Length‐weight relationships (LWRs) were estimated for 16 ornamental fish species from Amanã Lake and nine tributary streams, in Central Brazilian Amazonia. Sampling was carried out bimonthly for a year (2007–2008), using two sets of four gillnets (20 m × 2 m, 2,5; 3,5; 04; 4,5 cm stretch mesh size); trawls were performed with seine nets (35 m × 6 m, 3 mm stretch mesh size); native fish‐traps (fyke‐net like fish‐traps woven from local lianas), and dip nets (0.5 m × 0.5 m stretch mesh size). Measurements were done for standard length (SL – 0.1 cm precision) and total weight (Wt – 0.01 g precision). This study provides information on the length–weight relationships for all sampled species and, in addition, provides new maximum standard lengths for six species.

Western Pará, northern Brazil, is a significant region for mineral exploration, leading to the deposition of potentially toxic elements in soils and water basins. This study evaluated concentrations of mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As) in cattle muscle tissue from three municipalities: Oriximiná, Itaituba, and Monte Alegre. Metal concentrations were determined using inductively coupled plasma mass spectrometry (ICP-MS). The estimated daily intake (EDI) of toxic metals via beef consumption (71 g/person/day) was below oral reference doses values (RfDo). Target hazard quotient (THQ) and total THQ (TTHQ) values for all metals were below 1, indicating no significant non-carcinogenic health risk. Monte Alegre exhibited the highest THQ for As and Pb, Oriximiná for Cd, and Itaituba for Hg. Although the overall assessment suggests low risk, elevated Hg concentrations were detected in 10% of the samples, with at least one animal from each municipality exceeding the European Union maximum residue limit (0.01 mg/kg). These findings indicate localized contamination and potential mercury bioaccumulation. Given the rising anthropogenic activities (such as mining and deforestation), continued monitoring of heavy metal levels in animal tissues is recommended to ensure long-term food safety and public health.

The Amazon basin is undergoing rapid environmental transformation driven by agricultural expansion and mining activities, resulting in increased concentrations of toxic metals in aquatic ecosystems. This study quantified arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in six fish species and evaluated associated noncarcinogenic and carcinogenic health risks under two consumption scenarios: the Amazon Scenario (462 g/person/day) and the Brazil Scenario (24 g/person/day). Fish were sampled in five municipalities in western Pará, which differ in the intensity of the gold and bauxite mining activities. The results show that Hg concentrations exceeded legal limits in most carnivorous species; the target hazard quotients (THQ) indicate lifelong noncarcinogenic risk (THQ > 1) in nearly all samples under the Amazon Scenario, peaking at 28.97 for Cichla ocellaris from Porto Trombetas. Total target hazard quotients (TTHQs) also exceeded the safety threshold of 1 for all species in the Amazon Scenario, indicating significant noncarcinogenic risk for local consumers, whereas risks remained acceptable under the national consumption pattern. Carcinogenic risk analysis revealed that 25% of samples in the Amazon Scenario exceeded the 1 × 10^–4 threshold, primarily due to arsenic exposure. These findings demonstrate that traditional fish-based diets expose Amazonian riverine populations to hazardous levels of potentially toxic elements, underscoring the need for integrated environmental monitoring, public health surveillance, and nutritional guidance tailored to high-consumption communities.

This study evaluated the effects of feeding a whole shelled corn diet without roughage (WSC) on the metabolic profile of feedlot buffaloes (Bubalus bubalis) in the Amazon region. Twelve buffaloes were fed the WSC diet consisting of intact corn kernels plus a protein−mineral supplement, and 12 received a conventional diet (CON) composed of a commercial concentrate (ground corn and soybean meal) with 30% corn silage. The experiment lasted 64 days, with blood sampling on days 0, 7, 21, 35, 49, and 64. Biochemical analyses included total protein, albumin, urea, creatinine, cholesterol, triglycerides, β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFAs), glucose, lactate, calcium, phosphorus, magnesium, and the enzymes aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), and creatine kinase (CK). Feeding WSC without roughage did not cause adverse health effects compared with the CON diet. Most biochemical parameters were unaffected (p > 0.05), while urea and glucose differed significantly over time (p < 0.001). Urea was higher in CON (17.7 ± 5.2 mg/dL) than WSC (11.4 ± 4.6 mg/dL). Across both groups, temporal changes reflected adaptation from pasture to feedlot feeding. To our knowledge, this is the first report of the metabolic profile of water buffalo fed a whole shelled corn diet completely without roughage. Further studies with larger sample sizes are warranted to determine the economically viability of this feeding strategy.