Effects of conjugated linoleic acid. 1. Fatty acid modification of yolks and neonatal fatty acid metabolism

The purpose of this study was to evaluate the effects of conjugated linoleic acids (CLA) on neonatal fatty acid metabolism. In this study, layer hens (n = 40) were divided into four equal groups and subjected to the following treatments. Group A served as the control group, Group B received 1 g CLA every other day, Group C received 1 g CLA every 4th d, and Group D was sham-supplemented with 1 g safflower oil every other day. After 4 mo of feeding, Group B hens exhibited an increase in BW and egg size; however, there were no differences noted in feed consumption among the various treatment groups. At the same time, hens were inseminated with a constant dose of pooled rooster semen to evaluate changes in chick liver and yolk fatty acid metabolism during neonatal growth. At hatch and through 6 d of age, there were no significant differences in breakout data (fertility and numbers of early-, mid-, or late-dead chicks) or chick BW, respectively. However, Group B chicks exhibited an increase in liver 18:3n3 and 22:1n9 and a decrease in 20:3n6 and 22:5n3 fatty acids when compared with chicks from Groups A and D. Also noted for Group B chicks, yolk 18:0 fatty acid was higher than that for Group A and D chicks. These results suggest that CLA alters lipid metabolism in growing chicks.