Addition of neem seeds (Azadirachta indica A. Juss) to fattening pig diets

Neem products are biologically and pharmacologically active and could therefore serve as alternatives to antibiotics in pig feed. This study evaluated the effects of adding ground neem seeds (GNS) to the diets of fattening pigs on growth performance, carcass characteristics, and the physicochemical properties of the meat. In the growing and finishing I phases, 32 and 31 pigs, respectively, were used to evaluate five dietary treatments: control diet (T1), control diet + antibiotic (oxytetracycline, T2), control diet + 0.1% GNS (T3), control diet + 0.2% GNS (T4), and control diet + 0.3% GNS (T5). In the finishing II phase, 13 pigs were used to evaluate T1, T2, and T3, and the physicochemical properties of the meat from these pigs were determined. The study used a completely randomised, unbalanced experimental design. In growing pigs, 0.2% GNS reduced feed intake, while the other growth performance variables and carcass characteristics were not affected by the level of GNS inclusion. In the finishing I phase, 0.3% GNS reduced feed intake and the feed-to-gain ratio; however, there were no significant effects on the other measured variables. In finishing II pigs, GNS supplementation did not modify growth performance; however, 0.1% GNS modified the meat pH, L*, and a* values. Ground neem seeds at higher inclusion levels may improve the feed efficiency of pigs, but may also have a negative effect on some meat quality parameters. (Submitted 17 November 2022; Accepted 25 August 2025; Published 30 September 2025)