Abstract:
The effects of dietary nucleotide (NT) were evaluat
ed on some serum biochemical
parameters
and acute stress responses of the catfish (
Pangasianodon hypophthalmus
).
Five experimental diets including 0, 0.25, 0.5, 0.7
5, and 1%
NT were supplied to catfish
fry for 10 weeks. At the end of the experiment, fis
h fed the control and 1%
NT diets were
subjected to handling and crowding stress. The resu
lts showed that the fish supplied with
0.25-0.75%
NT had a lower level of lactate dehydrogenase (LDH
) (P<0.05) while other
serum enzymes including alkaline phosphatase (ALP),
asparate transaminase (ASP), and
alanine transaminase (ALT) were not significantly r
educed by NT inclusion in the diet
(P>0.05). The fish which received the highest doses
(0.75 and 1%
) of NT exhibited higher
levels of triglyceride than the other groups (P<0.0
5) while they showed no significant
differences in other biochemical parameters includi
ng total protein, albumin, globulin,
cholesterol, and glucose (P>0.05). To investigate s
tress responses, cortisol (primary
response), serum glucose, and serum ion concentrati
ons including sodium, potassium and
calcium (secondary responses) were measured. The re
sults showed significant fluctuations
in all the tested components during the sampling in
tervals for up to 48 h post-stress; the
exceptions, however, were glucose in the group on t
he 1%
NT diet as well as serum
cortisol and calcium levels in those supplied with
the control diet. Based on the results
obtained, it may be concluded that dietary NT can i
mprove liver function in iridescent
catfish, but it has no obvious positive effects on
other serum biochemical parameters and
stress responses.
Keywords
: Crowding stress,
Cortisol
, Handling stress, Liver function.
