Effects of dietary selenium and vitamin E on immune response and biological blood parameters of broilers reared under thermoneutral or heat stress conditions

Abstract

A study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125 and 250 mg/kg), selenium (Se, 0, 0.5 and 1 mg/kg), or their different combinations on immune response and blood biological parameters of broilers raised under either thermoneutral (TN, 23.9 °C constant) or heat stress (HS, 23.9 to 37 °C cycling) conditions. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Heterophil to lymphocyte (H/L) ratio also determined as an indicator of stress. Furthermore, at the end of the experiment, birds were bled for determination of some biological parameters. There was a significant reduction in body weight and feed intake, but the feed conversion ratio increased when the birds were exposed to HS (P<0.05). Body weight and feed intake were not influenced significantly by dietary vitamin E and Se (P>0.05), whereas feed conversion was improved significantly by 125 mg/kg vitamin E (P<0.05). The liver and lymphoid organ weights as well as IgM and IgG, antibody titers for primary and secondary antibody responses to SRBC were reduced significantly under HS (P<0.05). Heat stress also resulted in a significant increase in H/L ratio (P<0.05). Dietary vitamin E resulted in improvement of primary and secondary antibody responses both in TN and HS broilers (P<0.05). The HS birds also showed an improved antibody titer in secondary response with high concentration of Se (P<0.05). Vitamin E and Se had interactive effects on anti-SRBC titers; however, no consistent differences were found between dietary levels during the study. The H/L ratio decreased by feeding vitamin E at both levels either under HS or TN conditions (P< 0.05). The serum concentrations of glucose, triglycerides, total cholesterol, and LDL-cholesterol were increased but serum HDL-cholesterol decreased in HS broilers (P<0.05).

Effect of dietary supplementation with &lt;i&gt;Rhizopus oryzae&lt;/i&gt; or &lt;i&gt;Chrysonilia crassa&lt;/i&gt; on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

“…With this taken into account, C. crassa seemed to be beneficial for improving the resistance of HS chickens to pathogens. The HS has been attributed to the increase in LDL concentration in broilers (Habibian et al, 2014). Accordingly, our result showed higher LDL level in HS-CONT than in CONT and HS birds provided with either CAS or C. crassa.…”

<b>Heat stress and vitamin E in diets for broilers as a mitigating measure

“…Vitamin E is one of the vitamins supplemented in the diets, at different levels, as it is essential for the integrity of reproductive, muscular, circulatory, nervous and immune systems of the animals (Habibian et al, 2014). The inclusion of vitamin E in feed for broiler has resulted in positive effects on growth performance when supplemented at higher levels during heat stress (Bou et al, 2004;Souza et al, 2011).…”

Vitamin E and organic selenium for broilers from 22 to 42 days old: performance and carcass traits

“…Habibian et al (2013), in a study with broilers in a cyclic-heat stress environment with temperature ranging from 23.9 to 37°C, supplementing poultry diets with three levels of vitamin E (0, 125, 250 mg/kg) and three levels of selenium (0, 0.5, and 1.0 mg/kg), found lower weight gains, feed intake, and feed conversion in the animals subjected to high temperature. The selenium and vitamin E levels did not affect weight gain or feed intake; however, the vitamin E level of 125 mg/kg improved the feed conversion of birds at 49 days old.…”

“…The use of antioxidant vitamins and minerals such as selenium and vitamin E alone or combined, in broiler diets, can minimize the effects of stress caused by high temperatures due to the effect of freeradical sequestration and consequently improve the growth performance of birds (Marmoud and Edens 2005, Choct et al 2010, Habibian et al 2013.…”