Gastrointestinal and Hepatic Tissue Fatty Acid Composition and Interleukin-6 Concentration in Broiler Chickens: Effect of Maternal Dietary n-3 Fatty Acids
Early exposure to nutrients and fetal programming has gained increased attention because of its association with chick quality and viability. In chickens, the 21-day incubational period contributes to over 35% of a bird’s life span. During this period, the egg provides polyunsaturated fatty acids (PUFA) to the chick embryo. We hypothesized that early exposure of n-3 and n-6 PUFA through egg lipids can alter tissue fatty acid (FA) composition and interleukin-6 (IL-6) production in the progeny chickens during growth. The objectives of the study were to determine: 1) the extent to which maternal (yolk) n-3 or n-6 FA are retained in the duodenum, jejunum, ileum, and liver tissue of the chicken, and, 2) the effect of maternal FA composition on IL-6 concentrations in serum and hepatic tissue in broiler chickens when fed a diet lacking in long chain (>20-C) n-3 and n-6 FA during growth. Fertile eggs obtained from Lohman-Brown layer hens (n=75) fed corn-soy diets supplemented with 3.5% yellow grease, sunflower oil or fish oil were incubated. These fat supplements were selected as sources of saturated, n-6 or n-3 FA. Chicks were raised up to day 14 on a commercial diet lacking long-chain n-6 and n-3 FA. Chick tissues (duodenum, jejunum, ileum, liver, and blood) were collected on day 1, 7, and 14 and were subjected to FA and IL-6 analysis. The egg yolk arachidonic (20:4 n-6) and docosahexaenoic acid (DHA, 22:6 n-3) content was 3.1, 3.6, 1.0 and 1.6, 1.0 and 6.1 for eggs from hens fed yellow grease, sunflower or fish oil diets (P<0.001). The DHA content in duodenum was highest up to day 14 of growth in chicks from fish oil-fed hens (P<0.001). The long-chain n-6 to n-3 ratio was lowest in the duodenum, jejunum, ileum, and liver in chicks hatched from fish oil-fed hens (P<0.001) up to day 14 post-hatch. A significant maternal diet by age interaction was observed for liver and serum IL-6 concentrations (P<0.001). On the day of hatch, chicks from fish oil-fed hens had the lowest liver and serum IL-6 concentrations, whereas at day 14, chicks from fish oil-fed hens had higher liver and serum IL-6 concentrations than chicks from sunflower oil-fed hens (P<0.05). In conclusion, our results indicate that inflammatory pathways and eicosanoid metabolism of broiler chicks can be altered by the maternal dietary ratio of long-chain n-6: n-3 FA.
Keywords: chicken, interleukin-6, n-3 fatty acids