SOUTHERN ELEPHANT SEAL (MIROUNGA-LEONINA) .2. STUDIES OF MILK PROTEIN-FRACTIONS BY GEL-ELECTROPHORESIS

Milk protein fractions during various stages of lactation in the south ern elephant seal Mirounga leonina were analysed. Twelve milk samples were taken from ten females throughout the lactation period during 199 0 and 1991 at Stranger Point, King George Island, South Shetland Islan ds. Milk samples were subjected to polyacrylamide gel electrophoresis (PAGE). Samples from different days of lactation gave similar qualitat ive electrophoretic patterns. True protein content was significantly h igher (P < 0.05) at the beginning of lactation, and then remained cons tant until weaning. Caseins and whey proteins each consisted of severa l protein entities (four and five distinct bands respectively). Casein constituted only about 30% of the protein nitrogen, the remaining 70% being derived from whey proteins. There was some variation in concent ration of casein and whey proteins as a function of time (P < 0.0.5).