Effect Of Different Selenium Sources On Antioxidant Capacity And Immunity In Lipopolysaccharide Challenged Broilers

Reactive oxygen species are produced and degraded by aerobic organisms. The excessive quantities produce oxidative stress. Selenium (Se) is involved in the regulation of glutathione peroxidase enzymes, one of the important enzymes in antioxidant system. It increases the bioavailability of nutrients. Thus, increase the antioxidant capacity and immunity of the living body. The GPX4 and iodothyronine deiodinases type 1(D1), are important selenoproteins that can be used as a biomarker for Se determination in broilers. Lipopolysaccharide (LPS), endotoxin, increased the nitric oxide. LPS decreased the antioxidant capacity and increased the lipid peroxidation. It also reduced the activity of D1 in the liver that controls the major conversion of T4 to T3 in the body. LPS also increased the production of pro-inflammatory cytokines in the cells mainly involved in the immunity in living organisms.This study reports about:(1) the effect of different Se sources on growth performance, nutritive composition, Se content, antioxidant capacity, oxidative stability and sensory evaluation of broiler breast meat stored at 4℃ for 12 days. (2) It also tells us about the effect of different concentrations of NaCl on antioxidant enzyme activities, total antioxidant capacity and lipid peroxidation of Se enriched broiler breast meat stored at 4℃ for 12 days. (3) This study also gives us information about the Se contents, antioxidant enzyme activities, total antioxidant capacity and thiobarbituric acid reactive substances (TBARS) of serum and liver in broilers. It tells us about the thyroid hormones, mRNA expression of GPX4 and D1 selenoproteins in the liver of broilers. (4) The Se contents, antioxidant enzyme activities, total antioxidant capacity and thiobarbituric acid reactive substances (TBARS) of serum and liver in broilers. It tells us about the thyroid hormones; mRNA expression of GPX4 and D1 selenoproteins in the liver of LPS challenged broilers. (5) Dietary selenium attenuates lipopolysaccharide-induced inflammatory cytokines secretion in broilers.1. Effects of Dietary Sodium Selenite and Selenium Yeast on Antioxidant Enzyme Activities, Oxidative Stability, Meat Quality and Effect of Sodium Chloride on Antioxidant Capacity of Broilers Breast MeatThe effects of sodium selenite (SS) and selenium yeast (SY) alone or in combination (MS) on the selenium (Se) content, antioxidant enzyme activities (AEA), total antioxidant capacity (TAC), oxidative stability, meat quality, effect of different concentrations on antioxidant capacity of broilers breast meat were investigated.600 day old chicks with similar body weight were divided into 5 treatments. Each treatment had 6 replications with 20 broilers in each replicate. The results showed that there was no influenced of different Se sources and their levels on average daily gain and feed conversion ratio, however, the average daily feed intake was lower in SY and MS supplemented groups as compared to control and SS groups. The moisture and fat contents were highest in broilers breast meat of control group.There was no affect of Se sources on protein content among all treatments. The ash content was higher in control and MS groups. The highest (P<0.05) GSH-Px activity was found in the SS supplemented broilers breast meat; however, SY and MS treatments significantly increased (P<0.05) the Se content and the activities of CAT, T-SOD, and TAC, but decreased (P<0.05) the malondialdehyde (MDA) content at 42 days of age. Twelve days of storage at 4℃ decreased (P<0.05) the activity of the GSH-Px, but CAT, T-SOD, and TAC remained stable. Breast muscles pH24h was increased (P<0.05) in SY-IⅡ and MS groups, while, drip loss was significantly decreased at 48 h in breast muscles of MS group. The supplementation with SY and MS decreased the cooking loss of breast meat. The supplementation of SY-II and MS decreased the color lightness values; however, MS supplementation increased the color redness values of breast meat of broilers. NaCl significantly increased (P<0.05) thiobarbituric acid reactive substances (TBARS) values expressed as MDA content. TBARS values increased (P<0.05) and GSH-Px activity decreased (P<0.05) during 12 days of storage at 4℃, but CAT and T-SOD activities and TAC were stable. SY decreased the lipid peroxidation (LO) more effectively than SS in broilers breast meat. SY and MS are more effective than SS in increasing the AEA, TAC, and oxidative stability of broilers breast meat. It was also found that NaCl accelerated LO in breast meat of broilers stored for 12 days at 4℃.2. Effect of Different Se Sources on Antioxidant Enzyme Activities, Total antioxidant Capacity, MDA Content, Thyroid hormones, Expressions of Hepatic mRNA GPX4 and Dl in BroilersThe effect of supplementation of different Se sources (SS or SY), alone or in combination on serum and liver on Se contents, antioxidant capacities, LO, thyroid hormones, mRNA expressions of hepatic GPX 4 and D1 were investigated in the broilers at 42 days of age. Six hundred one day old chicks with similar body weight were procured from local hatchery. 5x6x20 factorial design was used in this study. It was found that Se supplementation significantly increased (P<0.05) the Se contents, AEA, TAC and decreased (P<0.05) the MDA contents in both serum and liver of broilers. SY supplementation had significant increased (P<0.05) of serum T3 hormone at 42n d of age. The higher levels of Se supplementation significantly decreased (P<0.05) the hepatic mRNA expression of D1 in broilers. However, expression of GPX4 mRNA was highest (P<0.05) in the MS group (0.30 mg/kg diet) as compared with Se supplemented and control groups. The concentration of Se required for the maximum expression of D1 mRNA in chicken hepatocytes was lower than Se concentration required for the maximum expression of GPx4 mRNA at 21st and 42nd d of age in broilers.3. Effect of Different Dietary Selenium Sources on Antioxidant Capacity, Thyroid Hormones, Hepactic GPX4 and D1 mRNA Expression and Immunity in LPS Challanged BroilersExposure of broilers to LPS induces immune responses that result in reductions of growth performance and antioxidant capacity and increase in MDA content. The present study was designed to investigate the protection of SY, if any, in lipopolysaccharide (LPS) challenged birds. Two hundred and eighty eight one day old chicks were allotted into 3 treatments and fed experimental diets, control diet (0.11 mg/kg Se) without any Se supplementation, or diets containing 0.3 mg/kg SS or SY. Half of the birds from each treatment were challenged with 0·9% NaCl solution or LPS (250mg/kg body weight) on 16,18 and 20 days of age. The results were evaluated to ascertain the feasibility of SY in LPS challenged broilers. The results indicated that significant decrease (P<0.05) in growth performance, Se contents of serum and liver in LPS challenged broilers. In LPS challenged birds significantly increased (P<0.05) the activities of serum alanine aminotransferase, aspartate aminotransferase. It was also found that malondialdehyde level was increased (P<0.05) and the activities of GSH-Px, CAT, T-SOD, total antioxidant capacity were decreased (P<0.05) in both serum and liver of LPS challenged broilers. The serum T3, T4, and TSH hormones were decreased (P<0.05) after LPS injections in the broilers. Birds with 0.3 mg/kg SY markedly reduced (P<0.05) the pathological changes in liver and decreased the serum PGE2 secretion in LPS challenged birds as compared to other groups. It was also found that when LPS-challenged birds were pretreated with 0.3 mg/kg SS or SY, they significantly increased (P<0.05) the plasma and hepatic concentrations of interferon-y, IL-1(3, IL-2, and IL-8. Also, significant decreased (P<0.05) of hepatic reactive oxygen species and phosphokinase C activity in birds pretreated with 0.3 mg/kg SS or SY. In conclusion, Se supplementation attenuated the oxidative stress by reducing the levels of MDA and restoring the levels of GSH-Px, CAT, T-SOD activities and TAC in LPS challenged broilers. The expression of hepatic mRNA GPX4 and D1 had no influence in LPS challenged broilers. The SS and SY were able to prevent LPS-induced inflammation response in broilers but SY was more effective than SS.ConclusionThe results of our all experiments indicated that SY may have ability to increase the Se contents of different organs, antioxidant capacity, immunity and decresed the lipidoxidation in LPS challenged or without LPS challenged broilers. It may also have potential to increase the oxidative stability of breast meat, mitigate the adverse affects of NaCl on antioxidant capacity and MDA content in refrigerated broilers breast meat stored for 12 days at 4℃.