The mammalian testis is an immunoprivileged organ where local tissue-specific cells acquire an effective innate immune function against invading microbial pathogens. The present study demonstrated that mouse Leydig cells had innate antiviral activities in response to viral DNA challenge through p204 activation. The DNA sensor p204 and its signaling adaptor stimulator of interferon (IFN) genes (STING) were constitutively expressed in Leydig cells. Synthetic herpes simplex virus DNA analog (HSV60), a p204 agonist, induced the expression of type I IFNs and various antiviral proteins, including IFN-stimulating gene 15, 2′5′-oligoadenylate synthetase, and Mx glutamyl transpeptidase 1, in Leydig cells. The HSV60-induced innate antiviral response in Leydig cells was significantly reduced by inhibiting p204 signaling using specific small interfering RNAs targeting p204 and Sting. The antiviral response did not affect steroidogenesis in Leydig cells. These results indicated a novel mechanism underlying the testicular innate antiviral response.

Neonatal piglets infected with Porcine Epidemic Diarrhea Virus (PEDV) experience a mortality rate of up to 90%, resulting in significant economic losses to the swine industry in China. Current strategies using specific antibodies in sow milk to prevent Porcine Epidemic Diarrhea (PED) in these piglets through specific antibodies in sow milk is unsatisfactory. Preliminary studies have shown limited success. Emerging evidence suggests that general immune factors in sow milk provide protection to neonatal piglets, particularly, lactoferrin, play a crucial role in protecting piglets by inhibiting PEDV replication. However, the precise mechanism by which lactoferrin exerts its antiviral effects remains unclear. This study sought to clarify these mechanisms through both in vitro and in vivo approaches, proposing that higher concentrations of lactoferrin lead to greater antiviral activity. It was hypothesized that lactoferrin can impede PEDV by blocking its binding to heparan sulfate proteoglycans (HSPG) on the surface of target cells, and molecular docking experiments was conducted to identify the binding sites between lactoferrin and HSPG. Additionally, the findings indicated that lactoferrin can effectively trigger the maturation of porcine dendritic cells and boosts their antigen-presenting functions, thereby improving intestinal mucosal immunity in neonatal piglets against PEDV. Overall, these findings aid to elucidate the antiviral actions and mechanisms of lactoferrin in sow colostrum, offering new insights for the effective prevention and control of PED in neonatal piglets.

Diarrhea in piglets causes intestinal inflammation and epithelial damage. Weaned piglets fed with Bacillus subtilis (B.S) have enhanced intestinal mucosal immunity and reduces diarrhea in piglets. However, the immune system of newborn piglets is immature, and B.S cannot effectively activate the intestinal mucosal reaction when given directly. This research explored the impact of the maternal supplementation of B.S-Dia during the final 35 days of gestation on piglet intestinal development and mucosal immunity. The results demonstrated that B.S-Dia administration significantly increased the body weight, jejunal villus height, and crypt depth in the piglets. In addition, B.S-Dia also significantly increased the proliferative activity of intestinal epithelial cells, as evidenced by proliferating cell nuclear antigen (PCNA) staining and the elevated mRNA expression of the proliferation-related gene (c-Myc). Furthermore, B.S-Dia supplementation also reinforced the intestinal mucosal barrier by increasing goblet cell numbers and upregulating the mRNA expression of antimicrobial peptides, such as Muc2 and Lyz-1. Finally, elevated levels of IL-4 and IFN-γ, along with an increased abundance of CD3⁺ T cells, revealed that the intestinal mucosal immunity of piglets was improved after B.S-Dia administration. Our study indicates that feeding B.S-Dia to sow spromotes intestinal development and improves intestinal mucosal immunity in piglets.

Transportation is a major stressor in swine production, inducing endocrine imbalance, oxidative stress, and immune dysfunction. This study investigated the effects of Astragalus polysaccharides (APS) on transport-induced stress in piglets. Piglets were assigned to a control group (CON), a transport stress group (TS), and two APS-supplemented groups receiving low (APS-L) or high (APS-H) doses. Blood samples were collected on 1, 3, and 7 days post-transportation to assess stress hormones, oxidative status, and inflammatory responses. Compared with the CON group, piglets of TS group significantly elevated norepinephrine (NE) and epinephrine (EPI) levels, increased reactive oxygen species (ROS), reduced glutathione peroxidase (GSH-Px) activity, and upregulated pro-inflammatory cytokines (TNF-α and IL-6). APS supplementation attenuated these transport-induced changes. At 1 day after transportation, piglets in both APS-L and APS-H groups exhibited lower NE, EPI, ROS, TNF-α, and IL-6 levels and higher GSH-Px activity than those in the TS group. The APS-H group showed greater protective effects than the APS-L group. By 3 and 7 days, oxidative and inflammatory parameters in APS-treated piglets gradually normalized, with the APS-H group showing values more comparable to those of the CON group. These results indicate that APS alleviates transport-induced stress by modulating the endocrine response, reducing oxidative stress, and attenuating inflammatory responses. APS supplementation may serve as a nutritional strategy to improve the health and welfare of piglets during transportation.