Exploring the link between gut microbiota, faecal SCFAs, pig muscle and backfat fatty acid profile

Abstract

The gut microbiota plays an important role in energy production and in degradation of complex dietary fibres. Hence, this study aimed to assess the relationships between the gut microbiota, the faecal profile of short chain fatty acids (SCFAs) and the fatty acid (FA) composition of the host adipose tissue and muscle. Samples from muscle, backfat and the rectal content of 285 crossbred Iberian × Duroc pigs were collected at slaughter. SCFAs and FA composition was determined by gas chromatography. Faecal DNA was extracted and the V3-V4 region of the 16S rRNA gene was sequenced. Taxonomy assignment was performed with QIIME2 using the SILVA database, whereas mixOmics R package was used for exploring the relations between datasets through the regularized Canonical Correlation Analysis (rCCA) method. Prevotella spp. had a high relative abundance and were positively correlated with n-butyric acid content and negatively with acetic acid in faeces. Conversely, the relative abundances of Akkermansia spp. and Cerasicoccus spp. were negatively correlated with n-butyric acid and positively with acetic acid. The relative abundance of Akkermansia spp. was negatively correlated with oleic acid levels in backfat, while Cerasicoccus spp. had a positive correlation with oleic acid and a negative correlation with palmitic acid. In muscle, Rikenellaceae RC9 spp. were positively correlated with palmitic acid and negatively with oleic acid. In summary, our results are indicative of the possible role that these genera may have in the modulation of backfat and muscle FA profile in pigs through the variation of SCFAs content in the digestive tract.