Stability of aflatoxins in solution.

The stability of aflatoxins B1, B2, G1, and G2 was studied in solutions containing different concentrations of water, acetonitrile, and/or methanol, and in autosampler vials treated with nitric acid or silanized. When stored at room temperature (20 degrees C) for 24 h, aflatoxins G1 and G2 were stable only in solutions containing 100% organic solvent, whereas aflatoxins B1 and B2 were stable in solutions of methanol-water and acetonitrile-water at greater than 60 and 40% organic content, respectively. At 5 degrees C, aflatoxins G1 and G2 showed a significant decrease in concentration only when kept in less than 20% aqueous organic solvent. Significant loss of aflatoxins was realized in standard, commercially available amber type I borosilicate autosampler vials, but chemical etching of the vials with nitric acid or with silanization prevented aflatoxin degradation. These results indicate that aflatoxins are unstable in aqueous solutions and that this instability can be counteracted by the presence of at least 20% organic solvent and keeping the solutions at 5 degrees C or by the use of treated vials.

Effect of feeding hens trout by-product meal or tuna fish oil on production parameters and yolk fatty acid profile / Efecto de la alimentación de gallinas con ensilaje de vísceras de trucha o aceite de atún en parámetros productivos y perfil de ácidos grasos en yema de huevo / Efeito da alimentação de galinhas com silagem de vísceras de truta ou óleo de atum nos parâmetros produtivos e o perfil de ácidos graxos na gema de ovo

Objective: a study was conducted to evaluate two sources of omega-3 (n-3) fatty acid enrichment, namely a trout by-product meal (TBPM) and tuna fish oil (TFO), as potential sources for egg yolk n-3 enrichment. Methods: Seventy-27 week old commercial layers were assigned to each of seven dietary treatments, as follows. Group 1: control; group 2: 5% TBPM; group 3: 10% TBPM; group 4: 15% TBPM; group 5: 20% TBPM; group 6: 2% TFO; and group 7: 3% TFO. The experimental diets were fed for 28 days. Results: no effect on production parameters was caused by the experimental diets. All diets containing TBPM or TFO significantly (p<0.05) increased n-3 egg yolk fatty acid content. Dietary levels of 5-20% TBPM increased egg yolk n-3 content between 1.97 and 3.54 times compared with control eggs. TFO levels of 2% and 3% increased the n-3 egg yolk content 3.37 and 4.13 times, respectively, compared with control eggs. The n-6/n-3 ratio in egg yolk lipids was significantly (p<0.05) decreased by the experimental diets. The n-6/n-3 ratio in control eggs was 16.79 compared with ratios ranging from 4.34 to 8.11 in enriched eggs. Conclusions: the results showed that both TBPM and TFO are good sources of n-3 fatty acid enrichment in eggs. Further studies are required in order to determine the effects of TBPM and TFO inclusion on the organoleptic quality of eggs.

Objetivo: se realizó un estudio para evaluar dos potenciales fuentes de enriquecimiento de ácidos grasos omega-3 (n-3) en yema de huevo: ensilaje de vísceras de trucha (TBPM) y aceite de atún (TFO). Métodos: un total de 70 gallinas de postura de 27 semanas se asignaron a siete tratamientos dietarios, así: grupo 1: control; grupo 2: 5% TBPM; grupo 3: 10% TBPM; grupo 4: 15% TBPM; grupo 5: 20% TBPM; grupo 6: 2% TFO y grupo 7: 3% TFO. Las dietas experimentales se suministraron durante 28 días. Resultados: no se encontraron efectos sobre los parámetros productivos a causa de las dietas experimentales, pero todas las dietas suplementadas con TBPM o TFO causaron un aumento significativo (p<0.05) en el contenido de n-3 de la yema. La suplementación de 5-20% de TBPM causó un incremento de n-3 de 1.97 a 3.54 veces, comparado con el contenido de n-3 de los huevos control. La suplementación de 2% y 3% de TFO incrementó en contenido de n-3 en 3.37 y 4.13 veces, respectivamente. La relación n-6/n-3 en los lípidos de la yema aumentó significativamente en las dietas experimentales siendo esta relación de 16.79 en los huevos control y de 4.34-8.11 en los huevos de gallinas suplementadas con las fuentes de n-3. Conclusiones: los resultados del presente estudio demuestran que tanto el TBPM como el TFO constituyen fuentes apropiadas de enriquecimiento de huevos con ácidos grasos n-3. Se requieren más estudios para determinar los efectos de estas materias primas en la calidad organoléptica del huevo.

Objetivo: Foi realizado um estudo para avaliar duas fontes potenciais de enriquecimento de ômega-3 (n-3) na gema de ovo: silagem de vísceras de truta (TBPM) e óleo de atum (TFO). Métodos: Um total de 70 galinhas poedeiras de 27 semanas, foram atribuídas a sete tratamentos dietéticos: grupo 1: controle, grupo 2: 5%TBPM, grupo 3: 10% TBPM, grupo 4: 15% TBPM, grupo 5: 20% TBPM, grupo 6: 2% TFO e grupo 7: TFO 3%. As dietas experimentais foram subministradas durante 28 dias. Resultados: Não foram encontradas diferencias nos parâmetros de produção por causa das dietas experimentais, mas todas as dietas suplementadas com TFO ou TBPM causaram um aumento significativo (p<0.05) no conteúdo de n-3 da gema. A suplementação de 5-20% de TBPM causou um aumento de n-3 de 1.97 a 3.54 vezes, em comparação com o conteúdo de n-3 do controle. A suplementação de 2% e 3% de TFO aumentou o conteúdo de n-3 em 3.37 e 4.13 vezes, respectivamente. A relação n-6/n-3 nos lipídios da gema aumentou significativamente nas dietas experimentais, sendo esta relação de 16.79 nos ovos do controle e de 4.43 a 8.11 em ovos de galinha suplementados com fontes de n-3. Conclusões: Os resultados deste estudo demonstram que o TFO e o TBPM são fontes apropriadas de enriquecimento de ovos com n-3 ácidos graxos. Mais estudos são necessários para determinar os efeitos dessas matérias primas na qualidade organoléptica do ovo.

The role of selected cytochrome P450 enzymes on the bioactivation of aflatoxin B1 by duck liver microsomes.

A study was conducted to determine the cytochrome (CYP) P450 enzymes responsible for the bioactivation of aflatoxin B1 (AFB1) into its epoxide form (AFBO) in duck liver microsomes. Six male and six female 6-week-old Pekin ducks were used. The biochemical toxicology strategies applied included the use of selective inhibitors, prototype substrate activity for specific human P450s, correlation between aflatoxin bioactivation and enzymatic activity of prototype substrates, and the expression of specific CYP450 enzymes using antibodies against human CYP450s. Enzymatic activity was detected for the duck orthologues CYP1A1/2, CYP2A6 and CYP3A4 but not for the CYP2D6 orthologue. Immunoreactive proteins for CYP1A1, CYP2A6 and CYP3A4 were also detected. Inhibition studies suggested that the duck turkey CYP2A6 orthologue and, to a lesser extent, the CYP1A1 orthologue are involved in the bioactivation of AFB1. Correlation studies, however, suggest that CYP3A4, CYP2A6 and CYP1A1/2 are all involved in AFBO formation. The finding that four CYP enzymes may be involved in AFB1 bioactivation in ducks could explain the high sensitivity of this species to AFB1. Further studies are needed to fully elucidate the phase I hepatic metabolism of AFB1 in ducks, the only poultry species that develops hepatic cancer from AFB1 exposure.