The objective of this study was to evaluate the risk associated with finishing crossbred Charolais × Nellore steers in feedlot at different slaughter weights (425, 467 or 510 kg), considering or disregarding the correlation amongst random input variables. Data were collected from 2004 to 2010 and used in the simulation of the financial indicator Net Present Value (NPV). Animals slaughtered with 425, 467 or 510 kg were fed diets containing a roughage:concentrate ratio of 60:40 for 30, 65 and 94 days, respectively. In the simulation of NPV, a Latin Hypercube type of sampling was used, running 2000 interactions. An analysis of stochastic dominance of first and second orders was carried out as well as the Kolmogorov-Smirnov asymptotic test (to check for differences between pairs of curves of cumulative distributions), followed by sensitivity analysis using stepwise multivariate regression. Simulations of NPV considering the correlation amongst the input variables produced more consistent estimates of this financial indicator than simulations that disregarded it. The risk analysis showed that 467 kg slaughter weight presented the lowest risk for finishing cattle in feedlots when compared with 425 and 510 kg. The most important variables influencing the NVP are the prices of feeder and finished steers, initial and final weights, concentrate and roughage costs, and minimum rate of attractiveness; therefore, farmers should pay particular attention to these variables when making the decision of whether or not to use feedlot to finish beef cattle.

Objetivou-se com o estudo avaliar duas metodologias de incorporação da enzima fitase comparando-as a uma dieta basal e ao método de aumentar a suplementação de Fósforo inorgânico na dieta, em busca de uma forma mais eficaz de atenuar o fator antinutricional ácido fítico. Foram observadas características de desempenho de poedeiras Isa Brown, durante 63 dias de período experimental. O delineamento experimental foi inteiramente casualizado com quatro tratamentos e cinco repetições de seis aves. As aves foram submetidas aos tratamentos (dietas): dieta basal (DB), dieta com farelo de arroz desengordurado tratado com fitase (FADFI), método tradicional de incorporação de fitase na dieta sem tratamento prévio do farelo de arroz desengordurado com fitase (MTFI) e dieta com farelo de arroz desengordurado e sem fitase (SEMFI). Os métodos de incorporação da fitase nas rações não influenciaram significativamente (P>0,05) o desempenho das aves, ambos equivalendo-se à dieta basal. O tratamento prévio do farelo de arroz desengordurado com fitase a nível de 300 FTU kg-1 é eficiente, ou seja, tratar somente um ingrediente da dieta com fitase permite incoporar uma quantidade menor de fitase, mantendo bom desempenho. Portanto, os métodos que envolveram fitase, independentemente da metodologia de incorporação, são indicados na alimentação de poedeiras.

The objective of the study to evaluate two methods of incorporation of the enzyme phytase by comparing them to a basal diet and the method of increasing the supplementation of inorganic phosphorus in the diet, in search of a more effective way to mitigate the anti-nutritional factor phytic acid. Were observed performance characteristics of Isa Brown hens for 63 days trial period. The experimental design was completely randomized design with four treatments and five replicates of six birds. The birds received the treatments (diets): basal diet (BD), diet with defatted rice bran treated with phytase (DRBF), the traditional method of incorporation of dietary phytase untreated defatted rice bran phytase (MTF) and diet with defatted rice bran and without phytase (DRB). The methods of incorporating phytase in the diets did not significantly (P>0.05) broiler performance, both equivalent to the basal diet. The treatment of DRBF with phytase at 300 FTU kg-1 is effective, ie, treating only one ingredient of the diet with phytase onboard allows a smaller amount of phytase, while maintaining good performance. Therefore, methods involving phytase, regardless of method of incorporation, are indicated in the diet of laying hens.

O objetivo neste trabalho foi determinar-se in vitro a atividade antibacteriana, antioxidante e tanante de subprodutos da uva (Vitis vinifera) para seu aproveitamento como ingredientes alternativos na indústria avícola e na conservação de alimentos. Compostos polares foram extraídos da semente de uva desengordurada, em solução contendo acetona, água e ácido acético, resultando em 10,3% de rendimento de extrato de semente de uva desengordurada (ESUD). O ESUD apresentou alta atividade antibacteriana in vitro contra cepas de S. aureus e E. coli, mas não contra cepas de Salmonella sp. A atividade antioxidante do ESUD foi comparável ao ácido ascórbico. A atividade tanante foi considerada baixa para a semente de uva e alta para o ESUD.

The aim of this research was to determine in vitro the antibacterial, antioxidant and tanning activity from grape by-products (Vitis vinifera), for its use as alternative ingredients in the poultry industry and food conservation. Polar compound had been extracted of the defatted grape seed (SUD) in a solution with acetone, water and acetic acid, in the 90: 9.5: 0.5 ratio respectively, resulting in a yield of 10.3% of defatted grape seed extract (ESUD). ESUD has high antibacterial activity against strains of S. aureus and E. coli, but not against Salmonella sp. The antioxidant activities of the ESUD had comparable to the ascorbic acid. The capacity to bind proteins was considered low for the seed and high for the ESUD.