No abstract

Aflatoxins (AF) can be cumulative in fish tissues and can influence weight, length, feed intake and survival depending on the species. The aim of this work is to measure performance and aflatoxin levels in tissues of matrinxã (Brycon cephalus) fish chronically exposed to aflatoxin. Aflatoxin was incorporated into fish diets at the following levels: Control Feed + 0 μg AFB1 kg-1; A. Feed + 10 μg AFB1 kg-1; B. Feed + 20 μg AFB1 kg-1; C. Feed + 50 μg AFB1 kg-1. It was used one tank per treatment, each one with 150 juvenile fish, and three replicates within each tank were used for sampling, that was carried out monthly over a period of six months. Aflatoxin was quantified by HPLC in fish liver and muscle after clean up using immunoaffinity columns. Performance was evaluated by using weight, length, consumption and survival rate. Muscle and liver aflatoxin levels were below the limit of detection in all control samples. Aflatoxins B2, G1 and G2 were not detected in any tissues. Traces (values between limits of detection and quantification) of AFB1 were observed in liver tissue in treatment A from day 30 through 90, reaching 0.32 μg AFB1 kg-1 at 150 days of exposure. Treatment B presented traces up to day 60 and had, with a maximum level of 0.39 μg AFB1 kg-1 at 150 days of exposure. Treatment C had aflatoxin residues after day 30, with values ranging from 0.17 to 0.61 μg AFB1 kg-1 during exposure. Muscle samples only had traces of AFB1 in all treatments. Fish was affected by exposure to AFB1 with higher values (P<0.05) for weight and length in treatments A, B and C relative to controls. Therefore, results indicate that matrinxã do not accumulate AFB1 residues in edible tissues, but chronic exposure affects the species.

The enrichment of meat with selenium is important to improve the intake of selenium by humans. The effects of supranutritional doses of sodium selenite or selenium-enriched yeast on performance, carcass characteristics and meat quality were evaluated using 63 Nellore cattle in a completely randomized design with two sources (sodium selenite and selenium-enriched yeast), three levels (0.3, 0.9 and 2.7 mg Se/kg DM) and control treatment (without addition of selenium). Final body weight (BW), average daily gain, dry matter intake and gain to feed ratio (G : F) at the end of 84 days of supplementation were not influenced by treatments (P>0.05). Values of pH, ribeye area, back fat thickness and marbling score were also not influenced by treatments ( P>0.05). Dressing percentage was greater (P=0.02) in Nellore cattle supplemented with organic Se (58.70%) compared to animals supplemented with inorganic Se (57.94%). Hot carcass weight increased ( P=0.05) with the increasing of Se levels in the diet. Colour, shear force (SF), cooking and drip loss remained unchanged ( P>0.05); however thiobarbituric acid reactive substances was 15.51% higher with inorganic Se compared with organic Se. The selenium concentration in the meat of animals receiving organic selenium was higher ( P<0.001) than that of animals receiving sodium selenite, at all levels (0.3; 0.9 and 2.7 mg/kg DM). The meat of animals receiving 2.7 mg of organic Se/kg of DM presented concentration of 372.7 μg Se/kg in the L.dorsi muscle, and the intake of 150 g of this meat by humans provides approximately 100% of the recommended Se intake (55 μg Se/day for adults). Therefore, the use of supranutritional doses of 2.7 mg Se/kg of DM, regardless of source, is a way of naturally producing selenium-enriched meat without compromising performance, carcass characteristics and quality of Nellore bovine meat.

The objective of this study was to evaluate biochemical parameters and histopathology of liver in Matrinxã (Brycon cephalus) and Pacu (Piaractus mesopotamicus) fish chronically exposed to dietary aflatoxins. Fish feed was artificially contaminated with aflatoxins and the treatments were: Control – feed without toxin; Treatment A – feed + 10 μg aflatoxin B1 (AFB1)/kg; Treatment B – feed + 20 μg AFB1/kg; and Treatment C – feed + 50 μg AFB1/kg. Matrinxã and Pacu juvenile fish were placed in tanks for 180 days. Five experimental units per treatment were monthly sampled and submitted to blood collection and removal of hepatic tissue. Thus, twenty blood and liver samples for each species were collected monthly, adding up to 240 samples analysed. To verify biochemical changes, analyses included total proteins, albumin, globulins, aspartate aminotransferase (AST) and alkaline phosphatase (ALP). The hepatic tissue was examined microscopically and the slides presenting histopathological changes were photo-documented. There was effect of treatment (P<0.05) for AST and ALP in Matrinxã, while no effect (P>0.05) was observed in Pacu. A reduction (P<0.05) in AST and ALP values during the time of exposure was observed in all treatments for both species. Fatty degeneration and liver damage were observed for both species in treatments exposed to aflatoxins. Fatty degeneration in Pacu was noticed after 30 days of exposure, while in Matrinxã it was observed after 60 days. Disorganisation of the hepatocyte cord arrangement was also observed in those treatments exposed to aflatoxin, following 90 days of exposure in Matrinxã, and after 60 days in Pacu. Therefore, aflatoxins have little influence on biochemical parameters in the species evaluated. However, exposure to aflatoxins caused liver changes, such as cell death, fatty and hydropic degeneration, thus it could be concluded that both species are susceptible to the toxic effects of long-term exposure to dietary AFB1.

The objective of this work was to evaluate the aflatoxins residues on tissues of Pacu (Piaractus mesopotamicus) fish chronically exposed to dietary aflatoxins, also evaluating the effects on fish performance. Aflatoxins were incorporated into the extruded fish feed and the concentrations were confirmed by high performance liquid chromatography (HPLC). The experimental design comprised the following treatments: Control – feed without toxin; Treatment A: feed + 10 μg aflatoxin B1 (AFB1)/kg; Treatment B: feed + 20 μg AFB1/kg and Treatment C: feed + 50 μg AFB1/kg. Pacu juvenile were allocated in tanks with density of one fish per litter. The experiment lasted 180 days with monthly sampling, and approximately ten fish per treatment were used to compose a sample. Biometric surveys were performed every 30 days, including standard weight and length. Aflatoxins were detected and quantified in fish muscle and liver by HPLC, using immunoafinity columns. Results showed AFB1 deposition in the liver throughout the experiment in all treatments, but only treatment C differed significantly (P<0.05) from the others after 150 days, while in muscle there was low residual deposition. Long-term exposed fish had negative influence in weight and length. The higher mortality was observed in treatment C. Although there were AFB1 residues at low levels in liver and only a slight amount in fish muscle, it should be noted that accumulation is possible in the Pacu species. The diets contaminated with AFB1 negatively interfered in weight and length of fish when compared to control. Therefore, it can be concluded that long-term exposure of Pacu to dietary AFB1 can cause losses to producers.