Influence of stress on gene expression and broiler meat quality / Influência do estresse pré-abate na expressão gênica e qualidade da carne de frango (Gallus gallus)
AUTOR(ES)
Erik Amazonas de Almeida
DATA DE PUBLICAÇÃO
2007
RESUMO
Brazilian broiler production yields a considerable amount of income for the nation. Brazil is currently the world's third broiler producer and the first chicken meat exporter, contributing with 41% of the whole world market. To reach new market frontiers it is inevitable the improvement of meat quality. Among the reasons that influences final products quality is the preslaughter stress. This study scoped establishing the relationships between meat quality and gene expression under thermal stressful conditions. Commercial broiler lines were submitted to high thermal stress prior to slaughter. Breast meat from these animals had their proprieties evaluated. Differentially expressed genes for stressed or non-stressed birds were investigated by macroarrays and further validated by qRT-PCR. Concerning to the meat attributes, breast meat from stressed birds was darker (L* values of 52,46 against 55,00; p<0,05), with lower pH at 24h postmortem (5,82 against 5,99; p<0,05) and had greater water holding capacity 1h after slaughter (0,29 vs. 0,22; p<0,05). Macroarray analysis revealed 259 differentially expressed genes between stressed and non-stressed control birds. From these, 149 were induced by heat stress (p<0,05). Some of these induced genes play a role in carbohydrate metabolism such as lactate dehydrogenase A (LDHA), glucose phosphomutase and piruvate kinase. Such enzymes acts on degradation of glucose in order to provide energy to the muscle cells which has direct effect upon meat quality processing. These findings suggest great mobilization of muscle glycogen stores, offering opportunity of a not efficient muscle-to-meat conversion. Genes that responds to heat stress damage also were induced with heat exposure. That provides a sort of heat tolerance and ensures the birds' survival under heat conditions. Some muscle-related genes were also induced by heat stress. Myostatin, actin 3 and IGFII showed greater amounts of mRNA under this condition (p<0,05). Among all genes differentially expressed, 9 were picked up for further studies with qRT-PCR. Myostatin, lactate dehydrogenase A and B, HSF1, HSF3, HSP70, HSP90, glycogen phosphorylase and citrate synthase were studied and only myostatin, HSP 70 and 90 confirmed the differentially expressed patterns between treatments (p<0,05). Unlikely, glycogen phosphorylase appeared repressed in heat stressed animals (p<0,05). These findings suggest an important role of energetic metabolism of birds at hot environments.
ASSUNTO(S)
abate heat stress gallus gallus expressão gênica frangos de corte carnes e derivados qualidade gene expression meat quality
Documentos Relacionados
- Bem-estar animal no manejo pré-abate e a influência na qualidade da carne suína e nos parâmetros fisilógicos do estresse
- Chicken meat quality: effects of pré-slaughter severe heat stress, color classification and marination
- Métodos de transporte e períodos de descanso pré-abate sobre nível de estresse e qualidade de carne de ovinos
- Macroscopia, histopatologia e bacteriologia de fígados de frangos (Gallus gallus) condenados no abate
- Relação vitamina E: vitamina C sobre a qualidade da carne de frangos submetidos ao estresse pré-abate