پژوهشهای علوم دامی ایران (Apr 2016)
Evaluation of α-tocopherol acetate, peel and extract pomogrante antioxidative potential in diet contained fish oil on meat quality boiler chicken
Abstract
Introduction Poultry meat enriched with long-chain polyunsaturated fatty acids n-3 (PUFA Lc n-3) can make a nutritionally meaningful contribution to Western diets in which consumption of PUFA Lc n-3 is low. Enrichment of poultry meat with this fatty acid is usually achieved by inclusion of fish oil in broiler diet (23, 24). However, meat enriched in this way is susceptible to quality deterioration by lipid oxidation during storage or cooking, leading to reduction in nutritive value and accumulation of lipid oxidation products (10). Oxidation is a very general process affecting lipids, pigments, proteins, DNA, carbohydrates, and vitamins (11). The objective of this study was to evaluate the effects of dietary α-tocopherol (α-Toc), pomegranate peel extract (PPE) and pomegranate peel (PP) on fatty acid profile, aoxidation and phenolic compounds in raw thigh and breast meat during refrigeration. Materials and methods Peels of pomegranate were harvested in October 2011 from pomegranate trees (Ardestani, variety) in Khorasan Razavi province (East, Iran). Dried powders of peels (2.5 g) were extracted with 40 mL of methanol solvent at room temperature for 6 hours. Three hundred and eighty four 1-d-old male broiler chicks (Ross 308) were randomly allotted to 8 groups with 4 replicates of 12 birds. Eight dietary treatments including control diet without feed additives, control diet mixed with 200 mg/kg α-Toc, control diet mixed with PPE (100, 200 and 300 mg/kg), and control diet mixed with PP (1, 2 and 3 g/kg). In all diets 2% fish oil were added to enhance the enrichment of unsaturated n-3 fatty acid in birds. One broiler chick was randomly selected from each pen of 42 d of age. The antioxidative potential and various meat quality characteristics were determined on 0, 7, and 11 days of refrigerated storage. Total phenols content in the aqueous supernatant was estimated by the Folin-Ciocalteu method (33). 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was estimated according to Blois’ (2). Lipid oxidation in sample was determined as the TBARS value by using the method described by Ahn et al. (1). Fatty acid profile of samples was determined by gas chromatography (7). Data were subjected to ANOVA using the GLM procedures of SAS (27). Results and discussion The FA composition of the diets, particularly PUFA Lc n-3, was modified and increased by the inclusion of fish oil in diet. The concentration of saturated fatty acid in the thigh and breast meat was not influenced in broilers fed PP, PPE, and α-Toc diets as compared to control group. The results indicated that the tissue of broilers have a limited capacity for alteration of their saturated fatty acids (7). Monounsaturated fatty acid (MUFA) content in thigh and breast was decreased in birds fed diet containing PP, PPE and α-Toc compared to control group (P
