The purpose of this study was to evaluate the effects of different levels of potassium magnesium sulfateon (PMS) on growth performance, diarrhea rate, intestinal morphology, antioxidant capacity, intestinal immunity, and gut microbiota in weaned piglets. A total of 216 weaned piglets were randomly divided into six dietary groups: the basal diet with 0% (CON), 0.15, 0.3, 0.45, 0.6, and 0.75% PMS. The results showed that the ADFI of 29–42 days and 1–42 days was linearly and quadratically increased by the PMS supplementation (P < 0.05), and significantly reduced the diarrhea rate in weaned piglets (P < 0.05). Moreover, dietary supplementation with PMS significantly reduced the serum adrenaline and noradrenaline levels in weaned piglets (P < 0.05). Furthermore, 0.3% PMS significantly increased the activity of glutathione peroxidase (GSH-Px) in the jejunum (P < 0.05) and tended to increase the activity of superoxide dismutase (SOD) in the jejunal mucosa of piglets (P < 0.1). Additionally, dietary supplementation with PMS significantly reduced the interleukin-1β (IL-1β) level in the jejunal mucosa (P < 0.05), and 0.3% PMS increased the serum IgM content in piglets (P < 0.05). Furthermore, the analysis of colonic microbiota by 16S RNA sequencing showed that the addition of PMS increased the Shannon index (P < 0.05) and Observed Species index (P < 0.05). Based on linear discriminant analysis effect size (LEfSe) and T-test analysis, the addition of PMS increased the relative abundance of Ruminococcaceae and Peptostreptococcaceae in the colonic digesta (P < 0.05). Spearman analysis showed that there was a positive correlation between intestinal GSH-Px activity and the relative abundance of Peptostreptococcaceae. These results showed that dietary supplementation with PMS could improve growth performance, alleviate diarrhea incidence, and modulate the antioxidant capacity and intestinal immunity in weaned piglets, which was partially related to the significant changes in colonic microbiota composition.

IntroductionMore effective and environment-friendly organic trace minerals have great potential to replace the inorganic elements in the diets of livestock. This study aimed to investigate the effects of dietary replacement of 100% inorganic trace minerals (ITMs) with 30–60% organic trace minerals (OTMs) on the performance, meat quality, antioxidant capacity, nutrient digestibility, and fecal mineral excretion and to assess whether low-dose OTMs could replace whole ITMs in growing-finishing pigs' diets.MethodsA total of 72 growing-finishing pigs (Duroc × Landrace × Yorkshire) with an initial average body weight of 74.25 ± 0.41 kg were selected and divided into four groups with six replicates per group and three pigs per replicate. The pigs were fed either a corn-soybean meal basal diet containing commercial levels of 100% ITMs or a basal diet with 30, 45, or 60% amino acid-chelated trace minerals instead of 100% ITMs, respectively. The trial ended when the pigs' weight reached ~110 kg.ResultsThe results showed that replacing 100% ITMs with 30–60% OTMs had no adverse effect on average daily gain, average daily feed intake, feed/gain, carcass traits, or meat quality (P > 0.05) but significantly increased serum transferrin and calcium contents (P < 0.05). Meanwhile, replacing 100% ITMs with OTMs tended to increase serum T-SOD activity (0.05 ≤ P < 0.1), and 30% OTMs significantly increased muscle Mn-SOD activity (P < 0.05). Moreover, replacing 100% ITMs with OTMs tended to increase the apparent digestibility of energy, dry matter, and crude protein (0.05 ≤ P < 0.1) while significantly reducing the contents of copper, zinc, and manganese in feces (P < 0.05).DiscussionIn conclusion, dietary supplementation with 30–60% OTMs has the potential to replace 100% ITMs for improving antioxidant capacity and nutrient digestibility and for reducing fecal mineral excretion without compromising the performance of growing-finishing pigs.