Dietary nucleotide rich yeast extract mitigated symptoms of colibacillosis in weaned pigs challenged with an enterotoxigenic strain of Escherichia coli

A study was conducted to investigate the effect of a nucleotide rich yeast extract (NRYE) on the growth performance and the colibacillosis of weaned pigs. In Experiment 1, a total of 168 mixed-sex piglets weaned at 17 +/- 2 days of age were fed diets formulated to meet or exceed nutrient requirements for 28 days. Diets consisted of i) Positive control (PC) containing antibiotics (110 mg/kg of chlortetracycline HCl and 31.2 mg/kg of tiamulin), ii) Negative control (NC) without antibiotics, iii) NC with the addition of 1 g/kg of NRYE (NRYE1), and iv) 2 g/kg of NRYE (NRYE2). No differences (P > 0.10) were found among treatments for average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR), whilst pigs fed NRYE1 weighed more (P < 0.05) than those fed NC on day 28. Pigs fed the NRYE2 diet had greater (P < 0.05) ADG and ADFI than those fed the NC diet from day 7 to 14. No differences (P > 0.10) were observed in ADFI among dietary treatments. In Experiment 2, a total of 144 barrows were randomly assigned to 4 treatments groups to give 6 replicates (6 pigs per pen) per group. Four treatment diets were similar to previous experiment. Pigs in PC fed a control diet without NYRE supplementation and also did not received an oral challenge. PC treatment was housed in a separate room within the same facility with a similar environment. Pigs in NC, NRYE1 and NRYE2 were fed the non-medicated control diet with 0g/kg, 1 g/kg or 2 g/kg NYRE, respectively and were orally challenged with enterotoxigenic Escherichia coli. K88 + (ETEC) after the 3 days of weaning. From day 3 to 28 post-challenge, pigs fed diets NRYE1 or NRYE2 had greater (P < 0.05) ADG compared with those fed a NC diet. Average daily feed intake and FCR were not affected by dietary treatment throughout the study. Challenged pigs consuming NRYE1 or NRYE2 diets had less (P < 0.05) diarrhea compared with those fed NC diet. The mortality due to coliform infection tended to be higher (P < 0.10) in the challenged NC and NRYE2 pigs compared with PC and NRYE1 pigs. In conclusion, diets supplemented with NRYE enhanced BW, ADG and ADFI of weaned pigs and reduced the incidence of diarrhea in ETEC challenged pigs suggesting that NRYE could be effective in controlling post-weaning diarrhea in piglets, which could represent a major economic advantage to the swine industry.