Effects of indole-3-butyric acid supplementation in diets containing high soybean meal on growth, intestinal inflammation, and intestinal flora of pearl gentian grouper (Epinephelus fuscoguttatus♀ x Epinephelus lanceolatus♂)

作者：Pang, Aobo; Zhang, Sen; Dong, Shaohan; Zhang, Xianxin; Liang, Junhui; Fang, Yanxin; Tan, Beiping; Zhang, Wei^*

来源：Aquaculture International, 2024, 32(4): 4429-4447.

DOI：10.1007/s10499-023-01382-3

• Carnivorous fish
• Fish meal substitution
• Enteritis
• Indole derivatives
• Gut microorganisms

Soybean meal and its processing products have been widely used in fish feeds. In aquaculture, there is a lack of effective targeted protection against food-borne enteritis caused by feeding soybean meal. Our preliminary research found that Indole-3-butyric acid (IBA) has the potential application value. The present research evaluated the influence of supplementing different levels of IBA to diets containing high soybean meal on juvenile pearl gentian grouper (Epinephelus fuscoguttatus female x E. lanceolatus male). The feeding experiment lasted for eight weeks and the initial weight of the fish was 21.17 +/- 0.02 g. The FM diet with fish meal as the main protein source was prepared. In addition, six diets were prepared in which soybean meal was used to replace some of the fish meal as a secondary protein source. IBA was added to these six diets at 0 g/kg, 0.8 g/kg, 1.6 g/kg, 2.4 g/kg, 3.2 g/kg, and 4.0 g/kg respectively. The growth performance of the 2.4 g/kg IBA-added group was significantly higher than that of the non-added group (P < 0.05); the group with IBA additions equal to or more than 2.4 g/kg had longer intestinal folds and more absorptive cells; the levels of ACP, LYS, C3, and C4 in the gut showed a significant quadratic trend of decreasing and then increasing with the increase of IBA and reached a minimum at 2.4 g/kg (P < 0.05); the gene expression of cytokines il1 beta, il17, tnf alpha, il4, il5, and tgf beta 1 varied significantly among the groups with different IBA additions (P < 0.05). In addition, this study investigated the role of feeding 2.4 g/kg IBA on fish from the perspective of intestinal flora. In this study, we concluded that 2.4 g/kg IBA could be added to diets using soybean meal replacing 40% of fish meal, which had beneficial effects on growth performance, intestinal inflammation alleviation and intestinal flora homeostasis. This provides a theoretical basis for IBA to mitigate SBMIE in pearl gentian grouper and promote the further application of soybean meal in carnivorous fish.

• 单位
  广东海洋大学