Effects of Medium Chain Fatty Acids, Organic Acids and Fructo-oligosaccharide on Cecal Salmonella Enteritidis Colonization and Intestinal Parameters of Broilers

Abstract

Medium chain fatty acids (MCA) are one of new additives used to control Salmonella infection and it is interesting to examine their physiological role in chickens comparing with other additives. The objective of this investigation was to study the effect of MCA, mixed organic acids (ORA) and fructo-oligosaccharide (FOS) on cecal Salmonella enterica serovar Enteritidis colonization and physiological changes of intestine in broilers. Six hundred, day old, male and female broiler chicks were allocated into 4 treatments. The treatments were CON: basal corn-soybean meal diet, FOS: basal diet supplemented with 4 g/kg FOS, ORA: basal diet plus water supplemented with ORA at 1:1,000 from day 1 to 45, MCA: basal diet plus water supplemented with MCA at 1:1,000 from day 1 to 35 and 1; 2,000 from day 36 to 42. All chickens were inoculated with 0.3 ml of 106 cfu/ml S. Enteritidis at day 3 and 1 ml of 108 cfu/ml at day 13 post-hatching. At days 21, 35 and 45 post-hatching, body weight and daily feed intake were recorded and averaged to calculate feed conversion ratio (FCR). Cecal samples were examined for S. Enteritidis colonization. In situ pH determination in crop small intestine and ceca were measured. Jejunal mucosal samples were collected for the determination of sucrase and maltase activity. Ileal digesta were collected for nutrient digestibility using the indigestible marker technique. Cecal contents were collected for the determination of short chain fatty acids (SCFA) and medium chain fatty acids (MCA). Plasma samples were collected from the portal vein to determine medium chain fatty acids. For the overall period (days 1-45 post-hatching), chicks in the MCA and ORA groups had a significantly (p<0.05) higher average daily gain and better feed conversion ratio than the CON group. Chicks in MCA, ORA and FOS groups had significantly (p<0.05) higher body weights than the CON group. Chicks in MCA and ORA groups showed a reduction of S. Enteritidis in the ceca which was significantly (p<0.05) lower than the CON group. Chicks in MCA, ORA and FOS groups had a significantly (p<0.05) lower pH of crop and intestines than the CON group. Chicks in MCA group had a significantly (p<0.05) higher disaccharidase enzyme, digestibility of nutrients, SCFA (acetic acid and valeric acid), MCA in plasma than the CON group. In conclusion, chicks in the MCA and ORA groups had a better growth performance, better digestibility, less S. Enteritidis colonization and lower pH in the crop and intestines. Chicks in the FOS group tended to have decreased Salmonella colonization in ceca. The chicks in the MCA and FOS groups had improved disaccharidase activity. Medium chain fatty acids had beneficial effects on increased medium chain fatty acid concentrations in the portal vein and SCFA concentrations in ceca. Therefore, MCA is one of the efficient additives appropriate for Salmonella control in broilers.