Effects of dietary <em>Clostridium butyricum</em> on growth performance, non-specific immunity, intestinal microbiota and disease resistance of <em>Scylla paramamosain</em>

Abstract

In this investigation, we examined how <em>Clostridium butyricum</em> influences the growth, innate immune reaction, intestinal microbiota, and disease resistance of <em>Scylla paramamosain</em>. Different concentrations of <em>C. butyricum</em> were sprayed on the feed: 0 (CC), 3.6×104CFU/g (CB1), 3.6×105CFU/g (CB2), 3.6×106CFU/g (CB3), and 3.6×107CFU/g (CB4) over a period of 42 days. The findings indicated that the final weight and specific growth rates of <em>S. paramamosain</em> in the CB2 and CB3 treatment groups were significantly greater compared to the other groups (P <0.05). In compared to the control group, the activities of alkaline phosphatase (AKP), superoxide dismutase (SOD), total antioxidant capacity (T-AOC) and intestinal lipase (LPS) were all elevated, with significant improvements noted particularly in the CB3 group (P < 0.05). Furthermore, the relative expression levels of the IL8 and TNF-α genes in the CB2 and CB3 groups, as well as the GPx3 and SpPO genes in CB3 and CB4 groups were markedly elevated compared to the other groups (P< 0.05). Incorporating 3.6×106CFU/g of <em>C. butyricum</em> into the diet improved the variety of the gut flora in <em>S. paramamosain</em>. Functional analysis conducted through KEGG Pathway Level 2 indicated that the experimental group had a greater abundance of metabolic-related pathways than the control group, with the CB3 group displaying the highest levels. In conclusion, including an appropriate level of <em>C. butyricum</em> within the dietary composition can foster the growth of <em>S. paramamosain</em>, enhance the diversity of gut microbiota, and improve immune function; the optimal concentration identified was 106 CFU/g in the feed.