Gut Microbiota Composition and Diversity in Different Commercial Swine Breeds in Early and Finishing Growth Stages.

The gut microbiota affects the metabolism, health and growth rate of pigs. Understanding the characteristics of gut microbiota of different pig breeds at each growth stage will enable the design of individualized feeding strategies. The present study aimed to compare the growth curves and development patterns of pigs of three different breeds (Duroc, Landrace and Yorkshire) using the mathematical models Gompertz, Logistic, Von Bertalanffy and Richards. For Duroc pigs, the Gompertz model showed the highest prediction accuracy (R 2 = 0.9974). In contrast, the best models for Landrace and Yorkshire pigs were Richards (R 2 = 0.9986) and Von Bertalanffy (R 2 = 0.9977), respectively. Path analysis showed that body length (path coefficient  =  0.507) and chest circumference (path coefficient  =  0.532) contributed more significantly to the body weight of pigs at the early growth stage, while hip circumference (path coefficient  =  0.312) had a greater influence on pig body weight in the late growth stage. Moreover, the composition of the gut microbiota of pigs at two growth stages (60 kg of body weight in the early growth stage and 120 kg in the finishing stage) was studied using 16S rRNA sequencing technology. Variations in gut microbiota composition of pigs at different growth stages were observed. KEGG pathway enrichment analysis of annotated metagenomes revealed that protein synthesis and amino acid metabolism pathways were significantly enriched in pigs at the early growth stage, which may be related to nutritional requirements of pigs during this stage. This study confirmed longitudinal variation in the gut microbiota of pigs pertaining to age as well as lateral variation related to pig breed. The present findings expand the current understanding of the variations in swine gut microbiota during production stages.