Antibacterial activity of chitosan biofilm for the conservation of fertile and table eggs / Atividade antibacteriana de biofilme de quitosana para conservação de ovos férteis e de mesa

The aim of this study was to develop a chitosan biofilm against Salmonella enteritidis, for the conservation of fertile and table eggs. Two experiments were performed. Experiment 1: 400 specific pathogen-free table eggs were divided in a completely randomized design into four treatments, five replicates and each replicate with 20 table eggs. Experimental groups were assigned to control and 1, 5 and 10% chitosan treatment. The eggs were immersed in the chitosan solution. They were then exposed to Salmonella enteritidis and stored for 1, 24, 96 and 168h at 4ºC. The eggs were then washed with 10mL of physiological saline solution. Experiment 2: 80 specific pathogen-free fertile eggs were tested, the assays were assigned to control and 1, 5 and 10% chitosan treatment. Each treatment had 20 fertile eggs. The eggs were immersed in the chitosan solution. They were individually weighed and incubated. Egg weight, humidity loss, and hatchability (weight and length of newly hatched chicks) characteristics were assessed. In Experiment 1, comparison between treatments showed differences (P< 0.05) in the total recovered of Salmonella enteritidis on eggshell, with the lower values in 5 y 10% chitosan treatment at 96 y 168h respectively. In Experiment 2, chitosan did not show any effect on the egg weight and chick weight, where the average was 57.44 and 38.23g respectively. The humidity loss and chick length showed differences (P< 0.05), with the lower values in 5 y 10% chitosan treatment. The antibacterial activity of chitosan biofilm provide a practical tool against Salmonella enteritidis in fertile and table eggs because the chitosan did not affect egg weight and chick weight, relevant parameters in the poultry industry.(AU)

O presente estudo teve como objetivo desenvolver um biofilme de quitosana contra Salmonella enteritidis, para conservação de ovos férteis e de mesa. Dois experimentos foram realizados. Experimento 1: 400 ovos de mesa livres de patógenos especificados foram divididos em delineamento inteiramente casualizado em quatro tratamentos, cinco repetições e cada réplica contendo 20 ovos de mesa. Grupos experimentais foram designados para controle e 1, 5 e 10% de tratamento com quitosana. Os ovos foram imersos em solução de quitosana. Em seguida foram expostos a Salmonella enteritidis, e armazenados por 1, 24, 96 e 168h a 4ºC. Após, os ovos foram lavados com 10mL de solução salina fisiológica. Experimento 2: 80 ovos férteis livres de patógenos especificados foram testados. Os ensaios foram atribuídos a controle e 1, 5 e 10% de tratamento com quitosana. Cada tratamento teve 20 ovos férteis. Os ovos foram imersos em solução de quitosana. Em seguida foram individualmente pesados e incubados. Peso dos ovos, perda de umidade e características de eclodibilidade (peso e comprimento dos pintinhos recém-nascidos) foram avaliados. No Experimento 1, a comparação entre tratamentos mostrou diferenças (P< 0,05) na quantidade total recuperada de Salmonella enteritidis na casca, com os menores valores em 5 e 10% de tratamento com quitosana a 96 e 168h respetivamente. No experimento 2, a quitosana não mostrou nenhum efeito no peso do ovo e no peso do pintinho, onde a média foi de 57,44 e 38,23g respetivamente. A perda de umidade e comprimento do pintinho apresentaram diferenças (P< 0,05), com os menores valores em 5 e 10% de tratamento com quitosana. A atividade antibacteriana do biofilme de quitosana, fornece uma ferramenta prática contra Salmonella enteritidis em ovos férteis e de mesa, pois a quitosana não afetou o peso do ovo e peso do pintinho, parâmetros relevantes na indústria avícola.(AU)

Serotyping and virulence genes detection in Escherichia coli isolated from fertile and infertile eggs, dead-in-shell embryos, and chickens with yolk sac infection.

Escherichia coli is a common avian pathogen mainly associated with extraintestinal infections such as yolk sac infection (YSI). The aim of this study was to determine the serotypes and the presence of some virulence genes of E. coli strains isolated from different samples in a vertically integrated poultry operation in Mexico. Two hundred sixty-seven E. coli isolates from different samples were serotyped using rabbit serum against the 175 somatic (O) and 56 flagellar (H) antigens of the typing schema. Virulence genes were determined by colony blot hybridization, using DNA probes for st, eae, agg1, agg2, bfp, lt, cdt, slt, and ipaH diarrhea-associated virulence factors. The serogroup of 85% of the strains was determined; O19 (12%), 084 (9%), 08 (6%), and 078 (5%) were the most common. Using the complete antigenic formula (O and H), O19:NM (n = 31) was the serotype most frequently isolated from dead-in-shell embryos and in broilers that had died on the fourth, fifth, sixth, and seventh days after hatch. One hundred ten strains (41.2%) hybridized with one or more of the used probes. Of these, ipaH (72%), eae (30%), and cdt (27%) were the most common. Considering the origin of the respective isolates, 40% of the broiler farm strains were positive for at least one probe. Results show that some avian E. coli strains isolated in Mexico are included in avian pathogenic E. coli serotypes not previously reported, suggesting that they could be specific for this geographic area. The wide distribution of the ipaH gene among nonmotile strains suggests that this invasiveness trait could be important in YSI pathogenesis. On the other hand, some other genes could contribute to E. coli virulence during YSI.

Evaluation of an early granulocytic response of chick embryos inoculated with herpesvirus of turkeys.

1. Early granulocytic response was evaluated in chick embryos inoculated with herpesvirus of turkeys (HVT). 2. Fifty 10-d-old specific pathogen-free embryos were divided into two groups, inoculated via yolk sac. Group 1 were inoculated with a complete dose of HVT and group 2 with vaccinediluent only. 3. Samples were taken for histological evaluation of yolk sac, liver, chorioallantoic membrane, brain and heart from 5 embryos per group on days 12, 14, 16, 18 and 20 of embryonic life. 4. Increases in numbers of granulocytes were detected on days 14 and 16 in the yolk sac, and on d 14 and 20 in the liver of in embryos, which received HVT. In addition, the chorioallantoic membrane was infiltrated with granulocytes. 5. The results confirm that granulopoiesis in the yolk sac is stimulated in the early stages of incubation if a viral antigen is present. The virus also appears to trigger the presence of granulocytes in embryonic liver and chorioallantoic membranes.