Role of nutrition in reducing antemortem stress and meat quality aberrations

ABSTRACT Antemortem stress reduces economic returns to beef, swine, and lamb producers whether animals are sold based on live weight or on carcass and quality grades. Physiological responses to antemortem stress include dehydration, electrolyte imbalances, negative energy balance, glycogen depletion in muscle, and catabolism of protein and fat. Consequently, events in the 24- to 48-h period immediately before slaughter influence many economic carcass traits, including live weight shrink, carcass yield, meat quality aberrations such as DFD and PSE meat, and intramuscular fat retention. The provision of small quantities of key nutrients either immediately before or after transport can reduce tissue dehydration or improve rehydration and reduce catabolism of muscle protein, glycogen, and lipid. Such improved homeostasis during exposure to unavoidable stress also improves animal well-being. Notably, the provision of electrolytes, at the correct tonicity, during the antemortem period improves water retention and repletion in carcass tissues and reduces acid-base and electrolyte imbalances. Supplementation of gluconeogenic amino acids seems to reduce tissue catabolism, maintain muscle glycogen, and prevent DFD meat. Certain nutrients such as specific amino acids and magnesium may modify the hypothalamic-pituitary-adrenal axis, influencing the physiological response to stress. Modification of the diet for a short period (1 to 2 d) immediately before livestock transport and(or) providing a relatively small amount of a nutrition supplement during lairage offer potential to improve carcass yields, improve quality grades through increased retention of marbling, and reduce meat quality defects.

Implications

Novel events to which domestic animals are exposed in the antemortem environment include transport, handling, mixing, and time off feed and water. These events are known to stimulate the hypothalamic-pituitary-adrenal axis and to drive a number of physiological changes including dehydration, energy depletion, ion depletion, and protein catabolism. These physiological changes have a significant economic impact on carcass yield and meat quality. Nutritional supplementation during the antemortem period has been shown to be effective in attenuating these conditions, thereby improving animal welfare, carcass yield, and meat quality.

Key Words: Beef, Meat Quality, Nutrition, Pork

© 2001, by the American Society of Animal Science. All rights reserved.

J. Anim. Sci. 2001. 79:E91-E101