Effects of Different Selenium Sources on Performance, Carcass Characteristics, Blood Metabolites and Immune Response of Broilers under Heat Stress Condition

Heat stress is one of the serious issue in poultry industry which causes significant economic losses. Decreasing feed consumption, increasing excretion and decreasing the bioavailability of nutrients during heat stress reduces the performance and immune response. Selenium is an essential trace element for humans and animals that plays a role in improving the antioxidant status and the immune system and inflammatory response. The goal of this study was to investigate the effects of different selenium sources [2-hydroxy-4- methyl seleno butanoic acid, selenomethionine and sodium selenite) on performance, carcass characteristics, antioxidant and immune response and blood characteristics in broiler under heat stress condition.

This experiment was conducted in a completely random designs with 240 Arbor Acres (Male) broilers chicks. Chicks were randomly distributed in 4 treatments and 6 replicates (10 chicks in each replicate). The experimental treatments include that: (1) basal diet + 0.3 mg 2-hydroxy-4- methyl seleno butanoic acid; (2) basal diet + 0.3 mg selenomethionine per kilogram of diet; (3) basal diet + 0.3 mg sodium selenite per kilogram of diet; (4) The basal diet that did not have any additives. The birds were kept at 32-340C (10.00 to 16.00; for 6 hours) from 22 to 42 days.

The results of this experiment showed that feed intake, body weight gains and feed conservation ratio were not affected by the experimental diets. The use of different sources of selenium had no significant effect on blood biochemical factors in broiler chickens under heat stress. dding selenium source with 0.3 mg/kg 2-hydroxy-4- methyl seleno butanoic acid significantly affected immunoglobulin G in comparison to other treatments. Diets containing selenium sources significantly increased the relative weight of the spleen compared to the control treatment (P < 0.05). The treatments of 2-hydroxy-4- methyl seleno butanoic acid and selenomethionine significantly decreased liver weight percent. The concentration of glutathione peroxidase, superoxide dismutase and catalase enzymes in blood were significantly increased by selenium sources in different treatments.

The use of selenium source improved the immune system and blood antioxidant status in broiler chickens.