Nutritional importance of colostrum in the piglet

Suckling of colostrum by piglets is very important in order to improve the survival rate. Colostrum provides maternal antibodies, energy and protein. Rearing piglets suckling an artificial milk of a similar chemical composition to that of sow's milk failed when the animals were housed in conventional conditions although numerous research workers succeeded in rearing 90% of animals delivered and fed in sterile conditions. Studies on the chemical analysis of colostrum showed a high dry matter content (30-40% higher than that of milk) in particular a high protein level (twice that of milk). The high proportion of globulins, i.e. 38% during farrowing, drops to 12% of the protein 4 days later; conversely the casein content rather low at birth doubles over the same period. Colostrum proteins are not used to proved energetic nutrients; some of them are absorbed without hydrolysis and have a special physiological rôle. The transmission of maternal immunity by gamma globulins is well known; lactotransferrin plays an important rôle as a transporter and a bacteriostatic factor. Enzymatic proteins such as lyzozyme govern the metabolism of glycoproteins. Hydrolyzed albumins, casein and proteose-peptone fraction provide the essential amino acids for de novo protein synthesis. The fat content is relatively low during the first 24 hours and increases threefold in the 4 days after farrowing. It provides the majority of the energy required by the young animal. A high proportion of some fatty acids, mostly oleic and linoleic acids, are used preferentially as sources of energy. Other components, including enzymes of the mammary cells, were found, but their particular rôle has not been explained. Colostrum contains in addition numerous vitamins (vitamins A and E) and some particular trace elements (iodine and selenium), and their transfer from the maternal diet to the young is particularity efficient by colostrum suckling. The nutritional rôle of those nutrients is important and their levels could affect the survival rate of the piglets. Hypotheses concerning the digestion and absorption of nutrients and antibodies are summarized, and finally, recommendations are made for further research and for the minimum amount of colostrum required by each piglet for survival and efficient postnatal growth to be assessed.