The effects of dietary supplementation with α-ketoglutarate on the intestinal microbiota, metabolic profiles, and ammonia levels in growing pigs

Abstract

The purpose of this study was to investigate the effects of dietary supplementation with α-ketoglutarate (AKG) on the intestinal microbiota and metabolites using the growing pig model. Sixteen healthy animals (Large White×Landrace; 84±1d of age) of similar initial weight (40.08±0.78kg) were randomly assigned to two dietary groups (n=8). The pigs were fed a basic diet containing either 0 (control) or 10g AKG kg−1 (supplemental diet). After a 28-d trial period, the luminal digesta of the cecum and ileum were collected to analyze the amounts of short-chain fatty acids and ammonia, as well as populations of gut microbiota. Supplementation with AKG decreased (P=0.043) the pH value of the digesta in the ileum. Moreover, the AKG concentration in the ileal digesta was significantly higher in pigs fed the supplemented diet than in control pigs (P=0.009). The addition of AKG also significantly increased the amounts of Lactobacillus (P=0.002) and Bifidobacterium (P=0.021) in the cecum, and Lactobacillus (P=0.029) and Firmicutes (P=0.045) in the ileum, but decreased the amounts of Escherichia coli in the ileum (P=0.034) and in the cecum (P=0.082) when compared with the control group. Dietary AKG also increased the concentrations of valerate (P=0.026) in the caecal digesta and butyrate in both the caecal digesta (P=0.017) and the ileal digesta (P=0.022). Concentrations of ammonia also declined in the caecal (P=0.042) and ileal (P=0.038) digesta in response to AKG. Therefore, our results suggest that this dietary supplement has the potential to promote the growth of beneficial bacteria, improve intestinal microbial populations, increase the concentrations of butyrate and valerate, and decrease the level of ammonia in the gut of growing pigs.