Hatching egg polyunsaturated fatty acids and the broiler chick

Abstract

Transgenerational effects of certain nutrients such as essential fatty acids are gaining increased attention in the field of human medicine and animal sciences as a new tool to improve health and animal performance during perinatal life. Omega-3 (n-3) and omega-6 (n-6) fatty acids are denoted by the position of the first double bond from methyl end of the hydrocarbon chain. Alpha-linolenic acid (18:3 n-3) and linoleic acid (18:2 n-6) are essential n-3 and n-6 fatty acids and cannot be synthesized by the vertebrates including chickens. Alpha-linolenic acid and linoleic acid are the parent fatty acids of long chain (> 20-22C) n-3 and n-6 polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (20:5 n-3, EPA), docosapentaenoic acid (22:5 n-3/or 22:5 n-6, DPA), docosahexaenoic acid (22:6 n-3, DHA) and arachidonic acid (20:4 n-6). As components of cell membrane phospholipids, PUFA serves as precursors of eicosanoids, act as ligands for membrane receptors and transcription factors that regulate gene expression and are pivotal for normal chick growth and development. Considering the role of egg lipids as the sole source of essential fatty acids to the hatchling, dietary deficiencies or inadequate in ovo supply may have repercussions in tissue PUFA incorporation, lipid metabolism, chick growth and development during pre and early post-hatch period. This review focus on studies showing how maternal dietary n-3 or n-6 fatty acids can lead to remodeling of long chain n-3 and n-6 PUFA in the hatching egg and progeny chick tissue phospholipid molecular species and its impact on chick growth and PUFA metabolism during early life.

Keywords: Chick; Egg; Fatty acid molecular species; Phospholipids.

Fig. 1

Lipid components in egg^*. ^*Gram per egg based on an average egg with 16 g yolk. TAG = Triacylglycerol, PC = phosphatidylcholine; PE = phosphatidylethanolamine, PS = phosphatidylserine; PI = phosphatidylinositol; LPC = lysophosphatidylcholine, Chol = cholesterol; SM = sphingomyelin

Fig. 2

Changes in fatty acid molecular species of egg yolk phosphatidylcholine as affected by maternal dietary high n-3 or low n-3 fatty acid diet. High n-3 and Low n-3 represent breeder hen diet containing 3.5% fish oil or sunflower oil as the source of long chain n-3 fatty acid or n-6 fatty acid (linoleic acid). *Significantly different (P < 0.05). n = 6

Fig. 3

Pattern of phosphatidylcholine and phosphatidylethanolamine transfer from hatching egg to the chick embryo during incubation. PC = phosphatidylcholine, PE = phosphatidylethanolamine, E = embryonic age. The weight of PC and PE in in egg yolk or remnant yolk sac (g) from day one of incubation through hatching period. n = 8

Fig. 4

Fatty acid composition of newly hatched chick cardiac tissue from eggs high or low in n-3 fatty acids. High n-3 and Low n-3 represent breeder hen diet containing 3.5% fish oil or sunflower oil as the source of long chain n-3 fatty acid or n-6 fatty acid (linoleic acid). LC = long chain (> 20C). *Significantly different (P < 0.05). n = 6

Fig. 5

Post hatch changes in arachidonic acid content in the cardiac ventricle (mg/100 g) of progeny chicks as affected by maternal diet. High n-3 and Low n-3 represent breeder hen diet containing 3.5% fish oil or sunflower oil as the source of long chain n-3 fatty acid or n-6 fatty acid (linoleic acid). Chicks were fed a diet devoid of long chain n-3 or n-6 fatty acids during the 42-day feeding trial. *Significantly different (P < 0.05). n = 6

Fig. 6

Post hatch changes in the cardiac tissue phospholipid molecular species in the cardiac tissue of progeny chicks at day 14 of age as affected by maternal diet. High n-3 and Low n-3 represent breeder hen diet containing 3.5% fish oil or sunflower oil as the source of long chain n-3 fatty acid or n-6 fatty acid (linoleic acid). PC = phosphatidylcholine; PE = phosphatidylethanolamine. Hatched chicks were fed a diet devoid of long chain n-3 or n-6 fatty acids during the 42-day feeding trial. All bars significantly different (P < 0.05). n = 6

Fig. 7

Post hatch changes in the cardiac tissue phospholipid classes of progeny chicks at day 14 of age as affected by maternal diet. High n-3 and Low n-3 represent breeder hen diet (2800 kcal and 16.5% CP) containing 3.5% fish oil or sunflower oil as the source of long chain n-3 fatty acid or n-6 fatty acid (linoleic acid). PC = phosphatidylcholine; PE = phosphatidylethanolamine, PS = phosphatidylserine; PI = phosphatidylinositol; LPC = lysophosphatidylcholine SM = sphingomyelin. Hatched chicks were fed a diet devoid of long chain n-3 or n-6 fatty acids during the 42-day feeding trial. *Significantly different (P < 0.05). n = 6

Fig. 8

Body weight gain of progeny chicks as affected by maternal diet. High n-3 and Low n-3 represent breeder hen diet containing 3.5% fish oil or sunflower oil as the source of long chain n-3 fatty acid or n-6 fatty acid (linoleic acid). All the chicks were fed the same diet devoid of long chain n-3 or n-6 fatty acids during the 42-day feeding trial. *Significantly different (P < 0.05). n = 6