EFFECT OF TEMPERATURE ON PORCINE-MUSCLE METABOLISM STUDIED IN ISOLATED MUSCLE-FIBER STRIPS

In the period before and after slaughter, muscle temperature differs b etween pigs, which is likely to influence muscle metabolism. Muscle-fi bre strips were isolated under anaesthesia from six halothane-negative Large White pigs and eight halothane-positive Pietrain pigs and kept in oxygenated Krebs mediwn at 38, 40, or 42-degrees-C, to study the ef fects of temperature on muscle metabolism. During a period of oxygenat ion, contraction measurements were carried out to assess the physiolog ical state of the muscle-fibre strips. Aerated Krebs solution was repl aced by paraffin oil at the same temperature to simulate post-mortem m uscle metabolism. Pietrain muscle-fibre strips were more affected by p reparation methods than Large White muscle strips, which led to a high er metabolite breakdown at the time of cessation of the oxygen supply. Pietrain muscle-fibre strips also showed a larger decrease in twitch- force contraction during the period of oxygenation. A moderate effect of temperature on energy metabolism could be seen in muscle-fibre stri ps of both types of pig, with increasing post-mortem metabolite breakd own at higher temperatures. However, this effect can play only a limit ed role in the tremendous acceleration of the post-mortem pH fall as o bserved in PSE muscle (up to five to ten times the normal rate).