Mitigation of False Layer Syndrome Through Maternal Antibodies Against Infectious Bronchitis Virus.

The relationship between passive immunity and the development of false layer syndrome (FLS) and its associated lesions was investigated in this study by comparing the long-term reproductive effects of an infectious bronchitis virus (IBV) DMV/1639 wild-type strain and the GA08 vaccine in birds with and without maternal antibodies. There was a clear protective effect provided by maternal antibodies against both the early vaccination and challenge. It was also observed that vaccination at an early age, in the absence of maternal antibodies, can induce reproductive issues, such as reduced egg production and FLS-associated lesions (e.g., cystic oviduct and egg yolk coelomitis). This might indicate that maternal antibodies and the timing of IBV infection are more important in the generation of FLS than the IBV strain type.

Mitigación del síndrome de la falsa ponedora mediante anticuerpos maternos contra el virus de la bronquitis infecciosa. En este estudio se investigó la relación entre la inmunidad pasiva y el desarrollo del síndrome de la falsa ponedora (FLS) y sus lesiones asociadas comparando los efectos reproductivos a largo plazo de una cepa de tipo silvestre DMV/1639 del virus de la bronquitis infecciosa (IBV) y la cepa vacunal GA08, en aves con y sin anticuerpos maternos. Hubo un claro efecto protector proporcionado por los anticuerpos maternos tanto contra la vacunación temprana como contra el desafío. También se observó que la vacunación a una edad temprana, en ausencia de anticuerpos maternos, puede inducir problemas reproductivos, como una reducción de la producción de huevo y lesiones asociadas al síndrome de la falsa ponedora (p. ej., oviducto quístico y celomitis de yema de huevo). Esto podría indicar que los anticuerpos maternos y el momento de la infección por el virus de la bronquitis infecciosa son más importantes en la generación del síndrome de la falsa ponedora que el tipo de cepa del virus de la bronquitis infecciosa.

Genetic architecture of body weight, carcass, and internal organs traits of Ghanaian local chickens.

Information on the genetic architecture of the production traits of indigenous African chicken is limited. We performed a genome-wide association study using imputed Affymetrix Axiom® 600K SNP-chip genotypes on 1,113 chickens from three agroecological zones of Ghana. After quality control, a total of 382,240 SNPs remained. Variance components and heritabilities for some growth, carcass and internal organ traits were estimated. The genetic and phenotypic correlations among these traits were also estimated. The estimated heritabilities of body weight at week 22 (BW22), average daily gain (ADG), dressed weight, breast weight, thigh weight, wing weight, drumstick weight, and neck weight were high and ranged from 0.50 to 0.69. Estimates of heritabilities for head weight, shank weight, and gizzard weight were moderate (0.31-0.35) while those of liver weight, back weight, dressing percentage, and heart weight were low (0.13-0.21). The estimated heritabilities of dressed weight, breast weight, wing weight, drumstick weight, neck weight, shank weight, and gizzard weight, corrected for BW22, were moderate (0.29-0.38), while the remaining traits had low heritability estimates (0.13-0.21). A total of 58 1-Mb SNP windows on chromosomes 1, 2, 4, 5, 6, 7, 8, 9, 13, 18, and 33 each explained more than 1% of the genetic variance for at least one of these traits. These genomic regions contained many genes previously reported to have effects on growth, carcass, and internal organ traits of chickens, including EMX2, CALCUL1, ACVR1B, CACNB1, RB1, MLNR, FOXO1, NCARPG, LCORL, LAP3, LDB2, KPNA3, and CAB39L. The moderate to high heritability estimates and high positive genetic correlations suggest that BW22, ADG, dressed weight, breast weight, thigh weight, wing weight, drumstick weight, and neck weight could be improved through selective breeding.

Differential Impact of Massachusetts, Canadian 4/91, and California (Cal) 1737 Genotypes of Infectious Bronchitis Virus Infection on Lymphoid Organs of Chickens.

Infectious bronchitis virus (IBV) induces severe economic losses in chicken farms due to the emergence of new variants leading to vaccine breaks. The studied IBV strains belong to Massachusetts (Mass), Canadian 4/91, and California (Cal) 1737 genotypes that are prevalent globally. This study was designed to compare the impact of these three IBV genotypes on primary and secondary lymphoid organs. For this purpose, one-week-old specific pathogen-free chickens were inoculated with Mass, Canadian 4/91, or Cal 1737 IBV variants, keeping a mock-infected control. We examined the IBV replication in primary and secondary lymphoid organs. The molecular, histopathological, and immunohistochemical examinations revealed significant differences in lesion scores and viral distribution in these immune organs. In addition, we observed B-cell depletion in the bursa of Fabricius and the spleen with a significant elevation of T cells in these organs. Further studies are required to determine the functional consequences of IBV replication in lymphoid organs.

Comparative pathogenicity of CA1737/04 and Mass infectious bronchitis virus genotypes in laying chickens.

Infectious bronchitis virus (IBV) is a respiratory virus causing atropism in multiple body systems of chickens. Recently, the California 1737/04 (CA1737/04) IBV strain was identified as one of the circulating IBV variants among poultry operations in North America. Here, the pathogenicity and tissue tropism of CA1737/04 IBV strain in specific-pathogen-free (SPF) hens were characterized in comparison to Massachusetts (Mass) IBV. In 30 weeks-old SPF hens, Mass or CA1737/04 IBV infections were carried out, while the third group was maintained as a control group. Following infection, we evaluated clinical signs, egg production, viral shedding, serology, necropsy examination, and histopathology during a period of 19 days. Also, certain tissue affinity parameters were investigated, which involved the localization of viral antigens and the detection of viral RNA copies in designated tissues. Our findings indicate that infection with CA1737/04 or Mass IBV strain could induce significant clinical signs, reduced egg production, and anti-IBV antibodies locally in oviduct wash and systemically in serum. Both IBV strains showed detectable levels of viral RNA copies and induced pathology in respiratory, renal, enteric, and reproductive tissues. However, the CA1737/04 IBV strain had higher pathogenicity, higher tissue tropism, and higher replication in the kidney, large intestine, and different segments of the oviduct compared to the Mass IBV strain. Both IBV strains shed viral genome from the cloacal route, however, the Mass IBV infected hens shed higher IBV genome loads via the oropharyngeal route compared to CA1737/04 IBV-infected hens. Overall, the current findings could contribute to a better understanding of CA1737/04 IBV pathogenicity in laying hens.

Genomic Regions and Candidate Genes Affecting Response to Heat Stress with Newcastle Virus Infection in Commercial Layer Chicks Using Chicken 600K Single Nucleotide Polymorphism Array.

Heat stress results in significant economic losses to the poultry industry. Genetics plays an important role in chickens adapting to the warm environment. Physiological parameters such as hematochemical parameters change in response to heat stress in chickens. To explore the genetics of heat stress resilience in chickens, a genome-wide association study (GWAS) was conducted using Hy-Line Brown layer chicks subjected to either high ambient temperature or combined high temperature and Newcastle disease virus infection. Hematochemical parameters were measured during three treatment phases: acute heat stress, chronic heat stress, and chronic heat stress combined with NDV infection. Significant changes in blood parameters were recorded for 11 parameters (sodium (Na+, potassium (K+), ionized calcium (iCa2+), glucose (Glu), pH, carbon dioxide partial pressure (PCO2), oxygen partial pressure (PO2), total carbon dioxide (TCO2), bicarbonate (HCO3), base excess (BE), and oxygen saturation (sO2)) across the three treatments. The GWAS revealed 39 significant SNPs (p < 0.05) for seven parameters, located on Gallus gallus chromosomes (GGA) 1, 3, 4, 6, 11, and 12. The significant genomic regions were further investigated to examine if the genes within the regions were associated with the corresponding traits under heat stress. A candidate gene list including genes in the identified genomic regions that were also differentially expressed in chicken tissues under heat stress was generated. Understanding the correlation between genetic variants and resilience to heat stress is an important step towards improving heat tolerance in poultry.

Local structural preferences in shaping tau amyloid polymorphism.

Tauopathies encompass a group of neurodegenerative disorders characterised by diverse tau amyloid fibril structures. The persistence of polymorphism across tauopathies suggests that distinct pathological conditions dictate the adopted polymorph for each disease. However, the extent to which intrinsic structural tendencies of tau amyloid cores contribute to fibril polymorphism remains uncertain. Using a combination of experimental approaches, we here identify a new amyloidogenic motif, PAM4 (Polymorphic Amyloid Motif of Repeat 4), as a significant contributor to tau polymorphism. Calculation of per-residue contributions to the stability of the fibril cores of different pathologic tau structures suggests that PAM4 plays a central role in preserving structural integrity across amyloid polymorphs. Consistent with this, cryo-EM structural analysis of fibrils formed from a synthetic PAM4 peptide shows that the sequence adopts alternative structures that closely correspond to distinct disease-associated tau strains. Furthermore, in-cell experiments revealed that PAM4 deletion hampers the cellular seeding efficiency of tau aggregates extracted from Alzheimer's disease, corticobasal degeneration, and progressive supranuclear palsy patients, underscoring PAM4's pivotal role in these tauopathies. Together, our results highlight the importance of the intrinsic structural propensity of amyloid core segments to determine the structure of tau in cells, and in propagating amyloid structures in disease.

Structural evolution of fibril polymorphs during amyloid assembly.

Cryoelectron microscopy (cryo-EM) has provided unprecedented insights into amyloid fibril structures, including those associated with disease. However, these structures represent the endpoints of long assembly processes, and their relationship to fibrils formed early in assembly is unknown. Consequently, whether different fibril architectures, with potentially different pathological properties, form during assembly remains unknown. Here, we used cryo-EM to determine structures of amyloid fibrils at different times during in vitro fibrillation of a disease-related variant of human islet amyloid polypeptide (IAPP-S20G). Strikingly, the fibrils formed in the lag, growth, and plateau phases have different structures, with new forms appearing and others disappearing as fibrillation proceeds. A time course with wild-type hIAPP also shows fibrils changing with time, suggesting that this is a general property of IAPP amyloid assembly. The observation of transiently populated fibril structures has implications for understanding amyloid assembly mechanisms with potential new insights into amyloid progression in disease.

Molecular characterization of Newcastle disease virus obtained from Mawenzi live bird market in Morogoro, Tanzania in 2020-2021.

Newcastle disease (ND) is among the most important poultry diseases worldwide. It is the major threat to poultry production in Africa and causes major economic losses for both local and commercial chickens. To date, half of ND class II genotypes have been reported in Africa (I, IV, V, VI, VII, XI, XIII, XIV, XVII, XVIII, and XXI). The information on the circulating NDV genotypes is still scarce despite the endemic nature of ND in most countries on the African continent.A total of 659 oro-cloacal swabs were collected from local chickens in Mawenzi live bird market located in Morogoro, Tanzania, between June 2020 and May 2021. Newcastle disease virus was detected by using reverse transcription real-time polymerase chain reaction (RT-qPCR) and conventional PCR followed by sequencing of PCR products. The prevalence of NDV in the surveilled live bird markets was 23.5%. Sequencing and phylogenetic analysis revealed the presence of sub-genotype VII.2. The detected sub-genotype VII.2 has phylogenetic links to Zambian NDV strains implying a Southeast dissemination of the virus, considering that it was first detected in Mozambique. This study underscores the need of active NDV surveillance to determine the distribution of this NDV genotype in the country and monitor its spread and contribution to the emergence of new ND viruses.

Whole-genome sequence of a genotype VIII infectious bronchitis virus isolated from California layer chickens in 2021.

Herein, we report the complete genome for an avian infectious bronchitis virus isolated from cecal tonsils of California layers in 2021. This whole-genome sequence belongings to genotype GVIII, previously classified as a unique variant.

Exploiting the aggregation propensity of beta-lactamases to design inhibitors that induce enzyme misfolding.

There is an arms race between beta-lactam antibiotics development and co-evolving beta-lactamases, which provide resistance by breaking down beta-lactam rings. We have observed that certain beta-lactamases tend to aggregate, which persists throughout their evolution under the selective pressure of antibiotics on their active sites. Interestingly, we find that existing beta-lactamase active site inhibitors can act as molecular chaperones, promoting the proper folding of these resistance factors. Therefore, we have created Pept-Ins, synthetic peptides designed to exploit the structural weaknesses of beta-lactamases by causing them to misfold into intracellular inclusion bodies. This approach restores sensitivity to a wide range of beta-lactam antibiotics in resistant clinical isolates, including those with Extended Spectrum variants that pose significant challenges in medical practice. Our findings suggest that targeted aggregation of resistance factors could offer a strategy for identifying molecules that aid in addressing the global antibiotic resistance crisis.

Infectious Bronchitis Virus California Variant CA1737 Isolated from a Commercial Layer Flock with Cystic Oviducts and Poor External Egg Quality.

False layer syndrome is a condition in which the reproductive tract of chicks is infected with infectious bronchitis virus (IBV) strains that cause permanent damage to the oviduct. These chickens subsequently develop cystic oviducts and do not lay eggs, and affected flocks fail to reach expected egg production peaks. The California Animal Health and Food Safety laboratory, Turlock Branch, received four separate case submissions from a 25-to-28-wk-old commercial ISA Brown layer flock. Birds were submitted for diagnostic evaluation due to suboptimal egg production and vent pecking. Submissions totaled 31 birds and consisted of live layers, recent mortality, and a flat of eggs. No clinical signs were observed in the submitted live birds. The most common gross findings included cystic left oviducts, signs of vent pecking, ovarian regression, and yolk coelomitis. The eggs were abnormally shaped with irregular, white, gritty deposits on the surface of the shell. Microscopically, there was atrophy of the oviducts, glandular hypoplasia, and lymphocytic salpingitis. In addition, lymphoplasmacytic tracheitis was observed, and renal tubules were dilated with multifocal areas of mineralization. IBV was identified by reverse transcription quantitative PCR from cecal tonsil tissue pools and tracheal swab pools. Sequencing of the S1 hypervariable region of IBV and whole-genome IBV sequencing were 97% homologous to the California variant CA1737/04. Definitive proof of the CA1737 strain's causing reproductive abnormalities will require challenge studies with fulfillment of Koch's postulates and evaluation of confounding and risk factors.

Reporte de caso- Virus de la bronquitis infecciosa Variante de California CA1737 aislada de una parvada comercial de ponedoras con oviductos quísticos y mala calidad externa del huevo. El síndrome de la falsa capa es una condición en la cual el tracto reproductivo de las gallinas está infectado con cepas del virus de la bronquitis infecciosa (IBV) que causan daño permanente al oviducto. Posteriormente, estas gallinas desarrollan oviductos quísticos y bajas en la postura de huevo, las parvadas afectadas no alcanzan los picos de producción de huevos esperados. El laboratorio de Salud Animal y Seguridad Alimentaria de California, con sede en Turlock, recibió cuatro casos separados de una parvada comercial de ponedoras ISA Brown de 25 a 28 semanas de edad. Las aves se enviaron para evaluación diagnóstica debido a una producción de huevos subóptima y por presencia de picoteo en las cloacas. Se recibieron un total de 31 aves y consistieron en aves de postura vivas, mortalidad reciente y además una charola de huevos. No se observaron signos clínicos en las aves vivas enviadas. Los hallazgos macroscópicos más comunes incluyeron oviductos izquierdos quísticos, signos de picoteo en las cloacas, regresión ovárica y celomitis de la yema. Los huevos tenían una forma anormal con depósitos irregulares, blancos y arenosos en la superficie de la cáscara. Microscópicamente, había atrofia de los oviductos, hipoplasia glandular y salpingitis linfocítica. Además, se observó traqueítis linfoplasmocítica y túbulos renales dilatados con áreas multifocales de mineralización. El virus de la bronquitis infecciosa se identificó mediante PCR cuantitativa de transcripción inversa a partir de grupos de tejidos de tonsilas cecales y muestras agrupadas de hisopos traqueales. La secuenciación de la región hipervariable S1 de IBV y la secuenciación de IBV del genoma completo fueron homólogas en un 97 % a la variante de California CA1737/04. La prueba definitiva de las anomalías reproductivas causantes de la cepa CA1737 requerirá estudios de desafío con el cumplimiento de los postulados de Koch y la evaluación de los factores de riesgo y de confusión.

Molecular characterization of the HMTp210 gene of Avibacterium paragallinarum and the proposition of a new genotyping method as alternative for classical serotyping.

Avibacterium paragallinarum (A. paragallinarum) is the aetiological agent of infectious coryza (IC) in chickens and characterized by acute respiratory distress and severe drop in egg production. Vaccination is important in the control of IC outbreaks and the efficacy of vaccination is dependent on A. paragallinarum serovars included in the vaccine. Classical serotyping of A. paragallinarum is laborious and hampered by poor availability of antigens and antisera. The haemagglutinin, important in classical serotyping, is encoded by the HMTp210 gene. HMTp210 gene analysis has been shown to have potential as alternative to classical serotyping. The aim of the present study was to further investigate the potential of sequence analyses of partial region 1 of the HMTp210 gene, the HMTp210 hypervariable region and the concatenated sequences of both fragments. For this analysis, 123 HMTp210 gene sequences (field isolates, A. paragallinarum serovar reference strains and vaccine strains) were included. Evaluation of serovar references and vaccine strains revealed a need for critical evaluation, especially within Page serovar B and C. Phylogenetic analysis of HMTp210 region 1 resulted in a separation of Page serovar A, B and C strains. Analysis of the HMTp210 HVR alone was not sufficient to discriminate all nine different Kume serovar references. The concatenated sequences of HMTp210 region 1 and HMTp210 HVR resulted in 14 clusters with a high correlation with Page serovar and with the nine currently known Kume serovars and is therefore proposed as a novel genotyping method that could be used as an alternative for classical serotyping of A. paragallinarum.

Disease-relevant ß2-microglobulin variants share a common amyloid fold.

ß2-microglobulin (ß2m) and its truncated variant ΔΝ6 are co-deposited in amyloid fibrils in the joints, causing the disorder dialysis-related amyloidosis (DRA). Point mutations of ß2m result in diseases with distinct pathologies. ß2m-D76N causes a rare systemic amyloidosis with protein deposited in the viscera in the absence of renal failure, whilst ß2m-V27M is associated with renal failure, with amyloid deposits forming predominantly in the tongue. Here we use cryoEM to determine the structures of fibrils formed from these variants under identical conditions in vitro. We show that each fibril sample is polymorphic, with diversity arising from a 'lego-like' assembly of a common amyloid building block. These results suggest a 'many sequences, one amyloid fold' paradigm in contrast with the recently reported 'one sequence, many amyloid folds' behaviour of intrinsically disordered proteins such as tau and Aß.

Enhanced therapeutic window for antimicrobial Pept-ins by investigating their structure-activity relationship.

The overconsumption and inappropriate use of antibiotics is escalating antibiotic resistance development, which is now one of the 10 top threats to global health. Introducing antibiotics with a novel mode of action into clinical use is urgently needed to address this issue. Deliberately inducing aggregation of target proteins and disrupting protein homeostasis in bacteria via amyloidogenic peptides, also called Pept-ins (from peptide interferors), can be lethal to bacteria and shows considerable promise as a novel antibiotic strategy. However, the translation of Pept-ins into the clinic requires further investigation into their mechanism of action and improvement of their therapeutic window. Therefore, we performed systematic structure modifications of 2 previously discovered Pept-ins, resulting in 179 derivatives, and investigated the corresponding impact on antimicrobial potency, cellular accumulation, and ability to induce protein aggregation in bacteria, in vitro aggregation property, and toxicity on mammalian cells. Our results show that both Pept-in accumulation and aggregation of target proteins in bacteria are requisite for Pept-in mediated antimicrobial activity. Improvement of these two parameters can be achieved via increasing the number of arginine residues, increasing Pept-in aggregation propensity, optimizing the aggregate core structure, adopting ß-turn linkers, or forming a disulphide bond. Correspondingly, improvement of these two parameters can enhance Pept-in antimicrobial efficacy against wildtype E. coli BL21 used in the laboratory as well as clinically isolated multidrug-resistant strain E. coli ATCC, A. baumannii, and K. pneumoniae.

Genetic Analyses of Response of Local Ghanaian Tanzanian Chicken Ecotypes to a Natural Challenge with Velogenic Newcastle Disease Virus.

Newcastle disease is a devastating poultry disease that often causes significant economic losses in poultry in the developing countries of Africa, Asia, as well as South and Central America. Velogenic Newcastle disease virus (NDV) outbreaks are associated with high mortalities, which can threaten household livelihoods, especially in the rural areas, and lead to loss of high-quality proteins in the form of meat and eggs, as well as household purchasing power. In this study, we exposed unvaccinated Ghanaian and Tanzanian chickens of six local ecotypes to velogenic NDV strains, measured NDV response traits, sequenced their DNA on a genotyping-by-sequencing platform, and performed variance component analyses. The collected phenotypes included: growth rates (pre- and post-exposure); lesion scores (gross lesion severity) in the trachea, proventriculus, intestine, and cecal tonsils; natural antibody levels; anti-NDV antibody levels at 7 days post exposure (dpe); tear and cloacal viral load at 2, 4, and 6 dpe; and survival time. Heritability estimates were low to moderate, ranging from 0.11 for average lesion scores to 0.36 for pre-exposure growth rate. Heritability estimates for survival time were 0.23 and 0.27 for the Tanzanian and Ghanaian ecotypes, respectively. Similar heritability estimates were observed when data were analyzed either separately or combined for the two countries. Survival time was genetically negatively correlated with lesion scores and with viral load. Results suggested that response to mesogenic or velogenic NDV of these local chicken ecotypes could be improved by selective breeding. Chickens that are more resilient to velogenic NDV can improve household livelihoods in developing countries.

Infectious Bronchitis Virus: A Comprehensive Multilocus Genomic Analysis to Compare DMV/1639 and QX Strains.

Infectious bronchitis virus (IBV) is a highly variable RNA virus that affects chickens worldwide. Due to its inherited tendency to suffer point mutations and recombination events during viral replication, emergent IBV strains have been linked to nephropathogenic and reproductive disease that are more severe than typical respiratory disease, leading, in some cases, to mortality, severe production losses, and/or unsuccessful vaccination. QX and DMV/1639 strains are examples of the above-mentioned IBV evolutionary pathway and clinical outcome. In this study, our purpose was to systematically compare whole genomes of QX and DMV strains looking at each IBV gene individually. Phylogenetic analyses and amino acid site searches were performed in datasets obtained from GenBank accounting for all IBV genes and using our own relevant sequences as a basis. The QX dataset studied is more genetically diverse than the DMV dataset, partially due to the greater epidemiological diversity within the five QX strains used as a basis compared to the four DMV strains from our study. Historically, QX strains have emerged and spread earlier than DMV strains in Europe and Asia. Consequently, there are more QX sequences deposited in GenBank than DMV strains, assisting in the identification of a larger pool of QX strains. It is likely that a similar evolutionary pattern will be observed among DMV strains as they develop and spread in North America.

Outreach Efforts to Prevent Newcastle Disease Outbreaks in Southern California.

In May 2018, an outbreak of virulent Newcastle disease (vND) affected backyard and commercial premises in Southern California. The re-occurrence of these outbreaks since the 1970s suggests that some poultry communities may not have reliable and stable resources available regarding biosecurity and disease prevention. Therefore, staff at the University of California, Davis (UCD) School of Veterinary Medicine (SVM), and the California Department of Food and Agriculture (CDFA) began organizing educational events and learning more about the gamefowl breeder community through a needs assessment exercise, during which local feedstores and neighborhoods were also visited. Focus groups were organized with breeders in various cities within the regional quarantine area, established by the CDFA during the vND outbreak. The focus groups were aimed at creating open communication networks with gamefowl breeders in the affected area, as well as to learn about their current sources of information, learning preferences, and current management practices. With the input from gamefowl breeders, as well as funding and input from the CDFA and the United States Department of Agriculture (USDA), a quality assurance program called the "Gamefowl Wellness Program" was established. Educational content was created and published through the UCD Gamefowl Wellness Program poultry health website. Additionally, with the help of the CDFA, the USDA, and pharmaceutical companies, Newcastle disease vaccines and training for their application were provided to feedstores with gamefowl breeder clientele. Nurturing trust with these poultry communities allowed us to receive the information needed to develop effective outreach strategies that could better serve them. Responding to community concerns might be a way to garner the trust necessary to prevent or at least promptly detect foreign animal disease outbreaks.

Hyperimmunized Chickens Produce Neutralizing Antibodies against SARS-CoV-2.

The novel severe acute respiratory syndrome (SARS) coronavirus, SARS-CoV-2, is responsible for the global COVID-19 pandemic. Effective interventions are urgently needed to mitigate the effects of COVID-19 and likely require multiple strategies. Egg-extracted antibody therapies are a low-cost and scalable strategy to protect at-risk individuals from SARS-CoV-2 infection. Commercial laying hens were hyperimmunized against the SARS-CoV-2 S1 protein using three different S1 recombinant proteins and three different doses. Sera and egg yolk were collected at three and six weeks after the second immunization for enzyme-linked immunosorbent assay and plaque-reduction neutralization assay to determine antigen-specific antibody titers and neutralizing antibody titers, respectively. In this study we demonstrate that hens hyperimmunized against the SARS-CoV-2 recombinant S1 and receptor binding domain (RBD) proteins produced neutralizing antibodies against SARS-CoV-2. We further demonstrate that antibody production was dependent on the dose and type of antigen administered. Our data suggests that antibodies purified from the egg yolk of hyperimmunized hens can be used as immunoprophylaxis in humans at risk of exposure to SARS-CoV-2.

Porphyrin Accumulation and Biliary Lithiasis Causing Diffusely Black Livers in Broiler Chickens.

Two 7-wk-old broiler chickens presented with uniformly black livers upon postslaughter examination, while all other organs as well as their carcasses were grossly normal. No clinical signs were reported by the field veterinarian prior to slaughter. Other broiler chickens within the same flock were unaffected. Microscopically, the liver exhibited variably sized, globoid concrements that were dark brown to green-brown and birefringent under polarized light. Ultrastructurally, concrements consisted of radially arranged electron-dense crystal spicules. Concrements were located in hepatocytes, within ecstatic bile canaliculi, or surrounded by small clusters of macrophages. Liquid chromatography assay determined the presence of protoporphyrin IX in the affected liver.Two 7-wk-old broiler chickens presented with uniformly black livers upon postslaughter examination, while all other organs as well as their carcasses were grossly normal. No clinical signs were reported by the field veterinarian prior to slaughter. Other broiler chickens within the same flock were unaffected. Microscopically, the liver exhibited variably sized, globoid concrements that were dark brown to green-brown and birefringent under polarized light. Ultrastructurally, concrements consisted of radially arranged electron-dense crystal spicules. Concrements were located in hepatocytes, within ecstatic bile canaliculi, or surrounded by small clusters of macrophages. Liquid chromatography assay determined the presence of protoporphyrin IX in the affected liver.