Changes in the activity of skeletal muscle calcium-activated neutral proteinase (EC3. 4. 22. 17) and its specific inhibitor in chickens grown at different rates in response to graded levels of dietary protein

Abstract

1. Two experiments are reported in which the effect of alteration in growth rate on the levels of avian skeletal muscle calcium-activated neutral proteinase (EC 3 . 4 . 2 2 . 17) (CANP or calpam) and its specific inhibitor (calpastatin), a system thought to be implicated in myofibrillar catabolism, was studied by means of manipulation of dietary protein concentration.2. In Expt 1 broiler chicks were given free access to diets containing 105, 149, 197 and 212 g protein/kg for 20 d. In Expt 2 the four dietary treatments were 119, 141, 182 and 227 g protein/kg diet given for 16 d. Chick growth rate and total leg skeletal muscle weight significantly increased ( P < 0.001) with increasing dietary protein concentration in both experiments. Total skeletal muscle protein increased with the level of dietary protein, the effect being significant ( P i 0.01 and P < 0,001 in Expts 1 and 2 respectively).3. Minced leg muscle was homogenized in low-salt buffers, and the extract chromatographed on DEAEcellulose to separate proteinase and inhibitor activity. The partially purified CANP enzyme and inhibitor proteins were present at a concentration broadly consistent with literature reports, and their elution characteristics and Ca" concentration dependence were not varied by dietary protein concentration.4. Both the muscle CANP and CANP inhibitor activities (units/kg muscle) exhibited upward trends with growth rate and increased muscle weight. However, these differences were not statistically significant ( P > 0.05) and were not present at all when the results were expressed as units/g muscle protein.

Comparison of calpain and calpastatin activities in skeletal muscle of broiler and layer chickens

“…As a result, calpain and calpastatin activities respectively were in the ranges 0-624 to 0-896 and 0-286 to 0-422 units/g muscle for broilers and 0-800 to 1-472 and 0-240 to 0-296 units/mg muscle for layer birds (data not shown in the Table). These results are similar to data of Ballard et al (1988), who reported that the calpain and calpastatin activities respectively in skeletal muscle of 16-d-old broilers were in the ranges 0-776 to 1-040 and 0-290 to 0-490 units/g muscle.…”

“…Ballard et al (1988) reported that there were no significant correlations between growth rates that were modified by dietary manipulation and changes in calpain and calpastatin activities in chickens. Higgins et al (1988) demonstrated that there was no direct relationship between dietary restriction and calpain and calpastatin activities.…”

Endogenous Proteolytic Enzymes in Chicken Muscles. Differences Among Strains with Different Growth Rates and Protein Efficiencies

“…Furthermore, Ouali and Talmant (1990) reported large differences in calpain and calpastatin distribution in different muscle types in beef, pork, and lamb. A mixture of different leg muscles was used in the study of Ballard et al (1988). This indicates that it is important to use well-defined muscles when comparing tissue growth characteristics and metabolic variables.…”

“…Johari et al (1993) found the same effects when comparing m-calpain and calpastatin values in layers and broilers. Ballard et al (1988) investigated the effects of alteration of growth rate, induced by different diets, on the levels of m-calpain and calpastatin in chicken leg muscle. They reported no differences between groups with different growth rates.…”

Changes of Calpain and Calpastatin Activities in Skeletal Muscle with Advancing Age in Growing Period of Broiler and Layer Chickens.

“…It is likely that differences among genetic stocks in muscle protein degradation rates are related to proteinase activity in muscle. BALLARD et al (1988) reported that both the muscle calpain and calpastatin activities (units/kg muscle) of chicken exhibited upward trends with growth rate and increased muscle weight, but were not present at all when the results were expressed as units/g muscle protein.…”