Índices parasitários e parâmetros fisiológicos de arraias cururu (potamotrygon cf. histrix) exportadas como peixes ornamentais: ferramentas para avaliação do estado de saúde da espécie

Abstract

This work studied the parasite fauna and the health status of cururu stingray, Potamotrygon cf. hystrix, the middle Rio Negro, Amazonas, Brazil, during a hydrological cycle and stages of the extraction of ornamental fish (nature, post-transport, 48 hours in quarantine and 15 days of quarantine), through the identification and quantification of parasites and the correlation of parasite abundance with health indicators for fish. The parasitic index and health indicators were assessed in relation to water level and between stages. The health indicators used included the relative condition factor (Kn), the hepato somatic index (HSI), spleen (SSI) and epigonal organ (ISEO), and erythrocyte parameters and biochemical blood analysis. We found two species of Cestoda, unidentified specimens of Nematoda and Achantocephala, two species of Monogenoidea and five species of Branchiura. The Monogenoidea and Cestoda occurred in all periods of the hydrological cycle, the Nematoda and Branchiura not occurred at high water. The Acanthocephala were recorded during periods of drought and flood. The abundance of Cestoda positively correlated with the HSI, ISEO, hematocrit, erythrocyte number, hemoglobin and glucose. The abundance of Monogenoidea and Branchiura positively correlated with hematocrit and MCH, respectively. In the post-transport were observed critical values in dissolved oxygen and high ammonia levels in water. The Kn in nature was higher than post-transport, 48 hours in quarantine and 15 days of quarantine. The SSI and HSI were minor in nature. There was a reduction in red blood cells, hemoglobin and MCHC, and increased MCV, post-transport in relation to nature. In 48 hours and 15 days of quarantine, there was an increase in hemoglobin and MCH, besides the reduction in MCV in relation to post-transport. Glucose and total protein were lower in post-transport in relation to nature and 48 hours of quarantine, respectively. The Cestoda and Monogenoidea showed the highest prevalences in nature and post-transport. Cestoda abundance was higher in nature and post-transport in relation to 48 hours and 15 days of quarantine. Monogenoidea intensity was higher in post-transport than in other stages. It s the first seasonal study of parasites at a stingray of middle Rio Negro and pioneer in correlate the parasite abundance with health indicators in potamotrygonids. The post-transport was the most critical stage in the chain to the extractive cururu stingray.