Characterization of Staphylococcus aureus isolates in milk and the milking environment from small-scale dairy farms of São Paulo, Brazil, using pulsed-field gel electrophoresis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Níveis de proteína digestível e energia digestível em dietas para tilápias-do-nilo formuladas com base no conceito de proteína ideal

This study was carried out to determine the best digestible energy and digestible protein ratio in feeds for Nile tilapia (Oreochromis niloticus) juveniles 30.0 +/- 4.21 g) based on digestible amino acids and the ideal protein concept). Twelve rations were formulated with protein levels 22.0; 26.0; 30.0 and 34.0% of digestible protein and levels 3,000, 3,300 and 3,600 kcal/kg digestible energy. The digestible energy/digestible protein ratio was between 8.94 and 15.19 kcal/g. Three hundred and twenty four tilapias were randomly distributed in thirty six 250 L circular tanks at a density of 9 fish/tank, a total of 12 treatments with three replications. After 60 days, there was no significant difference in weight gain, daily weight gain and feed conversion ratio among the studied treatments. A linear increase was observed in fillet yield with increasing digestible protein. With respect to feed cost/kg weight gain, the treatment with 30.0% DP and 3,000 kcal/kg DE presented low cost and better cost effectiveness index. Therefore, it was concluded that digestible energy did not influence the productive performance parameters and that effective feeds can be formulated with DP levels lower than 34% when feeding juvenile tilapias. The ration should be formulated based on the concept of ideal protein.

Hematologia e sinais clínicos de Piaractus mesopotamicus infectados experimentalmente com Aeromonas hydrophila

The purpose of this study was to evaluate the hematological response and clinical sign of Piaractus mesopotamicus infected by Aeromonas hydrophila. Were used 324 pacus, P. mesopotamicus weighing 102.84 [plus or minus] 27.1 g distributed in 27 water tanks with 300 L of capacity, 14 fish per tank. The fish were kept in the water tanks during one month, receiving appropriate diet. In this period was avoided stressing management. After this period, the fish were infected with 6 X 108 cfu of A. hydrophila fish-1, injected intraperitoneally. The blood collection was carried 24th before experimental infection and 2411 after its. The A. hydrophila infection in P. mesopotamicus is characterized by dark skin and clinical signs related to hemorrhage, hypochromic normocytic anemia, decrease on plasmatic proteins and globulins levels, leucopenia, lymphopenia, thrombocytopenia, eosinophilia, neutrophilia and monocytosis.

Comparison of artificial and natural, new and reused, brackish water for the larviculture of the freshwater prawn Macrobrachium rosenbergii in a recirculating system

Differences in culture duration, metamorphosis rate and the productivity in hatchery culture of M. rosenbergii using a closed system with natural and artificial brackish water were evaluated. Reuse of brackish water in more than one hatchery cycle was also evaluated. Natural and artificial brackish water constituted the two tested treatments, which were distributed in four independent recirculating systems (tank and respective biofilter). Four batches of cultures were conducted and the 2nd and 4th reused the water from the 1st and 3rd, respectively. Mean duration of the hatchery period was 28 d in natural brackish water and 31 d in artificial brackish water. The metamorphosis rate and the average productivity for the natural brackish water treatment were 74% and 60 postlarvae/ L. respectively, and values obtained with artificial brackish water were 55% and 44 postlarvae/L. The successful hatchery culture of M. rosenbergii in this specific artificial brackish water suggests its potential use in enterprises located far from the coast. Brackish water can be used in two consecutive cultures without a negative effect on productivity.

Growth of Channel Catfish, Ictalurus punctatus, in Southern Brazil

Despite successful introduction of channel catfish into Brazil in 1980, no studies have been conducted to assess the performance of channel catfish, Ictalurus punctatus, farming in southern Brazil. Fingerlings (27.0 ± 2.2 g) were stocked in sixteen 16-m2 tanks with cement walls and earthen bottoms. Four stocking densities were used: 0.5, 0.75, 1.0, and 1.25 fish/m2. Fish were fed a diet containing 32% protein according to a feeding chart for 257 days (from April to December). Water temperature ranged from 16.4°C to 30°C during the study. Final average weight (727.1 ± 70.6 g) was significantly higher (P < 0.05) for fish raised at 0.5 fish/m2. Food conversion ratio (FCR) was significantly higher (P < 0.05) for fish stocked at 1.25 fish/ m2. Survival averaged 95.4%, and no significant differences (P > 0.05) were found among treatments. There was no significant difference (P > 0.05) in tank production among the densities of 0.75, 1.0, and 1.25 fish/m2, but they were higher (P < 0.05) than the density of 0.5 fish/ m2. These results demonstrate the viability of channel catfish growth in southern Brazil.

Considerations in light truck suspension design

The present work aims at to approach considerations of trucks suspension design. The proposal of the work consists of discussing the aspects related to the acting of the suspension and of factors that interact with the system through representative models of the dynamic behaviour of the vehicle ride when operating in total load and/or empty conditions. The importance of this work is to revise some procedures of suspension study in the sense of adapting them to the Brazilian reality, tends in view the importance of the design characterisation and adaptation to the typical roads of Brazil. Copyright © 2000 Society of Automotive Engineers, Inc.