3.5. Nutritional status

To study the nutritional status of grey partridges, assimilation efficiency (metabolisable energy coefficient = MEC) was estimated, which in turn required close monitoring of food consumption and excretion (III). Daily gross energy (GE) intake and excretory energy (EE) were determined using a bomb calorimeter, and the metabolised energy (ME) amount was calculated (ME = GE–EE). The assimilation efficiency was then obtained from MEC = ME/GE (Lindén 1984a, Nikiforov 1992).

Food consumption and excretion were monitored in the study of the effects of quebracho tannin on the grey partridge (V). In this work the nitrogen and tannin contents of the excreta were studied assuming that they might indicate increased protein excretion. Tannin content of the excreta was estimated using the acid butanol method of Porter et al. (1986), and nitrogen content with Elemental Analyzer EA 1110 CHN.

Disparities in diets may be expressed in the chemical composition (water, protein, fat, ash) and glycogen content of certain tissues. The chemical composition of the pectoral muscle (musculus pectoralis major), leg muscle (m. iliotibialis cranialis), heart and liver of hand-reared and wild capercaillies (I) was estimated by the method described by Hissa et al. (1990). Glycogen content was analysed using the method of Lo et al. (1970) and the protein content of the mitochondrial fractions with the method of Lowry et al. (1951).