Effect of vitamin A deficiency on protein catabolism in chicks

Abstract

1. The changes in the concentration of some enzymes and their metabolites were studied in the first stages of vitamin A deficiency in chicks.2. Kidney arginase (EC3.5.3.1) and liver xanthine dehydrogenase activities had increased even before complete disappearance of vitamin A from the plasma. Similarly, an increase was found in plasma uric acid, and plasma urea also increased but to a lesser extent. Liver proteolytic activity also was slightly increased by vitamin A deficiency.3. Kidney D-amino acid oxidase (EC1.4.3.3) activity and plasma concentrations of total protein and free amino acids were not affected, at least in the first stages of the deficiency.4. Oral dosing of deficient chicks with retinyl palmitate to provide 300 μg retinol, 24 h before killing, brought about a decrease in the activities of both enzymes and of plasma uric acid, and an increase in plasma urea.5. Dietary levels of vitamin A were reflected not only in the liver concentrations of the vitamin but also in the plasma concentrations.

Renal pathology of the fowl — A review

“…Stoewsand and Scott (1959) only report plasma urate levels of 4.5-9 mg%, Bruckental et al (1974) about 9 mg% while Henk (1966) stated that there was a gradual rise between the first and seventh weeks and that birds with 22 mg% were very sick and those with 30 mg% never survived. Scott (1961) believed that in poults but not chicks the blood uric acid level could be used as a reliable indication of the severity of the deficiency.…”

Vitamin-A-dependent zinc-binding protein and intestinal absorption of Zn in chicks

“…At the age of 5 weeks, -A chicks, raised on a diet without vitamin A, manifested signs of severe avitaminosis A: their body-weight was about 60% of that of the controls and retinol was not detected in the liver. There was a considerable increase in serum uric acid in -A chicks, characteristic of avitaminosis A in birds (Bruckental et al 1974). The results also showed that -A chicks became Zn deficient.…”

“…The control group was given ad lib. the diet containing retinyl acetate (2752 pg/kg) added in oil to the basal diet in accordance with the recommended dosage (Bruckental et al 1974). The second group received the vitamin-A-free basal diet (-A chicks).…”

“…During the course of the experiment, chick growth and the extent of avitaminosis were regularly checked. The vitamin A content of the liver and blood serum levels of uric acid served as criteria to judge the degree of avitaminosis A in chicks (Bruckental et al 1974). Retinol was determined by spectrophotometry according to Dimitrovsky & Kryukov (1975), and uric acid by a modification of the method of Foline & Denis (Eichhorn et al 1961).…”