ABSTRACT Salmonella Heidelberg is an emerging pathogen in Brazilian poultry production. The traditional methods (quicklime, windrowing and tarpaulin-on-surface) used for disinfecting reused poultry litter between flocks does not guarantee its elimination, thus allowing the transmission of this agent from one flock to another. The new tarpaulin-on-surface method with controlled injection of ammonia gas has proven to be effective in its control, however, it is still unknown what dose of ammonia gas is needed to eliminate Salmonella Heidelberg in reused poultry litter. The objective of this study was to evaluate the effect of ammonia gas at different concentrations in sterile poultry litter artificially contaminated with Salmonella Heidelberg. Then, ammonia gas was injected in concentrations of 0.25%, 0.5%, and 1%, and 48 hours later, a sample was collected from each repetition in an entirely randomized design, and bacterial isolation was performed. All treatments, including positive and negative controls, were tested in quadruplicate and the parameters temperature, humidity, pH and water activity were evaluated. In the 0.5% and 1% treated samples the pathogen was not isolated, while in the 0.25% concentration one of the four samples tested was positive. The study reveals that ammonia gas is efficient in killing Salmonella Heidelberg in poultry litter at concentrations of 0.5 % or more within a 48-hour period and that the litter treated with ammonia gas increases its pH and water activity.

ABSTRACT Fusarium head blight, also known as fusariosis, is caused by a fungus called Fusarium graminearum that produces the mycotoxin deoxynivalenol (DON). This toxin causes problems to human and animal health. Ammonia gas has been shown to be effective in deactivating mycotoxins. The objectives of this study were to evaluate the effectiveness of ammonia gas in the deactivation of DON in wheat grains, the effect of this treatment on its protein composition and the toxicity in rats fed with ammoniated wheat grains. Wheat samples were exposed to ammonia gas at concentrations of 0% (Control), 0.5%, 1% and 1.5%. It was observed that ammonia gas was effective in deactivating DON at concentrations of 1% and 1.5%. There was no difference in crude protein observed in the bromatological analysis of treated wheat grains in relation to the control. Regarding the toxicity of wheat grains treated with ammonia in the feeding of Wistar rats (Rattus norvegicus), no histopathological alterations were observed in the liver, kidneys, intestine and in the hematological profile. The results of this study demonstrated that the treatment of wheat with ammonia gas can contribute to the deactivation of DON without compromising its protein composition and animal health.

RESUMO A giberela, também conhecida como fusariose, é causada por um fungo chamado Fusarium graminearum, que produz a micotoxina desoxinivalenol (DON). Essa toxina gera problemas à saúde humana e animal. O gás amônia demonstrou ser eficaz na desativação das micotoxinas. Os objetivos deste estudo foram avaliar a eficácia do gás amônia na desativação do DON em grãos de trigo contaminados naturalmente, o efeito desse tratamento na sua composição proteica e a toxicidade em ratos alimentados com os grãos de trigo amonizados. Amostras de trigo foram expostas ao gás amônia nas concentrações de 0% (controle), 0,5%, 1% e 1,5%. Observou-se que o gás amônia foi eficaz na desativação do DON na concentração de 1% e 1,5%. Não houve diferença na proteína bruta observada na análise bromatológica dos grãos de trigo tratados em relação ao controle. Quanto à toxicidade dos grãos de trigo tratados com amônia fornecidos aos ratos Wistar (Rattus norvegicus), não foram observadas alterações histopatológicas do fígado, dos rins e do intestino e no perfil hematológico. Os resultados deste estudo demonstraram que o tratamento de trigo com gás amônia pode contribuir na desativação do DON sem comprometer sua composição proteíca e a saúde dos animais.

ABSTRACT There are several causes of carcass condemnation in poultry processing plants, including dorsal cranial myopathy (DCM), in which the anterior latissimus dorsi (ALD) muscle is affected. DCM etiology has not been elucidated yet, but this lesion impairs the visual quality of carcasses and causes economic losses due to downgrading and condemnation. The effects of this lesion on the systemic health of broilers are still unknown. In this context, the objective of this study was to evaluate muscle injury and systemic health indicators in broilers presenting or not DCM. The following parameters were evaluated: complete blood count (CBC), total protein, albumin, globulin, cholesterol, lactate, and glucose serum levels, aspartate aminotransferase (AST) and creatine kinase (CK) serum activities, and breast muscle pH. Blood samples were collected from 800 42-day-old broilers before feed withdrawal and transportation. In the processing plant, 28 carcasses presented DCM during inspection, and 28 carcasses with no DCM were used as controls. Blood biochemical parameters were not significantly different between broilers with DCM and the controls, except for AST and CK, which activities were higher in the DCM group than in the control group, suggesting that the DCM does not affect the systemic health of the broilers.

ABSTRACT The routine use of antimicrobials in animal production for the treatment of infections, disease prevention, or as growth promoters is a predisposing factor for the development and dissemination of antimicrobial resistance. In food industries, sanitizers are used for the control of microbial colonization, and their efficacy depends on contact time and on the dilution of the products used. The present study assessed the effect of 12 antimicrobials and four commercial sanitizers on 18 Salmonella spp. strains isolated from poultry processing plants. None of the evaluated antimicrobials was 100% effective against the tested Salmonella spp. strains; however, 94% of the isolates were susceptible to ciprofloxacin, 77% to amoxicillin + clavulanic acid and to ampicillin, and 72% to enrofloxacin, whereas 100% of the isolates were resistant to penicillin G, 16% to tetracycline, and 11% to sulfonamide. The tested Salmonella spp. strains were 100% inhibited by peracetic acid after five minutes of contact, 0.5% by quaternary ammonium after 15 minutes, and 85.7% by chlorhexidine after 15 minutes. The results indicate the importance of testing of efficacy of antimicrobials used in animal production and in public health to monitor their action and the development of resistance.

ABSTRACT The aim of this study was to design a new mechanical nesting system based on scientific works on the behavior of laying hens, and to compare its performance with that of a hand-operated Dutch nest. The equipment was assessed in two poultry houses; in the first one, the eggs were collected manually, whereas in the second one, the newly designed mechanical nest was used for the collection. A total of 7,800 hens and 800 males were housed in each poultry house, and the percentages of eggs produced, nest dirty eggs, floor eggs, and cracked and discarded eggs were determined between weeks 25 and 52. The percentage of eggs with microcracks, infertility, embryo mortality, bacterial contamination, fungal contamination, chicks with stunting syndrome and hatching from both types of nest was assessed in the hatchery on a fortnightly basis. The mechanical nest designed herein proved to be a good alternative to the hand-operated Dutch nest, but it still has to be improved in order to have the same performance, especially with regard to reduction in the incidence of floor eggs.

Salmonella is traditionally identified by conventional microbiological tests, but the enumeration of this bacterium is not used on a routine basis. Methods such as the most probable number (MPN), which utilize an array of multiple tubes, are time-consuming and expensive, whereas miniaturized most probable number (mMPN) methods, which use microplates, can be adapted for the enumeration of bacteria, saving up time and materials. The aim of the present paper is to assess two mMPN methods for the enumeration of Salmonella sp in artificially-contaminated chicken meat samples. Microplates containing 24 wells (method A) and 96 wells (method B), both with peptone water as pre-enrichment medium and modified semi-solid Rappaport-Vassiliadis (MSRV) as selective enrichment medium, were used. The meat matrix consisted of 25g of autoclaved ground chicken breast contaminated with dilutions of up to 10(6) of Salmonella Typhimurium (ST) and Escherichia coli (EC). In method A, the dilution 10-5 of Salmonella Typhimurium corresponded to >57 MPN/mL and the dilution 10-6 was equal to 30 MPN/mL. There was a correlation between the counts used for the artificial contamination of the samples and those recovered by mMPN, indicating that the method A was sensitive for the enumeration of different levels of contamination of the meat matrix. In method B, there was no correlation between the inoculated dilutions and the mMPN results.

The threat to public health represented by Salmonella is at least partially a consequence of its ecology in poultry hosts. Good manufacturing practices in the processing plant can reduce the contamination of poultry products, and critical control point principles are essential throughout the chain production. One procedure adopted in critical points control to prevent and to reduce Salmonella in farms and poultry products is the use of disinfectants. This study aimed at evaluating disinfectant efficiency against Salmonella enteritidis samples isolated from broiler carcasses in Rio Grande do Sul State between 1995 and 1996. The tested disinfectants were: phenol 1:256, quaternary ammonium 1:2500, glutaraldehyde 1:200, and iodine 1:500, with contact times of 5, 10, 15, and 20 in an in vitro test. .Phenolic compounds showed better results, iodine and glutaraldehyde showed intermediary results, and quaternary ammonium presented efficiency at all contact times evaluated in the in vitro test.

Dirt floors are used on most Brazilian poultry farms since the construction of concrete floors is very expensive. In vitro tests carried out to verify the effectiveness of disinfectants do not consider the adverse conditions found in poultry farms. Therefore, the present study aimed at evaluating the effect of six commercial disinfectants on the reduction of total and fecal coliforms on the dirt floor of breeder houses. The amount of disinfectant solution to be used per square meter was defined by counting total and fecal coliforms at different soil depths and by analyzing soil physical properties. Coliforms were detected at 0.5 cm, and one liter of disinfectant solution was sufficient for soil saturation at this depth. After that, the efficacy of six commercial products (caustic soda, hydrated lime, phenols 1 and 2, iodine, glutaraldehyde, and quaternary ammonium) in reducing the number of coliforms, after six hours of contact with the dirt floor, was assessed using the most probable number (MPN) method. Escherichia coli specimens isolated from the dirt floor were used to evaluate in vitro effectiveness of disinfectants. Products that yielded the best results in the MPN method were also effective in the in vitro tests. Among the tested disinfectants, hydrated lime was the most efficient, reducing the initial contamination by 2.9 log after six hours of contact with the dirt floor.