Effects of a yeast-dried milk product in creep and phase-1 nursery diets on growth performance, circulating immunoglobulin A, and fecal microbiota of nursing and nursery pigs

Four experiments were conducted to evaluate effects of yeast-dried milk (YDM) product in creep and phase-1 nursery diets. In Exp. 1, 24 parity-4 litters were allotted to 3 dietary treatments (8 litters/treatment) including no creep (NC), control creep (CTL), and experimental creep (EC; 10% YDM). Creep diets were fed twice daily from d 7 after birth until weaning (23.6 ± 1.8 d). In Exp. 2, 108 weaned pigs were selected based on mean BW of pigs from the respective treatments in Exp. 1. For phase 1 (d 0 to 7 postweaning) of Exp. 2, NC and CTL pigs were fed the CTL diet and EC pigs continued to receive the EC diet. For phase 2 and 3 (d 7 to 28 postweaning) of Exp. 2, all pigs received a common diet containing antibiotics. Blood and fecal samples were collected on d 0, 7, 14, and 21 postweaning to evaluate serum IgA and fecal microbiota. In Exp. 1, pigs fed EC and CTL tended to have greater (P < 0.10) weaning BW compared with NC pigs. Pigs fed EC had greater (P < 0.05) ADFI compared with CTL pigs. In Exp. 2, pigs fed EC tended to have greater BW (P < 0.10) and greater ADG (P < 0.05) and ADFI (P < 0.01) compared with CTL and NC pigs (d 0 to 28). For serum IgA, EC and CTL pigs tended (P < 0.10) to have greater IgA compared with NC pigs. For microbial data, EC pigs had greater (P < 0.01) microbial diversity compared with CTL (d 7 postweaning). On d 7 and 21 postweaning, microbial similarity decreased (P < 0.01) in pigs fed EC compared with NC and CTL. Overall (d 0 to 14), lactobacilli gene copy numbers tended (P < 0.10) to be greater in EC (7.3 log₁₀) compared with NC pigs (6.9 log₁₀). In Exp. 3, 23 parity-1 litters were allotted to 3 dietary treatments as described for Exp. 1. In Exp. 4, 108 weaned pigs were selected based on mean BW of all pigs from Exp. 3 and dietary treatments were the same as described for Exp. 2 except no antibiotic was included in phase-2 diet. In Exp. 3, there were no treatment effects on litter ADFI, ADG, and serum IgA, but a tendency (P < 0.10) for lower Lactobacillus reuteri in the CTL (5.1 log₁₀) compared with NC pigs (5.6 log₁₀) was observed. Overall (d 0 to 21) in Exp. 4, pigs fed EC had greater ADG (P < 0.01) and G:F (P < 0.05) and tended to exhibit greater ADFI (P < 0.10) compared with the CTL. For microbial data, pigs fed CTL (4.8 log₁₀) and EC (4.8 log₁₀) had lower (P < 0.01) fecal Lactobacillus johnsonii compared with NC (5.2 log₁₀). Microbial ecology and immune parameters are affected by YDM.