Bone metabolism and inflammation in modern and random-bred meat- and egg-type domestic fowl

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Modern poultry (meat-type and egg laying chickens) have been intensively genetically selected for over 60years. Meat-type (boiler) chickens have been selected for rapid growth rate, breast muscle deposition, andefficient conversion of feed to muscle. Egg-type chickens (laying hens) have been selected for high levels ofegg production and efficient conversion of feed to egg mass. In both cases, commercial selection has likelyresulted in inadvertent selection against factors that counteract rapid growth or high levels of egg production.The inflammatory response is part of the innate immune system, and can cause systemic effects such asdecreased feed intake, slower growth rate, and decreased egg production. Even mild inflammation may subtlyreduce performance of commercial chickens. The rapid growth rate of broilers reduces the ability of the birdsto properly form bones, and the high output of eggs in layers creates a drain on bone calcium that can lead toosteoporosis. Cells of the inflammatory immune system and cells related to bone metabolism are related, andprevious research has shown that experimentally-induced inflammation has a negative effect on bonemetabolism in chickens.The University of Alberta maintains random-bred lines of chickens that have not been selected for any specifictraits over the last 50+ years. These birds provide a fascinating control to examine the unintendedconsequences of commercial genetic selection. In this research, we will use experimentally-induced systemicinflammation to compare the changes in bone metabolism in modern and unselected meat- and egg-type birds.We will examine the physiological responses to inflammation in each of the lines, as well as the genetic factorsthat control inflammation and bone metabolism.A greater understanding of avian innate immune function will benefit Canada through allowing Canadianpoultry producers to increase productivity and bird welfare, and may benefit Canadian consumers throughincreased confidence in the welfare of poultry raised for food and food safety of poultry food products.