A Glyphosate-based herbicide Induces effects in the early life stages of Nile tilapia (Oreochromis niloticus)

• Glyphosate exposure caused dose-dependent reductions in hatching rates and increased mortality. • OCT revealed glyphosate-induced deformities including yolk sac, organ development, and tail bone. • Glyphosate exposure inhibits AChE expression and alters acid and alkaline peptidase activity. • OCT is a novel tool for real-time, high-resolution assessment of morphological changes. In this study, we investigated the effects of a glyphosate-based herbicide (N-(phosphonomethyl) glycine-isopropylammonium 48% W/V SL) on the early developmental stages of Nile tilapia ( Oreochromis niloticus ), focusing on hatching rate, morphological development, enzyme activity, and acetylcholinesterase (AChE) expression. Significant dose-dependent developmental abnormalities were observed using Optical Coherence Tomography (OCT), including morphological deformities in eggs, embryos, and larvae. The hatching rate decreased by 30% at 144 mg/L compared with that of the control, with a 50% increase in abnormalities in the exposed groups. Biochemical analysis revealed a 45% reduction in acetylcholinesterase (AChE) expression and significantly lower alkaline and acid peptidase activities in larvae exposed to glyphosate. The cumulative mortality rate increased in a dose-dependent manner, with a 96 h-LC50 value of 108.4 mg/L. The decrease in AChE expression underscores the neurotoxic effects of glyphosate, highlighting the substantial ecological and human health risks. This study was conducted under controlled indoor laboratory conditions, which may differ from real-world outdoor environments. Future research should focus on validating these findings in natural ecosystems to better understand the environmental impact of glyphosate. These findings emphasize the need for careful glyphosate regulation and management to protect aquatic ecosystems and species, such as Nile tilapia.