Muscular pH and related traits in rabbits: a review

• Autores: F. Hulot, J. Ouhayoun
• Localización: World Rabbit Science, ISSN-e 1989-8886, ISSN 1257-5011, Vol. 7, Nº. 1, 1999, págs. 15-36
• Idioma: inglés
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• Dialnet Métricas: 13 Citas
• Resumen

  • After reviewing muscular biology and general relationships between muscular physico-chemistry and meat quality, this review analyses the variations in muscular pH and related traits in rabbits. Among biological factors (muscle, age, genotype, family), muscle factor is the most important. lt determines the differences in ultimate pH (pHu) between muscles, which can reach 0.7 units and which are due to differences in the fibre typology. lncrease in glycolytic metabolism during muscle growth is accompanied by pHu lowering; its variation depends on the precocity of muscle development. Comparative studies of breeds do not show any evidence of differences in pH above 0.2 units; no breed presents abnormal acidification or pHu kinetics, which might entail anomalies in Water Holding Capacity or other qualitative traits in meat. Wlthln breed, the existence of correlations between pHu and growth characteristics may lead to a reduction in meat quality when strains are selected for weight productivity. The effect of dietary faetors is relatively small. When they can be detected, pH variations mostly correspond to modifications in growth rate. Thus the pHu of meat is lowered when growth is stimulated by a high level of nutrition or a high protein content. Slaughter faetors have a marked influence on muscular pH. Transport leads to a noticeable rise in pHu, a result of ante mortem depletion of glycogenic reserves; when subjected to prolonged stress, meat is darker and has a higher water holding capacity. Electroanaesthesia accelerates muscular acidification without modifying pHu. careass ehllling slows down the physico-chemical processes of rigor mortis: it slows down the fall in pH and reduces the intensity of sarcomere retraction. Even when chilling is intense, in spite of sorne contradictions in published literature, the phenomenon of "cold shortening" does not seem to be of major significance in rabbits. During meat storage in refrigerated form, after a certain latency period, the maturation processes are witnessed by de-amination of the proteins and thus by a raised pH. Freezing slows down this process, but does not avoid a rise in pH after several months in storage.