Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Inhibitory effects of essential oils of Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) on the mycelial growth and aflatoxin B1 production by Aspergillus flavus have been studied previously in culture medium. The aim of this study was to evaluate aflatoxin B1 production by Aspergillus flavus in real food systems (corn and soybean) treated with Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) essential oils. Samples with 60 g of the grains were treated with different volumes of essential oils, 200, 100, 50, and 10 μL for oregano and 50, 30, 15, and 10 μL for mentrasto. Fungal growth was evaluated by disk diffusion method. Aflatoxin B1 production was evaluated inoculating suspensions of A. flavus containing 1.3 × 105 spores/mL in 60 g of grains (corn and soybeans) after adjusting the water activity at 0.94. Aflatoxin was quantified by photodensitometry. Fungal growth and aflatoxin production were inhibited by essential oils, but the mentrasto oil was more effective in soybeans than that of oregano. On the other hand, in corn samples, the oregano essential oil was more effective than that of mentrasto. Chemical compositions of the essential oils were also investigated. The GC/MS oils analysis showed that the main component of mentrasto essential oil is precocene I and of the main component of oregano essential oil is 4-terpineol. The results indicate that both essential oils can become an alternative for the control of aflatoxins in corn and soybeans.

The chemical composition and antifungal activity of the Ageratum conyzoidesessential oils, obtained from the leaves collected in Ibiúna (1), Ribeirão Pires (2) and Campinas (3) in the São Paulo state, Brazil, were investigated. The essential oils were obtained from A. conyzoidesleaves by hydrodestilation and analyzed by GC/MS. The chemical composition of the A. conyzoides oil collected in Ribeirão Pires and Ibiúna consisted mainly of precocene I and II. The essential oil from leaves collected in Campinas had only traces of precocene II and a highest proportion of precocene I, α-humulene and (E)-caryophyllene than the oils (1) and (2). The Aspergillus flavus growth was inhibited by essential oils (1) and (2) at 60 and 64%, respectively, and the oil (3) was inactive. On the other hand, the three essential oils inhibited the sporulation of the fungus for more than 120 days. The essential oils of leaves collected in sites that show similarities in the latitude, altitude and average temperatures, as Ribeirão Pires and Ibiúna, showed chemical composition and antifungal activity similar, either, which showed the importance of geo-ecological factors in production of metabolites of the plant.

This study evaluated the isolation, molecular typing and celular proliferation of C. perfringens in small intestine of cattle and sheep distributed in case and control groups. In the case group, out of the 61 bovine samples analyzed, C. perfringens was isolated in 29 (47.54%) and in 4 (33.34%) from 12 sheep samples. In the control group, we did not isolate the microorganism in the bovine samples (73 samples), however it was possible in 5 (20.83%) out of the 24 sheep samples.  All isolates (100%) were classified as type A, and cell quantification showed that in control group, all cattle samples resulted in 10 CFU/g of intestinal content while in the study group presented a median value of 104 CFU/g, varying from 10 CFU/g through 108 CFU/g. In ovine group there was a clear divison of values between the two groups. Molecular typing corroborates with other studies regardin the epidemiological importance of type A in enterotoxaemia in ruminants, thus cellular quantification data allow us to conclude that healthy animals present a basal level of C. perfringens lower than 10 CFU/g that does not allow its isolation.

We herein describe a typical episode of bacillary hemoglobinuria in buffalloes, triggered by liver fluke invasion proved by pathognomonic macro and micro lesions of fasciolosis in the biliary ducts and the nephrosis and hepatic focal necrosis characterizing the toxic-infectious process caused by Clostridium haemolyticum. This report is quite similar to another one described by AHOURAI et al. (1990) in cattle following liver fluke invasion and C. haemolyticum isolation and we both agree with the fact that foci of ischemic of toxic necrosis serve as a focus in which clostridial spores might vegetate and cause the disease by producing toxins. Vaccination with bacterin or toxoids is the most effective measure for preventing these histotoxic clostridial diseases since the endospores of the microorganism persist in the environment. Also, as the process is triggered by fluke liver migration, the prevention should cover the control of this trematode as well. Although the pathogenicity of bacillary hemoglobinuria is well known, there are only a few reports currently available, and to our knowledge this is the first case of the disease described in buffaloes.