Then, when studying the anti-oxidant properties and angiotensin converting enzyme (ACE) inhibitory activity of zebrafish (Salaria basilisca) protein hydrolysates (ZBPHs) in tetrazolopyrimidine diabetic rats (AIDR), it was found that the gavage of different ZBPHs to AIDR rats showed a significant decrease in anti-oxidant enzyme activity and a significant increase in malondialdehyde (MDA) levels in the liver tissue, and that ZBPHs could modulate ACE activity and prevent diabetes-related complications [143]. This evidence concerns the gene ACE and diabetes mellitus.