Influence of dietary energy and postmortem electrical stimulation on meat quality and collagen characteristics of lamb carcasses

Abstract

Sixty ram lambs, weighing 23.5 kg, were randomly assigned in a 2X3 factorial arrangement of two dietary energy (high; 11.7 and low; 9.0 MJ ME/kg DM) and three levels of poultry offal meal supplementation (0, 5 and 10%). Lambs were fed ad libitum for 120-day before slaughter. At slaughter, half the lambs in each dietary treatment group were randomly selected for electrical stimulation of their undressed carcasses. The M. Biceps femoris pH and temperatures were monitored at 1, 3, 5, 8 and 24 h postmortem, the M. biceps femoris was removed from the right side of each carcass and steaks were obtained for determination of Warner-Bratzler shear force, collagen content and collagen solubility. The results showed that temperature and pH values during the 24-h postmortem were consistently higher (P<0.01) and lower, respectively, for M. biceps femoris from lambs fed high energy diets than for those fed on low energy diets. Muscles from high energy fed lambs had lower (P<0.01) shear force values and higher (P<0.01) percent soluble collagen than for low energy fed lambs; total collagen content was not significantly influenced by dietary energy level. Increased the level of poultry