Western blot detection of infectious bursal disease virus infection

In order to evaluate the use of a Western blot methodology for the diagnosis of infectious bursal disease virus (IBDV) infection, chickens were experimentally infected with IBDV strains and tested for the presence of viral antigens and antibodies by a blocking Western blot test (bWB). The viral proteins obtained from the bursa of Fabricius (BF) were transferred to a nitrocellulose membrane after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the chicken sera obtained by heart puncture were used for the detection of these proteins. In order to eliminate nonspecific reactions, we used a rabbit anti-chicken serum (blocking tool). By the use of the bWB test, two distinct viral proteins of 43-kDa (VP2) and 32-kDa (VP3) were detected. We suggest the use of this methodology for the detection of IBDV infection in animals suspected of having IBDV reinfection and a chronic subclinical form of the disease. With the use of the rabbit anti-chicken sera for blocking, this method is practical, sensitive and less time consuming

A liquid phase blocking ELISA for the detection of antibodies against infectious bronchitis virus

A liquid phase blocking ELISA (LPB-ELISA) was developed for the detection and measurement of antibodies against infectious bronchitis virus (IBV). The purified and nonpurified virus used as antigen, the capture and detector antibodies, and the chicken hyperimmune sera were prepared and standardized for this purpose. A total of 156 sera from vaccinated and 100 from specific pathogen-free chickens with no recorded contact with the virus were tested. The respective serum titers obtained in the serum neutralization test (SNT) were compared with those obtained in the LPB-ELISA. There was a high correlation (r2 = 0.8926) between the two tests. The LPB-ELISA represents a single test suitable for the rapid detection of antibodies against bronchitis virus in chicken sera, with good sensitivity (88%), specificity (100%) and agreement (95.31%).

Indirect effects of oral tolerance to ovalbumin interfere with the immune responses triggered by Schistosoma mansoni eggs

The objective of the present study was to investigate whether the injection of a tolerated protein (indirect effects) affects the formation of granulomas around Schistosoma mansoni eggs trapped in the lungs after intravenous (iv) injection into normal (noninfected) C57BL/6 mice (6 animals per group). To induce oral tolerance to chicken egg ovalbumin a 1/5 dilution of egg white in water was offered ad libitum in a drinking bottle for 3 days. Control mice received water. After 7 days, control and experimental animals were injected iv with 2,000 S. mansoni eggs through a tail vein. In some mice of both groups the iv injection of eggs was immediately followed by intraperitoneal (ip) immunization with 10 µg of dinitrophenylated conjugates of ovalbumin (DNP-Ova) emulsified in complete Freund's adjuvant (CFA) or only CFA; 18 days later, mice were bled and killed by ether inhalation. The lungs were fixed in formalin and embedded in paraffin. Serial sections of 5 µm were stained with Giemsa, Gomori's silver reticulin and Sirius red (pH 10.2). Granuloma diameters were measured in histological sections previously stained with Gomori's reticulin. Anti-DNP and anti-soluble egg antigen (SEA) antibodies were analyzed by ELISA. In mice orally tolerant to ovalbumin the concomitant ip injection of DNP-Ova resulted in significantly lower anti-SEA antibodies (ELISA*: 1395 ± 352 in non-tolerant and 462 ± 146 in tolerant mice) and affected granuloma formation around eggs, significantly decreasing granuloma size (area: 22,260 ± 2478 to 12,993 ± 3242 µm²). Active mechanisms triggered by injection of tolerated antigen (ovalbumin) reduce granuloma formation.

Distribution of small proteoglycans and glycosaminoglycans in humerus-related articular cartilage of chickens

The expression of components present in the cartilaginous extracellular matrix is related to development, gender, and genotype, as well as to the biomechanical properties of each type of cartilage. In the present study, we analyzed small proteoglycans and glycosaminoglycans present in different cartilages of the chicken wing after extraction with guanidine hydrochloride or papain. Quantitative analysis of glycosaminoglycans showed a larger amount in humeral cartilage (around 200 mg/g tissue) than in articular cartilage of the radius and ulna, with 138 and 80 mg/g tissue, respectively. Non-collagenous proteins isolated were predominantly from cartilage in the proximal regions of the humerus and radius. D4 fractions obtained by ultracentrifugation were separated by DEAE-Sephacel and Octyl-Sepharose chromatography and analyzed by SDS-PAGE. Two bands of 57 and 70-90 kDa were observed for all samples treated with ß-mercaptoethanol. Immunoblotting of these proteins was positive for the small proteoglycans fibromodulin and decorin, respectively. Apparently, the 57-kDa protein is present in macromolecular complexes of 160 and 200 kDa. Chondroitin sulfate was detected in all regions. HPLC analysis of the products formed by chondroitinase AC and ABC digestion mainly revealed ß-D-glucuronic acid and N-acetyl ß-D-galactosamine residues. The 4-sulfation/6-sulfation ratio was close to 3, except for the proximal cartilage of the radius (2.5). These results suggest functional differences between the scapula-humerus, humerus-ulna, and humerus-radius joints of the chicken wing. This study contributes to the understanding of the physiology of cartilage and joints of birds under different types of mechanical stress.

Increased expression of keratinase and other peptidases by Candida parapsilosis mutants

Keratinases are enzymes of great importance involved in pathogenic processes of some fungi. They also have a widespread ecological role since they are responsible for the degradation and recycling of keratin. On the one hand, studying them furthers our knowledge of pathogenicity mechanisms, which has important implications for human health, and on the other hand, understanding their ecological role in keratin recycling has biotechnological potential. Here, a wild-type keratinolytic Candida parapsilosis strain isolated from a poultry farm was treated with ethyl methanesulfonate in order to generate mutants with increased keratinase activity. Mutants were then cultured on media with keratin extracted from chicken feathers as the sole source of nitrogen and carbon. Approximately 500 mutants were screened and compared with the described keratinolytic wild type. Three strains, H36, I7 and J5, showed enhanced keratinase activity. The wild-type strain produced 80 U/mL of keratinolytic activity, strain H36 produced 110 U/mL, strain I7, 130 U/mL, and strain J5, 140 U/mL. A 70% increase in enzyme activity was recorded for strain J5. Enzymatic activity was evaluated by zymograms with proteic substrates. A peptidase migrating at 100 kDa was detected with keratin, bovine serum albumin and casein. In addition, a peptidase with a molecular mass of 50 kDa was observed with casein in the wild-type strain and in mutants H36 and J5. Gelatinase activity was detected at 60 kDa. A single band of 35 kDa was found in wild-type C. parapsilosis and in mutants with hemoglobin substrate.

Effect of Leuconostoc mesenteroides 11 bacteriocin in the multiplication control of Listeria monocytogenes 4b

The activity of a crude preparation of bacteriocin produced by the chicken meat isolate Leuconostoc mesenteroides 11, was evaluated at 8ºC and 15ºC against Listeria monocytogenes. The pathogen was inoculated in a crude preparation of the bacteriocin and its population was enumerated after 0.5 and 10 days. The title of the bacteriocin in the preparation was determined immediately before inoculation and after 10 days of incubation at both temperatures. As a negative control, a non-bacteriocin producing strain, Leuconostoc mesenteroides A13, was used. Bacteriocin of L. mesenteroides 11 partially inhibited L. monocytogenes at 8ºC, but at 15ºC it was unable to prevent growth of the pathogen. Our findings suggest that the use of the semi-purified bacteriocin of L. mesenteroides 11 probably will not be suitable as a single hurdle to prevent L. monocytogenes growth in foods.

Influence of secondary packing on the freezing time of chiken meat in air blast freezing tunnels

Freezing of poultry cuts in continuous convective air blast tunnels is normally performed with the products protected by Low Density Polyethylene (LDPE) as a primary packaging and using Corrugated Cardboard Boxes (CCB) as secondary packaging. The objective of this work was to investigate the influence of these secondary packaging on the freezing of poultry cuts in continuous convective air blast tunnels. The study was performed by replacing CCB with Perforated Metal Boxes (PMB) in order to remove the packaging thermal resistance. The assays, performed in a industrial plant, demonstrated that CCB used commercially for meat freezing have a high heat transfer resistance. Their replacement with PMB can lead to shorter freezing times and spatially homogeneous freezing. Reductions of up to 45% in the freezing times were observed using PMB. The plateau of the temperature curve, related to the freezing time of free water, was significantly reduced using PMB, which is accepted to lead to better product quality after thawing. As the products were protected by the LDPE films as primary packaging, their appearance were not affected. The results presented in this work indicate that replacing CBB with PMB can be an excellent alternative to reduce freezing time and improve freezing homogeneity in industrial air blast tunnels, which could also be applied to other products.

Sensory analysis of hydrolysed meat preparations

The use of hydrolysed meat in diets contributes to the improvement of protein, vitamin and mineral supply. This work aims at checking the acceptance pattern in meat hydrolysates. Four preparations have been developed with three types of hydrolysates in domestic-like conditions. Acceptance was verified by means of sensory analysis using the nine-point hedonic scale. Sensory tests have been carried out in three sessions (according to the kind of hydrolysates). In the evaluation file, information on age groups has been included. The statistical analysis has been made by ANOVA and Tukey test. The best accepted preparation have been the turkey and chicken hydrolysed balls. Hydrolysates can be used in many different kinds of preparations, but it is necessary to know both the age group it will be used to and its sensory and chemical-physical features to ensure the taste and the original appearance of the final product.

Searching to combine technologies for safer food attainment

Campylobacteriosis is an infection frequently acquired through the consumption of animal origin products. Chicken can be considered the main responsible cause in the transmission chain of this disease. Ionizing radiation was used to verify the reduction of the microbiological load of Campylobacter jejuni present in chicken liver, which, in natura, can present contamination in up to 100% of the cases. The doses of irradiation used were: 0.20 kGy, 0.27 kGy, 0.30 kGy and 0.35 kGy. The samples of chicken liver were acquired in aviaries, local supermarkets and large chain supermarkets. The samples were analyzed for Campylobacter at FIOCRUZ. Irradiation was performed at COPPE/UFRJ, using a Gamma Cell Irradiator with a 60Co gamma source. Only the frozen sample acquired at the local supermarket did not contain the bacterium. Campylobacter sp. was present in all other samples, even when using procedures and technologies that aimed at the impediment of the presence of this bacterium in food and, consequently, at the protection of human health. On the whole, the results were satisfactory; nevertheless, it is known that the bacterial growth conditions required by this bacterium are uncommon when compared to other enteropathogenic bacteria.

Deep-fat frying of meat products in palm olein

This study investigated the discontinuous frying of breaded meat products in palm olein in a 28 L-electric fryer maintained at 182 ºC for 8 hours a day. Three 400-500 g batches of meat products were fried for 4.5 minutes daily. For comparison purpose, thermoxidation tests were performed using inert material with added moisture and without the addition of f ood (heating only). The total polar compound content did not reach the 25% limit, and nor did the formation of polymerized products exceed 5%, which indicates the good frying performance of palm olein for frying. Other analytical parameters and rapid tests were also evaluated. The sensory attributes, such as odor, colour, and foam formation determined when the frying oils should be discarded. The addition of water to the inert material contributed to the final value of 1.00 ± 0.01% (in palmitic acid), while the oil subjected only to heating reached respectively 0.26 ± 0.02%, and the oils used to fry breaded meat and breaded chicken reached 0.38 ± 0.00% and 2.35 ± 0.01%, respectively. This suggests a protective effect of the water during frying since the oil subjected only to heating was more prone to degradation.

Safety criteria for the acquisition of meat in Brazilian University restaurants

The present study's objective was to analyze the procedures aimed at guaranteeing sanitary conditions when acquiring meat. The study was conducted with university restaurants of the Federal Institutions of Higher Education (IFES) located in the five regions of Brazil. Data were collected using a questionnaire and an evaluation list, which was available online to restaurant professionals. The results showed that restaurants chose one or two types of meat, the most frequent of which were beef and chicken. In restaurants managed by the IFES, the acquisition of raw material occurred by bidding. For vendor selection, the restaurants required product registration with the Inspection Service and requested regulation of the supplier by the Health Surveillance. Monitoring was carried out through a technical visit to the supplier and a review of the past records of the supplier. A higher percentage of restaurants in the Southeast region met appropriate sanitary and hygienic criteria for the receipt of meat, followed by the South, Midwest, Northeast and North. We conclude that restaurants meet most of the safety criteria set in the legislation. However, some weaknesses are evident in the physical and functional structure, the system of transportation of raw material and the records of control measures at the place of reception.