Effect of "wooden breast" appearance on poultry meat quality, histological traits, and lesions characterization

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

Rapid, Sensitive, and Species-Specific Detection of Conventional and Recombinant Herpesvirus of Turkeys Vaccines Using Loop-Mediated Isothermal Amplification Coupled With a Lateral Flow Device Readout

Marek's disease, an economically important disease of chickens caused by virulent serotype 1 strains of the Mardivirus Marek's disease virus (MDV-1), is effectively controlled in the field by live attenuated vaccine viruses including herpesvirus of turkeys (HVT)-both conventional HVT (strain FC126) and, in recent years, recombinant HVT viruses carrying foreign genes from other avian viruses to protect against both Marek's disease and other avian viral diseases. Testing to monitor and confirm successful vaccination is important, but any such test must differentiate HVT from MDV-1 and MDV-2, as vaccination does not prevent infection with these serotypes. End-point and real-time PCR tests are widely used to detect and differentiate HVT, MDV-1 and MDV-2 but require expensive specialist laboratory equipment and trained operators. Here, we developed and validated two tube-based loop-mediated isothermal amplification tests coupled with detection by lateral flow device readout (LAMP-LFD): an HVT-specific test to detect both conventional and recombinant HVT strains, and a second test using novel LAMP primers to specifically detect the Vaxxitek (R) recombinant HVT. Specificity was confirmed using DNA extracted from virus-infected cultured cells, and limit of detection was determined using plasmid DNA carrying either the HVT or Vaxxitek (R) genome. The LAMP-LFD tests accurately detected all HVT vaccines, or Vaxxitek (R) only, in crude DNA as well as purified DNA extracted from field samples of organs, feathers, or poultry house dust that were confirmed positive for HVT by real-time PCR. These LAMP-LFD tests have potential for specific, rapid, simple, and inexpensive detection of HVT vaccines in the field

Protection Conferred by a Live Avian Metapneumovirus Vaccine when Co-Administered with Live La Sota Newcastle Disease Vaccine in Chicks

This paper examines the effects on specific pathogen-free (SPF) chicks when avian metapneumovirus (aMPV) and Newcastle disease virus (NDV) La Sota strain vaccines are co-administered. Day-old SPF chicks were divided into five groups. The first group was inoculated with sterile water (SW) and the rest of the groups were inoculated with live NDV vaccine VG/GA by the oculo-oral route. At 21 days-old, the unvaccinated chicks were again inoculated with SW. The four VG/GA-vaccinated groups were further inoculated with (i) SW, (ii) live aMPV vaccine, (iii) live NDV La Sota, or (iv) combined live NDV La Sota and live aMPV, respectively. Chicks were monitored for post-vaccination reactions and oropharyngeal swabs were collected for vaccines detection. Blood samples were collected to detect aMPV ELISA and NDV haemagglutination-inhibition antibodies. Twenty-one days following the second vaccination, six chicks from each group were challenged with virulent NDV or aMPV respectively. Chicks were monitored for clinical signs and mortality and oropharyngeal swabs collected for aMPV detection. Results showed that, when challenged with a virulent aMPV, both chicks previously vaccinated with VG/GA and subsequently given aMPV vaccine singly or in combination with La Sota were equally protected against clinical signs. Chicks that were vaccinated against NDV either once with VG/GA or followed by La Sota (singly or in combination with aMPV) were fully protected when challenged with velogenic NDV. We concluded that simultaneous administration of live aMPV and NDV La Sota vaccines have no adverse effects on protection conferred by either live vaccine

Migratory Wild Birds as Potential Long-Distance Transmitters of Toxoplasma gondii Infection

: Toxoplasma gondii is a worldwide distributed zoonotic protozoan capable of infecting a wide range of mammals (including humans) and birds as intermediate hosts. Migratory wild birds, through interconnecting countries along their flyways, can play a role in the spatial spread of T. gondii and could contribute to its sylvatic cycle. Additionally, hunted wild birds used for meat consumption could represent a further source of human infection. To determine the presence of T. gondii in wild birds, a total of 50 individuals belonging to the Anseriformes and Charadriiformes orders were sampled during the 2021-2022 hunting season in Northern Italy. Cardiac muscle samples of three Northern shovelers (Anas clypeata), two wild mallards (A. platyrhynchos), one Eurasian teal (A. crecca), and one Northern lapwing (Vanellus vanellus) were positive for the molecular detection of T. gondii based on a targeted amplification of the B1 gene. A 14% (7/50) overall positivity was observed in the sampled population. Results from this study suggest a moderate exposure of wild aquatic birds to T. gondii, highlighting the importance of a further characterization of T. gondii in its wildlife hosts

Effect of changes of vaccination strategies on IBV epidemiology, diagnosis and control: an Italian retrospective study

Infectious bronchitis virus (IBV) is among the most impactful poultry pathogens, whose control, based on biosecurity and routine vaccination, is hampered by the existence of countless genetic variants sharing poor cross‑protection. A retrospective study was conducted on IBV positive samples collected in Italian broiler farms from 2012 to 2019. In 2015, the adopted vaccination protocol shifted from a Mass and 793B‑based vaccines to the administration of Mass and QX vaccines, allowing to study how changes in vaccination strategies may affect IBV epidemiology, control and diagnosis in the field. The most frequently detected lineages were QX (70.3%), 793B (15.8%) and Mass (11.9%). The relative frequencies of QX and 793B detections remained stable throughout the study, while Mass detections significantly increased after the vaccination change. Rather than to an actual growth of Mass population size, this finding may be attributable to different vaccine interactions, with Mass strains being more frequently concealed by 793B vaccines than by QX ones. Based on the obtained results, the two vaccination protocols appear to be similarly effective in fighting IB outbreaks, which in the last decade have been caused primarily by QX field strains in Italy. These results indicate that vaccination strategies may significantly affect IBV epidemiology and diagnosis, and should therefore be considered when choosing and interpreting diagnostic assays and planning control measures

Molecular characterization of the meq gene of Marek's disease viruses detected in unvaccinated backyard chickens reveals the circulation of low- and high-virulence strains

ABSTRACT Marek's disease (MD) is an important lymphoproliferative disease of chickens, caused by Gallid alphaherpesvirus 2 (GaHV-2). Outbreaks are commonly reported in commercial flocks, but also in backyard chickens. Whereas the molecular characteristics of GaHV-2 strains from the commercial poultry sector have been reported, no recent data are available for the rural sector. To fill this gap, 19 GaHV-2 strains detected in 19 Italian backyard chicken flocks during suspected MD outbreaks were molecularly characterized through an analysis of the meq gene, the major GaHV-2 oncogene. The number of four consecutive prolines (PPPP) within the proline-rich repeats of the Meq transactivation domain, the proline content, and the presence of amino acid (aa) substitutions were determined. Phylogenetic analysis was performed using the Maximum Likelihood method. Sequence analysis revealed a heterogeneous population of GaHV-2 strains circulating in Italian backyard flocks. Seven strains, detected from birds affected by classical MD, showed a unique meq isoform of 418 aa with a very high number of PPPP motifs. Molecular and clinical features are suggestive of a low oncogenic potential of these strains. The remaining 12 strains, detected from flocks experiencing acute MD, transient paralysis, or sudden death, had shorter Meq protein isoforms (298 or 339 aa) with a lower number of PPPP motifs and point mutations interrupting PPPP. These features allow us to assert the high virulence of these strains. These findings reveal the circulation of low- and high-virulence GaHV-2 strains in the Italian rural sector

Molecular detection and characterization of Mycoplasma gallisepticum and Mycoplasma synoviae strains in backyard poultry in Italy

ABSTRACT Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) represent the most important avian Mycoplasma species in the poultry industry, causing considerable economic losses. In Italy, the presence of MG or MS has been investigated especially in commercial poultry farms. To our knowledge, no systematic investigations on MG or MS presence using highly specific diagnostic assays have been performed in backyard poultry. The aim of this study was to detect and molecularly characterize MG and MS strains in 11 backyard poultry flocks located in different regions of Italy. Tracheal swabs were collected and DNA was extracted. For MS, a PCR targeting a vlhA gene fragment was performed, and typing and subtyping was attempted. The presence of MG was investigated by a screening PCR, then MG typing by gene-targeted sequencing (GTS). All the amplicons were sequenced, then MG and MS dendrograms were constructed. All the flocks examined resulted Mycoplasma positive: 5 out of 11 (45.45%) were MG and MS positive, 3 (27.27%) were MG positive, and the remaining 3 (27.27%) were MS positive. The MS detections were assigned to types C, D, and F. All strains of type D belonged to subtype D1 and 2 unknown subtypes were identified. A MS sequence showed peculiar characteristics, which did not allow assignment to a known MS type or subtype. MG GTS analysis identified 6 MG strains belonging to 5 subclusters circulating in Italian backyards chicken flocks. The results of this study provide evidence of a risk for commercial poultry farms, especially in areas where backyard and commercial farms are close, suggesting the implementation of biosecurity measures

A comparison of AMPV subtypes A and B full genomes, gene transcripts and proteins led to reverse-genetics systems rescuing both subtypes

Avian metapneumovirus (AMPV) infection of poultry causes serious disease in most countries and subtype A reverse-genetic (RG) systems have allowed a generation of viruses of known sequence, and proved useful in developments towards better control by live vaccines. While subtype B viruses are more prevalent, bacterial cloning issues made subtype B RG systems difficult to establish. A molecular comparison of subtype A and B viruses was undertaken to assess whether subtype A RG components could be partially or fully substituted. AMPV subtype A and B gene-end sequences leading to polyadenylation are, to our knowledge, reported for the first time, as well as several leader and trailer sequences. After comparing these alongside previously reported gene starts and protein sequences, it was concluded that subtype B genome copies would be most likely rescued by a subtype A support system, and this assertion was supported when individual subtype A components were successfully substituted. Application of an advanced cloning plasmid permitted eventual completion of a fully subtype B RG system, and proved that all subtype-specific components could be freely exchanged between A and B systems

Genetic variability and limited clonality of Mycoplasma hyorhinis in pig herds

Mycoplasma hyorhinis is a common inhabitant of the upper respiratory tract and tonsils of pigs. Its role as a possible pathogen remains controversial. In order to gain more insight into the epidemiology and population structure of M. hyorhinis we genetically characterized 60 isolates by multi locus sequence typing (MLST). The M. hyorhinis strains originated from Swiss and German pig herds with knowledge on the clinical background. The MLST scheme of Tocqueville et al. (J. Clin. Microbiol. 2014) was optimized, primers for the six MLST gene fragments were newly designed to allow amplification and sequencing with a single protocol. A total of 27 ST were observed with the 60 strains, 26 of those were previously unknown types. Generally identical genotypes were observed within a farm but they differed between farms. The identical genotype was also observed in three different Swiss farms. On the other Hand different genotypes within a farm were found with three German farms. The Swiss isolates formed a distinct cluster but otherwise there was no geographical nor a clinical association with specific Clusters observed. Data shows a high variability of M. hyorhinis comparable to what is observed for Mycoplasma hyopneumoniae. Similar to this pathogen the population structure of M. hyorhinis also shows some limited clonality with predominant genotypes within an animal and a single farm but different ones between farms. The comparable population structure of M. hyopneumoniae and M. hyorhinis could indicate a similar evolution of the two species in the common pig host

Influences of swab types and storage temperatures on isolation and molecular detection of Mycoplasma gallisepticum and Mycoplasma synoviae.

Routine diagnosis of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) is performed by collecting oropharyngeal swabs, followed by isolation and/or detection by molecular methods. The storage temperature, storage duration and the type of swabs could be critical factors for a successful isolation or molecular detection. The aim of this study was to compare the influence of different types of cotton tipped swabs stored at different temperatures, on detection of MG and MS. To achieve this, a combined use of traditional culture analysis (both agar and broth), with modern molecular detection methods was utilised. Performances of wooden and plastic shaft swabs, both without transport medium, were compared. Successful culture of M. gallisepticum was significantly more efficient from plastic swabs when compared to wooden, whereas no difference was seen for re-isolation of M. synoviae. Storage at 4 oC compared to room temperature also increased the efficiency of culture detection for both Mycoplasma species. When stored at room temperature, PCR detection limits of both MG and MS were significantly lower for wooden compared to plastic swabs. The qPCR data showed similar detection limits for both swab types when stored at both temperatures. Results suggest that swabs with plastic shaft should be preferred for MG and MS detection by both culture and PCR. While a lower storage temperature (4°C) is optimal for culture recovery, it seems that both temperatures investigated here are adequate for molecular detection and it is the swab type which carries a greater influence