Effects of dietary Bacillus amyloliquefaciens on the growth, immune responses, intestinal microbiota composition and disease resistance of yellow catfish, Pelteobagrus fulvidraco

Abstract

The influence of dietary probiotic Bacillus amyloliquefaciens on the growth performance, digestive enzyme activity, immune parameters and disease resistance of yellow catfish (Pelteobagrus fulvidraco) was evaluated. Commercial diet (C) or diet containing 106 cfu/g B. amyloliquefaciens (T) was fed for 4 weeks, and final weight (FW), specific growth rate (SGR) and feed conversion ratio (FCR) were improved (p<0.05) in the T group. Dietary B. amyloliquefaciens increased protease and amylase activities in the digestive tract after 2 and 4 weeks, respectively. Respiratory burst (RB), plasma lysozyme (LZM) activity, total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity were also elevated (p<0.05). Immune-related genes signal transducer and activator of transcription 1 (STATA-1), immunoglobulin M (IgM) and C-type lectin (CTL) were upregulated (p<0.05), but interleukin-1 β (IL-1β) was not (p >0.05). Intestinal microbiota analysis showed that the community structure was significantly different between the two groups; the relative abundance of Cetobacterium was increased but Plesiomonas was decreased in T. Moreover, challenge tests showed that the resistance of fish fed B. amyloliquefaciens against Aeromonas veronii and Edwardsiella ictaluri was significantly enhanced (p<0.05). In conclusion, dietary supplementation of B. amyloliquefaciens can effectively improve the growth performance, digestive enzyme activity, immune responses, intestinal microbiota composition and disease resistance of yellow catfish.

Effects of Solid-State Fermented (SSF) Pelleted Feed with Lactobacillus plantarum on Tachysurus fulvidraco: Growth, Digestion, Antioxidant, Immunity, Intestinal Morphology, and Microbiota

“…In this study, we aimed to investigate the effect of Lactobacillus plantarum fermented feed and fermented liquid on the intestinal microbiota of T. fulvidraco by observing the microbiota in different segments of the intestine. Firmicutes, Fusobacteriota, Proteobacteria, and Bacteroidota were the four dominant phyla in the intestine, regardless of diet and intestinal segment, which was consistent with previous research about T. fulvidraco [26,54]. Among these dominant phyla, Proteobacteria are well adapted to survive in the fish intestine and aquatic environment, and they contribute to significant host functions such as nutrition [55].…”

“…Some studies have suggested that Cetobacterium is a potentially beneficial microbiota for fish [57,58]. Most studies proposed that the proportion of Cetobacterium in intestinal microbiota increased after some probiotics were applied, including Bacillus and Enterococcus [26,59,60]. Interestingly, the opposite result was observed with a significant decrease in the Cetobacterium ratio in the foreintestine when feeding a diet fermented with Lactobacillus plantarum, which was consistent with Standen's study showed that in tilapia fed a mixture of multiple probiotics, including Lactobacillus reuteri and Enterococcus faecium, the percentage of Cetobacterium decreased from 13.80% to 0.02% [61].…”

“…Under intensive aquaculture conditions, T. fulvidraco is highly susceptible to bacterial diseases, which can result in significant economic losses [25]. Recent research reports [25,26] on the probiotics of T. fulvidraco show that probiotics have a positive effect on growth performance while also enhancing the immune system and improving the composition of the intestinal microbiota, reducing the proportion of pathogenic bacteria. However, there have been relatively few studies on the effects of fermented feed on T. fulvidraco and even other fish species.…”

Oral Vaccination of Largemouth Bass (Micropterus salmoides) against Largemouth Bass Ranavirus (LMBV) Using Yeast Surface Display Technology

“…The obtained supernatant was used for subsequent enzyme activity determination. Based on the Bradford method, bovine serum albumin (BSA) was used as the standard to determine the total intestinal protein content [ 36 ]. Each group of samples was repeated three times.…”

Bacillus amyloliquefaciens: Harnessing Its Potential for Industrial, Medical, and Agricultural Applications—A Comprehensive Review

“…For instance, studies [ 13 , 20 , 23 , 24 , 25 , 26 , 27 ] have exhibited enhancements in the production of enzymes, such as protease and lipase, due to genetic engineering. Other research [ 28 , 29 ] has focused on the bacterium’s potential in plant disease control and its role in promoting plant growth. The wide range of applications and the potential for further improvements underline the importance of ongoing research and development.…”