Vla Pereira

Avian mycoplasmosis update

Avian mycoplasmas occur in a variety of bird species. The most important mycoplasmas for chickens and turkeys are Mycoplasma gallisepticum (MG), M. synoviae (MS), and M. meleagridis. Besides, M. iowe (MI) is an emerging pathogen in turkeys, but of little concern for chickens. Mycoplasmas are bacteria that lack cell wall and belong to the class Mollicutes. Although they have been considered extracellular agents, scientists admit nowadays that some of them are obligatory intracellular microorganisms, whereas all other mycoplasmas are considered facultative intracellular organisms. Their pathogenic mechanism for disease include adherence to host target cells, mediation of apoptosis, innocent bystander damage to host cell due to intimate membrane contact, molecular (antigen) mimicry that may lead to tolerance, and mitotic effect for B and/or T lymphocytes, which could lead to suppressed T-cell function and/or production of cytotoxic T cell, besides mycoplasma by-products, such as hydrogen peroxide and superoxide radicals. Moreover, mycoplasma ability to stimulate macrophages, monocytes, T-helper cells and NK cells, results in the production of substances, such as tumor necrosing factor (TNF-α), interleukin (IL-1, 2, 6) and interferon (α, β, γ). The major clinical signs seen in avian mycoplasmosis are coughing, sneezing, snicks, respiratory rales, ocular and nasal discharge, decreased feed intake and egg production, increased mortality, poor hatchability, and, primarily in turkeys, swelling of the infraorbital sinus(es). Nevertheless, chronic and unapparent infections are most common and more threatening. Mycoplasmas are transmitted horizontally, from bird to bird, and vertically, from dam to offspring through the eggs. Losses attributed to mycoplasmosis, mainly MG and MS infections, result from decreased egg production and egg quality, poor hatchability (high rate of embryonic mortality and culling of day-old birds), poor feed efficiency, increase in mortality and carcass condemnations, besides medication costs. Mycoplasmas are diagnosed by serologic tests, culture and PCR and are sensitive to antimicrobials whose action sites are other than the bacterial cell wall, such as tetracyclines, macrolides, quinolones and tiamulin. However, mycoplasma control is more efficiently achieved by acquisition of birds free of MG, MS, MM and/or MI, vaccination of layers, and monitoring of breeder flocks, followed by elimination of the infected flocks that are detected.

Avian infectious bronchitis and deep pectoral myopathy—A case control study

Abstract Infectious bronchitis is caused by a coronavirus, infectious bronchitis virus (IBV). Infectious bronchitis is an acute and highly contagious disease of economic importance due to the reduction in weight gain observed with infected broilers and the drop in egg quality and production associated with infected laying hens. The presence of deep pectoral myopathy has been associated with IBV variants. This lesion is detected at slaughterhouses and is characterized by paleness and atrophy of the deep pectoral muscle, including necrosis of the region, leading to condemnations of the breast muscle, a valuable meat cut in the market. This work aimed to study the relationship between deep pectoral myopathy and IBV by describing tracheal and muscle lesions and comparing the frequency of IBV detection via reverse-transcription (RT) PCR in muscle, tracheal, and cecal tonsil samples from broilers with and without myopathy. A case-control study was conducted in 40 broiler flocks vaccinated with the Massachusetts strain. The case group consisted of 23 flocks that presented myopathic lesions under sanitary inspection and a control group of 17 flocks without myopathic lesions. The tracheal, cecal tonsil, and supracoracoid muscle (with and without lesions) samples from the 40 broiler flocks were screened by RT-PCR to detect IBV. Histopathology of muscle and tracheal tissue was carried out. Upon microscopic examination, the muscle samples from the case group presented extensive necrosis, intense mononuclear inflammatory infiltration, muscle fiber fragmentation, and fibrotic tissue, confirming myopathy, whereas muscles from the control group showed no alterations. The tracheal samples presented a large number of infiltrated mononuclear inflammatory cells that in some areas formed submucosal nodules. A total of 25 flocks tested IBV positive by RT-PCR: 14 from the case group and 11 from the control group. The IBV was detected by RT-PCR directly in muscle samples. Despite that, the relationship between deep pectoral myopathy and IBV was not established. The higher positive IBV RT-PCR percentage noted in the cecal tonsil samples demonstrates how important the choice of organs is for diagnostic purposes.

Chicken feet bacteriological quality at 4 steps of technological processing

The production of chicken feet is primarily intended for foreign markets, and there is still no specific legislation in Brazil that determines the quality standard of these products. The bacteriological quality of chicken feet was evaluated as a product for human consumption at different steps of the technological processes. Eighty broiler feet from 20 lots at 4 steps of processing were collected for quantitative analysis, total count of aerobic mesophilic bacteria, and determining the most probable number of coliforms and fecal coliforms. Thirty-eight pools of 15 broiler feet each from 19 lots were used for qualitative analysis and the isolation of Salmonella enterica spp. and Escherichia coli O157:H7. Escherichia coli O157:H7 was not found in any of the samples. Salmonella spp. were isolated in 68% (13/19) of the lots. The Salmonella Schwarzengrund serotype was found in 12 of the 13 lots of positive samples and the Salmonella Anatum and Salmonella Corvallis serotypes were identified in the remaining lot. Processing is effective in reducing contamination by mesophilic bacteria, coliforms, and Salmonella spp. in these products. This work constitutes the first study in Brazil on microbiological quality of chicken feet.

Egg quality in laying hens exposed to Mycoplasma gallisepticum F-strain attenuated vaccine

&NA; Mycoplasma gallisepticum causes coughing, ocular and nasal discharge, reduction in feed intake, lower and uneven growth, decline in egg production and quality, and increase in mortality. Among the attenuated vaccination strains, MGF can reduce clinical signs and lesions in layer hens, stimulate immune responses of cellular and humoral basis, act as an instrument of competitive exclusion in relation to field strains, and reduce the use of antimicrobials. This study aimed to investigate the effects of attenuated MG F‐strain vaccination on egg quality in 3 groups of 30 hens each, being one control and 2 vaccinated. Vaccination was applied by ocular route at 8 and 12 wk of age. Comparisons were made among unvaccinated hens; vaccinated at 8 wk of age; and vaccinated at 8 and 12 wk of age. There were no statistical differences in eggshell thickness and weight among groups. Eggs from twice vaccinated birds yielded a Haugh unit significantly lower than the other groups without affecting egg classification. There was no significant difference in ELISA results between the vaccinated groups.

The effect of eggshell apex abnormalities on table egg quality during storage in 2 seasons of the year

Mycoplasma synoviae infection of hens has been associated with problems of eggshell quality called eggshell apex abnormalities (EAA). Little is known about the quality of EAA eggs from a commercial point of view, especially during their storage. The study aimed to examine the differences between EAA and normal eggs during storage under controlled conditions in 2 seasons, summer and winter, by comparing internal and external quality parameters. In a conventional egg production farm with white laying hens of varying ages in the city of Bastos, state of São Paulo, Brazil, 232 eggs were used in the summer season and 400 eggs in the winter season. Half of the eggs had EAA, and the other half were considered normal eggs for each season. The eggs were analyzed at 2, 7, 14, 21, and 28 d after being laid and stored from 24.6 to 25.8°C in summer and from 24 to 25°C in winter. There was no difference (P > 0.05) in the average egg weight between EAA and normal eggs at any studied time point, but in both seasons, the weight loss in EAA eggs was higher than in normal eggs. The losses in Haugh unit scores from the first to the last measurements were approximately 40% regardless of egg type or season of production. In comparing eggshell thickness, only the apices of the EAA eggs were thinner (P < 0.0001) than normal eggs in the summer, but in the winter, the EAA egg apices (P < 0.0001) and sides (P = 0.03) were both thinner. The presence of EAA did not affect the eggshell weight (P > 0.05) or eggshell percentage (P > 0.05). The eggshell strength of the EAA eggs was lower (P < 0.0001) than normal eggs in both the summer (16.57%) and winter (19.86%). The presence of EAA did not affect the internal quality of the egg, but was related to a greater loss of external quality and weight during storage.

Serotyping and Genotyping of Salmonella Strains Isolated From Broilers, Chicken Carcasses Before and After Chilling, and Frozen Chicken Breasts Produced in The States of Mato Grosso do Sul and Santa Catarina, Brazil

The present study investigated the effectiveness of a single Salmonella prevention and control program applied in two different processing plants, located in the states of Mato Grosso do Sul (plant A) and Santa Catarina (Plant B), belonging to the same company, and identified Salmonella strain subtypes isolated from broilers, carcasses before and after chilling, and frozen chicken breasts. The Salmonella prevention and control program was 90% effective in plant A and 100% in plant B, considering a level of 10% positive samples per frozen chicken breast batch acceptable. A total of 128 strains were serotyped, being 10 from drag swabs, 31 from cloacal swabs, 83 from carcasses, and 4 from frozen chicken breasts. After serotyping analysis, 30 strains isolated at different processing steps and drag swabs, and three Salmonella Minnesota strains isolated in 2012 in plant A, were genotyped by PFGE. In plant A, the most frequently strain isolated was Salmonella Minnesota (90.35%), followed by Salmonella Newport (8.77%), and in Plant B, Salmonella Senftenberg (80%). Salmonella Minnesota strains were differentiated by PFGE into 19 pulsotypes distributed in three clusters. The phenotypic identification by serotyping of four strains diverged from their PFGE genotypic results. Most Salmonella Minnesota strains genotyped in plant A and the strains isolated from environmental samples in 2012 in the same broiler processing plant belong to a single cluster, confirming the dominance and persistence of this clone over time.

Pathological Aspects of a Subclinical Marek's Disease Case in Free-Range Chickens

The present report aims at describing the occurrence of Mareks Disease (MD) in a free range poultry farm based on macroscopic and microscopic lesions. For this purpose, seven free-range chickens were evaluated by gross and microscopic examination. Tumor lesions were observed in the liver and ovary, in addition of enlarged kidney and spleen, skin thickening and whitish lesions in streak form in the breast muscle. Fragments of the affected organs were collected and placed in 10% formalin for processing by the usual histopathology techniques, and stained with hematoxylin-eosin. Under microscopic evaluation, we observed pleomorphic populations of neoplastic lymphoreticular cells with pyknotic nuclei in the same organs, all compatible with MD. The macroscopic and microscopic lesions presented in this study were consistent with MD, meaning that the MD virus is present in the rearing environment of the studied chicken farm.

Detecção de resíduos de enrofloxacina por ensaio imunoenzimático e cromatografia líquida acoplada à espectrometria de massas em ovos comerciais de galinha após tratamento

Enrofloxacin is one of the most used antibiotics in the poultry industry and the deposition of residues in poultry products, such as eggs, are of great concern to public health. In Brazilian law there is no standard withdrawal period for enrofloxacin in eggs and there is no Maximum Residue Limit (MRL) established for this antimicrobial in eggs. In this study, (Bioo Scientific(r)) commercial ELISA kit and LC-MS/MS were used to investigate enrofloxacin in eggs of 30 hens pretreated via drinking water at 10mg/kg of enrofloxacin for five days. Six eggs were collected daily and analyzed during treatment and after the end of treatment, for 15 days. Residues obtained maximum levels on the fifth day of treatment, declined gradually and were no longer detected from the ninth day to the end of treatment. Based on the MRL of 100mg/kg established for edible tissues of poultry by Brazillian law and for muscle, fat and skin, by the European Union, after six days of treatment withdrawal, the residue levels were below that limit, with the average of 37.43mg/kg in LC-MS/MS and 14.731mg/kg in ELISA. Within the conditions of this study, a withdrawal period of six days would be more appropriate to use the eggs for human consumption. The values obtained by ELISA for residues in eggs were lower than those obtained in LC-MS/MS for the same sample, however both methods showed statistical agreement. LC-MS/MS is the recommended method by Brazilian legislation for analysis of residues in food, however, according to the results the ELISA kit used can also be applied to the detection of enrofloxacin residues in eggs, with the advantages of speed and simplicity.

PRINCIPAIS ALTERAÇÕES NO LEITE POR AGENTES CAUSADORES DE MASTITE NO REBANHO CAPRINO DOS ESTADOS DE MINAS GERAIS E RIO DE JANEIRO

Goat mastitis causes significant economic losses due to the discarding of milk, costs of drugs and veterinary care, reducing the quantity and quality of milk and dairy products. In this study, 129 raw milk samples from 11 goat farms were investigated by the Tamis test, California mastitis test (CMT), bacteriological exam, presence of Mycoplasma spp. and physicochemical parameters. Seven (4.6%) and four samples (3.1%) were positive by CMT and Tamis test respectively. Bacteriological exam was positive from 57.4% of samples and coagulase-negative Staphylococcus was the most frequent bacteria isolated showing 56% of the strains resistant to penicillin and no resistance to gentamicin. Negative results were obtained from traditional culture as well as by PCR for Mycoplasma spp. The diagnosis of mastitis, the bacteriological exam and the CMT results differed significantly and no association was observed (chi squared, p 0.05). The physicochemical parameters differed significantly (ANOVA, Tukey-Kramer, p < 0.05) among the herds. These results indicate the need to associate microbiological exam when the CMT is used for the diagnosis of goat mastitis.