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Changes on intestinal microbial fermentation pattern of piglets fed diets including different components
Low digestibility plant protein sources fed to weaned piglet’s, coupled with their low digestive capacity, favors fermentation of undigested protein by opportunistic bacteria, producing branched chain fatty acids (BCFA) and ammonia, which are toxic for gastrointestinal mucosa thus causing digestive disorders. Post-weaning diarrhea syndrome has been associated to high protein diets, which together with banning of antibiotics use in feeds, worsens the problem. One alternative is to reduce the level of dietary protein to decrease substrate availability for bacterial fermentation. Another is the use of probiotics. This study consisted of two experiments to evaluate the effect of feeding piglets two levels of dietary protein, and the addition of antibiotics or probiotics, on intestinal microbial fermentation. One included 72 piglets weaned at 20 days old distributed into three treatments (diets): 1) high protein (20%) with antibiotics (HCPa); 2) high protein (20%) without antibiotics (HCP) and 3) low protein (16%) without antibiotics (LCP). Second included 90 piglets weaned at 19 days old distributed into three treatments (diets): 1): high protein (20%) with antibiotics (HCPa); 2) high protein (20%) without antibiotics (HCP) and low protein (16%) without antibiotics but with probiotics (LCPpb). In both experiments, on day 21 post-weaning, three piglets per treatment were slaughtered to obtain individual ileum and proximal colon, and their contents analyzed for total VFA’s, short chain fatty acids (SCFA), branched chain fatty acids (BCFA) and lactic acid (LA) and ammonia (AM). Experiments were statistically analyzed as completely randomized designs. First experiment showed that use of antibiotics limited total microbial fermentation in the gut (38 vs. 114 and 96 μmol·g-1 VFA’s in HCPa, HCP and LCP, respectively) (P<0.01), but its absence in HCP resulted in 60% of total VFA’S as BCFA (P<0.01) and increased in AM concentration (515 vs 290 and 200 mg·kg-1 in HCP, HCPa and LCP respectively)(P<0.01). When protein level was reduced, a high fermentation was observed, but now 95% of total VFA’s were SCFA (P<0.01) and LA production increased (37 vs 30 and 15 μmol·g-1in LPC, HCP and HCPa respectively) (P<0.01). In the second experiment, inclusion of probiotics to LCP resulted in an increase of fermentation, but concentration of SCFA was higher in comparison to animals receiving a LCP diet. Changes in dietary components modified intestinal environment. Moreover the use of a low protein diet with or without probiotics promoted a healthy intestinal environment through the production of SCFA.
Keywords: Piglets, Fermentation, SCFA