Effects of different feeding methods on digestive enzyme activity, microflora structure, and short chain fatty acids in colon of Tibetan pigs

Abstract:

[Objective] To explore the effects of feeding methods on the digestive enzyme activity, microflora structure, and short chain fatty acids in the colon of Tibetan pigs. [Methods] Five free-ranging Tibetan pigs and 5 captive Tibetan pigs with the same age were randomly selected. The pigs were slaughtered for the collection of colonic feces samples. The digestive enzyme activity, microflora structure, and content of short chain fatty acids in the samples were determined by enzyme linked immunosorbent assay (ELISA), high-throughput sequencing, and gas chromatography, respectively. [Results] The free-ranging Tibetan pigs had lower average daily gain and higher activities of cellulase and hemicellulase in the colon than the captive Tibetan pigs (P<0.05). The alpha diversity indexes of colon microflora had no significant difference (P>0.05) and the principal component analysis showed similarity in the microflora structure between the two groups of pigs. At the phylum and family levels, the colon of the free-ranging Tibetan pigs had higher relative abundance of Verrucomicrobia, Flavobacteriaceae, Selenomonadaceae, Planctomycetaceae, and Eggerthellaceae and lower relative abundance of Streptococcaceae, Veillonellaceae, Pseudomonadaceae, Rhodocyclaceae, Rhodospirillaceae, Lactobacillaceae, Rikenellaceae, and Pasteurellaceae than that of the captive Tibetan pigs (P<0.05). At the genus and species levels, 7 genera and 4 species showed significant differences in the relative abundance between the pigs fed with the two methods, including Treponema, Ruminococcus, Eggerthella, Megasphaera, Alistipes, Pseudomonas, Streptococcus, Prevotella copri, Lactobacillus reuteri, Megasphaera elsdenii, and Faecalibacterium prausnitzii. The content of acetic acid in the colon of free-ranging Tibetan pigs was higher in that in the colon of captive Tibetan pigs (P<0.05). [Conclusion] Feeding methods affect the activities of cellulase and hemicellulase, microflora structure, and acetic acid content in the colon of Tibetan pigs. The free-ranging grazing Tibetan pigs showed poorer growth performance and stronger cellulose-degrading ability than the captive Tibetan pigs.

Key words:feeding method;Tibetan pigs;colon;digestive enzymes;microflora structure;short chain fatty acid