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 (control), 0.25%, 0.50%, and 0.75% PMS. Each of the 4 treatments included 30 replicate sows, each sow serving as an experimental unit. 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, total solids, 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 producing and other potentially beneficial microbiota in the rectum, with 0.50% PMS showing a favorable overall response.