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.

Staphylococcus aureus causes intramammary infections (IMIs), which are refractory to antibiotic treatment and frequently result in chronic mastitis. IMIs are the leading cause of conventional antibiotic use in dairy farms. Phage therapy represents an alternative to antibiotics to help better manage mastitis in cows, reducing the global spread of resistance. A mouse mastitis model of S. aureus IMI was used to study the efficacy of a new cocktail of five lytic S. aureus-specific phages (StaphLyse™), administered either via the intramammary (IMAM) route or intravenously (IV). The StaphLyse™ phage cocktail was stable in milk for up to one day at 37 °C and up to one week at 4 °C. The phage cocktail was bactericidal in vitro against S. aureus in a dose-dependent manner. A single IMAM injection of this cocktail given 8 h after infection reduced the bacterial load in the mammary glands of lactating mice infected with S. aureus, and as expected, a two-dose regimen was more effective. Prophylactic use (4 h pre-challenge) of the phage cocktail was also effective, reducing S. aureus levels by 4 log10 CFU per gram of mammary gland. These results suggest that phage therapy may be a viable alternative to traditional antibiotics for the control of S. aureus IMIs.

Modern pig farming practices, characterized by highly-productive and fast-growing genetics, early weaning, and uncontrolled factors such as heat stress and various nutritional challenges, impose cumulative stress on the animal. Elevated concentrations of reactive oxygen species within cells can compromise cellular function and decrease reproductive performance of breeding stock and the growth of progeny up to market age, and deteriorate pork quality, ultimately causing economic losses. Antioxidants and micronutrients can be supplemented in animal feed to alleviated the adverse impact of oxidative stress on pig health and production performance. Selenium is an essential micronutrient required for an efficient antioxidant defense system. Se-enriched yeast serves as a natural source of organice selenium. Its effectiveness in improving selenium (Se) assimilation and oxidative status in modern pigs, especially under intensee stress conditions, has been well documented. This review aims to address oxidative stress challenges encountered by pigs during commercial production and elaborate on the capacity of organic Se to mitigate oxidative stress in pigs. Se-enriched yeast provides biologically and nutritionally important amounts of SeMet and SeCys. The review summarizes evidence that, compared wtih inorganic Se, dietary Se-enriched yeast effectively alleviates oxidative stress in pigs while enhancing production performance and pork quality.

Weanling piglets, with immature immune system and physiological functions, often experience post-weaning diarrhea. This study investigated the effects of combined supplementation of live yeast and yeast postbiotics on the growth performance, antioxidant capacity and intestinal health of weaned piglets. A total of 224 weaned piglets (22 days old) were randomly assigned to four groups: a basal diet (CON) or the same diet supplemented with 1600 ppm zinc oxide (ZnO), high-dose live yeast and yeast postbiotics (LYYP-H), or low-dose live yeast and yeast postbiotics (LYYP-L). The trial lasted 28 days, with diets divided into 2 phases. The results showed that dietary combined supplementation with live yeast and yeast postbiotics did not significantly affect the average daily gain (ADG), average daily feed intake (ADFI), or the diarrhea rate (p > 0.05). However, dietary combined supplementation with live yeast and yeast postbiotics significantly enhanced fecal consistency in piglets (p < 0.05). Moreover, dietary combined supplementation with live yeast and yeast postbiotics significantly improved representative antioxidant indices, notably superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and strengthened immune capabilities; additionally, a marked improvement in intestinal morphology was observed (p < 0.05). In conclusion, the combination of live yeast and yeast postbiotics can improve antioxidant capacity and intestinal health and show the potential to replace high doses of ZnO during the first two weeks post-weaning.