Dietary supplementation of organic selenium could improve performance, antibody response, and yolk oxidative stability in laying hens fed on diets containing oxidized fat.

The present study was carried out to investigate the effect of dietary supplementation of organic selenium (Se) on performance, egg quality indices, and yolk oxidative stability in laying hens fed diets with different fat sources. A total of 270 Hy-line W-36 Leghorn hens of 47 weeks of age were randomly distributed into the 5 replicate cages of 9 dietary treatments. Experimental diets consisted of a 3 × 3 factorial arrangement of treatments with three different fat sources (soybean oil, SO; yellow grease, YG; and palm fat powder, PFP) and three different levels of supplemental Se (0, 0.2, and 0.4 mg/kg of diet) as supplied by zinc-L-selenomethionine (ZnSeMet) complex, which fed during a 77-day feeding trial including 7 days for adaptation and 70 days as the main recording period. Results showed that the highest (P < 0.05) egg weights assigned to the hens fed on SO-supplemented diets. Hen-day egg production was affected by both dietary fat source (P < 0.01) and Se level (P < 0.05) throughout the trial period. Regardless of dietary fat source, dietary supplementation of ZnSeMet improved (P < 0.05) egg mass during all trial periods. Moreover, the significant (P < 0.05) fat  source× Se interactions were observed for egg mass, so that dietary supplementation with 0.4 mg/kg Se was more effective in diets supplemented with YG. Although feed intake was not affected by experimental diets during the first 35-day period, dietary inclusion of PFP reduced feed intake during both second 35-day (P < 0.01) and entire trial period (P < 0.05). The best (P < 0.01) feed conversion ratio during the first 35-day period was assigned to the birds fed on SO-diets, followed by those fed YG-diets. Dietary supplementation of ZnSeMet improved (P < 0.05) feed efficiency during the first 35-day period. Supplementation of ZnSeMet into the diets increased yolk index, with more impact in hens fed on YG-diets. The highest concentration of yolk malondialdehyde was observed in YG-fed groups, and ZnSeMet supplementation of diets decreased (P < 0.05) yolk malondialdehyde. The highest (P<0.01) glutathione peroxidase activity was observed for hens fed on diets supplemented by YG, followed by those on SO-diets. Although different fat sources had no effect on antibody titer against Newcastle disease virus, supplemental ZnSeMet improved (P < 0.05) antibody response. The present findings indicate that dietary supplementation of ZnSeMet could improve performance parameters and egg oxidative stability in laying hens, with the highest impact in diets containing oxidized (high peroxide values) fat sources.