Studies on the nutrition of marine flatfish. The pyridoxine requirement of turbot ( Scophthalmus maximus )

• Published in: British Journal of Nutrition
• Main Authors: Adron, J. W., Knox, D., Cowey, C. B., Ball, G. T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1978
• Subjects: Nutrition and Dietetics; Medicine (miscellaneous); Scophthalmus maximus; Turbot
• Online Access: http://dx.doi.org/10.1079/bjn19780121; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007114578000379

1. Diets containing graded levels of pyridoxine hydrochloride (to supply 0.26–30 mg pyridoxine/kg) were given to seven duplicate groups of turbot ( Scophthalmus maximus ) for 12 weeks and their growth rate was measured during this period. 2. Good growth was obtained on all treatments except those groups given less than 1.0 mg pyridoxine/kg diet. These fish grew normally until weeks 8–10 but thereafter their weight gain was significantly less than that for other treatments. 3. Measurements of aspartate aminotransferase ( EC 2.6.1.1) in muscle and liver and of alanine aminotransferase ( EC 2.6.1.2) in liver of the turbot showed that the activities of these enzymes increased with increasing dietary pyridoxine intake up to a level of 2.5 mg pyridoxine/kg. The activities of these enzymes were not further enhanced by additional dietary pyridoxine. 4. Percentage stimulation of these enzymes by pre-incubation of extracts with pyridoxal phosphate was minimal with those groups of turbot given 2.5 mg pyridoxine/kg diet or more. 5. It is concluded that the dietary requirement of turbot for vitamin B 6 can be safely met with a diet containing between 1.0 and 2.5 mg pyridoxine/kg. 6. An eighth group of turbot given the pyridoxine antagonist 4-deoxypyridoxine hydrochloride (20 mg/kg) showed retarded growth after 2 weeks, together with a high mortality rate.