Abstract

This paper discusses recent work by the authors which has investigated the nutritional regulation of glycogenconcentration in skeletal muscle of sheep and cattle. Several experiments are summarised which show a clear relationshipbetween the level of glycogen in muscle and the intake of metabolisable energy. This translates into strong seasonal effectson the level of muscle glycogen in pasture fed cattle that correlate with live weight change. The clear message is thatanimals destined for slaughter should be on a high plane of nutrition as this will contribute to an increased level of muscleglycogen at slaughter and so help alleviate the problem of dark cutting meat. Acute regulation of glycogen is moreproblematical since the rate of glycogen repletion in skeletal muscle is relatively slow and the scope for rapid dietarychange in ruminants is constrained by the need to allow rumen adaptation to high starch/sugar diets. However the suddenintroduction of a high energy diet (based on cereal grain) in the presence of a ‘rumen modifier’ to reduce ruminal acidosiscan increase muscle glycogen concentration within 1 week of feeding. The ability to further modify glycogen level inskeletal muscle using carbohydrate and electrolyte products is discussed. In particular the possibility of using oral glycerol/propylene glycol as a means for increasing blood glucose and so glycogen synthesis is proposed. Experiments to examine the effectiveness of MgO as a means for reducing the stress response are also discussed.

DW, Pethick, L Cummins, GE Gardner, RH Jacobs, BW Knee, M McDowell, BL McIntyre, G Tudor, PJ Walker, and RD Warner

Proceedings of the New Zealand Society of Animal Production, Volume 60, Hamilton, 94-98, 2000