Hydroxy-Selenomethionine Improves Selenium Status and Antioxidant Capacity Under Heat Stress Conditions

This study investigated whether hydroxy-selenomethionine (OH-SeMet) improves broiler oxidative stress response to a greater extent than sodium selenite (SS) or seleno-yeast (SY) under environmental stress. Day-old male Cobb 500 broilers (12 cages/diet, 9 broilers/cage) were fed a selenium (Se)-deficient diet (0.047 mg Se/kg) supplemented with SS, SY or OHSeMet at 0.3 mg Se/kg for 42 days. Animals were raised at a high stocking density (18 broiler/m²) and during the summer period inducing heat stress conditions (average 1-42 days temperature 33.4°C ± 0.7, average relative humidity 70.9%). OH-SeMet significantly improved the mortality corrected feed conversion ratio (FCR) and Se concentration in pectoral muscle, liver and jejunum as compared with SS (P < 0.05, Table 1). Relative selenoprotein W (SELENOW) quantities were also significantly (P< 0.05) increased by OH-SeMet compared to SS as observed in pectoral muscle (SS:100; SY:128; OH-SeMet:141) and jejunum (SS:100; SY:112; OH-SeMet:324). OH-SeMet increased total antioxidant capacity compared to SS, and it reduced malondialdehyde and protein carbonyl in the muscle more than SY (P < 0.05, Figure 1). Cortisol blood levels were significantly (P< 0.05) reduced by SY and OH-SeMet as compared with SS (SS:22.8; SY:20.3; OH-SeMet:18.9 ng/ml). Circulating anti-inflammatory cytokine IL-10 was higher (P< 0.05) for OH-SeMet compared to SS and SY, indicating a better ability of OH-SeMet to promote an anti-inflammatory response (IL-10: SS:8.7; SY:9.2; OHSeMet:12.4 pg/ml). Intestinal morphology measures indicated that OH-SeMet resulted in higher (P< 0.05) villus height to crypt depth ratio than SS in the duodenum and ileum (SS:3.53; SY:3.93; OH-SeMet:4.14 and SS:3.87; SY:4.80; OH-SeMet:4.76, respectively).

OH-SeMet as a pure organic form of selenium, has the potential to improve Se status, antioxidant capacity and anti-inflammatory response under oxidative stress situation.