Toxicological effects of aflatoxin B1 on the earthworm Eisenia fetida as determined in a contact paper test.

In this study, aflatoxin B1 (AFB1) toxicity toward the earthworm Eisenia fetida (Savigny 1826) was evaluated in contact paper test systems containing distilled water and ethanol or 20 to 400 µg/ml of AFB1 over 72 h of exposure. The results indicated that AFB1 could induce significant damage to earthworms (coiling, curling, excessive mucus secretion, clitellum swelling) at greater than 75 µg/ml. Moreover, AFB1 had harmful effects on E. fetida (degenerative changes such as bulging of the clitella regions) at levels higher than 150 µg/ml. The calculated LD50 was 168.5 µg/ml. These findings confirm that E. fetida and standardized methods based on this organism (OECD 207 1984) are applicable and useful in mycotoxin related toxicity studies.

Comparison of the amount of bioaccessible fumonisin B1 and B2 in maize and rice inoculated with Fusarium verticillioides (MRC 826) and determined by in vitro digestion-preliminary results.

In this study the occurrence of hidden fumonisin B1 (FB1) and fumonisin B2 (FB2) was analysed, on two cereal substrates (maize and rice), inoculated with Fusarium verticillioides (MRC 826), in order to determine the ratio of hidden FB1 and FB2. Two parallel methods were applied: an in vitro human digestion sample pre-treatment and the routine extraction procedure, in both cases with subsequent LC-MS analysis. It was found that all samples showed higher concentration of total fumonisin B1 after digestion, as compared to that of free fumonisin analysed only after extraction. The percentage of the hidden form by maize was 18.8 % (±2.4) for FB1 and 36.8 % (±3.8) for FB2, while for rice it was 32.3 % (±11.3) and 58.0 (±6.8), respectively, expressed as the proportion to total fumonisin B1, for the total dataset. Significant differences were found in the FB1 and FB2 concentration measured after the different digestion phases (saliva, gastric and duodenal) in case of both matrixes. The results are useful for human risk assessment, since both humans and animals may be exposed to markedly higher toxin load, as determined merely by conventional analytical methods.

Short-term effects of T-2 toxin exposure on some lipid peroxide and glutathione redox parameters of broiler chickens.

The purpose of this study was to investigate the short-term effects of T-2 toxin exposure (3.09 mg/kg feed) on lipid peroxidation and glutathione redox system of broiler chicken. A total of 54 Cobb 500 cockerels were randomly distributed to two experimental groups at 21 days of age. Samples (blood plasma, red blood cell, liver, kidney and spleen) were collected every 12 h during a 48-h period. The results showed that the initial phase of lipid peroxidation, as measured by conjugated dienes and trienes in the liver, was continuously, but not significantly higher in T-2 toxin-dosed birds than in control birds. The termination phase of lipid peroxidation, as measured by malondialdehyde, was significantly higher in liver and kidney as a result of T-2 toxin exposure at the end of the experimental period (48th hour). The glutathione redox system activated shortly after starting the T-2 toxin exposure, which is supported by the significantly higher concentration of reduced glutathione and glutathione peroxidase activity in blood plasma at 24 and 48 h, in liver at 12, 24 and 36 h, and in kidney and spleen at 24 h. These results suggest that T-2 toxin, or its metabolites, may be involved in the generation of reactive oxygen substances which causes an increase in lipid peroxidation, and consequently activates the glutathione redox system, namely synthesis of reduced glutathione and glutathione peroxidase.

Oral administration of fumonisin B1 and T-2 individually and in combination affects hepatic total and mitochondrial membrane lipid profile of rabbits.

Weaned rabbits were fed diets contaminated with 2 mg/kg diet T-2 toxin alone, or 10 mg/kg diet fumonisin B1 (FB1) alone, and both toxins in combination (2 + 10 mg/kg, respectively) compared to a toxin-free control diet. Samplings were performed after 4 weeks (blood and liver). Bodyweight of T-2-fed group was lower after 4 weeks; the liver weight was increased dramatically (threefold of control). Liver total phospholipids (PLs) provided slight alterations in the fatty acid (FA) composition; all three toxin-treated groups showed a decrease in palmitoleic acid (C16:1 n7) proportion. In the liver mitochondrial PL FA composition, margaric acid (C17:0) proportion decreased in the separated toxin treatments compared to the combined setting. Oleic acid (C18:1 n9) proportion was increased and arachidonic acid (C20:4 n6) was decreased in the FB1-treated group, while docosapentaenoic acid (C22:5 n3) was decreased in the separated treatments. The total monounsaturation was significantly higher in the FB1 group's mitochondrial PL FA profile. After 4 weeks, all toxin treatments decreased the blood plasma reduced glutathione and glutathione peroxidase activity, and FB1 increased the plasma sphinganine/sphingosine ratio. Both mycotoxins seem to cross the hepatocellular and the hepatic mitochondrial membrane, without drastic membrane disruption, as assessed from the PL FA composition, but inducing detectable lipid peroxidation.

Effect of different weaning ages (21, 28 or 35 days) on production, growth and certain parameters of the digestive tract in rabbits.

The effect of different weaning ages, that is, 21 (G21), 28 (G28) or 35 (G35) days, on growth and certain parameters of the digestive tract was examined in rabbits to assess the risk of early weaning attributable to the less-developed digestive system. On days 35 and 42, G35 rabbits had 10% to 14% and 10% higher BW, respectively (P < 0.05), than those weaned at days 21 and 28. In the 4th week of life, early weaned animals had 75% higher feed intake than G28 and G35 rabbits (P < 0.05). The relative weight of the liver increased by 62% between 21 and 28 days of age, and thereafter it decreased by 76% between 35 and 42 days of age (P < 0.05), with G21 rabbits having 29% higher weight compared with G35 animals on day 35 (P < 0.05). The relative weight of the whole gastrointestinal (GI) tract increased by 49% and 22% after weaning in G21 and G28 rabbits, respectively (P < 0.05). On day 28, the relative weight of the GI tract was 19% higher in G21 than in G28 rabbits, whereas on day 35 G21 and G28 animals had a 12% heavier GI tract compared with G35 rabbits (P < 0.05). Age influenced the ratio of stomach, small intestine and caecum within the GI tract; however, no effect of different weaning age was demonstrated. The pH value of the stomach and caecum decreased from 5.7 to 1.6 and from 7.1 to 6.3, respectively, whereas that of the small intestine increased from 6.8 to 8.4 (P < 0.05); the differences between groups were not statistically significant. Strictly anaerobic culturable bacteria were present in the caecum in high amounts (108), already at 14 days of age; no significant difference attributable to weaning age was demonstrable. The concentration of total volatile fatty acids (tVFA) was higher in G21 than in G28 and G35 throughout the experimental period (P < 0.05). The proportion of acetic and butyric acid within tVFA increased, whereas that of propionic acid decreased, resulting in a C3 : C4 ratio decreasing with age. Early weaning (G21) resulted in higher butyric acid and lower propionic acid proportions on day 28 (P < 0.05). No interaction between age and treatment was found, except in relative weight of the GI tract and caecal content. In conclusion, early weaning did not cause considerable changes in the digestive physiological parameters measured, but it resulted in 10% lower growth in rabbits.