Evaluation of the activity and mechanisms of oregano essential oil against PRV in vivo and in vitro.

BACKGROUND: The Pseudorabies Virus (PRV) leading to pseudorabies and causes huge economic losses in pig industry. The development of novel PRV variations has diminished the efficacy of traditional vaccinations, and there is yet no medication that can stop the spread of PRV infection. Therefore, PRV eradication is challenging. Oregano essential oil, the plant-based ingredient for medication feed have been shown to has strong anti-herpesvirus activity, but no anti-PRV function has been reported. RESULTS: The current study assessed the anti-pseudorabies virus (PRV) activity of oregano essential oil and explored its mechanisms and most effective components against PRV. Our in vivo findings demonstrated that oregano essential oil could decrease the PRV load in tissues, mitigate tissue lesions, and enhance the survival rate of mice. The potential antiviral mechanism involves augmenting humoral and cellular immune responses in PRV-infected mice. To further investigate the most effective components of oregano essential oil against PRV, an in vitro study was conducted, revealing that oregano essential oil and its main constituents, carvacrol and thymol, all diminished PRV intracellular proliferation in vitro. Carvacrol exhibited the most potent anti-PRV effect, serving as the primary contributor to oregano essential oil's anti-PRV activity. The mechanisms underlying carvacrol's anti-PRV properties include the upregulation of cytokines TNF-α, IFN-ß, IFN-γ, IL-12, and the inhibition of PRV-induced apoptosis in BHK-21 cells. CONCLUSIONS: Our study provides an effective drug for the prevention and control of PRV infection.

Research progress on diarrhoea and its mechanism in weaned piglets fed a high-protein diet.

In order to pursue faster growth and development of weaned piglets, increased dietary protein (CP) levels were favoured by the pig industry and the feed industry. The digestive organs of piglets were not fully developed at weaning, and the digestive absorption capacity of protein was limited. High-protein diets can cause allergic reactions in piglets, destroy intestinal structural integrity, reduce immunity, and cause intestinal flora imbalance. Undigested proteins were prone to produce toxic substances, such as ammonia and biogenic amines, after fermentation in the hindgut, which negatively affects the health of the intestine and eventually causes reduced growth performance and diarrhoea in piglets. This review revealed the mechanism of diarrhoea caused by high-protein diets in weaned piglets and provided ideas for preventing diarrhoea in weaned piglets.