Physiological and biochemical mechanisms of the hen’s body recovery from dermanyssosis associated with deacarization

The purpose of the research is to study the efficacy of the insectoacaricide "5% D-cyphenotrine emulsion" against infestation of birds with Dermanyssus gallinae (dermanyssosis) after the deacarization of the poultry building and to characterize physiological and biochemical mechanisms of the recovery of Hy-Line hens after removed parasites.Materials and methods. A parasitological examination of the poultry farm found D. gallinae in one of the poultry buildings. Given positive results of the drug efficacy against the poultry red mite, we analyzed the morpho-physiological and physiological and biochemical parameters of the hen’s blood before and 10 and 20 days after the treatments. Changes in the ethological status of birds were recorded. We used 0.005% aqueous emulsion of "5% D-cyphenothrin emulsion" for treatment. To obtain it, the drug was diluted with water at a ratio of 1:1000 immediately before use.Results and discussion. After double treatment with "5% D-cyphenotrine emulsion" of the shop with hens from the test group, no live poultry red mite was found. Within 20 days after the disease reduction, representatives of this group showed high concentrations of cortisol which were 2.3–2.4 times (p < 0.001) higher than those of healthy hens. This indicates that the stress state of hens still remains after the parasitizing of D. gallinae. In addition, the recovery process takes a long time and with great stress for all systems of their body. This is also confirmed by a high level of lipid peroxidation. At the same time, high intensity of gluconeogenesis and, as a result, deterioration of lipid and protein metabolism were recorded in the hens in question. The positive results indicate an increasing need for additional energy expenditures which are paramount for the effective and well-timed implementation of adaptation mechanisms. It should be noted here that the values of all the above-mentioned indicators tend to normalize by the end of the study period. The changes noted in the blood of birds indicate the restoration of a number of body systems. The poultry red mite as an emergency factor affects the morphophysiology of the blood, in particular, the level of white blood cells, which is restored by the 10th day after deacarization, which triggers regenerative and reparative processes. There were also changes in the number of cells of the immune system, an increase in hemoglobin concentration to control values and optimization of behavior in representatives of the test group which are largely related to the normalized physiological activity of the thyroid gland after the poultry building deacarization. We found a partial recovery of the hen’s body systems after the poultry building deacarization with the drug "5% D-cyphenotrine emulsion", which is due to the long-term parasitizing of D. gallinae, a stressor of extreme strength.

Genome-wide Investigation of Genetic Diversity in the Poultry Red Mite, Dermanyssus Gallinae, From European Farms Utilising a NGS-Multiplex Platform

The poultry red mite (Dermanyssus gallinae), an obligatory blood feeding ectoparasite, is primarily associated with egg laying hens where it is estimated to cause losses of ~€230 million per annum from European farmers. Current control strategies, including the use of acaricidal chemicals and desiccant dusts, are often ineffective and there is widespread resistance to acaricides across Europe. Alternative methods to control D. gallinae are urgently required and strategies include development of recombinant subunit vaccines and discovery of new potential acaricides. These strategies will benefit hugely from knowledge of the extent and rates of occurrence of genetic diversity within D. gallinae populations. In this study, genetic diversity of mites harvested from the UK and from sites across mainland Europe was studied at inter- and intra-farm levels. To achieve this, the genome analysis toolkit (GATK) best practices pipeline for single nucleotide polymorphism (SNP) and insertion/deletion variant calling was modified to be self-validating and used to identify 32,599 D. gallinae SNPs by comparing transcriptomic sequences (derived from mites harvested in Germany, Schicht et al.) with a D. gallinae genome assembly (derived from mites harvested in Scotland, Burgess et al.). Dermanyssus gallinae populations were sampled from 22 UK farms and 57 farms from 15 countries in mainland Europe. Analysis of 144 high-quality SNP markers across 117 pooled D. gallinae samples showed high spatial genetic diversity with significant linkage disequilibrium. Revisiting a subset of farms revealed notable temporal changes in genetic diversity.

Characterization of a Novel Cysteine Protease Inhibitor from Poultry Red Mites: Potential Vaccine for Chickens

Poultry red mite (PRM; Dermanyssus gallinae) is a hazardous, blood-sucking ectoparasite of birds that constitutes a threat to poultry farming worldwide. Acaricides, commonly used in poultry farms to prevent PRMs, are not effective because of the rapid emergence of acaricide-resistant PRMs. However, vaccination may be a promising strategy to control PRM. We identified a novel cystatin-like molecule in PRMs: Dg-Cys. Dg-Cys mRNA expression was detected in the midgut and ovaries, in all stages of life. The PRM nymphs that were artificially fed with the plasma from chickens that were immunized with Dg-Cys in vitro had a significantly reduced reproductive capacity and survival rate. Moreover, combination of Dg-Cys with other antigen candidates, like copper transporter 1 or adipocyte plasma membrane-associated protein, enhanced vaccine efficacies. vaccination and its application as an antigen for cocktail vaccines could be an effective strategy to reduce the damage caused by PRMs in poultry farming.

Genotype–environment interaction in layer chickens in the growing stage: comparison of three genotypes at two different feeding levels with or without red mite (<i>Dermanyssus gallinae</i>) infestation

This study investigated how early growth was affected in various chicken genotypes, which were fed ad libitum or restricted and with or without poultry red mite (PRM) infestation. Atak-S (AS), New Hampshire Red (NHR), and Light Sussex (LS) genotypes were used in the study. In total, 120 chicks were used from each genotype. Four groups were formed: feed-restricted (FR) and infested with parasite (P+), FR only, fed ad libitum and P+ , and fed ad libitum only. Feed restriction was applied as 20 % of the feed consumption of the group fed ad libitum the day before for each genotype. The study was conducted between 2 to 12 weeks of age. Weekly live weights and feed consumption were recorded, and the feed conversion ratio was calculated. Traps were placed in cages to count parasites. Regarding the live weight, NHR tolerated the PRM infestation in the ad libitum feed conditions better than other genotypes. While the infested NHR and AS birds had lower live weights than the non-infested ones under FR conditions, there was no difference between infested and non-infested birds of NHR and AS genotypes when they fed ad libitum. The feed consumption of infested AS and NHR birds was higher than that of non-infested counterparts when fed ad libitum. By contrast, the LS chicks consumed less food in the infested environment. In conclusion, the genotypes responded differently to PRM infestation in different feeding environments.

Importance and Impact of the Poultry Red Mite (Dermanyssus Gallinae) in Layer Farms - Analysis of Farmers’ Perception

Poultry red mite (PRM), Dermanyssus gallinae, causes egg drop production, anemia and can be a vector in transmitting diseases. The PRM control mainly focuses on usage of the conventional chemical biocides. The objective of this study was to analyze the farmers’ perception regarding the impact, management and control of PRM in Macedonian layer farms. The data were collected with direct on-site visits using a unified questionnaire. In total, 29 poultry farms (28% of farms in the country), all with conventional cages, were part of this study. The data were analyzed by descriptive statistics, inferential statistics and Naïve Bayes Classifier technique. In 30% of the poultry farms the farmers had observed that the flock was infested with PRM. In total, 32 different treatments against PRM were reported from the farmers, and three of them were non-biocide treatments. The most used biocides (17% of the farms) were crude oil, Formalin, Neopitroid® and disinfectants. The highest agreement regarding biocides application among the farms (38%) was before the production starts. Most of the farmers applied biocides routinely, before the infestation is evident (75%). The median costs for PRM treatment were 175€ per flock, higher in the infested farms 493±677€ compared to non - infested 100±71€, p<0.05. None of the Macedonian farmers included in the study was using monitoring method for PRM infestation, contributing to poor data records. This study highlights the need of developing unified strategy for PRM control included in the Integrated Pest Management in poultry layer farms.

A Rickettsiella Endosymbiont Is a Potential Source of Essential B-Vitamins for the Poultry Red Mite, Dermanyssus gallinae

Many obligate blood-sucking arthropods rely on symbiotic bacteria to provision essential B vitamins that are either missing or at sub-optimal levels in their nutritionally challenging blood diet. The poultry red mite Dermanyssus gallinae, an obligate blood-feeding ectoparasite, is a serious threat to the hen egg industry. Poultry red mite infestation has a major impact on hen health and welfare and causes a significant reduction in both egg quality and production. Thus far, the identity and biological role of nutrient provisioning bacterial mutualists from D. gallinae are little understood. Here, we demonstrate that an obligate intracellular bacterium of the Rickettsiella genus is detected in D. gallinae mites collected from 63 sites (from 15 countries) across Europe. In addition, we report the genome sequence of Rickettsiella from D. gallinae (Rickettsiella – D. gallinae endosymbiont; Rickettsiella DGE). Rickettsiella DGE has a circular 1.89Mbp genome that encodes 1,973 proteins. Phylogenetic analysis confirms the placement of Rickettsiella DGE within the Rickettsiella genus, related to a facultative endosymbiont from the pea aphid and Coxiella-like endosymbionts (CLEs) from blood feeding ticks. Analysis of the Rickettsiella DGE genome reveals that many protein-coding sequences are either pseudogenized or lost, but Rickettsiella DGE has retained several B vitamin biosynthesis pathways, suggesting the importance of these pathways in evolution of a nutritional symbiosis with D. gallinae. In silico metabolic pathway reconstruction revealed that Rickettsiella DGE is unable to synthesize protein amino acids and, therefore, amino acids are potentially provisioned by the host. In contrast, Rickettsiella DGE retains biosynthetic pathways for B vitamins: thiamine (vitamin B1) via the salvage pathway; riboflavin (vitamin B2) and pyridoxine (vitamin B6) and the cofactors: flavin adenine dinucleotide (FAD) and coenzyme A (CoA) that likely provision these nutrients to the host.

Who Is Dermanyssus gallinae? Genetic Structure of Populations and Critical Synthesis of the Current Knowledge

Despite the economic and animal welfare importance of the Poultry Red Mite Dermanyssus gallinae, its genetic structure has been studied in a scattered way so far. The prophylaxis and control of such a globally distributed ectoparasite can be significantly improved by understanding its genetic population structure (composition in species and intraspecific variants). The present study aims to establish a rigorous framework for characterizing the neutral genetic structure of D. gallinae based on a literature review combined with an integrative analysis of the data available in GenBank on population-level nucleotide sequence diversity supplemented by a new dataset. The integrative analysis was conducted on sequence data extracted from GenBank coupled with new sequences of two fragments of the mitochondrial gene encoding Cytochrome Oxidase I (CO1) as well as of an intron of the nuclear gene encoding Tropomyosin (Tpm) from several PRM populations sampled from European poultry farms. Emphasis was placed on using the mitochondrial gene encoding CO1 on which the main universal region of DNA barcoding in animals is located. The species D. gallinae sensu lato is a species complex, encompassing at least two cryptic species, i.e., not distinguishable by morphological characters: D. gallinae sensu stricto and D. gallinae L1. Only D. gallinae s.s. has been recorded among the populations sampled in poultry farms worldwide. Current knowledge suggests they are structured in three mitochondrial groups (haplogroups A, B, and C). Haplogroup A is cosmopolitan, and the other two present slightly contrasted distributions (B rather in the northern part of Europe, C most frequently found in the southern part). Recent data indicate that a dynamic geographic expansion of haplogroup C is underway in Europe. Our results also show that NUMT (nuclear mitochondrial DNA) pseudogenes have generated artifactual groups (haplogroups E and F). It is important to exclude these artifact groups from future analyses to avoid confusion. We provide an operational framework that will promote consistency in the analysis of subsequent results using the CO1 fragment and recommendations for future analyses.

A Rickettsiella endosymbiont is a potential source of essential B-vitamins for the poultry red mite, Dermanyssus gallinae

Obligate blood-sucking arthropods rely on symbiotic bacteria to provision essential B vitamins that are either missing or at sub-optimal amounts in their nutritionally challenging blood diet. The poultry red mite Dermanyssus gallinae, an obligate blood-feeding ectoparasite, is primarily associated with poultry and a serious threat to the hen egg industry. Thus far, the identity and biological role of nutrient provisioning bacterial mutualists from D. gallinae are little understood. Here, we demonstrate that a Rickettsiella Gammaproteobacteria in maternally transmitted in D. gallinae and universally present in D. gallinae mites collected at different sites throughout Europe. In addition, we report the genome sequence of uncultivable endosymbiont “Candidatus Rickettsiella rubrum” from D. gallinae eggs. The endosymbiont has a circular 1. 89 Mbp genome that encodes 1973 protein. Phylogenetic analysis confirms the placement R. rubrum within the Rickettsiella genus, closely related to a facultative endosymbiont from the pea aphid and Coxiella-like endosymbionts from blood feeding ticks. Analysis of the R. rubrum genome reveals many protein-coding sequences are either pseudogenized or lost, but R. rubrum has retained several B vitamin biosynthesis pathways, confirming the importance of these pathways in evolution of its nutritional symbiosis with D. gallinae. In silico metabolic pathway reconstruction revealed that R. rubrum is unable to synthesise protein amino acids and therefore these nutrients are likely provisioned by the host. In contrast R. rubrum retains biosynthetic pathways for B vitamins: thiamine (vitamin B1) via the salvage pathway; riboflavin (vitamin B2) and pyridoxine (vitamin B6) and the cofactors: flavin adenine dinucleotide (FAD) and coenzyme A (CoA) that likely provision these nutrients to the host. We propose that bacterial symbionts which are essential to blood-feeding arthropod survival provide attractive targets for the development of novel control methods.