Comparing the efficacy of dietary α-tocopherol with that of dl-α-tocopheryl acetate, both either alone or in combination with ascorbic acid, on growth and stress resistance of angelfish, Pterophylum scalare, juveniles

This study aimed to compare the efficacy of dietary alpha-tocopherol with that of dl-alpha-tocopheryl acetate, both either alone or in combination with vitamin C (ascorbic acid), on the growth performance, survival, and stress resistance of angelfish, Pterophylum scalare, juveniles. Juveniles were fed ad libitum for four weeks with Artemia enriched with no vitamins (control), vitamin C (T-c), alpha-tocopherol (T-alpha), dl-alpha-tocopheryl acetate (T (dl) ), alpha-tocopherol and vitamin C (T alpha+C), and dl-alpha-tocopheryl acetate and vitamin C (T (dl+C)). After four weeks, an osmotic stress test was performed using seawater (25 g/L) to evaluate juvenile's resistance to stress. Whole-body glucose and cortisol were used as stress indicators. At the end of the feeding trial, growth performance and survival of the juveniles fed vitamin-enriched Artemia were significantly (P < 0.05) higher than for the control fish. Best performance was recorded for the T alpha+C group. Survival, however, was not significantly (P > 0.05) different between the vitamin-fed groups. Osmotic stress significantly elevated the stress indicators, whole-body cortisol and glucose levels (P < 0.05), highest and lowest values being observed in control and T alpha+C groups, respectively. Survival after osmotic stress of juveniles fed the T alpha+c diet was significantly higher (by 46.2%, P < 0.001) than for controls. Results suggested that alpha-tocopherol has greater efficacy than dl-alpha-tocopheryl acetate and enriching Artemia with alpha-tocopherol and vitamin C together improves growth performance, survival, and stress resistance of angelfish juveniles.