Effect of fructose, leucine and prefeeding of sucrose on transport of nutrients.

Effect of fructose and leucine (5 and 20 mM) has been observed separately on transport of glucose, xylose, glycine, leucine and tyrosine (2.5 mM) in two teleost fishes of different feeding habits, carnivorous Ophiocephalus punctatus and omnivorous Heteropneustes fossilis. Addition of the nutrient was made at 30 min stage and its effect was observed at 35, 40, 50 and 60 min intervals. Fructose stimulated amino acid transport while in all other cases the uptake decreased being greater in more rapidly absorbable substances. Sucrose prefeeding also inhibited the transport rate of glucose and leucine in both fishes.