Maternal potassium-magnesium sulfate supplementation in low-protein diets improves performance and health of sows and suckling piglets

Minerals such as magnesium and potassium in low-protein diets are critical for the relief of inflammation and enhancement of immune function in sows. This study investigated the potential of potassium-magnesium sulfate (PMS) supplementation on the performance and health of sows and their piglets from d 107 of gestation to weaning. A total of 120 Yorkshire × Landrace sows (parity 3–4; initial body weight 263.62 ± 3.60 kg; d 107 of gestation) were fed low-protein diets supplemented with 0.00, 0.25%, 0.50%, and 0.75% PMS. Compared with the control, 0.50% PMS significantly increased average daily feed intake (ADFI) in sows and average weaning weight in piglets, weight gain per litter, and average daily gain (ADG), while also reducing diarrhea incidence ( P < 0.05). Furthermore, the weaning-to-estrus interval decreased linearly with increasing PMS supplementation ( P = 0.022). Compared with the control, PMS supplementation elevated serum magnesium, potassium, immunoglobulin (Ig) A, IgG and interleukin (IL)-10 levels in sows, and enhanced colostrum/milk magnesium, potassium, protein, and IgG levels ( P < 0.05). Compared with the control, PMS increased serum magnesium, potassium, IgA, IgG, IgM, and IL-10 levels, and reduced IL-1β, IL-6, and tumor necrosis factor-α (TNF-α) levels during lactation ( P < 0.05) in piglets. Microbiota analysis using linear discriminant analysis effect size (LEfSe) and t -tests showed that, compared with the control, 0.50% PMS enriched Ruminococcus_gauvreauii_group , Lachnospiraceae_AC2044_group , Subdoligranulum , and Butyrivibrio in the sow rectum ( P < 0.05). Collectively, these results indicate that PMS supplementation in low-protein diets during lactation can improve the productivity and health of sows and their offspring by alleviating inflammatory responses, improving immune function, and increasing the abundance of short-chain fatty acids (SCFAs)-producing and other potentially beneficial microbiota in the rectum, with 0.50% PMS showing a favorable overall response.