Egg fat is of considerable importance in the nutrition of the developing chick as a source of energy and essential fatty acids such as linoleic (18:2 n-6) and α-linolenic (18:3 n-3) acids. During incubation, yolk lipids provide fatty acids that are utilized for energy, synthesis of polyunsaturated fatty acids (PUFA)-rich membrane phospholipids, and eicosanoids by the embryo. Eicosanoids derived from n-6 fatty acid are more potent and pro-inflammatory than eicosanoids derived from n-3 fatty acids.
Two models of early life programming as affected by n-3 PUFA are investigated. Egg PUFA enrichment through breeder hen diet (pre-hatch or in ovo) or early post-hatch (within first 5 hours) feeding is investigated. Early access to nutrients (pre- and early post-hatch) is important because in broiler hatchlings that are selected for rapid early growth much of the immune system development occurs early in life. However, the current industry practice of feeding breeding hens diets high in n-6 fatty acids, limits the supply of essential n-3 PUFA in the hatchling. Early access to n-3 PUFA through in ovo or early post-hatch diet led to: (1) increase in the retention of n-3 PUFA in cell membranes, (2) reduction in plasma non-esterified fatty acids, (3) reduced production of pro-inflammatory eicosanoids, (4) suppression of cell-mediated immunity, and (5) alteration in cyclooxygenase-2 protein expression. The effects of an early exposure persisted from 14 to 35 days in different tissues and cells.
Given the fact that broiler birds are raised for 39 to 56 days, and that the effect of pre-hatch and early post-hatch nutrition persists for up to and over 36-47% of post-hatch life, using an early life programming approach will generate new knowledge about the role of maternal and early post-hatch diet in enhancing bird health and welfare.