Effects of using polyethylene glycol‏ ‏and sodium bicarbonate to improve the ‎nutritional value of tannin containing diets in broilers

With the aim of investigation, the effects of oak acorn (OA) (0 or 20 % of diet) and tannin-reducing feed additives (without additive, 10 g polyethylene glycol (PEG)/kg of diet and 0.25 % diet sodium bicarbonate) on performance and liver and kidney tissues of broiler chickens, a total of 480 Ross 308 broiler chicks (average body weight of 41 gram and same male to female ratio) were distributed among 6 experimental treatments (4 replicates of 20 birds) in a 2×3 factorial arrangement and reared for 42 days. The results indicated that application of OA had no significant effect of overall feed conversion ratio, but significantly decreased overall body weight gain. However, sodium bicarbonate improved overall body weight gain, compared to the diet without additive. Feeding birds with OA significantly increased relative weight of gizzard, ileum and caecum at 24 d of age and relative weight of caecum and duodenum at 42 d of age. On d 24, more sever cellular congestion was observed in liver tissue of OA fed birds, but on d 42, the number of liver fat vacuole was less in these birds. Feeding with OA increased diameter of renal corpuscle. In conclusion, dietary inclusion of 20% OA had no significant effects on feed conversion ratio and liver as well as kidney tissue of broilers, but because of significant reduction in overall body weight gain and production efficiency factor, this level is not recommended. However, inclusion of additives did not prevent this reduction.