Effect of Dietary Levels of Hydroxy-Selenomethionine on Growth Performance, Meat Quality, Tissue Selenium Content and Glutathione Peroxidase Activity in Lambs

This study aimed to compare the effects of hydroxy-selenomethionine (OH-SeMet), a novel organic selenium (Se) source, with sodium selenite (SS) on growth performance, carcass characteristics, meat quality, serum glutathione peroxidase (GSH-Px) activity, and Se concentrations in the serum and meat of lambs. Twenty-one Kıvırcık male lambs (3–4 months old; 26.96 ± 4.83 kg body weight) were assigned to one of three treatment groups in a randomized complete block design following a 10 days adaptation and 56 days feeding period. The lambs were individually fed concentrate-based diets supplemented with 0.2 mg Se/kg dry matter (DM) from SS (SS-0.2 group), or 0.2 and 0.4 mg Se/kg DM from OH-SeMet (OH-SeMet-0.2 and OH-SeMet-0.4 groups, respectively). Results showed no significant effects of Se source or dose on growth performance, carcass yield, or meat quality. However, OH-SeMet significantly increased Se concentrations in both serum and longissimus dorsi muscle compared to SS ( P < 0.001). Notably, 0.2 mg Se/kg from OH-SeMet increased meat Se content by 61.17% compared to SS, and Se accumulation in muscle increased linearly with OH-SeMet dose. No differences were observed in serum GSH-Px activity among groups. These findings suggest that while OH-SeMet does not affect growth or meat quality under normal conditions, it is more effective than SS in enhancing tissue Se deposition. Thus, replacing SS with OH-SeMet may be a viable strategy for producing Se-enriched lamb meat with higher nutritional value for human consumption.