Effect of a minor vitamin A deficiency on the course of infection with Ascaridia galli (Schrank, 1788) and the resistance of chickens

The effect of vitamin A deficiency was studied in chickens infected with 500 Ascaridia galli eggs and controls. Diet 1 (deficient, 500 IU vitamin A or 172 μg retinol acetate per kg diet), Diet 2 (deficient, 1000 IU vitamin A or 344 μg retinol acetate per kg diet) and Diet 3 (sufficient, 1500 IU vitamin A or 516 μg retinol acetate per kg diet) were assigned to 46 chickens each. Clinical signs, weight gains, livers’ weights, vitamin A levels, worm burdens and parasite eggs’ excretions were recorded.

Infected chickens had lower weight gains than the controls fed alike. Chickens given Diet 1 stored lesser vitamin A in liver than those fed Diet 3. Although worm counts in the 3 groups did not differ significantly, chickens fed Diet 1 excreted more A. galli eggs than those fed the 2 other diets. Female worms harboured by chickens fed Diet 1 had higher fecundity at week 5 pi than those of chickens fed Diet 2. Results indicated that Vitamin A is important for poultry in the moderation of the infection with A. galli.