Animal performance and biochemical parameters are sex-dependent in peripubertal rats exposed to deoxynivalenol.

Deoxynivalenol (DON), a mycotoxin produced mainly by Fusarium graminearum and F. culmorum commonly contaminates food commodities across the globe. Due to this, exposure to DON might pose potential health hazards to humans and animals. Biological factors like sex and age can influence the toxicity of DON. However, in toxicological studies involving DON, the sex and age-dependent response has been often overlooked. Thereby, the objective of this study was to evaluate if sex differences are evident in DON's systemic effects in peripubertal rats. Juvenile animals (n = 24) with 28 days postnatal day were randomly assigned to two experimental groups: Control group (n = 12, 6 females and 6 males, mycotoxin-free diet) and DON group (n = 12, 6 females and 6 males, diet containing 10 mg DON/kg of feed). During 28 days of treatment, the animals were weighed weekly and body weight gain and food intake were calculated for each week. After the experimental period, blood samples, intestine, liver, and kidney were collected and destined for biochemical, hematological, histopathological, and oxidative stress analyses. Greater anorectic responses were seen in males, while only females showed increased levels of creatinine and triglycerides. Regardless of sex, DON induces an increased number of white blood cells, particularly lymphocytes and a significant reduction in the levels of hemoglobin, hematocrit, mean corpuscular hemoglobin, and neutrophils. In males and females fed a DON-contaminated diet, histological lesions were observed in the intestine, liver, and kidney. Ingestion of DON induced a significant increase in the antioxidant potential in the intestine, liver, and kidney. However, this effect was not able to prevent oxidative stress in the renal tissue. Taken together, our results showed a sex-related response in food intake, weight gain, and biochemical parameters in rats exposed to DON during the juvenile and peripubertal periods. In addition, we have verified that oxidative stress is an important mechanism in the nephrotoxicity of DON.

In vitro mechanism of antibacterial action of a citrus essential oil on an enterotoxigenic Escherichia coli and Lactobacillus rhamnosus.

AIM: This study investigated the in vitro mechanism of action of a commercial citrus EO, Brazilian orange terpenes (BOT), on an enterotoxigenic Escherichia coli (ETEC) isolated from pig gut and on Lactobacillus rhamnosus. METHODS AND RESULTS: Firstly, bacteria were exposed sequentially to BOT every 3 h (three times) at sub-minimal inhibitory concentrations and results showed that sequential exposure to BOT provoked a higher reduction of bacteria viability than a single exposure and the reduction of ETEC viability was higher compared to that of L. rhamnosus. Then, evaluation of the BOT effects on the cell membrane permeability and integrity, indicated that BOT increased the membrane permeability and caused disruptive effects on the integrity of bacterial cells as reflected by an increase of the relative electric conductivity and the release of essential cell constituents. Interestingly, BOT effects were more pronounced on the ETEC than on L. rhamnosus. This was ratified by scanning electron microscopy, which showed more noticeable morphological damages and disturbances on ETEC cells than on the L. rhamnosus cells. Limonene was detected as the major compound in BOT by polar/nonpolar GC-MS (78·65%/79·38%). CONCLUSIONS: Results revealed that the probable mechanism of the selective antibacterial action of the citrus EO, BOT, can be described as altering more remarkable the permeability and integrity of the cytoplasmic membrane as well as the external structure of ETEC cells than L. rhamnosus cells. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides information about the mechanism of antibacterial action displayed by a citrus EO, a by-product of the citrus processing industry, as a natural alternative to antibiotics used in pig production sector to combat pathogens such as ETECs.

Mycotoxin-contaminated diets and an adsorbent affect the performance of Nellore bulls finished in feedlots.

Mycotoxins are present in almost all feedstuffs used in animal nutrition but are often ignored in beef cattle systems, even though they can affect animal performance. The objective of this study was to evaluate the effects of mycotoxins and a mycotoxin adsorbent (ADS) on performance of Nellore cattle finished in a feedlot. One hundred Nellore cattle (430 ± 13 kg) were used in a randomized complete block design with a 2 × 2 factorial arrangement of treatments. The factors consisted of two diets with either natural contamination (NC) or exogenous contamination (EC) and the presence (1 g/kg of DM; ADS) or absence of a mycotoxin adsorbent. The NC and EC diets had the following contaminations, respectively: 0.00 and 10.0 µg/kg aflatoxins, 5114 and 5754 µg/kg fumonisins, 0.00 and 42.1 µg/kg trichothecenes B, 0.00 and 22.1 µg/kg trichothecenes A and 42.9 and 42.9 µg/kg fusaric acid. At the beginning of the experiment, all animals were weighed, and four randomly selected animals were slaughtered to evaluate the initial carcass weight. After 97 days of treatment, all animals were weighed and slaughtered. There was no interaction among factors for the DM intake (DMI; P = 0.92); however, there was a tendency for the EC diets to decrease the DMI by 650 g/day compared to animals fed NC diets (P = 0.09). There was a trend for interaction among factors (P = 0.08) for the average daily gain (ADG), where the greatest ADG was observed for cattle fed the NC diet (1.77 kg), and the lowest was observed for those fed the EC diet (1.51 kg). The NC + ADS and EC + ADS treatments presented intermediate values for ADG. The animals fed the NC diet had a greater final BW (596 kg) than animals fed the EC treatment (582 kg; P = 0.04). There was a tendency for interaction among factors for carcass gain (P = 0.08). Similarly to ADG, the highest carcass gain was observed for animals fed the NC diet (1.20 kg), and the lowest was observed for those fed the EC diet (1.05 kg). The NC + ADS and EC + ADS treatments presented intermediate values. The natural contamination groups had greater carcass gain than that of the EC groups, and the use of the ADS recovered part of the weight gain in animals fed the EC diet. In conclusion, mycotoxins at the levels evaluated affected the performance of beef cattle, and adsorbents may mitigate their impact.

Control of Rhizopus stolonifer in strawberries by the combination of essential oil with carboxymethylcellulose.

Strawberry has a limiting postharvest shelf life, especially because of soft rot. The antifungal activity of the essential oils (EOs) of Eucalyptus staigeriana, Lippia sidoides and Pimenta pseudocaryophyllus was tested in vitro against plant pathogen Rhizopus stolonifer. The chemical composition of the EO with the highest activity and its effects on pathogen morphology were verified. The in vivo antifungal activity of this EO associated with carboxymethylcellulose (CMC) coating, in preventive and curative applications, was also evaluated. L. sidoides EO presented the highest in vitro antifungal activity. The analysis of the chemical composition of this EO showed a prevalence of the compound thymol and the scanning and transmission electron microscopy showed that L. sidoides EO was able to cause damage to the cell wall and the intracellular components of the pathogen. Strawberries treated with L. sidoides EO associated with CMC presented a reduction in disease severity, especially when treated in a curative way.

Analysis of DNA damage induced by aflatoxin B1 in Dunkin-Hartley guinea pigs.

Aflatoxin B1 (AFB1) is among the most potent naturally occurring carcinogens and classified as a group I carcinogen. Since the ingestion of aflatoxin-contaminated food is associated with several liver diseases, the aim of the present study was to evaluate the effect of 2, 20, and 200 ppb of AFB1 on DNA damage in peripheral blood lymphocytes and liver cells in Dunkin-Hartley guinea pigs. The animals were divided into four groups according to the given diet. After the treatment the lymphocytes and liver cells were isolated and DNA damage determined by Comet assay. The levels of DNA damage in lymphocytes were higher animals treated with 200 ppb of AFB1-enriched diet (P = 0.02). In the liver cells there were a relationship between the levels of DNA damage and the consumption of AFB1 in all studied groups. These results suggest that Comet assay performed on lymphocytes is a valuable genotoxic marker for high levels of exposure to AFB1 in guinea pig. Additionally our results indicate that the exposure to this toxin increases significantly and increases the level of DNA damage in liver cells, which is a key step on liver cancer development. We also suggest that the Comet assay is an useful tool for monitoring the genotoxicity of AFB1 in liver.

Evaluation of the black light test for screening aflatoxin-contaminated maize in the Brazilian food industry.

The results of the black light test for aflatoxin-contaminated maize carried out in a large food factory in the State of São Paulo was evaluated against bi-directional thin layer chromatography (TLC) analysis for 286 samples of maize. All 286 samples were accepted by the black light test (< 7 fluorescent points), however, the results from TLC analysis showed that 96 samples were contaminated and 14 showed aflatoxin B1 contamination levels higher than 20 micrograms/kg. There were 14 false negative results and no false positives and out of the 14 samples, six did not show visible fluorescent points. If the rejection criterion of one or more fluorescent points were applied, the six samples would be accepted by the black light test. But, in this case, 95 samples would be rejected and 87 results would be false positives because they did not have contamination levels over 20 micrograms/kg which is the acceptance limit of the black light test. The results indicate that the black light test, as utilized by this factory, was not able to indicate lots with possible contamination and the black light test, as recommended in the literature, would produce a high number of false positives. It is necessary to make more studies on the use of black light as a screening test for possible aflatoxin B1-contaminated maize.

Influence of bag materials on the moisture loss and final aflatoxin content of in-shell peanuts stored moist. First studies.

In the present work the influence of bag materials on the moisture loss and final aflatoxin content of stored moist in-shell peanuts (MIP) was studied in the rainy season of 1990, in Marília, São Paulo, and in the rainy season of 1991, in Jaboticabal, São Paulo. In each season, MIP were ventilated, as they arrived from the field, to get rid of extraneous materials and then put into 120 bags of jute and into 120 bags of polypropylene, and stored in stacks (12 bags base x 10 bags high). In the rainy season of 1990 (February-April) moisture and aflatoxin were determined at the beginning (average moisture = 14.31%; aflatoxin not detected). Subsequently, moisture was determined twice a week in samples taken from the external part of the stacks for 80 days, when the stacks were dismantled and moisture and aflatoxin were determined in six samples of each stack. In the rainy season of 1991 (February-March), because of operational difficulties, closed mesh jute bags were used (green coffee type) and the experiment lasted only 30 days. Moisture and aflatoxin were determined only at the beginning (average moisture = 15%; aflatoxin not detected). At the end of the storage period three samples were taken from each lot, for moisture and aflatoxin analyses.(ABSTRACT TRUNCATED AT 250 WORDS)

Influência do tipo de sacaria na perda de umidade e no conteúdo final de aflatoxinas de amendoim em casca armazenado úmido / Influence of bag materials on the moisture loss and final aflatoxins content of unshelled peanuts stored with high moisture.preliminary studies

No presente trabalho foi estudada a influência do tipo de sacaria na perda de umidade e no conteúdo final de aflatoxinas (B1+G1) de amendoim em casca armazenado úmido.O experimento foi realizado em Marília, SP, na safra das águas de 1990 e em Jaboticabal, SP, na safra das águas de 1991.Em cada safra, o amendoim em casca úmido recém chegado do campo sofreu pré-limpeza para a retirada de material estranho e impurezas em geral e foi colocado em 200 sacos de juta e 200 de polipropileno(safra de 1990) e em 120 sacos de juta e em seguida armazenados em pilhas.Na safra das águas de 1990(fevereiro/março) determinou-se, inicialmente, umidade e aflatoxinas em 3 amostras (umidade média=14, 31 por cento e aflatoxinas näo detectadas).Duas vezes por semana, durante os dias subsequentes, determinou-se umidade da parte externa das pilhas, após o que estas foram desmanchadas e determinou-se umidade e aflatoxinas em 6 amostras de cada pilha.Na safra das águas de 1991, devido a dificuldades operacionais, utilizou-se sacaria de juta de trama fechada(para café) e o experimento durou apenas 30 dias.Umidade e aflatixinas foram determinadas apenas no início do experimento (umidade=15, 0 por cento e aflatoxinas näo detectada).No final foram retiradas 3 amostras de cada lote para análise de umidade e aflatoxinas.Os resultados mostraram, em ambas as safras, que em sacos de juta, mesmo com trama fechada, a perda de umidade média de 9, 68 por cento na sacaria de juta e de 10, 38 por cento na de polipropileno em 1990 e 9, 50 por cento na juta e de 10, 36 por cento na de propileno com valores médios de 51 µg/Kg(1990) e 361 µg/Kg (1991) para juta contra 1380 µg/Kg(1990) e 3703 µg/Kg para polipropileno.Estes resultados levam à conclusäo de que o uso de sacaria de juta é altamente vantajoso e pode ser indicado como o mais conveniente para prevenir o desenvolvimento de aflatoxinas no amendoim em casa, durante o armazenamento quando o mesmo for colhido e ensacado úmido