Avaliação de tratamentos químicos, físicos e biológicos sobre características de camas aviárias na produção de frangos de corte

Abstract

The use of quicklime (CaO), tarping and bacterial complexes in poultry litter samples aims at sanitary control by the minimization of effects of used litters in the Brazilian poultry industry. Few scientific studies have proven the effectiveness of these methods aimed to reduce the pathogenic microbial load during poultry depopulation. The first study aimed to evaluate the following litter treatments: T1 no treatment (control), T2 quicklime (300gm−2), T3 tarping, andT4 tarping + quicklime (300gm−2). Litter samples were collected on day zero and the sixth and twelfth days after the start of sanitary depopulation (fallowing?). The use of quicklime alone or quicklime + tarping was more effective (P<0.05) in reducing bacteria when compared to litter tarping. Except for the control group, all treatments resulted in a reduction of over 84% in colony-forming unit (CFU) count at the end of fallowing. It was concluded that the use of quicklime alone in practical terms is the best treatment for bacterial load reduction in poultry litter. The second study aimed at the in vitro control of the proliferation of potentially pathogenic microorganisms in reused poultry litter of aviaries through the use of an in vitro biological modulator. The experiment was performed at the Bacteriology Laboratory of the Department of Biotechnology and Animal Nutrition of the Federal University of Pelotas (UFPEL) by using samples of both new and used litter materials. As poultry litter biological treatment, a biological modulator was used at different levels at known concentrations of microorganisms such as Bacillus subtilis, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus cereus and Lactococcuslactis. The design was completely randomized, and the modulator dosage was presented in a litter reuse factorial scheme (4x6) through the use of 2 factors at different levels: modulator dosage (0, 2, 4, 8 g) and litter reuse (2, 4, 6, 8, 10,12 litter uses), where collection periods (at 24, 48 and 72 h) were included in the mean analysis, totaling 24 treatments. Tukey´s tests were performed to compare treatment means. Specific culture media were used for total bacteria analysis (Brain Heart Infusion media), Enterobacteriacea (MacConkey), Sthaphylococcus spp. (Chapman). Chemical physical tests were also carried out for pH and ammonia quantification of samples. Colony Forming Unit (CFU) count both before (initial control) and after the application of treatments in reused poultry litter samples and chemical physical analyses were performed. According to dosage increase (4 g and 8 g) and biological modulator permanence in litter samples, a significant bacterial reduction trend in each medium, as well as modulator interference in pH reduction and better ammonia emission control, was observed.