[Effects of different dietary levels of selenium on metabolic parameters and humoral immunity in broiler chickens]

ABSTRACT

Selenium is an essential trace mineral and has a profound impact on immune function, health and productive performance. An experiment was conducted to evaluate the effects of dietary selenium in different levels on performance and humoral immunity in broiler chicks. Male broiler chicks [Arbor Acres, 1-d old, n=225] were randomly assigned to 3 treatment groups of 5 replicates each including 15 chicks per replicate in a completely randomized design arrangement. Chicks were offered three levels of selenium including basal diet [no supplemental dietary selenium], diets containing selenium as recommended by NRC [0.15 mg/kg diet] and 0.3 mg/Kg diet. Birds in each pen were injected with 0.2 mL of 5% sheep red blood cell [SRBC] solution at days 21 and 35 via intrapectoral injection. Blood collection was done at 7 and 14 days later and total IgY and blood metabolites were determined. Addition of selenium to diets did not make significant difference in daily weight gain, feed intake and feed conversion ratio [FCR]. Selenium supplementation to diets resulted in significant effect on blood cholesterol, high density lipoprotein cholesterol [HDL-C] and low density lipoprotein cholesterol [LDLC-C] [p<0.05]. It had no effect on triglyceride and very low density lipoprotein cholesterol [VLDL-C]. Diets with 0.3 mg selenium increased total IgY titer and gammaglobulins 7 days after secondary injection [p<0.01]. Different levels of selenium did not make significant effect on performance and weight of spleen and bursa. These results indicated that selenium at higher levels can improve humoral immunity and blood biochemical parameters