The Effects of Dietary Manganese and Selenium on Growth and the Fecal Microbiota of Nursery Piglets

SIMPLE SUMMARY: Piglets experience great stress when they are weaned from their mothers at about three weeks of age. One of those types of stress occurs at a cellular level and can impact what types of bacteria can grow and live in the piglets’ digestive systems. There are certain enzymes that fight cellular stress, and certain ingredients (manganese and selenium, two mineral feed ingredients) can be provided to the weaned piglets to boost their stress defense. The objective of this study was to demonstrate how increased mineral concentration in the diet can impact how the pig grows and how it affects the piglets’ digestive systems. This study provides preliminary evidence that a specific mineral, manganese, can impact piglet growth and the gut of the pig in a positive way by decreasing bacteria that are considered to be pathogenic or “bad” and increasing bacteria that are considered to be beneficial or “good”. In this study, selenium had no significant impacts on animal or bacterial growth. This study can be used as a foundation for future research that can dive into greater detail into further application of these minerals in the field of animal nutrition. ABSTRACT: The objective of this study was to determine the impact of varying dietary manganese and selenium concentrations, antioxidant cofactors, on the growth performance and fecal microbial populations of nursery pigs. The piglets (N = 120) were blocked by weight (5.22 ± 0.7 kg) and sex. The pens (n = 5/treatment) within a block were randomly assigned to diets in a 2 × 3 factorial design to examine the effects of Se (0.1 and 0.3 mg/kg added Se) and Mn (0, 12, and 24 mg/kg added Mn) and were fed in three phases (P1 = d 1–7, P2 = d 8–21, P3 = d 22–35). The pigs and orts were weighed weekly. Fecal samples were collected d 0 and 35 for 16S rRNA bacterial gene sequencing and VFA analysis. The data were analyzed as factorial via GLM in SAS. There was a linear response (p < 0.05) in overall ADG across dietary Mn. Supplementing 24 mg/kg Mn tended to decrease (p < 0.10) the relative abundance of many bacteria possessing pathogenic traits relative to Mn controls. Meanwhile, increasing Mn concentration tended to foster the growth of bacteria correlated with gut health and improved growth (p < 0.10). The data from this study provide preliminary evidence on the positive effects of manganese on growth and gut health of nursery pigs.