Tryptic activity in the digestive tract of roach larvae (Rutilus rutilus) fed on natural and artificial diets (Abstract)
Hofer, R.; Köck, G. (1989). Tryptic activity in the digestive tract of roach larvae (Rutilus rutilus) fed on natural and artificial diets (Abstract), in: De Pauw, N. et al. (Ed.) Aquaculture: a biotechnology in progress: volume 1. pp. 649
In: De Pauw, N. et al. (1989). Aquaculture: a biotechnology in progress: volume 1. European Aquaculture Society: Bredene. ISBN 90-71625-03-6. 1-592 pp., more
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Document type: Conference paper
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| Abstract |
In roach larvae fed Artemia total tryptic activity.mg-1 body weight increased slowly during development, whereas tryptic activity per volume gut contents (foregut and hindgut) remained more or less constant. On the other hand, in larvae fed artificial diets tryptic activity increased strikingly during the first few days of their life, reaching a maximum between 13 and 20 days after first feeding. This can be interpreted as a mechanism compensating an inadequate diet. During the first week, the rate of growth of artificially fed larvae was nearly as high as that of roach fed Artemia , but later it dropped and the mortality increased. Despite the high tryptic activity in the foregut of artificially fed larvae (during the first 2 weeks) reabsorption of trypsin in the hindgut is as efficient as in fish fed Artemia , the activity in the hindgut varying between 10 and 30% of that in the foregut. After this period, however. when tryptic activity in the foregut has dropped to the level of that in fish fed Artemia , specific tryptic activity in the hindgut increases to 50-75% of that in the foregut, signalling an apparent failure of the reabsorption mechanism. The partial loss of the ability to reabsorb trypsin in larvae fed exclusively artificial diets for 2-3 weeks is surprising and indicates a sensitive period during development. |
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