João Paulo Aquino Santos

Atividade antibacteriana, antioxidante e tanante de subprodutos da uva

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.

Diphenyl diselenide induces anxiolytic-like and sedative effects on the chick social separation-stress behavior.

The purpose of this research was to investigate the anxiolytic-like effect of diphenyl diselenide [(PhSe)(2)] on the chick social separation-stress behavior. Male chicks (six day-old) received, per oral route, a single administration of (PhSe)(2) at doses of 1, 10 and 50mg/kg. Thirty minutes after treatment, chicks were submitted to the behavioral tests. The behavioral tests: number of separation-induced distress vocalizations and jumps, time of active wakefulness, time of standing/sitting motionless with eyes open, time of standing motionless with eyes closed and time of sleeping posture, during 10 min, were recorded. (PhSe)(2) at doses of 10 and 50mg/kg reduced the number of vocalizations and jumps and the time of active wakefulness and increased the time of standing/sitting motionless with eyes open of chicks. The sleeping posture time was increased in animals treated with (PhSe)(2) at the dose of 50mg/kg. In conclusion, treatment with (PhSe)(2), in a dose dependent-manner, caused anxiolytic-like and sedative effects in chicks.

Risk assessment of finishing beef cattle in feedlot: slaughter weights and correlation amongst input variables

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.

Métodos de incorporação da enzima fitase em rações para 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.