Differences of intestinal microorganism in pigs under different feeding modes

Different feeding methods, such as extensive feeding pattern (EP) and complete intensive feeding pattern (CP), have an influence on growth, fat accumulation and disease resistance of pigs. Intestinal microorganisms may be an important factor leading to this phenomenon. Therefore, in order to investigate and compare the gut microbiota structure in CP and EP groups, a total of 20 Chuying black pigs were divided into two groups as CP (n = 10) and EP (n = 10) and fed the same diet. The fecal microbial composition was profiled using 16S ribosomal RNA (rRNA) gene sequencing. Our results showed that seventeen predominant genera，which account for more than 95% of all gut microbes at the class level, present in each pig sample and constituted a phylogenetic core microbiota. Most of core microbial flora, such as Actinobacteria, Bacilli, Deltaproteobacteria, Fibrobacteria, Epsilonproteobacteria, Oligosphaeria, Sphingobacteriia, Spirochaetia, in CP group were significantly higher than that of EP group (P < 0.05), while the Gammaproteobacteria was significantly lower than the EP group (P < 0.05). The CP group had significantly higher community diversity, richness and evenness than the EP group (P < 0.05) in present study. Functional prediction indicated that intestinal microbial species may lead to higher growth and fat accumulation capacity in CP group than in EP group, but the disease resistance was weaker than EP group. In conclusion, this study suggested that extensive feeding pattern pigs have a wide range of sports venues and better animal welfare, which has a certain impact on reducing the occurrence of diseases and neurological symptoms. Therefore, it is suggested that in the process of raising hogs in captivity, a certain degree of free range or appropriate expansion of the exercise space for hogs should be carried out to improve animal welfare, which is conducive to reducing the occurrence of diseases and neurological symptoms.