The effect of a low–fat maternal diet on neonatal rats

1. Rats were raised on a low-fat diet containing 6 g fat/kg. Females of the second generation were bred and only 11% of their pups survived to weaning age compared with a 66% survival for control pups. Pups were killed 8–12 h after birth and their tissues were analysed.2. Pups in the low-fat group had smaller body, brain and liver weights than control pups; the lipid contents of body, brain and liver were also significantly less.3. In the liver triglycerides from the control group the C20and C22polyenoic fatty acids constituted 33% of the total fatty acids. The liver triglyceride concentration in the low-fat group was lower and the concentration of the long-chain polyenoic fatty acids in this fraction was 20% of the control value. The milk fatty acids from the low-fat group contained only 33% as much of the C18to C22polyenoic fatty acids compared with the control group.4. In the brain lipids from the low-fat group, changes in the fatty acid composition were less marked than in the liver lipids. In these experiments there were only small amounts of 20:3ω9 in the tissue lipids; the ratio to 20:4ω6 was less than 1.5. These changes are discussed in relation to the influence of dietary lipids on tissue growth especially of lipid-rich tissues such as the brain.