Effects of Acute Hypoxia on Danio rerio

The purpose of this research experiment was to determine the effects of acute hypoxia on the embryonic zebrafish (Danio rerio) cardiovascular system and assess the critical oxygen level at which embryonic function is compromised. This goal was achieved by exposing embryos to decreasing oxygen concentrations, (6.0 mg/L-0 mg/L) and observing the heart under an inverted microscope. Data analysis was conducted to determine end systolic volume, end diastolic volume, stroke volume, heart rate, and cardiac output. It was hypothesized that hypoxia would stimulate cardiac activity, because in early developmental stages, tissues are supplied with oxygen through bulk diffusion, and an increase in metabolic demand would require more work out of the cardiovascular system. The results revealed an increase in end diastolic volume, end systolic volume, stroke volume, and cardiac output from baseline, but a decrease in heart rate in the 0 mg/L concentration exposure group. It is necessary to understand how acute hypoxia affects the physiology of aquatic animals as many natural and anthropogenic factors are contributing to rising hypoxia in aquatic ecosystems across the globe