Effects of Adding Hydroxytyrosol to the Diet of Pigs in the Nursery Phase on Growth Performance, Biochemical Markers, and Fatty Acid Profile.

This study evaluated the effects of dietary hydroxytyrosol (HT) addition on piglets during the nursery phase across two experiments. In the first, 72 weaned male piglets (~26 days old, 7.3 ± 0.5 kg) were assigned to one of four diets containing 0, 5, 10, or 50 mg HT/kg feed. Growth performance, serum biochemistry, histological and behavioral parameters, and meat lipid profiles were assessed. In the second study, the apparent digestibility of diets containing 0, 25, or 50 mg HT/kg feed was evaluated using 15 male piglets (21.5 ± 1.5 kg) through total excreta collection. Results revealed that HT influenced serum glucose and gamma-glutamyl transferase, histological inflammation, and active behaviors. HT modified lipid profiles, reduced capric, lauric, linolenic, arachidonic, cis-5,8,11,14,17-eicosapentaenoic fatty acid concentrations, and increased the nervonic acid profile. The digestibility of dry matter, organic matter, energy, and protein increased with HT use up to 50 mg/kg of feed. These findings demonstrate that HT positively impacts piglet efficiency, changing the fatty acid profile with increased nervonic acid, highlighting its potential as a dietary additive for improving nursery pig production.