Exploration of the Chicken Pituitary Gland

The pituitary gland is a neuroendocrine organ that is involved in several processes within the body such as metabolism, growth, immune function, and reproduction. Increased ambient temperatures are environmental stressor that leads to several welfare concerns in poultry production but also economic losses. Because of the involvement of the pituitary gland in several processes that are affected by heat stress, it is hypothesized this tissue's gene expression will be impacted by heat stress. The objectives of the project are to (a) identify genes that constitue the pituitary gland when compared to other collected chicken tissues (Insert tissues) and (b) identify genes that respond to heat stress via differential expression analysis to better understand the chicken's response to heat at the transcriptomic level. Overall design: Ross 708 broiler chickens were raised from day of hatch to day 42, typical market age, on the University of Delaware farm. Birds were placed into two separate houses, one thermoneutral house and one experimental (heat stress) house. Both houses were kept at 23 hours of light and 1 hour of dark and birds were placed on litter and given feed (meeting all NRC requirements) and water with ad libitum access. Both houses were kept at 35 degrees celsius for the first week and the temperature was decreased 5 degrees celsius each week until 25 degrees celsius. The thermoneutral hosue was maintained at 25 degrees celsius for the remainder of the study. Starting on day 21, the experimental house began a cyclical heat stress scheme with 8 hours per day of increased temperatures (35 - 37 degrees celsius) through completion of the trial at day 42. Necropsies were performed at several points throughout the trial (days 21, 22, 26, 32, and 42).