The content of short chain fatty acids in the jejunal digesta, caecal digesta and faeces of growing pigs

Short chain fatty acids (SCFAs) are intermediates from microbial fermentation of proteins or saccharides. Little is known about their production in different parts of intestine and therefore the aim of the present study was to examine, using 7 double-cannulated gilts (initial BW: 25 ± 0.5 kg), the production of the SCFAs in a jejunal digesta, caecal digesta and faeces. After a 25-d recovery period, a 70-d experimental period followed. On days 28; 42; 56 and 70, samples of jejunal, caecal digesta and faeces were collected. In the samples of jejunal and caecal digesta and in faeces, the content of dry matter (DM), crude protein (CP) and SCFAs was determined. The highest content of DM (P < 0.001) was found in faeces (29.2%), then in caecal digesta (10.5%) and in jejunal digesta (8.8%). The content of CP in jejunal digesta was lower (P < 0.001) when compared with that in the caecal digesta and faeces. The content of lactate was greater (P < 0.001) in jejunal (69.1 mmol/L) than in caecal digesta (36.3 mmol/L) or faeces (2.5 mmol/L). However, the content of other SCFAs was higher (P < 0.001) in caecal digesta and faeces when compared with that in jejunal digesta. Concentrations of acetate, butyrate and propionate were higher (P < 0.001) in caecal digesta and faeces when compared to jejunal digesta, however in the faeces were lower (P < 0.001) than in caecal digesta. The contents of isobutyrate, isovalerate and caproate were greater (P < 0.001) in the faeces (2.2; 4.1; 0.28 mmol/L) than in caecal digesta (0.3; 0.6; 0.11 mmol/L). In caecal digesta, the content of acetate, propionate and butyrate increased with decreasing the content of lactate (P < 0.05). On d 28 and 70 the concentration of lactate in faeces was higher (2.9; 2.6 mmol/L) when compared with d 42 and 56 (1.8; 0.8 mmol/L; P < 0.001). The content of acetate in jejunal digesta was higher (P < 0.05) on d 56 (17.8 mmol/L) in comparison with d 28, 42 and 70 (11.5; 10.0 and 12.1 mmol/L), and isobutyrate was the lowest on d 28 (P < 0.05). The content of SCFAs, with the exception of lactate, was greater in caecal digesta and faeces in comparison with that in jejunal digesta, and the content of acetate propionate and butyrate in caecal digesta increased with decreasing content of lactate.