Effects of the transportation during hot season and electrical stimulation on meat quality characteristics of goat Longissimus dorsi muscle

Abstract

A factorial experimental design was used to study the effects of transportation during the hot season and low voltage electrical stimulation (90V) on physiological, and meat quality characteristics of goats. Twenty male Dhofari goats (12-month old) were divided into two treatment groups: transported for 6h during hot season (42°C day time temperature) or non-transported. Goats were blood-sampled before loading for transportation and prior to slaughter. Five carcasses from each group were randomly electrically stimulated for 60s, nearly 20min postmortem using V1.3-R3B stimulator (7.5ms duration positive pulses only and an output of 90–95V, AgResearch, New Zealand). Ultimate pH, shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and CIE L*, a* and b* color were measured on samples from Longissimus dorsi muscles. The transported goats had higher plasma cortisol (P<0.01), adrenaline, nor-adrenaline and dopamine concentrations (P<0.05) than non-transported goats. Transportation and electrical stimulation for 6h had a significant effect on quality characteristics of meat. Muscles from electrically stimulated carcasses had significantly (P<0.05) lower ultimate pH values (5.68 vs. 5.84), longer sarcomeres (1.67μm vs. 1.46μm), lower shear force values (5.05kg vs. 8.35kg), higher expressed juice (39.5 vs. 37.45) and myofibrillar fragmentation index (MFI) (77.25 vs. 71.45) than those from non-stimulated ones. Electrically stimulated meat had significantly (P<0.05) lighter color than non-stimulated meat based on L* value. Meat from transported goats had significantly higher ultimate pH (5.84 vs. 5.67), expressed juice (40.2 vs. 36.8), shear force (7.85kg vs. 5.55kg), but significantly lower sarcomere length (1.53μm vs. 1.60μm). This study indicated that transporting goats for 6h during hot season can cause physiological responses and deteriorate meat quality characteristics. Applying low voltage electrical stimulation may reduce negative effects of transportation on meat quality characteristics of goats.