Abstract

Biochemical parameters of fish are important indicators of homeostasis as they represent an organism's response to the environment. Lophiosilurus alexandri is an endemic and endangered species of the Sao Francisco River in Brazil with potential for aquaculture; however, blood biochemical studies of this species are scarce. The present study compared blood biochemical parameters of male and female L. alexandri, at four different ages. The following analytes were evaluated: alanine aminotransferase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), calcium, chlorine, magnesium, total proteins, albumin, urea, glucose, triglycerides and cholesterol. Male fish had higher values than females for ALT at 372 days after hatching (DAH), magnesium at 481 DAH and triglycerides at 372 and 481 DAH (p < 0.05). The other analytes did not differ significantly (p > 0.05) between males and females at any of the collection times. The results allow us to conclude that biochemical differences between males and females are less pronounced than those observed among different ages of the same sex.