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The Cymbopogon nardus L. is a plant popularly known as "citronella grass", originating from Ceylon and India, used in Indonesia as a soothing and digestive tea. The essential oil of the species Cymbopogon nardus (OECN) is used in the manufacture of cosmetics and perfumes, besides having shown antimicrobial action against Escherichia coli, Salmonella spp., Pseudomonas spp., Streptococcus spp., and in addition antioxidant, anti-inflammatory. The objective of this study was to determine the larvicidal and fungicide potential of OECN extracted from the fresh leaves of C. nardus. L at the beginning of the dry season in Teresina, PI. From the OECN extracted by hydrodistillation, the actives were identified by mass gas chromatography. The larvicidal action of OECN was tested against the third and fourth larval stages of Aedes aegypti at concentrations (2.5, 5.0, 7.5 and 10 μL/20 ml) for 24 to 48 hours. Antifungal activity for Aspergillus flavus and A. parasiticus at concentrations (1.0, 2.0, 4.0 6.0 and 8.0 μL/10 mL). The OECN showed a good yield (1.0%), with 26 assets (93.2%) identified with the majority: citronelal (31.6%), geraniol (22.1%), elemol (11.8%) and citronellol (8.2%). Mortality of 100% of the larvae was observed at concentrations of 7.5 and 10.0 µl / 20 ml in 24 hours. After 48 hours 93.3% in 5.0 µl/10 ml OECN and 70% in 2.5 µl/10 ml. A. flavus showed greater sensitivity to OECN at 8.0 µl / 10 ml than A. parasiticus at concentrations. A. parasiticus was the most sensitive at concentrations of 1.0 and 2.0 µL / 10 mL. OECN has a larvicidal action and antifungal activity at the tested concentrations.

Com este estudo, objetivaram-se isolar e identificar leveduras presentes na microbiota intestinal de Litopenaeusvannamei cultivados em estuário tropical e testar in vitro a capacidade probiótica e adsorvente de aflatoxina B1(AFB1)por cepas de Saccharomyces cerevisiae isoladas. Foram adquiridos 40 camarões da espécie L. vannamei, fizeram-se o isolamento e a identificação de leveduras intestinais por sequenciamento molecular, e foram escolhidas três cepas de S. cerevisiae (C2B, C2D e C9) para avaliar o potencial probiótico. Realizaram-se os seguintes testes: inibição homóloga, autoagregação, coagregação, atividade antibacteriana, viabilidade às condições gastrointestinais etambém a análise de adsorção de AFB1. Foram identificadas as seguintes espécies: Candida spp., Candida tropicalis, Lodderomyces elongisporus, Rhodotorula spp. e S. cerevisiae. As cepas de S. cerevisiae isoladas apresentaram atividadeantibacteriana, e a cepa C9 obteve melhor desempenho nos testes de atividade antimicrobiana, na viabilidade em pH e na adsorção da AFB1 do que as demais. Concluiu-se que é possível isolar Candida spp., C.tropicalis, Rhodotorula sp. e S. cerevisiae, e o estudo demonstrou pela primeira vez que L. elongisporus pode estar presente no intestino em viveiros. As cepas de S. cerevisiae isoladas do intestinos de L. vannamei possuem potencial probiótico e adsorvente de AFB1 em testes in vitro.

Mycotoxins are products resulting from fungi metabolism normally present in the environment and which can develop in food. The aim of this study was the fungi quantification, aflatoxin detection and investigation of ergot alkaloids occurrence in pelleted feed for adult equines during storage. The feed samples were collected from three rural properties with equideoculture activity in the city of Teresina, Piauí, Brazil. The results showed that was no significant difference (p<0.05) for the counting of colony-forming units (CFU/g) of filamentous fungi and yeasts in the samples. Aflatoxins B1, B2, G1 and G2 were found in acceptable amounts and the other fungal metabolites: ergometrine, griseofulvin, festuclavin, ergine and lysergol. Concluding, the results of this study demonstrate that amount of filamentous fungi and the water activity present in the original package remain constant after six days of storage. Four types of aflatoxins were found: AFB1, AFB2, AFG1, AFG2 and the Ergot alkaloids: ergine, ergometrine, festuclavine, griseofulvin and lisergol in amounts within acceptable limits. These groups of toxic compounds produced by fungi can be present in equine feed and may lead to a risk to their health.

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