Effects of berberine on growth performance, intestinal microbial, SCFAs, and immunity for Ira rabbits

Berberine (BBR), recognized for its anti-inflammatory and bactericidal properties, has been extensively studied for its effects on mammalian gut microbiota. This study specifically addresses the need for more research on the regulatory effects of BBR on the gut microbiota of Ira rabbits. To fill this gap, we administered varying concentrations of BBR to weaned Ira rabbits to assess its impact on their growth and gut microbiota. In our experiment, 245 healthy weaned rabbits, aged 33 days, were randomly assigned into five groups. The CG group received a standard diet, while groups I, II, III, and IV were given diets supplemented with BBR at doses of 5 mg/kg, 10 mg/kg, 20 mg/kg, and 40 mg/kg, respectively. A 7-day pre-feeding period was implemented for acclimatization, followed by a 30-day experimental phase. The results revealed that BBR significantly improved the Average Daily Feed Intake (ADFI) and Average Daily Gain (ADG) of the rabbits. Notably, group III showed a significantly higher final weight compared to other groups (P<0.05). BBR supplementation also increased serum levels of GSH-Px, SOD, and T-AOC, while decreasing MDA levels compared to the control group (P<0.05). It also upregulated pro-inflammatory mediators IL-1{beta}, IL-6, and TNF-, and downregulated anti-inflammatory mediators IL-10 and TGF-{beta}1. Furthermore, BBR treatment led to a significant increase in Short-Chain Fatty Acids (SCFAs), specifically acetic and butyric acids (P<0.05). Regarding gut microbiota, BBR significantly enhanced the relative abundance of Bacteroidota and Verrucomicrobiota at the phylum level and reduced Firmicutes (P<0.05). At the genus level, there was a significant increase in Akkermansia and Alistipes and a decrease in Ruminococcus (P<0.05). Overall, BBR appears to promote the growth of Ira rabbits by enriching beneficial bacteria, modulating inflammatory mediators in the TLR4/NF-{kappa}B pathway, and reducing inflammation and oxidative stress. Among the tested dosages, 20 mg/kg BBR had the most substantial impact.