Center of studies on
Subterranean Biology

The set of characteristics presented by subterranean environments, in addition to causing physical changes in the organisms living in that environment, can interfere with the metabolism of these animals. This work aimed to make a comparison between lipid profile and hepatic lipogenesis in two fish species: the species Ancistrus cryptophthalmus and the epigean Ancistrus sp .. 10 troglobitic fish were collected for this study in the Lapa do Angélica cave, located in Terra Ronca State Park in the state of Goias, and 10 non-cave fish of the same genus (Ancistrus sp.) in the epigean part of Rio Angelica. The results obtained for the characterization of the cave environment, showed a higher temperature (25.2° C) than for the epigean environment (24.8° C) and reduced organic matter availability (1.84 and 0.38 g/cm2 respectively). For the levels of total lipids, higher accumulations were found in cave fish species (18.36 g/100 g of tissue), which can be attributed to adaptation of fish to environments with limited food resource availability. The profile of muscle fatty acids also varied between the two species. Worth mentioning is arachidonic acid, which was identified only in fish of epigaen origin and docosahexaenoic acid that predominated in cave fish. In the lipid profile of Ancistrus cryptophthalmus there was greater proportion of saturated fatty acids followed by monounsaturated and polyunsaturated. Ancistrus sp. showed a predominance of monounsaturated fatty acids. Significant differences were also observed in the activity of the malic and glucose-6-phosphate dehydrogenase hepatic enzymes. The activity of both enzymes was higher in epigean animals. These results may also be related to food availability in the two different environments. We also observed the existence of an ecotone zone located near the Angélica cave entrance, where the fish have characteristics intermediate between hypogean species and epigean. We conclude, therefore, that the characteristics specific to the cave environment significantly influence muscle fatty acid composition and lipogenesis in the fish species Ancistrus cryptophthalmus.