Synthetic and natural hormones impact the zootechnical and morphological characteristics of Nile tilapia (Oreochromis niloticus)

This work aimed to investigate the effects of the endocrine disruptors 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) on Nile tilapia (Oreochromis niloticus) development, emphasizing the zootechnical and morphological aspects. The concentrations of E2 and EE2 tested were 250, 500, and 1,000 μg·L. The evaluated compounds were capable of producing intersex individuals and causing zootechnical damage in Nile tilapia, with a significant decrease in the condition factor as the concentrations increased. Besides, these concentrations were also able to induce the development of morphological anomalies without any significant difference between them. E2 and EE2 exposure were shown to be lethal for Nile tilapia larvae, having no effect on the incubation time and the percentage of larvae hatching. Morphological anomalies such as head shape malformation, oral malformation, operculum malformation, belly retraction, distended abdomen with fluid accumulation (ascites), exophthalmos, signs of bleeding in the belly, and curved pectoral fin radii, were also observed, which impaired the fish development.