8 g β‐mannanase/kg to formulate four experimental diets. Each treatment contained three net cages with 50 fish per net. The experiment lasted for 8 weeks. The results revealed that all β‐mannanase levels have significantly improved the growth performance compared with the control. β‐mannanase addition at 0.5 g/kg diet showed the best results of the growth performance, survival rate and feed utilization efficiency. The results also indicated that β‐mannanase supplementation improved protease, lysozyme, esterase, immunoglobulin and alkaline phosphatase activities and decreased alanine aminotransferase and aspartate aminotransferase activities compared with the control. Moreover, the dietary β‐mannanase supplementation significantly improved intestinal morphology by increasing the muscle thickness and villi length. Salinity challenge showed that β‐mannanase supplementation at 0.2 and 0.5 g/kg diet significantly increased fish survival compared with 0.8 and 0.0 g/kg diet. In conclusion, β‐mannanase inclusion in S. rivulatus diets improved growth performance, feed utilization, non‐specific immunity, intestinal morphology and fish quality. The recommended level of mannanase inclusion in S. rivulatus diets is 0.5 g/kg diet.

中文翻译：

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用β-甘露聚糖酶饲喂大理石化的棘足兔鱼（Siganus rivulatus）：一种有效的工具，可增强生长和免疫力并诱导低盐度耐受性

进行该实验以评估商业日粮β-甘露聚糖酶对棘足兔鱼（Siganus rivulatus）的生长性能，免疫力，肠道完整性和耐盐性的影响）青少年以大豆饮食为食。在基础饮食（蛋白质，400 g / kg；总能量，20 MJ / kg）的基础上补充0.0（对照），0.2、0.5或0.8 gβ-甘露聚糖酶/ kg，以配制四种实验饮食。每个处理包含三个网箱，每个网箱50条鱼。实验持续了8周。结果表明，与对照相比，所有β-甘露聚糖酶水平均显着改善了生长性能。以0.5 g / kg的日粮添加β-甘露聚糖酶显示出最佳的生长性能，成活率和饲料利用率。结果还表明，与对照组相比，补充β-甘露聚糖酶改善了蛋白酶，溶菌酶，酯酶，免疫球蛋白和碱性磷酸酶的活性，并降低了丙氨酸氨基转移酶和天冬氨酸氨基转移酶的活性。此外，日粮中添加β-甘露聚糖酶可通过增加肌肉厚度和绒毛长度来显着改善肠道形态。盐度挑战表明，与0.8和0.0 g / kg饲料相比，添加0.2和0.5 g / kg饲料的β-甘露聚糖酶显着提高了鱼类的存活率。总之，β-甘露聚糖酶包含在小号。rivulatus日粮改善了生长性能，饲料利用率，非特异性免疫，肠道形态和鱼类质量。建议在小菜链霉菌饮食中添加甘露聚糖酶含量为0.5 g / kg饮食。