Body lipid composition in the winter fed and control populations of the wild male black grouse ( Lyrurus tetrix L.) in autumn and spring

Abstract

1. 1. Effects of oat feeding during winter on the weight and adipose tissues and their fatty acid composition were investigated in a wild Finnish male black grouse population. 2. 2. The body weight was higher in spring than in autumn in the wild fed black grouse population. In the wild control population no essential change in the body weight was seen. 3. 3. In the fed population the amount of anatomically collected adipose tissue was elevated 150% after feeding period. In the control group the spring weight was only 66% higher than that in the autumn. 4. 4. Most fat was accumulated in the peritoneal cavity in the fed group. In the subcutaneous adipose tissue no great difference was seen between the groups. 5. 5. The unsaturated fatty acids of the adipose tissue in spring in the control group exceeded by 16% units the autumn level whereas the respective difference in the fed group was only 3% units. 6. 6. In autumn the most prominent fatty acid was oleic acid (33%). In the fed birds oleic acid was most common in spring, too. In the control birds the relative amounts of linoleic and C18:3 acids were remarkably high in spring. 7. 7. In spring 5,9,12-octadecatrienoic acid emerged very prominently (over 15% of total fatty acids) in the controls being thus ten-fold in comparison to the fed ones. 8. 8. It seems that the carbohydrate-rich winter food given to the black grouse will be metabolized to saturated lipids and stored principally to the visceral adipose tissues of the fed birds, while there is a fat accumulation in subcutaneous adipose tissue in all birds. 9. 9. It is recommended to test winter feeding using also seeds rich in soft lipids instead of carbohydraterich seeds.