THE COLOSTRUM-DEPRIVED PIGLET AS A MODEL FOR STUDY OF INFANT LIPID NUTRITION

The large proportions of arachidonic acid (20:4omega-6) and docosahexaenoic acid (22:6omega-3) in brain and retina structural lipids are important for normal central nervous system function. Study of dietary requirements for omega-6 and omega-3 fatty acids for brain growth is difficult in the human infant because of variabilities in human milk fatty acids, lack of correspondence between blood lipids and central nervous system (CNS) lipids and ethical limits of tissue analyses. Comparison of nutrient requirements, lipid digestion, absorption and transport and milk and brain lipids and the timing of intestinal maturation and the brain growth spurt during fetal-infant development show the piglet to be an excellent choice for studies relevant to lipid nutrition of term gestation infants. Of practical relevance, piglets are easily hand-fed and, with a relatively large body size and rapid growth, provide ample tissue for analyses of the effects of diet fat on specific CNS cell membranes. Use of the piglet to define omega-6 and omega-3 fatty acid requirements and the effects of addition of marine oils to formulas and the lactating mother's diet on the developing CNS are described.