Vitamin A in diets for Nile tilapia.

CAMPECHE, D. F. B.; CATHARINO, R. R.; GODOY, H. T.; CYRINO, J. E. P.

Vitamin A in diets for Nile tilapia.

Autores

Descripción

Dietary vitamin supplementation decrease stress caused by high stocking density, and boosts immunological system of farmed fish. A studied was carried out to determine vitamin A requirements ofNile tilapia (Oreochromis niloticusv in an ali mal e group (13.8 ± 1.2 g) and a mixed sex population (9.8 ± 2.3 g). Fish stocked in I OO-L plastic aquaria (26.0 ± I.O°C) were fed to near satiety, twice a day, seven days a week, during 75 days with vitamin A-free, semi-purified diets supplemented with O; 600; 1,200; 1,800; 2,400; 3,000; 3,600; 4,200; 4,800 and 5,400 International Units (lU) of retinyl palmitate (30% vitamin A) per kg of diet in a completely randomized experimental design, factorial arrangement 2Xl0 (n = 4). Deficiency signs ofvitamin A were observed in fish fed O to 1.200 lU vitamin A kg " diet; moderate signs were observed in fish fed diets with 1.800 to 3.600 lU vitamin A kg-I diet; no interactions group*level (p < 0.05) were detected. Dietary levels of vitamin A up to 5.400 lU kg I influenced final weight and weight gain of fish (p < 0.05), but did not influence feed consumption (p> 0.05). A group effect was observed regarding ali performance variables (p < 0.000 I). Quantification of hepatic retinol (HPLC) detected vitamin A only in fish fed 5.400 lU retinol kg' of diet, therefore characterizing that dietary retinol was used and stored. The quantity of 5.400 lU of retinol kg-I of diet is recommended for adequate nutrition of Nile tilapia. Key words: Oreochrotnis niloticus, retinol, nutrition.