PROTEIN, FATS, VITAMIN AND MINERAL CONCENTRATIONS IN PORCINE COLOSTRUM AND MILK FROM PARTURITION TO 60 DAYS

The concentrations of protein, protein fractions, amino acids, total s olids, fat, fatty acids, fat soluble vitamins (A, D-3, E, K-3) vitamin C, macro- and micro-elements and biological value of colostrum and mi lk of 10 Danish Large White, 10 Danish Duroc and 10 Norwegian Landrace sows were determined. The total protein content of the first colostru m (16.65%) was approximately three times the level in milk at the end of lactation (5.83%). All protein fractions decreased during lactation , with the exception of casein, which reached its maximum between 24-7 2 h of lactation with a value of 3.4-3.6%, and non-protein nitrogen, w hich increased fi om the beginning (0.41%) to the end of lactation (0. 47%). Significant differences were observed between the free amino aci d content of colostrum and milk. Colostrum contained less acidic and h ydroxy, and more basic amino acids than milk. The concentrations of am ino acids in colostrum and milk, similar to the change in total protei n, decreased during lactation. However, when amino acid concentrations were expressed as g AA 100 g(-1) protein, most of the essential amino acids (threonine, cystine, valine) decreased, while the non-essential glutamic acid and proline increased. This explains why the biological value of colostral protein was approximately 11% higher during the fi rst 5 days of lactation (118-129) than thar of milk protein on the 10- 60th days of lactation. The first colostrum contained 24.03% total sol ids and 5.32% fat; these increased to 27 and 13.1%, respectively, at 4 8-72 h, bur decreased afterwards to 18.7 and 6.5%, respectively, at th e end of lactation. The fat of sow's milk contained only very low conc entrations (in fact just above the limit of identification) of saturat ed fatty acids with 4-12 C. Sow's milk contained significantly mole un saturated fatty acids than cow's milk; particularly large differences were found in the case of linolenic acid. Sow's milk contained more as h (0.843%), calcium (1965 mg kg(-1)), phosphorus (1510 mg kg(-1)), zin c (6.49 mg kg(-1)), iron (2.44 mg kg(-1)) and copper (1.34 mg kg(-1)), and less potassium (748 mg kg(-1)), sodium (387 mg kg(-1)) and magnes ium (111 mg kg(-1)) than cow's milk, while there were no differenes be tween the two species in manganese content. Potassium, sodium, iron an d copper contents decreased while the concentrations of calcium and ph osphorus increased during lactation. The concentrations of vitamins A, D-3, E, K-3 and C in colostrum were 1.61, 0.015, 3.69, 0.092 and 68.4 mg kg(-1), respectively, and with the exception as vitamin K-3, were 1.5-2.0 times the levels in late lactation milk (0.92, 0.009, 2.53, 0. 089 and 45.3 mg kg(-1)). These concentrations of vitamins in sow's mil k were 2-3 times those in cow's milk. There were no significant differ ences among breeds or interaction between breeds and sampling dates re lative to the composition of colostrum and milk samples. Copyright (C) 1996 Published by Elsevier Science Limited