Lack of protein can harm outward appearance, stress sensitivity, and learning by impairing brain growth and plasticity. While protein enrichment is well studied in mammals and poultry birds, little is known about protein impacts for most birds. Thus, we are studying protein enrichment in the zebra finch, a common avian lab model because its song learning mimics human language learning. While zebra finches mainly eat seeds, protein is increased by consuming insects and young seeds, especially during breeding, and may be beneficial in captivity.
A poor diet results in an unhealthy appearance in humans? Normally, female zebra finches are attracted to males with big, bright, red cheek patches. Since low protein may reduce attractiveness, we will quantify the size and color of male cheek patches and test mate preferences of birds on low and high protein diets. We expect males and females will prefer to associate with mates fed high protein diets.
Ever go on a fad diet and find yourself irritated and jumpy? If a healthy diet lowers stress in zebra finches, baseline and reactive stress hormone levels, the latter induced by holding birds in a breathable cloth bag for 30 minutes, will be lower when fed high protein.
|The Escape Maze||Fear Conditioning Chamber|
We will test two forms of learning: spatial learning and classical conditioning to determine if, like mammals, protein aids learning. The Escape Maze tests birds’ spatial learning, the ability to store and recall locations. We test spatial ability by seeing how many trials it takes for birds to learn to escape a clear cylinder using visual cues hanging around the maze to triangulate the escape hole’s position. In Fear Conditioning, birds are placed in a box, a tone plays, and a small shock is delivered. Birds should learn to take flight to avoid the shock when they hear the tone, similar to Pavlov’s dogs salivating when a bell rang. We expect that a high protein diet will help birds learn at a faster rate than a low protein diet.
After behavioral tests, we will determine if high protein aided brain growth and plasticity in the areas of the brain involved in anxiety, spatial ability, and fear conditioning. If protein has positive impacts, we suggest all lab zebra finches be providing protein supplementation. Such results would suggest that despite inconsistent protein in the wild, zebra finches, like mammals, have an evolutionarily conserved benefit from protein, the building block of life.
- Bonaparte, K. M., Riffle-Yokoi, C., & Burley, N. T. (2011). Getting a Head Start: Diet, Sub-Adult Growth, and Associative Learning in a Seed-Eating Passerine. PLoS ONE, 6(9). https://doi.org/10.1371/journal.pone.0023775
- Burley, N. T., Hamedani, E., & Symanski, C. (2018). Mate choice decision rules: Trait synergisms and preference shifts. Ecology and Evolution, 8(5), 2380–2394. https://doi.org/10.1002/ece3.3831
- Paula-Barbosa, M. M., Andrade, J. P., Castedo, J. L., Azevedo, F. P., Camões, I., Volk, B., & Tavares, M. A. (1989). Cell Loss in the Cerebellum and Hippocampal Formation of Adult Rats after Long-Term Low-Protein Diet. Experimental Neurology, 103, 186–193.
PhD Student, Day Lab