The effects of dietary supplemental guanidinoacetic acid (GAA) on performance, biochemical indices and meat pH of broilers with cold-induced ascites were studied. A total of 640 day-old male broiler chicks (Cobb 500) were assigned to four dietary treatments including control diet; control diet supplemented with either 0.6, 1.2 or 1.8 g of GAA per kg of feed. Each treatment was replicated in 8 battery cages (n=20). At day 14, temperature was reduced to amplify the incidence of ascites. The birds fed the control, 1.2 and 1.8 g/kg GAA diets exhibited higher average daily gain (ADG) compared to those fed 0.6 g/kg GAA (P<0.05). Bird fed diet with 1.2 g/kg GAA also showed poorer feed conversion ratio (FCR) compared to birds in other dietary groups (P<0.05). Higher average daily feed intake (ADFI) were observed in birds fed the diet with 1.2 g/kg GAA (P<0.05). The mortality due to ascites was significantly lower in birds fed diet with 1.2 g/kg GAA compared to birds fed the control, 0.6 and 1.8 g/kg GAA diets. Moreover, there was a quadratic effect of GAA levels on mortality due to ascites. No significant effects of dietary treatments on leucocyte subsets and relative weights of lymphoid organs were observed. Lower meat pH was detected in chicks fed the GAA-supplemented diets compared to birds fed the control diet. Dietary GAA supplementation resulted in a linear (P=0.01) and quadratic (P=0.03) responses in meat pH. In conclusion, diet supplementation with GAA had reducing effects on the occurrence of ascites-related mortality in broiler chicks. پرونده مقاله

The objective of this study was to evaluate myostatin (MSTN) gene by polymerase chain reaction -restriction fragment length polymorphism (PCR-RFLP) and sequencing methods in four goat breeds including Mohabadi, Markhoz, Lori and Bital breeds. A573 bp fragment of MSTN gene was amplified by PCR. A new 5 bp deletion in 5`UTR (206TTTTA) of the MSTN gene was directly identified by sequencing. The AA and AB genotypes were observed in all above breeds, while the BB genotype was found only in Mohabadi breed. The AA genotype had the highest genotypic frequency in all breeds. On the other hand, the BB genotype in Mohabadi goat breed had the lowest genotypic frequency. The A allele frequency was higher than that of the B allele in the four breeds investigated in this study. The A allele frequency significantly differed between two (litter size) subgroups in Mohabadi breed. This difference in the allele frequency was not significant in Lori and Mohabadi breeds. Therefore, odds ratios statistics (ORs) showed no significant differences between genotypes for twining rate. Evaluation of MSTN gene 5`UTR region demonstrated the presence of two TATA boxes (important putative regulatory elements) which are located in the promoter region (position 32-36, 56-60) and one E-box (position 42-48) motifs. In conclusion, our results showed that the 5`UTR region polymorphism cannot be a key factor in the occurrence of twining in the above native goat breeds. It seems that more studies in large populations are needed to investigate the effect of MSTN gene on twining with more focus on other mutations in MSTN gene or other genes. پرونده مقاله