Aquaculture Reports (Dec 2024)
Supplementation of sodium alginate-coated Clostridium butyricum after cottonseed protein concentrate replacement of fishmeal can improve growth, immunity, and intestinal health in Litopenaeus vannamei
Abstract
The present study evaluated the effects of supplementation with sodium alginate-coated Clostridium butyricum (SACB) on growth, immune response, and intestinal health of Litopenaeus vannamei following the replacement of fishmeal with cottonseed protein concentrate (CPC). The freeze-drying method was used for bacterial agent preparation, with the optimal ratio of freeze-dried protectant being 15 % skimmed milk, 12 % β-cyclodextrin, 8 % glucose, and 0.5 % dipotassium hydrogen phosphate. Six isonitrogenous and isolipid diets were formulated, with one serving as the control group (CG, 25 % fishmeal content). The remaining five diets were formulated as fishmeal replacement groups (CPC replacing 40 % of fishmeal). The content of SACB (5.1 × 108 CFU/g) in the alternative groups were 0 % (SACB0), 0.06 % (SACB1), 0.24 % (SACB2), 0.96 % (SACB3) and 3.84 % (SACB4), respectively. The results showed that SACB improved the growth performance (P > 0.05). Malondialdehyde content was significantly inhibited in hepatopancreas after SACB addition (P < 0.01). In the SACB3 group, intestinal trypsin, amylase, and lipase activities were remarkably enhanced (P < 0.05). The alpha diversity index was significantly higher in the SACB3 group (P < 0.001). LEfSe analysis showed that the relative abundance of beneficial bacteria such as Lactobacillus_murinus, Lactobacillus_johnsonii_FI9785, and Ruminiclostridium_5 increased in the SACB3 group (P < 0.05). Propionic and butyric acid contents were significantly higher in the SACB3 group (P < 0.05). The relative expression of genes including phenoloxidase, relish, penaeidin-3a, and crustins was significantly upregulated in the SACB3 and SACB4 groups (P < 0.05). Contents of total essential amino acids, total non-essential amino acids, and total amino acids in muscles were significantly higher in SACB3 and SACB4 groups (P < 0.05). In summary, suitable SACB improved shrimp growth, immune response, intestinal short-chain fatty acids, and muscle amino acids. The optimum SACB addition of 1.96 % was determined through binary regression analysis of specific growth rate.
