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Vol. 47 No. 2, 2008
Feed Deprivation and Re-feeding on Alterations of Proteases in Tilapia Oreochromis mossambicus
Chi-Ru Chan1, Der-Nan Lee2, Yeong-Hsiang Cheng2, Dennis Jine-Yuan Hsieh3, and Ching-Feng Weng1,*
1Department of Life Science and Institute of Biotechnology, National Dong Hwa University, Hualien 974, Taiwan
2Department of Animal Science, National Ilan University, Ilan 260, Taiwan
3School of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan
Chi-Ru Chan, Der-Nan Lee, Yeong-Hsiang Cheng, Dennis Jine-Yuan Hsieh, and Ching-Feng Weng (2008) Regulation of gastrointestinal proteases becomes particularly important when fish starved. In this work, tilapia (Oreochromis mossambicus)
were allotted to various treatments including starvation times (3, 5,
and 7 d) and 1 d of re-feeding after various starvation times to test
whether food deprivation causes changes in protease activities in the
gastrointestinal tract. No significant differences in body
weights were found among all groups. The relative stomach weights
of the starved groups (3 and 5 d) were significantly higher than those
of the control group. The relative intestinal weight of the
starved group after 7 d of starvation was significantly higher than
that of the control group. Additionally, re-feeding resulted in
relative stomach and intestinal weight increases after 5 and 7 d of
starvation, respectively. The activity of trypsin (T) in fish
subjected to a short starvation period was lower than that in fish fed
normally, whereas chymotrypsin (C) activity increased. The T/C
ratio decreased with starvation time, indicating the possibility that
the growth of tilapia is inhibited by starvation. Furthermore,
re-feeding after starvation resulted in increased trypsin and
chymotrypsin activities, and a decrease in the T/C ratio compared to
before feeding. These data suggest that short-term starvation
dampens trypsin activity and the T/C ratio in relation to the growth of
tilapia, and that re-feeding consequently stimulates the activities of
intestinal proteolytic enzymes in tilapia.
Key words: Pepsin, Trypsin, Chymotrypsin, Starvation, Oreochromis mossambicus.
*Correspondence: Tel: 886-3-8633637. Fax: 886-3-8630255. E-mail:cfweng@mail.ndhu.edu.tw
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