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Enzymatic digestion in stomachless fishes: how a simple gut accommodates both herbivory and carnivory
journal contribution
posted on 2023-05-18, 04:13 authored by Ryan DayRyan Day, German, DP, Manjakasy, JM, Farr, I, Hansen, MJ, Tibbetts, IRThe lack of a stomach is not uncommon amongst teleost fishes, yet our understanding of this reductive specialisation is lacking. The absence of a stomach does not restrict trophic preference, resulting in fishes with very similar alimentary morphology capable of digesting differing diets. We examined the digestive biochemistry of four beloniform fishes: two herbivorous halfbeaks (Hemiramphidae) and two carnivorous needlefish (Belonidae) to determine how these fishes digest their respective diets with their simple, short gut. We found that although the halfbeaks showed significantly greater a-amylase activity than that of the needlefish (P < 0.01), trypsin, lipase, aminopeptidase and maltase activity were not substantially different between the two families. We also found that habitat (freshwater vs. marine) appears to play a significant role in digestive capability, as the two freshwater taxa and the two marine taxa were significantly different (ANOSIM; dietary Gobal R = 0.544, P = 0.001, habitat Global R = 0.437, P = 0.001), despite their phyletic and dietary similarities. Our findings offer partial support for the adaptive modulation hypothesis, support the Plug-Flow Reactor model of digestion in herbivorous halfbeaks and also support the compartmental model of digestion but suggest that another model is required to describe stomachless carnivorous needlefish.
History
Publication title
Journal of Comparative Physiology. BVolume
181Issue
5Pagination
603-613ISSN
0174-1578Department/School
Institute for Marine and Antarctic StudiesPublisher
Springer-VerlagPlace of publication
175 Fifth Ave, New York, USA, Ny, 10010Rights statement
Copyright 2011 SpringerRepository Status
- Restricted