抄録
The effect of maintenance (zero-energy balance) and submaintenance (negative-energy balance) feeding, and of subsequent compensatory growth (repletion) on chemical and bio-chemical aspects of lamb L. dorsi muscle were studied. Maintenance and submaintenance feedings were found to cause marked decrease in the contents of lipid, sarcoplasmic proteins and free amino acids nitrogen, while increase in water and stroma proteins (including alkali-soluble and alkali-insoluble stroma fractions) of muscle. Besides the amount, the physico-chemical nature of stroma (connective tissue) was also changed by nutritional stress, where by the ‘acid-stable’ cross-linkages in the structure increased significantly. The myofibrillar pro-teins, however, decreased only in the case of submaintenance feeding regime.
Almost all the chemical characteristics of muscle from repleted lambs were statistically comparable to those of respective control. However, myofibrillar proteins (on a fat-free, dry weight basis) were slightly less and stroma proteins were slightly high with relatively more ‘acid-stable’ cross-linkages in muscle from the lambs which experienced compensatory growth. In the light of these results the previous concepts of ‘labile proteins reserve’ and ‘fixed’ proteins in muscle have also come under secrutiny.
