Institute of Biological Resources, Jiangxi Academy of Sciences, Nanchang, 330029, China.
Department of Animal Science and Technology, Konkuk University, Seoul, 05029, Republic of Korea.
Probiotics Antimicrob Proteins. 2021 Aug;13(4):1106-1118. doi: 10.1007/s12602-021-09762-y. Epub 2021 Mar 4.
In recent years, considerable and growing attention has been given to the application of host-associated microorganisms as a more suitable source of probiotics in aquaculture sector. Herein, we isolated and screened the olive flounder gut microbiota for beneficial bacterial strains that might serve as potential probiotics in a low fishmeal extruded aquafeed. Among the ten identified isolates, Bacillus amyloliquefaciens SK4079 and B. subtilis SK4082 were screened out based on their heat-resistant ability as well as enzymatic and non-hemolytic activities. Although both strains were well able to utilize carboxymethyl cellulose (CMC), xylan, and soybean meal (SBM) as a single carbon source in the minimal nutrient M9 medium, B. subtilis exhibited significantly higher cellulase, xylanase, and protease activities than B. amyloliquefaciens. The two selected strains were well able to degrade the undesirable anti-nutritional component of the SBM, which would limit its utilization as protein source in aquafeed industry. Significantly higher biofilm formation capacity and notably stronger adhesive interactions with the flounder's skin mucus were detected in B. subtilis than B. amyloliquefaciens. Immobilization of the spores from the selected strains, in a SBM complex carrier, remarkably enhances their thermal resistance at 120 °C for 5 min and different drying conditions. It was also interesting to learn that the B. subtilis spores could survive and remain viable after being sprayed onto extruded low-fish meal feed pellets for as long as 6 months. Overall, the findings of the present study could help the food/feed industries achieve their goal of developing cost-effective yet efficient products.
近年来，人们越来越关注利用宿主相关微生物作为水产养殖中更合适的益生菌来源。在此，我们从牙鲆肠道微生物群中分离和筛选了有益的细菌菌株，这些菌株可能作为潜在的益生菌应用于低鱼粉挤压水产饲料中。在鉴定出的 10 个分离株中，根据耐热能力以及酶和非溶血活性，筛选出解淀粉芽孢杆菌 SK4079 和枯草芽孢杆菌 SK4082。虽然这两种菌株都能够很好地利用羧甲基纤维素（CMC）、木聚糖和豆粕（SBM）作为最小营养 M9 培养基中的单一碳源，但枯草芽孢杆菌的纤维素酶、木聚糖酶和蛋白酶活性明显高于解淀粉芽孢杆菌。这两种选定的菌株能够很好地降解 SBM 中不良的抗营养成分，这将限制其在水产饲料工业中作为蛋白质来源的利用。与解淀粉芽孢杆菌相比，枯草芽孢杆菌具有更高的生物膜形成能力和更强的与牙鲆皮肤黏液的粘附相互作用。在 SBM 复合载体中固定所选菌株的孢子，可显著提高其在 120°C 下 5 分钟的耐热性和不同干燥条件下的耐热性。有趣的是，我们还发现枯草芽孢杆菌孢子在喷到低鱼粉挤压饲料颗粒上后，经过长达 6 个月的时间仍然能够存活并保持活力。总的来说，本研究的结果可以帮助食品/饲料行业实现开发具有成本效益和高效的产品的目标。
