Xu Wei, Lutz Charles Greg, Taylor Christopher M, Ortega Miriam Contin
Department of Life Sciences, College of Science and Engineering, Texas A&M University Corpus Christi, Corpus Christi, Texas, USA.
Agricultural Center, Louisiana State University, Baton Rouge, Louisiana, USA.
Aquac Nutr. 2022 Oct 28;2022:5715649. doi: 10.1155/2022/5715649. eCollection 2022.
Finfish aquaculture is expected to continue to benefit from significantly improved fish diets, which are the source of energy to support the growth and health of fish. Strategies to enhance the transformation rate of dietary energy and protein to fish growth are greatly desired by fish culturists. Prebiotic compounds can be used as supplements to human, animal, and fish diets to populate beneficial bacteria in the gut. The goal of the present study is to identify low-cost prebiotic compounds with high efficacy in increasing the absorption of food nutrients by fish. Several oligosaccharides were evaluated as prebiotics in Nile tilapia (), one of the most widely cultured species in the world. Several parameters of the fish on different diets were evaluated, including feed conversion ratios (FCRs), enzymatic activities, expression of growth-related genes, and the gut microbiome. Two age groups of fish (30 days old and 90 days old) were used in this study. The results indicated that the addition of xylooligosaccharide (XOS), galactooligosaccharide (GOS), or XOS and GOS combination to the basic fish diet significantly decreased the feed conversion ratio (FCR) of the fish in both age groups. Both XOS and GOS decreased the FCR of 30-day-old fish by 34.4% compared to the fish on the control diet. In the 90-day-old fish group, XOS and GOS decreased the FCR by 11.9%, while the combination of the two prebiotics led to a 20.2% decrease in FCR compared to the control group. The application of XOS and GOS also elevated the production of glutathione-related enzymes and the enzymatic activity of glutathione peroxidase (GPX), indicating the enhancement of antioxidation processes in fish. These improvements were associated with significant changes in the fish gut microbiota. The abundance of , , , , and were upregulated by XOS and GOS supplements. The findings of the present study suggested that the prebiotics would be more effective when they were applied to the younger fish, and the application of multiple oligosaccharide prebiotic compounds could result in a greater growth enhancement. The identified bacteria can be potentially used as probiotic supplements in the future to improve fish growth and feeding efficiency and ultimately reduce the cost of tilapia aquaculture.
鱼类养殖有望继续受益于显著改良的鱼饲料，鱼饲料是支持鱼类生长和健康的能量来源。鱼类养殖者迫切需要提高饲料能量和蛋白质向鱼类生长转化率的策略。益生元化合物可用作人类、动物和鱼类饲料的补充剂，以在肠道中繁殖有益细菌。本研究的目的是确定低成本且能高效提高鱼类对食物营养吸收能力的益生元化合物。几种低聚糖被评估为尼罗罗非鱼（世界上养殖最广泛的鱼类之一）的益生元。对不同饲料喂养的鱼类的几个参数进行了评估，包括饲料转化率（FCR）、酶活性、生长相关基因的表达以及肠道微生物群。本研究使用了两个年龄组的鱼（30日龄和90日龄）。结果表明，在基础鱼饲料中添加低聚木糖（XOS）、低聚半乳糖（GOS）或XOS与GOS的组合，显著降低了两个年龄组鱼类的饲料转化率（FCR）。与对照饲料喂养的鱼相比，XOS和GOS均使30日龄鱼的FCR降低了34.4%。在90日龄鱼组中，XOS和GOS使FCR降低了11.9%，而两种益生元的组合使FCR相比对照组降低了20.2%。XOS和GOS的应用还提高了谷胱甘肽相关酶的产量以及谷胱甘肽过氧化物酶（GPX）的酶活性，表明鱼类抗氧化过程得到增强。这些改善与鱼类肠道微生物群的显著变化有关。XOS和GOS补充剂上调了、、、和的丰度。本研究结果表明，益生元应用于幼鱼时效果更佳，多种低聚糖益生元化合物的应用可带来更大的生长促进作用。所鉴定的细菌未来有可能用作益生菌补充剂，以提高鱼类生长和喂养效率，并最终降低罗非鱼养殖成本。
