Impactos por agrotóxicos na piscicultura: alterações na morfologia reprodutiva de tilápia, atores sociais e alternativa para a sustentabilidade

Abstract

The use of pesticides has grown worldwide and represents an environmental risk, with impacts on the social, human, and biotic spheres. Insecticides commercially available in the market present toxicity to non-target organisms such as fish and other aquatic organisms, potentially causing losses to aquaculture and other crops. In this context, this thesis work aims to: (i) Evaluate the gonadal morphology of freshwater fish exposed to pyriproxyfen and fenthion; (ii) Present the social actors involved with pesticides and understand the dynamics and contributions of these actors; and (iii) Report the experience of achieving sustainability for an interactive production activity of Aquaculture-Agriculture, focusing on verifying the environmental, economic, social dimensions, and the management of aquaculture. For the objectives of each article, the following methodologies were adopted: (i) For the experimental study approved by the Ethics Committee on Animal Use of the Federal University of Rio Grande do Norte (protocol No. 066/2017, Certificate No. 154.066/2017), forty-five juvenile male Nile tilapia (Oreochromis niloticus) were used, divided into control, exposed to pyriproxyfen (0.01 g/L), and exposed to fenthion (0.001 g/L) groups evaluated at three time points (30, 60, and 90 days). The analyzed variables were gonadosomatic index (GSI), weight/length ratio, tubule morphometry (diameter and height), tissue damage, and immunohistochemical analysis for caspase-3, tumor necrosis factor alpha (TNF- ), and vascular endothelial growth factor (VEGF); (ii) The exploratorydescriptive research is based on pesticide descriptors and social actors around the theme, and, in light of the understanding of Hannigan's social arena; and (iii) field visit conducted in the territory of Mato Grande in the State of Rio Grande do Norte, Municipality of Pureza, at an interactive aquaculture and agriculture production unit, with the research based on the MESMIS proposal and the model of experience report to bring dialogical and experienced communication of sustainable productive practice and literature review. The results showed that: (i) Pyriproxyfen and fenthion damaged the seminiferous tubule tissue, and the damage progressed with the exposure time. Additionally, the GSI gradually decreased over time in all groups compared to the first time point (30 days), while caspase-3, TNF- , and VEGF values increased only in the fenthion-exposed group. Therefore, pyriproxyfen and fenthion altered the gonadal morphology of Oreochromis niloticus males, which may affect their reproduction in nature or captivity; (ii) The well-defined role in the social arena is that of the risk bearer, constituted by rural workers, residents, and consumers. Other actors (risk advocates and investigators) have roles that will converge due to the effects and damages of pesticides that complexly radiate risks to different actors in society; and (iii) Based on the on-site visit to the agroecosystem production unit aquaculture-agriculture, we visualize that the more production units there are, the more interactive processes can be formed, directing a sustainable and productive cycle since damages and impacts can be transformed into input for another productive system.