Sanidade de grãos fermentados de ceva ofertada aos peixes do rio Teles Pires

Abstract

Cevas used as food attractants for fish has been widely used along the banks of the Teles Pires River. Consisting mainly of soybeans and corn, it is used as an attractant to facilitate fishing. However, this practice may be causing risks to the survival and health of the fish due to the poor quality of the grains and the possibility of contamination by mycotoxins. The aim of this study was to determine the incidence of fungi present in the grains of food attractants offered to fish in the Teles Pires River and its tributary, the Renato River. Grain samples were collected monthly from the Teles Pires River over a period of four months, from February to May 2022. A total of 19 samples of fermented grains were obtained from the food attractants, 15 of which were soybean samples and 4 corn samples. In the Renato River, four samples of cevas used for fishing were collected, three of which were soybeans and one a mixture of soybeans and corn. A total of 23 samples of barley grains were collected. The filter paper method, known as the "blotter test", was used to analyze the health of the grains. The grains were previously washed in running water, disinfected and distributed in Petri dishes with sterilized and moistened germ paper. The plates were incubated in a chamber with a 12-hour photoperiod and a temperature of ±25°C for a period of 7 to 8 days. The pathogens present in the grains were identified and counted to determine the incidence of each pathogen. An experiment was also carried out to simulate the ceva used by the fishermen, assessing the health of the grains by means of tests on water agar, at different times over 21 days of fermentation (0, 7 and 21 days after the test was set up). This study highlights, for the first time, the presence of potentially mycotoxin-producing fungi, such as species of Fusarium (F. oxysporum, F. proliferatum), Aspergillus (A. tamarii), and Penicillium spp., in samples of food attractants composed of soybeans and corn collected from the Teles Pires and Renato rivers. Aspergillus spp. and Fusarium spp. fungi have a higher incidence in grains with a shorter fermentation time, while in grains with a prolonged fermentation time, the occurrence of bacteria and yeasts prevails. The presence of toxigenic fungi and mycotoxins (aflatoxin and fumonisins) suggests a potential risk to the health of fish that feed on these fermented grains, with implications for human consumers who consume these fish.