PSIII-4 Effect of Two Torula Yeast Sources on Growth Performance, Intestinal Health, and Immune Function of Weanling Pigs

Abstract

Abstract An experiment was conducted to test the hypothesis that dietary inclusion of either a conventional or a novel source of torula yeast in diets for weanling pigs improves growth performance and intestinal health. The novel torula yeast was produced using forestry byproducts (i.e., wood hydrolysate) as the carbon source, whereas the conventional torula yeast was produced using wheat dextrose as the carbon source. A total of 120 weanling pigs (6.53 ± 0.78 kg) were allotted to three treatments with four pigs per pen and ten replicate pens per diet. Pigs were fed one of three diets from d 1 to 14 post-weaning (phase 1), whereas all pigs were fed a common diet in phase 2 (d 15 to 28). The three dietary treatments included a control diet that contained 5% fishmeal, 3.5% plasma protein, and no torula yeast. The second diet contained 1.5% fishmeal, 14% of the novel torula yeast, and no plasma protein, whereas the third diet contained 1.5% fishmeal, 14% of the conventional torula yeast, and no plasma protein. Pig weights were recorded on d 1, d 14, and d 28. Feed allotments were recorded daily, and feed left in the feeders was recorded on d 14 and 28 to calculate average daily gain, average daily feed intake, and average gain to feed ratio. Fecal scores were visually assessed every other day. On d 7, one pig per pen was euthanized to collect ileal tissue for assessment of morphology. At the end of phases 1 and 2, blood samples were collected, and cytokines, plasma urea nitrogen, peptide YY, immunoglobulin G, total protein, and albumin were analyzed. Data were analyzed using an ANOVA in the Mixed Procedure of SAS with pen as the experimental unit. Diet was the fixed effect, whereas weaning weight was the random effect. Results indicated that both sources of torula yeast could replace fish meal and plasma protein without negatively affecting overall growth performance, intestinal morphology, or blood characteristics of pigs (Table 1). Pigs fed one of the diets containing torula yeast had reduced (P < 0.05) fecal scores during phase 1 compared with pigs fed the control diet. On d 14, pigs fed the conventional torula yeast diet had greater (P < 0.05) concentration of interleukin-2 in plasma compared with pigs fed the control diet. Greater (P < 0.05) concentrations of interleukin-4 and interleukin-10 were observed in plasma from pigs fed one of the diets containing torula yeast compared with pigs fed the control diet on d 14. In conclusion, inclusion of either a conventional or a novel source of torula yeast at the expense of animal proteins in diets for weanling pigs may improve intestinal health without influencing growth performance of weanling pigs.