| dc.description.abstract | Protection of newly hatched chicks against disease depends greatly on innate immunity and maternal antibodies acquired in a passive manner through the yolk sac. The impact of fasting on yolk utilization in fasted vs fed chicks has been well studied; however, the impact of a neonatal fast on the assimilation of maternal antibodies is not well established. Several studies were conducted to examine the impact of a 4-day fast on yolk and IgY assimilation in broiler chicks. The hypothesis was that fasted chicks will catabolize IgY to supply nutrients at the expense of maternal immunity. All chicks hatching within a 2-hour period were immediately placed into one of three treatment groups (Fasted, Water only or Feed and water). Blood samples were collected from the jugular or brachial vein in the first hour post hatch and on day (d) four IgY titers were measured by sandwich ELISA. Blood volume was estimated by treatment using the Evans Blue technique and whole body IgY levels were estimated. Body weights were recorded on d 0, BW and yolk sac weight were measured on d 4. Day 0 BW was not significantly different among the treatments, d 4 BW of the fed group was significantly higher than that of water only and the fasted treatments. Compared to the fasted birds, absolute yolk weight d 4 was significantly lower for the water only and fed birds, relative yolk weight (% of BW) was significantly lower in fed birds compared to fasted or water only treatments. IgY titers did not differ on d 0. Day 4 IgY titers were significantly higher in fasted birds compared to those given water only, which in turn was significantly greater than fasted birds. Blood volume estimates indicated that the blood volume of the fasted chicks was greatly reduced compared to those receiving feed. When total IgY per bird was estimated from blood volume measurements, there were no significant differences among the treatments. The level of the gene expression of the (IL-8, IL-17, and TNF) were measured and were less in the fasting group compared to the fed group.
These data indicate that compared to fed birds, fasted birds and those provided water only do not utilize yolk materials nor assimilate maternal antibodies at differing rates. Indicating that under these conditions, fasted or birds provided water only do not catabolize maternal antibodies at rates differing from fed birds. Gene expression analysis revealed that this will negatively affect the local immunity of intestine. | |
