Qualidade nutricional e teores de mercúrio e aminas bioativas em peixes comercializados no município de Humaitá, AM

The objective of this work was to investigate the levels of fatty acids, mercury, bioactive amines and free amino acids in four of the most commercialized fish species in Humaitá, AM: curimatã, jaraqui, pacu and sardinha. The samples were collected in two different places of the Madeira river (Puruzinho and Santa Rosa), at the dry and rainy seasons in 2015. The fatty acids were determined by GC-FID after methylation; total mercury by gold amalgation absorption spectrometry; the amines by ion pair-HPLC and fluorometric detection; and the amino acids by UPLC and UV detection. Total lipids varied from 1700 (jaraqui), 1920 (curimatã), 7060 (sardinha) and 7690 mg/100 g (pacu). Palmitic acid was the prevalent saturated fatty acid (350 - curimatã; 1230 - pacu and 1547 mg/100 g sardinha); sardinha had the highest monosaturated (2900 mg/100 g), and pacu the highest polyunsaturated (1900 mg/100 g). Pacu had higher levels of linoleic (1056 mg/100 g), linolenic (673 mg/100 g) and EPA+DHA (60.13 mg/100 g). There was seasonal variation of saturated and polyunsaturated fatty acids for pacu and sardinha, with higher values in the rainy season. The levels of total mercury varied from 0.01 to 0.46 mg/kg in the fish. Higher levels were in sardinha (0.22 mg/kg), followed by curimatã (0.15 mg/kg), jaraqui (0.15 mg/kg) and pacu (0.05 mg/kg). The place of fish capture and season affected mercury levels in jaraqui and sardinha. The health risk calculated by means of predicted tolerable weekly ingestion (PTWI) using mean levels (135 µg/kg) was 43.4% over the tolerable limit, providing evidence of potential health risk to riverines due to high fish consumption. 16 amino acids were found with prevalence of histidine (55.5- 67.9%). Only five amines were detected in the fish and the occurrence and levels varied among fish: spermidine, putrescine and cadaverine were detected in every species. Agmatine was only detected in pacu, and tyramine in curimatã, jaraqui and pacu. Curimatã and jaraqui had higher total amines, with higher contribution of tyramine to total levels. Fish captured in the rainy season had higher levels of amines compared to dry season. Higher levels of tyramine and cadaverine were found in Santa Rosa sugesting higher water contamination at this place. Tyramine levels in fish are worysome to the riverines, specialy those under MAOI drugs.