Universidade Federal de Viçosa

About: Universidade Federal de Viçosa is a education organization based out in Viçosa, Brazil. It is known for research contribution in the topics: Population & Biology. The organization has 16012 authors who have published 26711 publications receiving 353416 citations.

Qualidade nutricional e escore químico de aminoácidos de diferentes fontes protéicas

Abstract: As proteinas sao moleculas essenciais para aos organismos animais, devendo, portanto, estar presentes na alimentacao em quantidades adequadas. Alem do aspecto quantitativo deve-se levar em conta o aspecto qualitativo, isto e, seu valor nutricional, que dependera de sua composicao, digestibilidade, biodisponibilidade de aminoacidos essenciais, ausencia de toxicidade e de fatores antinutricionais. O objetivo deste trabalho foi avaliar a digestibilidade in vivo, o escore quimico de aminoacidos (EQ) e o escore quimico de aminoacido corrigido pela digestibilidade proteica (PDCAAS) das seguintes fontes de proteina: carne de ra sem osso, carne de ra com osso, carne de ra mecanicamente separada (CMS), carne bovina, ovo em po, caseina, trigo, milho, soja convencional, soja isenta de inibidor de tripsina Kunitz e de lipoxigenases (soja KTI-LOX-), proteina texturizada de soja (PTS) e feijao. As proteinas de origem animal apresentaram maiores valores de digestibilidade que as de origem vegetal. Carne de ra sem osso apresentou a proteina com maior digestibilidade proteica de todas as proteinas estudadas, nao diferindo, entretanto, da caseina, CMS, carne bovina e ra com osso. Das proteinas de origem animal, a do ovo em po foi aquela que apresentou menor digestibilidade proteica. Nenhuma das proteinas de origem animal apresentou aminoacidos essenciais limitantes quando comparadas com o padrao da FAO/WHO. Feijao, soja convencional, soja KTI-LOX- e PTS, tiveram os aminoacidos sulfurados (metionina+cisteina) como limitantes. Enquanto que para trigo e milho, o aminoacido mais limitante foi a lisina. Soja KTI-LOX- e PTS apresentaram valores de PDCAAS superiores aos da soja convencional, mostrando uma possivel elevacao na qualidade proteica da soja melhorada geneticamente e da soja processada.

Nematophagous fungi for biological control of gastrointestinal nematodes in domestic animals

Abstract: Several studies have been conducted using fungi in the biological control of domestic animals and humans. In this respect, a large amount of research has been undertaken to understand the particularities of each fungus used. These fungi have been demonstrated to act on all classes of helminthes. Therefore, they should not only be called nematophagous but also helmintophagous. Evidence of enzymatic action has also revealed their mechanism of action, as well as potential metabolites that could be synthesized as bioactive molecules. Cultural barriers to the use of fungi should be broken down, since the impact on the environment is minimal. In this context, much is already known about the mechanism of interaction of these organisms with their 'targets'. Recent research has pointed to the search for substances derived from nematophagous fungi that have demonstrated their ovicidal and/or larvicidal activity, thus being a global premise to be studied further. Crude extracts derived from nematophagous fungi of predator and ovicidal groups reduce the amount of larvae of gastrointestinal nematodes and prevent the hatching of their eggs, since they have been demonstrated to act with extracellular proteases and other enzymes. Furthermore, the activity of these enzymes has begun to be explored regarding their possible interaction with the exoskeleton of arthropods, which could emerge as an alternative method of tick control. Finally, it should be clear that nematophagous fungi in general are 'old friends' that are ready to the 'fight with our old enemies', the gastrointestinal helminth parasites harmful to human and animal health.

Influência dos sistemas de preparo nas propriedades químicas e físicas do solo

Abstract: Different tillage systems cause changes in the chemical, physical and biological attributes of a soil, requiring modifications in the requirements of fertilization and liming. The aim of this work was to evaluate the effects of tillage systems on chemical and physical attributes of a soil, in a long-term experiment installed in 1985. Since then, the soil has been cultivated with annual cultures and submitted to six tillage systems: no-tillage (SD), disc plow (AD), moldboard plow (AA), heavy disc harrow (GP), heavy disc harrow + moldboard plow (GP + AA) and heavy disc harrow + disc plow (GP + AD). The experimental design was in completely randomized blocks with four replications. Samplings were collected after the culture of maize (crop 2001/02), at depths of 0-5, 5-10 and 10-20 cm. Soil samples were submitted to chemical and physical analyses and the averages compared by the Tukey test. The tillage systems affected the chemical and physical attributes of a soil distinctly. Greatest differences were observed between the SD treatment and the others. SD showed higher bulk density values than the other treatments, in the average of the three depths. In the 0-5 cm layer of SD, increments of the medium values of organic matter, pH, cation-exchange capacity, exchangeable calcium, exchangeable magnesium, exchangeable potassium and phosphorus available were observed; in relation to the other depths. The aluminum value was smaller in the SD treatment in the 0-5 cm layer than the others; at the depth 10-20 cm, this value was higher than the treatments AD, GP and GP + AA. Treatments AD, GP, GP + AD and GP + AA showed higher values of exchangeable potassium than the treatments SD and AA, at the depth 0-5 cm. Treatment SD presented values of available phosphorus superior to the other treatments, at the depth 0-5 cm and in the average of the three depths.

The importance of termites (Isoptera) for the recycling of herbivore dung in tropical ecosystems: a review

Abstract: While the key role of termites in the decomposition of litter in the tropics has been acknowledged for a long time, much less information exists on their importance in the recycling of dung of primary consumers, especially herbivores. A review of published studies shows that a diverse group of termites (at least 126 species) has been reported to feed on a wide range of mammalian dung (18 species). Predominantly, wood-feeding and polyphagous wood-litter feeding species were found to feed also frequently on dung. Moreover, we found that termites can quickly remove large amounts of mammalian dung, especially in the dry season, when on average about 1/3 of the dung deposited in a given habitat is removed by termites within one month (with the highest rates observed in savannas). No distinctive preference for mammalian dung over other organic food sources was observed for fungus-growing termites (Macrotermitinae), whereas the majority of the non-fungus growing taxa studied prefer dung over other food. As termites bring large quantities of dung below the soil surface, disturb and enrich soils with nutrients, dung feeding by termites appears to be a previously underestimated process important in the functioning of tropical ecosystems.