Dalle Zotte A., Tasoniero G., Puolanne E., Remignon H., Cecchinato M., Catelli E., Cullere M. (2017): Effect of "Wooden Breast" appearance on poultry meat quality, histological traits, and lesions characterization. Czech J. Anim. Sci., 62, 51-57.The purposes of the study were to investigate the effects of Wooden Breast (WB) myodegeneration on poultry meat quality and to give a contribution in typing lesions morphology. At a poultry meat cutting facility, 474 carcasses of a high-breast-yield hybrid chickens were inspected for WB condition, and 30 normal (N) and 30 affected (WB) breast fillets (Pectoralis major) were randomly selected. The WB condition represented 53.2% of the examined carcasses. Weight, cross sectional area (CSA), pH, L*, a*, b* colour values, water-holding capacity, and Warner-Bratzler shear force were determined. Samples were also visually and histologically evaluated. Affected samples were heavier, thicker, paler (P < 0.001), and characterized by palpatory hardness and lower water holding capacity (P < 0.05). Macroscopically, abnormalities were primarily localized in the cranial portion of the fillet and defined by the presence of bulges, petechiae, fluid and clear exudate, and higher pH. Microscopically, the WB condition was characterized by muscle fibres with greater CSA (P < 0.001) and higher giant fibres prevalence (P < 0.01). Data suggest a relationship between breast weight and WB condition.

No abstract

A subgroup B isolate of turkey rhinotracheitis virus (TRTV) or avian pneumovirus (APV), obtained from a flock of commercial breeding chickens experiencing poor egg production, mortality and swollen head syndrome, was shown to cause substantial respiratory signs in both young SPF chickens and chicks with high levels of maternally derived TRT antibodies.This isolate replicated to high titre in the respiratory tract of experimentally inoculated SPF chickens for approximately 5 days after inoculation, but was recovered only occasionally after that time. It was never recovered from non-respiratory tract tissues. A detailed, sequential histological and immunoperoxidase study was performed. This revealed that, whilst TRT virus could be demonstrated consistently in the epithelium of upper respiratory tract tissue, although only for a short time after inoculation, the damage which it caused was minimal and recovery was rapid. This study, using a pathogenic TRT isolate obtained from diseased chickens, provides clear evidence that TRT virus can cause damage to the respiratory tract of chickens and that this damage is both localized and short lived.

The extreme variability and rapid evolution of Infectious bronchitis virus (IBV) has always represented the key challenge for its control because of the limited cross-protection among different strains. Several experimental trials have proven a broadening of the protection spectrum when animals are vaccinated with multiple genotypes. Nevertheless, the conditions of vaccine administration in field are so different that the generalization of experimental results is, at least, questionable. In the present study a large scale epidemiological-phylodynamic approach was used to reconstruct the demographic history of the major field genotype (i.e. the QX one) circulating in Italy and Spain. These two countries were selected because, even if they share a comparable epidemiological scenario, the implemented vaccination protocols did not vary in Spain while changed dramatically in Italy over the time period considered. One hundred and ninety-five Italian and 98 Spanish non-recombinant sequences of the hyper-variable region of the S1 gene obtained between 2012 and 2016 were analyzed using a serial coalescent-based approach to reconstruct viral population history over time. While the IBV QX population dynamics remained constant in Spain, a much more complex pattern was evidenced in Italy; both in terms of viral population size and clinical outbreak frequency. Remarkably, a strong association with changes in vaccination strategies was recognized. This allowed demonstrating, by accomplishing all Hill's criteria for causation, the cause-effect relationship between the vaccine administration/withdrawal and the variation in viral population dynamics and, above all, IBV related outbreaks. Thus, a robust confirmation about the efficacy of IBV vaccination in field conditions was provided. Additionally, the history herein reported testifies the primary importance of rigorously planning not only the intervention strategies but also their monitoring and evaluation.

No abstract