Protein, fats, vitamin and mineral concentrations in porcine colostrum and milk from parturition to 60 days

Abstract

The concentrations of protein, protein fractions, amino acids, total solids, fat, fatty acids, fat soluble vitamins (A, D 3 , E, K 3 ), vitamin C, macro- and micro-elements and biological value of colostrum and milk of 10 Danish Large White, 10 Danish Duroc and 10 Norwegian Landrace sows were determined. The total protein content of the first colostrum (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 24–72 h of lactation with a value of 3.4−3.6%, and non-protein nitrogen, which increased from the beginning (0.41%) to the end of lactation (0.47%). Significant differences were observed between the free amino acid content of colostrum and milk. Colostrum contained less acidic and hydroxy, and more basic amino acids than milk. The concentrations of amino acids in colostrum and milk, similar to the change in total protein, 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 first 5 days of lactation (118–129) than that of milk protein on the 10–60th days of lactation. The first colostrum contained 24.03% total solids and 5.32% fat; these increased to 27 and 13.1%, respectively, at 48–72 h, but decreased afterwards to 18.7 and 6.5%, respectively, at the end of lactation. The fat of sow's milk contained only very low concentrations (in fact just above the limit of identification) of saturated fatty acids with 4–12 C. Sow's milk contained significantly more unsaturated fatty acids than cow's milk; particularly large differences were found in the case of linolenic acid. Sow's milk contained more ash (0.843%), calcium (1965 mg kg −1 ), phosphorus (1510 mg kg −1 ), zinc (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 magnesium (111 mg kg −1 ) than cow's milk, while there were no differences between the two species in manganese content. Potassium, sodium, iron and copper contents decreased, while the concentrations of calcium and phosphorus 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 of 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 milk were 2–3 times those in cow's milk. There were no significant differences among breeds or interaction between breeds and sampling dates relative to the composition of colostrum and milk samples.