Anabas testudineus (climbing perch), average
body weight 21+/-1 g, were maintained in culture tanks and fed a 35%
protein feed plus an additional supplementation of three
dietary oils (20% each of
coconut oil,
palm oil, or
cod liver oil).
Body weight gain was similar among all groups. However, several hepatic lipogenic
enzymes such as malic
enzyme (ME),
NADP-isocitrate dehydrogenase (ICDH),
glucose 6-phosphate
dehydrogenase (G6PDH),
6-phosphogluconate dehydrogenase (6PGDH) and beta-hydroxy-1-methyl
glutaryl CoA reductase (
HMG CoA reductase) were assayed, and they responded differently. Hepatic ME and G6PDH activities showed a significant decrease in the
coconut oil and
palm oil groups, but there was no significant change in ICDH activity. The 6PGDH activities were reduced, whereas
HMG CoA reductase activity was increased in the
palm oil-treated group.
Cholesterol synthesis in the liver and muscle increased in the
palm oil-treated group, but liver
phospholipids did not show any significant change in fish supplemented with
oils rich in
saturated fatty acids.
Triacylglycerol and
free fatty acid concentrations were high in the
coconut oil- and
palm oil-supplemented groups. Lipid peroxidation products such as
thiobarbituric acid-reactive substances and conjugated dienes decreased in the same two groups.
Antioxidant potential was high in all groups as evidenced by increased activity of
superoxide dismutase,
glutathione peroxidase, and
glutathione content. The results of this study indicate that in fish, dietary
lipids depress hepatic lipogenic activity as well as lipid peroxidation products by maintaining high levels of
antioxidant enzymes.