ABSTRACT
A 4-week feeding trial on 22 grey partridges Perdix perdix was conducted in this study. Seven birds were fed commercial poultry food, seven natural food and eight commercial poultry food containing 6% of quebracho-tannin. Our results suggest that 6% dietary tannin, when added to a commercial food with high protein content, effects the grey partridge only slightly. No difference was seen in food consumption and body mass remained stable. However, birds fed tannin had longer small intestines, which most probably indicate gastrointestinal detoxication. They also excreted a high amount of tannin in their faeces. In addition, no between-group variation was seen in cytochrome P450 enzymes. Birds fed natural food had high concentration of nitrogen in intestinal excreta and high plasma alanine concentrations. They also suffered a rapid decrease in body mass after the change in diet and their body mass remained low. This may indicate increased protein excretion and/or catabolism of endogenous nutrient reserves. Potential short-term effects of the change in diet were seen in plasma. These findings coincide with the high mortality period of birds released into the wild.
Subject(s)
Birds/physiology , Cytochrome P-450 Enzyme System/drug effects , Eating/drug effects , Feces/chemistry , Nitrogen/analysis , Tannins/adverse effects , Adaptation, Physiological , Alanine/blood , Alanine/drug effects , Animals , Animals, Wild/metabolism , Blood Proteins/drug effects , Body Weight/drug effects , Dietary Supplements/adverse effects , Eating/physiology , Female , Intestinal Secretions/chemistry , Intestinal Secretions/drug effects , Intestinal Secretions/metabolism , Intestine, Small/drug effects , Liver/enzymology , Male , Tannins/analysisABSTRACT
Morphological and physiological disparities between 20 captive and 11 wild capercaillies were determined. Birds, their pectoral and leg muscles, hearts, livers and gizzards were weighed. The length of small intestines and caeca were measured. Haemoglobin, haematocrit, glucose, triglycerides, total protein, uric acid and thyroid hormones as well as the cytochrome c-oxidase activity of the pectoral muscle and heart were determined. The glycogen and protein contents of pectoral and leg muscles and liver were analysed. Chemical composition (water, fat, protein, ash) of muscles and liver was determined. Captive males had heavier pectoral muscles than wild ones. The result was opposite in females. Wild birds had heavier hearts, livers, and gizzards, and also longer small intestines and caeca than captive birds. The cytochrome c-oxidase activity of pectoral muscle and heart was higher in wild than in hand-reared birds. The chemical composition of livers of wild birds differed significantly from that of hand-reared capercaillies. Plasma uric acid and T(4) concentrations were higher in captive than in wild birds. The observed differences in digestive system and liver can result in diminished ability of captive birds to utilise natural food nutrients. Decreased cytochrome c-oxidase activity of hand-reared birds can affect their takeoff and flying capacity and increase their vulnerability to predation. These facts may contribute to the low survival of hand-reared birds after release.
