Effects of Microencapsulated and Nanoemulsified β-Carotene on Antioxidant and Anti-Inflammatory Function in Weaned Piglets

β-carotene has excellent antioxidant and anti-inflammatory activities. However, its poor chemical stability and susceptibility to oxidative degradation strongly limit its practical application. Therefore, encapsulation technology serves as a crucial delivery method to achieve the bioavailability of β-carotene. The study aimed to explore effects of microencapsulated and nanoemulsified β-carotene on antioxidant and anti-inflammatory function in weaned piglets. A total of 147 healthy weaned piglets with similar initial body weight (7.75 ± 0.09 kg) were randomly divided into three groups: control group (CON), microencapsulated β-carotene treatment group (B1) and nanoemulsified β-carotene treatment group (B2). Results showed that the two β-carotene preparations remarkably improved growth performance, antioxidant capacity and immunity of weaned piglets compared with the CON group (p < 0.05). In tissues of liver, jejunum and colon, B1 and B2 groups increased antioxidase activity (CAT, SOD, T-AOC) and concentrations of anti-inflammatory cytokines (IL-2, IL-4, IL-10, IFN-γ), with reduced MDA and pro-inflammatory cytokines (IL-1β, IL-6, IL-12, TNF-α) contents. Both B1 and B2 treatments improved intestinal barrier function and optimized jejunal microbial composition compared with the CON group (p < 0.05). The B2 group exerted far superior antioxidant and anti-inflammatory effects compared with the B1 group (p < 0.001). In conclusion, the nanoemulsion delivery system can improve antioxidant and anti-inflammatory function of β-carotene in weaned piglets compared with the traditional microencapsulated form. Our findings provide a theoretical basis for the popularization and application of nanoemulsified β-carotene to improve the bioavailability of β-carotene.