Effect of adding a microbial phytase and polyethylene glycol to sorghum based diet on growth performance and meat oxidative stability of broiler chickens

This experiment was conducted to investigate the effect of a microbial phytase and polyethylene glycol (PEG) supplementation in sorghum based diet on performance and meat oxidative stability of broiler chickens. A total of 400 one-day old Ross 308 chicks were used by employing a completely randomized design with 5 treatments and 4 replicates. Treatments including a corn based diet with no additive (control), sorghum based diets with no additive or with phytase (500 FTU/kg), PEG (1 g/kg) or phytase‌‌ + ‌‌PEG were fed to birds for a period of 42 days. Digesta and carcass were sampled on day 24 following the slaughter. According to the results, a similar weight gain for chickens on sorghum based diet with no additive (2410.3 g) and control (2442.5 g), and an improved weight gain for those received the additives was observed (P<0.01). Gizzard digesta pH value and ash content of tibia bone of chickens on sorghum based diet were increased by phytase or PEG (P<0.05). The amount of malondialdehyde in breast and thigh meats of broilers fed with sorghum with no additive (0.22 and 0.25 mg/kg respectively) and supplemented with phyatse (0.28 and 0.33 mg/kg respectively) was decreased compared with control (0.34 and 0.40 mg/kg respectively) (P<0.001). In comparison with control phytase declined the cost of feed (15340 vs. 16701 Rls) and increased gross profit (20610 vs. 15593 Rls) (P<0.05). Based on the findings, sorghum can be replaced for corn of broiler diets and its nutritive value can be improved by phytase or PEG supplementation. However, to achieve high meat oxidative stability and economic broiler production using phytase is preferred.

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