Ventilatory biomechanics

Here at the University of Manchester Dr Jonathan Codd and Dr Peter Tickle combine expertise in respiratory biology, biomechanics and metabolism to increase understanding of the changes that occur in broilers during growth. In particular, we are interested in how the growth of very large breast muscles affects how these birds breathe. This is because chickens often suffer from a variety of health problems, likely related to the stress placed upon the heart and lungs by the development of substantial muscles.

Therefore we are implementing a variety of research approaches in order to measure how chicken breathing biology changes during development. By mapping how the skeleton changes and breathing muscles grow in the egg all the way through to adulthood, we can establish whether chickens can breathe effectively, or if it may become more difficult as they age. The pictures below show how we measure the skeletal changes in the broiler chicken (this one is 15 days into it’s incubation period, a few days away from hatching). Blue areas correspond to cartilage while pinker areas are bone (bird skeletons change from cartilage to bone as they develop). We are particularly interested in how the ribs, sternum (breastbone) and uncinate processes (little hooked bones that connect to the ribs) develop, shown in the picture on the right, since these bones are a critical part of the breathing system. You can see that there are areas of cartilage, ┬ámeaning that these bones are immature and may not function well as stiff struts for muscles to pull upon.









Extending this research theme, we are also working towards an understanding of how energy is used by broiler chickens. Using state-of-the-art gas analysis technology we are able to work out how much energy is being used by a chicken by measuring the rate of it’s oxygen consumption and carbon dioxide production. Birds are allowed to rest quietly inside a large, clear box, from which we take a sample of air. This air is pumped through our gas analysers and then we can calculate how much energy is being consumed, or more technically, the bird’s metabolic rate. We aim to work out how changing body size may alter the amount of energy required to move around, breathe, sit and stand in the broiler.

Shown above: 2, 4, and 6-week old broiler chickens. Watch their behaviours and note how different the activity levels are in these birds. We seek to understand why there is this change during growth, and how to potentially alter it to promote greater activity and health in older chickens.

Cluck away!