Live Yeast or Live Yeast Combined with Zinc Oxide Enhanced Growth Performance, Antioxidative Capacity, Immunoglobulins and Gut Health in Nursery Pigs

SIMPLE SUMMARY: The stress after weaning is the critical problem for nursery pigs. Although antibiotics and zinc oxide (ZnO) could be efficient methods to alleviate weaning stress, the abuse of them might be harmful for the environment. The current study found that live yeast (LY, Saccharomyces cerevisiae (strain CNCM I-4407, 10(10) CFU/g)) or S. cerevisiae combined with ZnO replacing antibiotics and ZnO could enhance performance and reduce the diarrhea rate in nursery pigs via improving their nutrient utilization, antioxidant capacity, immunoglobulins, fecal volatile fatty acid composition, and microbiota community. The results of this study could be helpful for finding some novel strategies replacing in-feed antibiotics and ZnO to alleviate weaning stress in pigs. ABSTRACT: This study aimed to investigate the effects of dietary LY or LY combined with ZnO supplementation on performance and gut health in nursery pigs. 192 Duroc × Landrace × Yorkshire piglets (weaned on d 32 of the age with 9.2 ± 1.7 kg BW) were allocated into four treatments with eight replicate pens, six piglets per pen. The treatments included a basal diet as control (CTR), an antibiotic plus ZnO diet (CTC-ZnO, basal diet + 75 mg/kg of chlortetracycline + ZnO (2000 mg/kg from d 1 to 14, 160 mg/kg from d 15 to 28)), a LY diet (LY, basal diet + 2 g/kg LY), and a LY plus ZnO diet (LY-ZnO, basal diet + 1 g/kg LY + ZnO). The results showed that pigs fed LY or LY-ZnO had increased (p < 0.05) average daily gain, serum IgA, IgG, superoxide dismutase, fecal butyric acid, and total volatile fatty acid concentrations, as well as decreased (p < 0.05) feed conversion ratio and diarrhea rate compared with CTR. In conclusion, pigs fed diets with LY or LY combined with ZnO had similar improvement to the use of antibiotics and ZnO in performance, antioxidant status, immunoglobulins, and gut health in nursery pigs.