Promoting sustainable production of fish in aquaculture: Mechanistic action ofdiketopiperazine Cyclo-Phe-Pro in combating oxidative stress-induced infertilityin zebrafish

Aquaculture and fisheries are essential for conserving fish stocks and producing animal feed. Annual Fisheries Statistics indicate that fish imports are approximately 1.9 times greater than exports, contributing to a decline in Malaysia's fish self-sufficiency from 95.27% in 2020 to 91.74% in 2021. High-density farming, temperature fluctuations, salinity changes, and chemical contaminants induce free radical generation in fish. These free radicals damage lipids, proteins, and DNA, leading to physiological impairments such as reproductive failure. Specifically, oxidative stress compromises sperm membrane integrity and motility—reducing fertilization success—while simultaneously lowering egg production and embryo viability. Addressing oxidative stress-induced subfertility is therefore crucial for sustainable aquaculture as a high-value protein source. Prior investigations demonstrate that fermentative extracts from Streptomyces spp. possess significant radical-scavenging, neuroprotective, and anticancer properties. Among these active compounds, the diketopiperazine Cyclo-phenylalanyl-proline (Cyclo-Phe-Pro) exhibits strong potential in mitigating free radical accumulation.