Search

Simple Summary: Rabbit hemorrhagic disease virus 2 (RHDV2) was reported in the United States in 2018 and has since spread across most of the country where it has a potential for adverse impacts on ecosystems, economic losses, and pet rabbit health. Using an emergency use authorized vaccine, seroconversion and protection was demonstrated in 3- to 7-week-old specific pathogen free laboratory rabbits. The purpose of the current study was to examine this protocol in pet rabbits, which would be inclusive of varied breeds and ages. Importantly, no significant differences were observed in routine clinical pathology measures. Seroconversion was also observed but was variable, and lower levels of seroconversion were associated with increased age. In general, while variable outcomes to vaccination are expected, these preliminary data underlie the importance of examining the response of pet rabbits to help optimize new vaccine protocols. We propose this will complement traditional vaccine studies, aid in maintaining the health of pet rabbits, and help in the ultimate control of this highly infectious virus. A recombinant vaccine for rabbit hemorrhagic disease virus 2, a highly pathogenic virus, was granted emergency use authorization in the United States after the detection and spread of the virus starting in 2018. The goal of the current study was to assess pet rabbits (n = 29) through physical examination and routine clinical pathology testing using repeated assessments post-vaccination. In addition, seroconversion was also monitored after the initial vaccination and booster vaccination. Neither owners nor clinicians detected any physical abnormalities in relationship to the vaccine protocol. Hematological and clinical biochemistry testing showed some changes although median values were within species specific reference intervals. A significant increase in antibody levels was observed at day 21 (post-initial vaccination) and day 49 (post-booster vaccination) versus that present at baseline (p < 0.0001). However, variability in study rabbits was noted with some individuals showing low antibody levels as well as a lower overall response in older rabbits (r = −0.56, p = 0.006). A second cohort of rabbits was assessed at 11–12 months post-initial vaccination. In this second group, antibody levels were not significantly different from baseline levels (p = 0.21). Additional studies should be conducted to further define the variability in seroconversion and the term of protection in pet rabbits as the industry moves forward in the optimization of RHDV2 vaccines. [ABSTRACT FROM AUTHOR]

Simple Summary: Oregano essential oil has recently garnered attention for its potential health benefits in both humans and animals. In rabbits, it can significantly enhance performance by promoting overall health and well-being. The active compounds in oregano oil, such as carvacrol and thymol, possess antimicrobial, antioxidant, and anti-inflammatory properties, that support the immune system and protect rabbits from diseases. Additionally, oregano essential oil help regulate gut flora, promoting digestion and nutrient absorption, which enhances rabbit performance. However, proper dilution and dosage are crucial to ensure the safety and effectiveness of oregano essential oil in rabbits. With careful consideration and expert guidance, oregano essential oil can be a valuable natural remedy for supporting rabbit health and performance. Antimicrobials long been used to enhance the performance and immunity of rabbits, typically by adding them to feed or drinking water to prevent illness. However, increasing consumer concerns about antibiotic-resistant microorganisms have led to a shift toward natural, eco-friendly, non-antibiotic feed supplements that can improve rabbit health and productivity. Recently, aromatic herbs and their extracts have gained considerable attention as natural antioxidants with growth-promoting and health-boosting properties. Essential oils and secondary metabolites play a central role in these effects, with Origanum vulgare (oregano) emerging as a standout option. Compared to synthetic alternatives, oregano is a natural, residue-free feed supplement with fewer harmful side effects. Its key bioactive components, thymol and carvacrol, have been shown to deliver significant benefits when incorporated into rabbit diets, particularly in improving production performance, immunity, and antioxidant capacity. Supplementing rabbit diets and drinking water with oregano essential oil (OEO) has been found to enhance growth performance, feed efficiency, and meat quality, while also lowering cholesterol levels and boosting antioxidant activity. Despite these promising results, research on the use of oregano in rabbit farming remains limited. This review aims to provide an up-to-date overview of the potential effect of oregano supplements, on growth parameters, carcass and meat quality, hemato-biochemical parameters, antioxidant capacity, immunity response, gut health, and gene expression in rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: Mammary carcinomas have been diagnosed with increasing frequency in pet rabbits. Prognostic biomarkers are limited, and the only available treatment is surgical excision. Additional treatment options are needed, e.g., for animals in which metastases to internal organs preclude complete tumor removal. Human breast cancer may express the immunosuppressive enzyme indoleamine 2,3-dioxygenase 1 (IDO1), that represents a prognostic biomarker and a possible therapeutic target. Since previous studies revealed similarities between human breast cancer and pet rabbit mammary carcinomas, this study investigated IDO1 immunostaining in 96 mammary carcinomas of 96 pet rabbits with an average age of 5.5 years. All rabbits with reported sex were female. Variable percentages of IDO1-positive tumor cells were detected in 90 (94%) carcinomas. Furthermore, IDO1 immunostaining was observed in the secretory epithelial cells of the adjacent non-neoplastic mammary tissue. This study provides further information on the molecular features of mammary carcinomas in rabbits. It also shows similarities in IDO1 expression between rabbit mammary carcinomas and human breast cancer. These findings can have a mutual benefit. They could lead the development of novel treatment options for rabbits with mammary carcinomas. In addition, they further support the value of rabbits with mammary carcinomas for breast cancer research. For mammary carcinomas in pet rabbits, prognostic biomarkers are poorly defined, and treatment is limited to surgical excision. Additional treatment options are needed for rabbit patients for which surgery is not a suitable option. In human breast cancer, the immunosuppressive enzyme indoleamine 2,3-dioxygenase 1 (IDO1) represents a prognostic biomarker and possible therapeutic target. This retrospective immunohistochemical study examined IDO1 in 96 pet rabbit mammary carcinomas with known mitotic count, hormone receptor status, and percentage of stromal tumor infiltrating lymphocytes (TILs). Tumors were obtained from 96 pet rabbits with an average of 5.5 years. All rabbits with reported sex (n = 88) were female or female-spayed. Of the carcinomas, 94% expressed IDO1, and 86% had sparse TILs consistent with cold tumors. Statistically significant correlations existed between a higher percentage of IDO1-positive tumor cells, lower mitotic counts, and increased estrogen receptor expression. The threshold for significance was IDO1 staining in >10% of tumor cells. These results lead to the assumption that IDO1 expression contributes to tumorigenesis and may represent a prognostic biomarker and possible therapeutic target also in pet rabbit mammary carcinomas. They also support the value of rabbits for breast cancer research. [ABSTRACT FROM AUTHOR]

Simple Summary: The study focuses on the shadow of prion protein (Sho) encoded by the shadow of prion protein gene (SPRN), which associates with PrP and promotes the progression of prion diseases. While genetic polymorphisms in SPRN are linked to susceptibility in several species, rabbit SPRN gene polymorphisms have not been extensively studied. Through amplicon sequencing, we identified novel single nucleotide polymorphisms (SNPs) in the rabbit SPRN gene and found strong linkage disequilibrium (LD) between them. However, strong LD was not observed between polymorphisms in the prion protein gene (PRNP) and SPRN genes in rabbits. Comparison of amino acid sequences revealed differences in SPRN between rabbits and other species susceptible or resistant to prion diseases. This study represents the first examination of genetic features of the rabbit SPRN gene. Prion disorders are fatal infectious diseases that are caused by a buildup of pathogenic prion protein (PrPSc) in susceptible mammals. According to new findings, the shadow of prion protein (Sho) encoded by the shadow of prion protein gene (SPRN) is associated with prion protein (PrP), promoting the progression of prion diseases. Although genetic polymorphisms in SPRN are associated with susceptibility to several prion diseases, genetic polymorphisms in the rabbit SPRN gene have not been investigated in depth. We discovered two novel single nucleotide polymorphisms (SNPs) in the leporine SPRN gene on chromosome 18 and found strong linkage disequilibrium (LD) between them. Additionally, strong LD was not found between the polymorphisms of PRNP and SPRN genes in rabbits. Furthermore, nonsynonymous SNPs that alter the amino acid sequences within the open reading frame (ORF) of SPRN have been observed in prion disease-susceptible animals, but this is the first report in rabbits. As far as we are aware, this study represents the first examination of the genetic features of the rabbit SPRN gene. [ABSTRACT FROM AUTHOR]

Simple Summary: In recent years, research has shown that animals' gut microbiota can regulate various physiological functions such as nutrition, metabolism, and immunity, and play an indispensable role in maintaining host gut health. At present, there are few reports on the establishment of rabbits' gut microbiota and its relationship with the host. To clarify the colonization of rabbits' gut microbiota, the changes in species during development, and the relationship between gut microbiota and rabbits' growth and development, this study determined the 16s rRNA of gut microbiota in rabbits of different age groups and preliminarily explored the changes in the types of gut microbiota during the colonization process. Six amplicon sequence variants (ASVs) that significantly affect body weight were obtained. The research results provide a firm theoretical basis for maintaining gut health and constructing new methods for rabbit breeding. This study used feces from 0-day-old (36 rabbits), 10-day-old (119 rabbits), and 60-day-old (119 rabbits) offspring rabbits and their corresponding female rabbits (36 rabbits) as experimental materials. Using 16s rRNA sequencing, the study analyzed the types and changes of gut microbiota in rabbits at different growth and development stages, as well as the correlation between gut microbiota composition and the weight of 60-day-old rabbits. All experimental rabbits were placed in the same rabbit shed. Juvenile rabbits were fed solid feed at 18 days of age and weaned at 35 days of age. In addition to identifying the dominant bacterial phyla of gut microbiota in rabbits at different age stages, it was found that the abundance of Clostridium tertium and Clostridium paraputrificum in all suckling rabbits (10-day-old) was significantly higher than that in rabbits fed with whole feed (60-day-old) (p < 0.05), while the abundance of Gram-negative bacterium cTPY13 was significantly lower (p < 0.05). In addition, Fast Expected Maximum Microbial Source Tracing (FEAST) analysis showed that the contribution of female rabbits' gut microbiota to the colonization of offspring rabbits' gut microbiota was significantly higher than that of unrelated rabbits' gut microbiota (p < 0.05). The contribution of female rabbits' gut microbiota to the colonization of gut microbiota in 0-day-old rabbits was significantly higher than that to the colonization of gut microbiota in the 10- and 60-day-old rabbits (p < 0.05). Finally, the correlation between gut microbiota composition and body weight of 60-day-old rabbits was analyzed based on a mixed linear model, and six ASVs significantly affecting body weight were screened. The above results provide important theoretical and practical guidance for maintaining gut health, improving growth and development performance, and feeding formulation in rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: The aim of this study is to provide information about the Pasteurella multocida strains that are responsible for pasteurellosis in rabbits. A total of 114 strains responsible for different lesions in rabbits from industrial farms were investigated. In detail, the serogroup belonging to and the presence of 15 virulence-associated genes were investigated using PCR (polymerase chain reaction) protocols. The tested strains belonged to serogroups A, D, and F. Type A was the most frequently identified and it was prevalently found in strains responsible for rhinitis and pneumonia. Type D was the prevalent capsular type of strains responsible for metritis, while F was identified in strains detected from otitis, mastitis, subcutaneous abscesses, and septicaemia. Among the virulence-associated genes, sodC was found in all tested strains. Gene pfhA was more frequently found in strains belonging to type A than in type D and it was prevalently found in strains responsible for respiratory lesions. In addition, it was found in all F strains, suggesting a strong relationship between pfhA and this capsular type. Conversely, gene tadD was rarely found in strains belonging to capsular type F. Gene fur occurred more frequently in strains belonging to type D and involved with rhinitis. Gene hgbB was detected prevalently in strains responsible for metritis. Additionally, based on the results, the presence of more than 8 virulence-associated genes in the strains seems to increase the risk of the occurrence of severe lesions in the affected rabbits. Nevertheless, the detection of some strains responsible only for rhinitis which were equipped with 10 and 11 virulence-associated genes, seems to emphasise the importance of a gene's expression rather than its presence in strains. Pasteurellosis, a disease caused by Pasteurella multocida, is responsible for economic losses in rabbit industrial farms due to rhinitis, conjunctivitis, pneumonia, metritis, mastitis, orchitis, subcutaneous abscesses, otitis, encephalitis, and septicaemic forms. Although the occurrence of the disease is conditioned by predisposing factors that affect the rabbit immune response, the strains of P. multocida involved in the infection may have a different pathogenic ability. Therefore, typing of strains spread among the rabbits is important to assess their pathogenic potential. The aim of this study is to investigate the P. multocida strains responsible for disease in rabbit industrial farms. A total of 114 strains identified from different lesions were serotyped. Additionally, the presence of virulence-associated genes was investigated using three PCR (polymerase chain reaction) protocols. Capsular type A was prevalently found in strains from respiratory lesions while types D and F in those from metritis, mastitis, and other lesions. Different associations between some virulence-associated genes and both capsular type and lesions found in rabbits were detected. The presence of 8 virulence-associated genes seems to increase the occurrence of metritis. In addition, strains belonging to capsular type A and responsible for respiratory disorders especially, were found equipped with 10 and 11 virulence-associated genes. Nevertheless, the presence of strains responsible only for rhinitis was also detected among the latter, suggesting that the pathogenic ability of the bacteria depends on the expression rather than the presence of a gene. [ABSTRACT FROM AUTHOR]

Simple Summary: Domestic rabbits are one of the most commonly kept pets with a hypselodontic type of dentition, possessing teeth that grow throughout the animal's life. These animals often show signs of disease in the stomatognathic system. Dental disease can also affect the function of other organs and systems. The most common clinical signs of dental disease in domestic rabbits are the following: lack of appetite, weight loss, apathy, and difficulty chewing and swallowing food. These clinical signs are non-specific, and, therefore, a definitive diagnosis usually requires additional methods, such as an X-ray examination, a CT scan, MRI, and endoscopic examination. The most common dental disease found in this study's animals was malocclusion secondary to abnormal clinical crown abrasion and abnormal tooth growth. In domestic rabbits, osteomyelitis is a common complication of dental abscesses. Computed tomography is an invaluable diagnostic method in the diagnosis of dental disease and secondary diseases of the head area, such as inflammation of the nasal cavities or otitis media, in pet rabbits. Domestic rabbits have teeth that grow throughout the animal's life and are prone to disease. Clinical signs of dental disease in domestic rabbits are non-specific, and, therefore, a definitive diagnosis usually requires additional methods. This study was carried out on a group of 105 domestic rabbits aged 3 to 9 years. In total, 90 domestic rabbits with dental disease visible on CT images and other secondary diseases of the head area qualified for this study. Malocclusion was found in 57 (63.3%). Retrograde elongation of the tooth apices in the mandible was present in 39 (43.3%), and it was present in the maxilla in 48 (53%). Clinical tooth crowns were overgrown in 39 (43%). Dental abscesses were present in 54 (63%). Secondary to the presence of a dental abscess, osteomyelitis was found in 43 (79% of the animals with a dental abscess). Dental inflammatory resorption was found in 36 (40%). Secondary to dental disease, nasal cavity inflammation was found in 18 (20%). Otitis media was present in six (6.7%). The most common dental disease found in this study's animals was malocclusion secondary to abnormal clinical crown abrasion and abnormal tooth growth. In domestic rabbits, osteomyelitis is a common complication of dental abscesses. Computed tomography is an invaluable diagnostic method in the diagnosis of dental disease and secondary diseases of the head area, such as inflammation of the nasal cavities or otitis media, in pet rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: Rabbits' participation in Animal-Assisted Interventions is increasing. Rabbits are loveable animals, their handling is quick to learn, their body language is simple to read and they can be easily transported into several institutions from kindergarten to palliative care homes. While the positive impact of interventions on humans is indisputable, there is little available information about the effects on animals themselves. Regularly transporting the rabbits to the place of the intervention can be a source of stress, but we assume that they can be trained, and animals can get used to it by offering feed (hay, carrot and apple) and providing appropriate circumstances. Cortisol hormone secretion is initiated as the response to stress and metabolites of cortisol can be isolated in feces samples by laboratory analysis. Using this method we can obtain adequate information about the experienced stress caused the transportation, without disturbing the animals. According to our results, based on the laboratory analysis, repeated transportation causes a significant rise in stress hormone metabolite levels in feces samples regardless of the offered treats during the transport. Those owners who use rabbits for Animal-Assisted Intervention purposes need to take into account that transportation itself is a stressful experience for the animals. (1) Background: the popularity of rabbits has increased during the last decade and become the third most common companion animal in the EU. Rabbits' participation in Animal-Assisted Interventions (AAIs) is growing. It is highly important to ensure the well-being of the animals in AAIs. Whereas the needs and the advantages of people involved in AAI are becoming more and more evident, the needs of animals are not clearly defined, therefore, it is a great field of inquiry. Animals who are used for AAI need to be transported regularly, which itself might be a source of stress. (2) Methods: the stress of rabbits—caused by transportation—was measured in a non-invasive way: cortisol levels were determined from feces, based on their breakdown products. Eighteen animals were involved in the study. Rabbits experienced a 30 min transportation every second day for two weeks (altogether six times) while 126 samples were collected. (3) Results: rabbits could handle the transportation procedure the first time but subsequently the stress hormone metabolites in feces samples increased regardless of the offered treatments (hay, carrot and apple) during the carriage. (4) Conclusions: those owners who use rabbits for Animal-Assisted Interventions need to take into account that transportation itself is a stressful experience for the animals. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, multi-omics techniques were used to reveal the effects of actual temperature and humidity index (THI) on intestinal microbe, function and serum metabolism of Ira rabbits. The increase of THI had a significant effect on the intestinal microbial structure of meat rabbits. In response to environmental THI changes, intestinal microorganisms with similar functions were replaced with each other, harmful bacteria were increased, heat-sensitive factors were upregulated, and disease-related biomarkers were increased in serum. In addition, the potential biomarkers of serum metabolism could be predicted with high predictive accuracy. In future production, the rapid detection of biomarkers, which has guiding significance for scientific meat rabbit production, can be attempted to determine whether the use of THI in the small environments of meat rabbits is suitable. This study investigates the effects of different THI values on growth performance, intestinal microbes, and serum metabolism in meat rabbits. The results showed that there were significant differences in THI in different location regions of the rabbit house. The high-THI group (HG) could significantly reduce average daily gain and average daily feed intake in Ira rabbits (p < 0.05). The low-THI group (LG) significantly increased the relative abundance of Blautia (p < 0.05). The HG significantly increased the relative abundance of Lachnospiraceae NK4A136 group and reduced bacterial community interaction (p < 0.05). The cytokine–cytokine receptor interactions, nuclear factor kappa B signaling pathway, and toll-like receptor signaling pathway in each rabbit's gut were activated when the THI was 26.14 (p < 0.05). Metabolic pathways such as the phenylalanine, tyrosine, and tryptophan biosynthesis and phenylalanine metabolisms were activated when the THI was 27.25 (p < 0.05). Meanwhile, the TRPV3 and NGF genes that were associated with heat sensitivity were significantly upregulated (p < 0.05). In addition, five metabolites were found to be able to predict THI levels in the environment with an accuracy of 91.7%. In summary, a THI of 26.14 is more suitable for the growth of meat rabbits than a THI of 27.25, providing a reference for the efficient feeding of meat rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: Vitamin D is an important hormone that can be acquired through diet or exposure to ultraviolet B (UVB) radiation. Few studies have evaluated the effects of UVB radiation on vitamin D concentrations in the domestic rabbit (Oryctolagus cuniculus); however, initial findings have found they can increase their serum 25-hydroxyvitamin D3 (25-OHD3) following 12 h of artificial UVB exposure. Current husbandry recommendations for rabbits do not include specific UVB lighting requirements. Rabbits are a common pet and research model and are frequently housed indoors without access to natural UVB lighting. Rabbits that are chronically vitamin D deficient may develop mineral deficiencies that can lead to poor calcification of the teeth and skull, predisposing these animals to dental abnormalities, bone infections, and other debilitating diseases. While initial results suggest artificial UVB is positive for rabbits, UVB can also be detrimental to the health of vertebrates. The aim of this study was to determine if shorter-duration UVB exposure could also increase 25-OHD3 concentrations. Rabbits were provided 6 h of artificial UVB daily for 14 days, and there was a significant increase in 25-OHD3 concentrations over time. These findings affirm that rabbits can use short-duration artificial UVB to increase 25-OHD3 concentrations. Vitamin D is an important hormone that can be acquired through diet, exposure to ultraviolet B (UVB) radiation, or a combination of these methods. In domestic rabbits (Oryctolagus cuniculus), both methods appear viable, but there is limited research evaluating the effects of UVB on this species. Previous studies found that 12 h of artificial UVB radiation significantly increased 25-hydroxyvitamin D3 (25-OHD3) concentrations over time. While these findings suggest UVB can be beneficial in rabbits, this form of radiation can also be detrimental to vertebrates. The purpose of this study was to determine if shorter-duration UVB could elicit a similar physiological response in rabbits while minimizing potential negative effects. Six rabbits were used for this pilot study. The baseline serum 25-OHD3 was measured for each rabbit and following 14 days of 6 h/day exposure to artificial UVB, a second 25-OHD3 sample was collected. There was a significant increase (p = 0.001) in serum 25-OHD3 over time (Baseline: 27.7 ± 8.1 nmol/L; Day 14: 79.8 ± 9 nmol/L). This study affirmed that 6 h of UVB produced 25-OHD3 concentrations similar to those found in rabbits exposed to 12 h of UVB. Future studies should continue to determine how the duration of UVB exposure affects 25-OHD3 concentrations. [ABSTRACT FROM AUTHOR]

Simple Summary: There has been an increase in domestic rabbit ownership in the recent years. The type of dentition of this exotic (non-traditional) animal pet, predisposes it to the development of Acquired Dental Disease (ADD), a disease that affects tooth quality, generates malocclusion, among other dental and non-dental consequences. The aim of this study was to assess the factors that modify the risk for ADD in domestic pet rabbits. For this, 1420 owned rabbits' clinical records from a private practice from 2018 to 2021 were used, recording several variables, including the clinical signs at diagnosis. ADD was detected in 25.4% of the individuals, mostly on their cheek teeth. In addition, age and sex (male) were found to be significant risk factors for ADD. In contrast, a free lifestyle and consuming hay in the diet were protective factors. Understanding the factors that modify the risk of ADD increases the chances of prevention and helps to improve the education of owners and/or guardians of domestic rabbits. Rabbits (Oryctolagus cuniculus) have elodont dentition, a characteristic that predisposes them to the development of Acquired Dental Disease (ADD), which is a multifactorial disease. The aim of this study was to assess the risk factors for ADD in domestic pet rabbits. To do this, a retrospective analysis of 1420 rabbits treated at a private practice during 2018–2021 was performed. For this, several variables were retrieved from clinical records, in addition to signology at the time of diagnosis. ADD was found on 25.4% of rabbits, mostly on their cheek teeth. In addition, age (OR = 1.029; 95% CI = 1.023–1.035; p < 0.001) and sex (male) (OR = 1.591; 95% CI = 1.226–2.064; p < 0.001) were found to be significant risk factors for ADD. In contrast, a free lifestyle (OR = 0.565; 95% CI = 0.362–0.882; p = 0.012) and consuming hay in the diet (OR = 0.323; 95% CI = 0.220–0.473; p < 0.001) were protective factors. In conclusion, ADD has a high prevalence and is usually underdiagnosed, highlighting the need for an exhaustive evaluation of patients during the clinical examination. This study improves our knowledge of ADD and its prevention. [ABSTRACT FROM AUTHOR]

Simple Summary: In rabbits, milk is the primary source of nutrition from early growth to weaning. The ability of the mother rabbit to produce milk, which is also influenced by the maternal genotype, is particularly important in the case of the larger litters. The hormone prolactin is responsible for the initiation and maintenance of lactation and for the synthesis of the major components of milk. Prolactin acts through membrane receptors in target tissues. Point mutations and microsatellites in receptor genes can affect production characteristics. Our aim was to examine the prolactin receptor gene in a wild rabbit (Oryctolagus cuniculus) population with a diverse genetic background. Our hypothesis was that the detected polymorphisms could be associated with milk production. By sequencing the promoter region of the PRLR gene, we detected four point mutations and one microsatellite. Among the genotypes of point mutations in the regulatory region of the PRLR gene, the homozygous genotype and the short repeat of the microsatellite resulted in higher milk production. These could be potential marker candidates for the development of marker-assisted selection. One of the problematic points of rabbit breeding is that the nutritional requirements of the kits are not fully satisfied by the does' milk production from the third week of lactation onwards. The prolactin receptor gene has a significant effect on reproductive processes, and its polymorphisms have been associated with milk production in several species (cattle, goats, sheep, and buffalo). The European wild rabbit (Oryctolagus cuniculus), has a more diverse genetic background compared to domesticated lines. In the course of our study, sequencing of the 1210 bp long segment of the PRLR gene promoter region was accomplished. We detected four point mutations (SNP1-407G > A, SNP2-496G > C, SNP3-926T> and SNP4-973A > C) and one microsatellite at position 574. In our population, the four SNPs were segregated into four genotypes: AACCCCCC, GGGGTTAA, AAGGTTAC, and GGGGTCAC. Our results show that the genotype in the homozygous form is associated with higher milk production (1564.7 ± 444.7 g) compared to the other three genotypes (AACCCCCC 1399.1 ± 326.8 g; GTGACCTT 1403.8 ± 517.1 g; GGGGTCAC 1220.0 ± 666.2 g), and the short microsatellite repeat (167 bp) also coincides with significantly higher milk production (1623.8 ± 525.1 g). These results make the marker-assisted selection possible also for domesticated lines. [ABSTRACT FROM AUTHOR]

Simple Summary: China is not only a huge meat rabbit consumer but also the largest meat rabbit producer in the world, contributing a large amount of rabbit meat products to the domestic and foreign markets every year. Therefore, it is important for the domestic and international rabbit meat market to improve rabbit breeding production efficiency and rabbit meat quality based on the good use of domestic feed resources in China. It is well known that dietary amino acid nutrition is of great importance to animal growth. Lysine and methionine are limited in the common domestic rabbit feed sources in China, but they play an important role in rabbit growth. Moreover, different lysine and methionine compositions of the diets respond differently to rabbit growth. Consequently, the search for a better composition of dietary lysine and methionine is the main objective of this study. In recent years, ensuring food security has been an important challenge for the world. It is important to make good use of China's domestic local feed resources to provide safe, stable, efficient, and high-quality rabbit meat products for China and the world. Lysine and methionine are the two most limiting essential amino acids in the rabbit diet. However, little is known about the rational composition of lysine and methionine in rabbit diets and the mechanisms that affect growth and development. Accordingly, in this study, we sought to address this knowledge gap by examining the effects of different compositions of lysine and methionine in rabbit diets. Subsequently, the growth status, nitrogen metabolism, blood biochemical indexes, muscle development, muscle quality, and the growth of satellite cells were evaluated in the animals. The results showed that diets containing 0.80% Lys and 0.40% Met improved average daily weight gain, feed conversion, nitrogen use efficiency, and muscle quality in the rabbits (p < 0.05). Additionally, it altered the amino acid transport potential in muscle by upregulating the expression of the SLC7A10 gene (p < 0.05). Meanwhile, the cell viability and the rate of division and migration of SCs in the 0.80% Lys/0.40 % Met composition group were increased (p < 0.05). SLC38A2 and P–mTOR protein expression was upregulated in the 0.80% lysine/0.40% methionine composition group (p < 0.05). In conclusion, 0.80% Lys/0.40% Met was the most suitable lysine and methionine composition in all tested diets. SLC38A2 acted as an amino acid sensor upstream of mTOR and was involved in the 0.80% Lys/0.40% Met regulation of muscle growth and development, thus implicating the mTOR signaling pathway in these processes. [ABSTRACT FROM AUTHOR]

Simple Summary: The high incidence of stress-associated diseases post rabbit weaning results in great losses threatening the rabbit industry. The increasing emergence of multidrug resistant (MDR) methicillin-resistant Staphylococcus aureus (MRSA) causes life threatening infections worldwide. Thus, the necessity to look inward for natural alternative treatments is now compelling. In this perspective, Nigella sativa extract (NSE) could serve as an effective antibiotic alternate source against MRSA. Herein, NSE was found to possess iin vitro antimicrobial activities against MRSA clinical isolates. Moreover, the synergistic activity between NSE and other antimicrobials was employed to overcome the MRSA resistance. Our findings added new insights for application of NSE in diets of growing rabbits as a growth promoting and an immunostimulant agent, which in turn reduced the high risk associated MRSA infections in growing rabbits. Weaning is the most crucial period associated with increased stress and susceptibility to diseases in rabbits. Methicillin-resistant Staphylococcus aureus (MRSA), a historic emergent pathogen related to post weaning stressors, adversely affects rabbit's growth rate and productive cycle. Since MRSA is rapidly evolving antibiotics resistance, natural products are desperately required to tackle the public health threats posed by antimicrobial resistance. Thus, this study aimed to screen the iin vitro antibacterial activity of Nigella sativa extract (NSE) and its interactions with antibiotics against MRSA isolates. Moreover, 200 weaned rabbits were divided into 4 groups to investigate the iin vivo superiority of NSE graded levels towards growth performance, tight junction integrity, immune responsiveness and resistance against MRSA. Herein, NSE showed promising antimicrobial activities against MRSA isolates from animal (77.8%) and human (64.3%) origins. Additionally, MRSA isolates exposed to NSE became sensitive to all antimicrobials to which they were previously resistant. Our results described that the growth-promoting functions of NSE, especially at higher levels, were supported by elevated activities of digestive linked enzymes. Post-NSE feeding, rabbits' sera mediated bactericidal activities against MRSA. Notably, upregulated expression of occludin, CLDN-1, MUC-2 and JAM-2 genes was noted post NSE supplementation with maximum transcriptional levels in 500 mg/kg NSE fed group. Our data described that NSE constitutively motivated rabbits' immune responses and protected them against MRSA-induced experimental infection. Our results suggest the antimicrobial, growth stimulating and immunomodulation activities of NSE to maximize the capability of rabbits for disease response. [ABSTRACT FROM AUTHOR]

Simple Summary: This work aims to address the use of biomarkers that can provide us with information on the previous nutrition levels of wild rabbits, a keystone species that has drastically reduced in the last few years. Non-esterified fatty acids (NEFA), plasmatic urea nitrogen (PUN), albumin, glutamate and total protein metabolites were analysed. Additionally, we examined the potential of these metabolites as biomarkers for the nutritional and conservation status of European rabbits to further the biological knowledge of this species and contribute to its conservation. European wild rabbit (Oryctolagus cuniculus) populations have drastically reduced, and recently, rabbits have been classed as "endangered" by the IUCN. This animal plays an important ecological role in Mediterranean ecosystems and its introduction could significantly contribute to ecological restoration. Rabbits have high nutrient requirements that apparently cannot be covered in all ecosystems, and there are clues that nutrition can limit their abundance and density. On the other hand, some studies reflect the effects of food availability on the metabolomic status of other animal species, but there are no specific studies on this keystone species. The main aim of this work is to find biomarkers to assess the previous levels of ingestion of European rabbits (Oryctolagus cuniculus). To address this gap, gastric content and blood samples were collected from European rabbits (n = 99) in a Mediterranean area for the analysis of glucose, non-esterified fatty acids (NEFA), plasmatic urea nitrogen (PUN), albumin, glutamate and total protein metabolites. Depending on their previous feed intake (gastric content and the ratio between the gastric content and the weight of the animal), the animals were divided into two groups (lower and normal previous feed intake). Our work shows that the metabolomic profiles of the animals were affected. Levels of glucose (+82%; p = 0.0003), NEFA (−61%; p = 0.0040) and PUN (+139%; p < 0.001) were different in the animals with lower previous feed intake than the animals with normal previous feed intake. This work summarises that metabolic phenotype can be interesting when seeking to discover the limiting nutrients and food availability in diets that could affect the ecological fitness and conservation of European wild rabbits. It is important to mention that in this work, only the effects on six different metabolites have been analysed and more studies are necessary to complement the knowledge of possible metabolites that indicate the level of ingestion in this species and others. These (and new) biomarkers could be used as a tool to provide information about individual or population characteristics that other physiological parameters cannot detect, improving the conservation physiology field. [ABSTRACT FROM AUTHOR]

Simple Summary: Weaning is a crucial period associated with great stress and susceptibility to infection, implying adverse impacts on farmed rabbits' production. Recently, probiotics have been provided as direct microbial feed supplements, which are considered the ideal antibiotic substitutes during pathogenic infections with an emphasis on promoting rabbits' growth and modulating their immune functions. Therefore, our experiment was carried out to explore the efficacy of multi-strain probiotics (MSP) on rabbits' growth, molecular aspects, such as nutrients transporters, cytokines, and intestinal integrity, and effectiveness against Listeria monocytogenes (L. monocytogenes) infection. Altogether, our findings proposed the beneficial consequences of MSP on rabbits' growth, gut health, and immunity. After post-experimental infection of rabbits with L. monocytogenes, administration of MSP during the whole rearing period greatly reduced the detrimental impact of infection and consequently renovated efficient rabbits' production. Multi-strain probiotics (MSP) are considered innovative antibiotics' substitutes supporting superior gut health and immunity of farmed rabbits. The promising roles of MSP on performance, intestinal immunity, integrity and transporters, and resistance against Listeria monocytogenes (L. monocytogenes) were evaluated. In the feeding trial, 220 rabbits were fed a control diet or diet supplemented with three MSP graded levels. At 60 days of age, rabbits were experimentally infected with L. monocytogenes and the positive control, enrofloxacin, prophylactic MSP (MSPP), and prophylactic and therapeutic MSP (MSPTT) groups were included. During the growing period, MSP at the level of 1 × 108 CFU/kg diet (MSPIII) promoted the rabbits' growth, upregulated the nutrient transporters and tight-junction-related genes, and modified cytokines expression. Supplementing MSPTT for L. monocytogenes experimentally-infected rabbits restored the impaired growth and intestinal barriers, reduced clinical signs of severity and mortalities, and attenuated the excessive inflammatory reactions. Notably, enrofloxacin decreased L. monocytogenes and beneficial microbial loads; unlike MSPTT, which decreased pathogenic bacterial loads and sustained the beneficial ones. Histopathological changes were greatly reduced in MSPTT, confirming its promising role in restricting L. monocytogenes translocation to different organs. Therefore, our results suggest the use of MSPTT as an alternative to antibiotics, thereby conferring protection for rabbits against L. monocytogenes infection. [ABSTRACT FROM AUTHOR]

Simple Summary: Rabbit breeding is an important branch of agricultural animal breeding; their fur color and weight are desirable traits for artificial breeding. Polymorphism can provide potential molecular markers for studying rabbit traits and improve rabbit breeds with such markers in the future. In this study, single-nucleotide polymorphism markers in genotyping-by-sequencing data were used to analyze rabbit traits. In total, three genes were identified to be associated with fur color and four with weight. The results of this study provide a data base for the research and improvement of rabbit breeding program. The domestic rabbit (Oryctolagus cuniculus f. domesticus) is a very important variety in biomedical research and agricultural animal breeding. Due to the different geographical areas in which rabbit breeds originated, and the long history of domestication/artificial breeding, rabbits have experienced strong selection pressure, which has shaped many traits of most rabbit varieties, such as color and weight. An efficient genome-wide single-nucleotide polymorphism (SNP) detection strategy is genotyping-by-sequencing (GBS), which has been widely used in many organisms. This study attempted to explore bi-allelic SNPs associated with fur color and weight-related traits using GBS in five rabbit breeds. The data consisted of a total 831,035 SNPs in 150 individuals from Californian rabbits (CF), German Zika rabbits (ZK), Qixing rabbits (QX), Sichuan grey rabbits (SG), and Sichuan white rabbits (SW). In addition, these five breeds of rabbits were obviously independent populations, with high genetic differentiation among breeds and low genetic diversity within breeds. A total of 32,144 SNP sites were identified by selective sweep among the different varieties. The genes that carried SNP loci in these selected regions were related to important traits (fur color and weight) and signal pathways, such as the MAPK/ERK signaling pathway and the Hippo signaling pathway. In addition, genes related to fur color and weight were identified, such as ASIPs, MITFs and KITs, ADCY3s, YAPs, FASs, and ACSL5s, and they had more SNP sites. The research offers the foundation for further exploration of molecular genetic markers of SNPs that are related to traits. [ABSTRACT FROM AUTHOR]

Simple Summary: Sarcoptic mange is a common rabbit disease that can be spread directly from sick to healthy rabbits. Infection in rabbits causes intense pruritus, head shaking, and scabby lesions on the inner side of the pinnae and on the external ear canal, as well as diminished growth performance and an increased rate of oxidative stress. Ivermectin has been shown to be an effective treatment for sarcoptic mange in rabbits; however, it has side effects on their performance. Botanicals such as turmeric extract have a remarkable antioxidant potential contributing to the deterrence of Sarcoptes-induced oxidative discrepancy in rabbits. The goal of this study was to investigate if turmeric extract can alleviate side effects in Ivermectin-treated rabbits while simultaneously improving their performance and antioxidant status. The results indicated that turmeric extract was utilized with varied efficacy against mites, and also helped rabbits recover faster and improved Ivermectin's miticidal efficacy by improving performance and compromised immunity. Turmeric extract has strong antioxidant properties, suggesting that it could be used as an adjunctive remedy to reduce the side effects of Ivermectin while treating clinical rabbit sarcoptic mange. Furthermore, no adverse effects were observed in turmeric extract adjunctively supplemented rabbits, and the provided dose regimen of these supplements was found to be safe. In this experiment, the protective effect of turmeric extract (TE) on side effects of Ivermectin-treated rabbits, while improving their performance, blood characteristics, and antioxidant status, was investigated. Sixty-three clinically Sarcoptes-infested rabbits aged 60 days were randomly allocated into three groups, with 21 rabbits in each group, to receive either no TE or TE supplementation (1 or 2 mg/kg diet) for 30 days after being subcutaneously injected with Ivermectin (IVM) 1% w/v at a dose of 0.2 mg/kg body weight twice a week. Another 21 healthy rabbits were used as the control. Treatment with IVM + 1 and 2 mg TE improved body weight (BW), body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) in infested rabbits (p < 0.05). The IVM alone treatment had the highest mortality rate compared with the other treatments. Rabbits treated with IVM + 1 and 2 mg TE demonstrated progressive recovery manifested by improved nutrient digestibility and nitrogen balance. On day 7, the serum total protein, albumin, and albumin/globulin (A/G) ratio were significantly lower in the treated groups compared with the control group; also, the lowest values were observed in rabbits treated only with Ivermectin, followed by IVM + 1 and 2 mg TE. Treated rabbits had higher thiobarbituric acid reactive substance (TBAR) levels, but lower total antioxidant capacity (TAC), superoxidase dismutase (SOD), and glutathion peroxidase (GSH-Px) levels compared with the control group. On day 30 post-treatment, the rabbits in the IVM + 1 and 2 mg TE treatment groups showed progressive recovery manifested by improved biochemichal parameters, as well as a remarkable improvements in the oxidant/antioxidant balance towards normalcy (p < 0.05), and became comparable to that of the control compared with IVM alone treatment. In conclusion, turmeric extract improved rabbits' performance toward normalcy, and has remarkable antioxidant properties and can be used in conjunction with a miticide to treat sarcoptic mange in rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: The commercial canine ehrlichiosis vaccine is still not available. A limitation of developing vaccines is the knowledge of the humoral immune response against E. canis infection is still unknown. In this study, we designed the peptide vaccine candidate, namely GP194-43, for inducing hyperimmune serum in rabbits. The rabbit sera were used to examine for E. canis infective inhibition in macrophage-like cells (DH82). A decrease in E. canis infection (<50% of infection) was observed on DH82 cells in the treated group with GP194-43 antiserum on the third day of the post-infection period. Cytokine genes in DH82 with/without rabbit sera were investigated and showed marked up-regulation of the IFNG expression level in DH82 cells in the treated group with GP194-43 antiserum. This study provides the preliminary information of immune response against E. canis of immunized animals and directions for genomic or/and proteomic studies involved in phagocyte-cell mediated immune response. In terms of its veterinary importance, vaccine development against Ehrlichia canis is needed. However, the effect of developing vaccines on humoral immune response against E. canis infection is still unknown. Novel GP194-43 was synthesized according to E. canis GP19 epitope prediction. To restrict any loss and/or illness in the host animal, rabbits were used in this study to produce GP194-43 hyperimmune sera. The effect of GP194-43 hyperimmune sera on neutralization was examined in vitro by determining the inhibition of E. canis infection of the macrophage-like cell line (DH82) in the presence of the sera. Four groups of DH82 cells received differing treatments. These included E. canis experimentally infected DH82 cells, E. canis-infected DH82 cells with control rabbit serum (untreated group), E. canis-infected DH82 cells with GP194-43 rabbit antiserum (treated group) and uninfected cells (negative control group), respectively. The treated group developed a decrease (p < 0.01) in the percentage of E. canis infected cells after 3 days post-infection at 48.57 ± 1.28. In addition, real-time PCR analyses of cytokine mRNA expression involved with the macrophage, humoral, and cellular immune responses were conducted. The findings revealed an upregulated expression of IFNG in the treated group during the infection. This study demonstrated neutralization in the GP194-43 peptide hyperimmune sera of immunized rabbits. Notably, IFN-γ production could be effectively promoted in canine macrophages in relation to the activation of macrophages and adaptive immune responses. The results of this study indicate the potential for the use of this immunogen in further investigations involving immunized and infected dogs as E. canis host species. [ABSTRACT FROM AUTHOR]

Simple Summary: Veterinary inspection at the slaughterhouse plays an important role in the surveillance system for animal health and welfare. The study focused on the quantification and identification of pathological findings in rabbits slaughtered at the slaughterhouses in the Czech Republic in the period from 2010 to 2019. The ratio of the number of pathological findings to the total number of rabbits slaughtered was 0.0214, i.e., for every hundred rabbits, 2.14 findings were made documenting the impairment of health and/or welfare to an extent leading to pathological changes detected during the post-mortem inspection of the rabbits at the slaughterhouse. The pathological findings that occurred most often were those on the limbs (0.84%), trunk (0.71%), kidneys (0.17%), and liver (0.05%), along with generalized changes (0.37%). The results show that findings on the limbs and trunk were dominated by findings of traumatic origin. Findings in the kidneys and liver were most often of a chronic nature. Findings of abscesses were most frequent among generalized findings. The aim of the study was to assess post-mortem findings according to their localization and the nature of damage and to assess the standard of health and welfare of farmed rabbits on the basis of these findings. A total of 40,206 pathological findings were recorded in 1,876,929 rabbits slaughtered at slaughterhouses in the Czech Republic in the period from 2010 to 2019. Pathological findings on the limbs (0.84%), the trunk (0.71%), the kidneys (0.17%), and the liver (0.05%), along with generalized changes (0.37%), occurred most frequently. Findings of traumatic origin dominated among findings on the limbs and trunk, which indicates the inappropriate housing and handling rabbits on farms and during transport. Findings in the kidneys and liver were most often of a chronic nature having an evident correlation with the diet of intensively fed rabbits, with shortcomings in the diet having an impact on the parenchyma with chronic manifestations in the liver and kidneys. Among the generalized findings, multiple abscesses, which were probably associated with the infection of injuries occurring during fattening, and emaciation resulting from current husbandry practices, leading to insufficient feed intake or the development of disease in some individuals, predominated. [ABSTRACT FROM AUTHOR]

Simple Summary: Coat color is an important breed characteristic and economic trait for rabbits, and it is regulated by a few genes. In this study, the gene frequencies of some pigmentation genes were investigated in four Chinese native rabbit breeds with different coat colors. A total of 14 genetic variants were detected in the gene fragments of MC1R, MITF, TYR, TYRP1, and MLPH genes, and there was low-to-moderate polymorphism in the populations. The gene frequency showed significant differences among the four rabbit populations. The above results suggest that these genetic variations play an important role in regulating the coat color of rabbits. This study will provide potential molecular markers for the breeding of coat color traits in rabbits. Pigmentation genes such as MC1R, MITF, TYR, TYRP1, and MLPH play a major role in rabbit coat color. To understand the genotypic profile underlying coat color in indigenous Chinese rabbit breeds, portions of the above-mentioned genes were amplified and variations in them were analyzed by DNA sequencing. Based on the analysis of 24 Tianfu black rabbits, 24 Sichuan white rabbits, 24 Sichuan gray rabbits, and 24 Fujian yellow rabbits, two indels in MC1R, three SNPs in MITF, five SNPs (single nucleotide polymorphisms) in TYR, one SNP in TYRP1, and three SNPs in MLPH were discovered. These variations have low-to-moderate polymorphism, and there are significant differences in their distribution among the different breeds (p < 0.05). These results provide more information regarding the genetic background of these native rabbit breeds and reveal their high-quality genetic resources. [ABSTRACT FROM AUTHOR]

Simple Summary: We report an unusual clinical case in a pet rabbit vaccinated against rabbit haemorrhagic disease virus (RHDV, GI.1), that developed a prolonged hepatic disease, and was diagnosed RHDV2 (GI.2) positive post-mortem. This finding is a warning to all veterinarians that rabbit haemorrhagic disease should also be considered for differential diagnosis despite the history of RHDV vaccination and the need to update vaccination programs against the current RHDV2 circulating strains. Rabbit haemorrhagic disease (RHD) is a highly contagious infectious disease of European wild and domestic rabbits. Rabbit haemorrhagic disease virus (RHDV, GI.1) emerged in 1986 in Europe, rapidly spreading all over the world. Several genotypes of RHDV have been recognised over time, but in 2010, a new virus (RHDV2/RHDVb, GI.2) emerged and progressively replaced the previous RHDV strains, due to the lack of cross-immunity conferred between RHDV and RHDV2. RHDV2 has a high mutation rate, similarly to the other calivirus and recombines with strains of RHDV and non-pathogenic calicivirus (GI.4), ensuring the continuous emergence of new field strains. Although this poses a threat to the already endangered European rabbit species, the available vaccines against RHDV2 and the compliance of biosafety measures seem to be controlling the infection in the rabbit industry Pet rabbits, especially when kept indoor, are considered at lower risk of infections, although RHDV2 and myxoma virus (MYXV) constitute a permanent threat due to transmission via insects. Vaccination against these viruses is therefore recommended every 6 months (myxomatosis) or annually (rabbit haemorrhagic disease). The combined immunization for myxomatosis and RHDV through a commercially available bivalent vaccine with RHDV antigen has been extensively used (Nobivac® Myxo-RHD, MSD, Kenilworth, NJ, USA). This vaccine however does not confer proper protection against the RHDV2, thus the need for a rabbit clinical vaccination protocol update. Here we report a clinical case of hepatitis and alteration of coagulation in a pet rabbit that had been vaccinated with the commercially available bivalent vaccine against RHDV and tested positive to RHDV2 after death. The animal developed a prolonged and atypical disease, compatible with RHD. The virus was identified to be an RHDV2 recombinant strain, with the structural backbone of RHDV2 (GI.2) and the non-structural genes of non-pathogenic-A1 strains (RCV-A1, GI.4). Although confirmation of the etiological agent was only made after death, the clinical signs and analytic data were very suggestive of RHD. [ABSTRACT FROM AUTHOR]

Simple Summary: The domestic rabbit doe can have several reproductive diseases, including infertility. These were causes for consultations from rabbit producers. This led us to study the reproductive diseases of farmed does. To do this, we relied on visits to rabbitries, made since 1994. Low fertility, which in our case we considered less than 70% pregnancies (85.5% was the average observed on farms), plus an abortion rate equal to or greater than 2% of inseminated does, were the most frequent problems. Then, we scheduled work from 2014, through pregnancy checks with abdominal palpation. We recorded the results for each rebred lactating doe examined, along with data on her body and sanitary condition, and parity order. We found an effect of low body condition or diseases, such as mastitis, on infertility. Age also had an effect: first parity does were less fertile. Therefore, before servicing a doe, it is necessary to evaluate its condition, as well as various management practices (reproductive rhythm) or environmental factors (lighting). In this study, we determined the occurrence of reproductive diseases in does on 1373 visited farms in Spain and Portugal, between 1994 and 2019. The retrospective information obtained was entered in a database classified as follows: apparent infertility (≤70% pregnancy rate), abortions (≥2% of serviced does), high fetal death risk at parturition (≥10%) or dystocia, amongst others. Infertility was the reason for 181 visits. The median of prevalence of apparent infertility in these cases was 35% (minimum to maximum: 25–90%) and the mean, 37.4%. We performed a prospective study to determine risk factors at the individual and farm level, with a second database corresponding to 2014–2019. We carried out pregnancy checks, assessed sanitary status and body condition, and recorded the age of 17,297 rebred lactating does on 142 farms. The median size of the farms was 800 does, and the examined cohorts, 350 does. Predisposing risk factors for infertility were observed: e.g., mastitis had an effect. During the 5-year study, we made a third database with the results from 190,508 does palpated by producers in a subset of 134 farms. In this case, the median of the prevalence of apparent infertility was 14.5% (minimum to maximum: 4.1–50%), which could be considered baseline occurrence when monitoring the theriogenology of rabbit doe farms. Reproductive rhythm was an enabling risk factor: does serviced ≤25 d postpartum were less fertile than at ≥32 d. We made a database with the body condition score (BCS) on a linear scale from 1 (emaciated) to 9 (obese). The pregnancy rate (PR) of underweight and borderline does (4/9) was 73.1%. The PR of overweight and borderline does (6/9) was 82.6% and those classified with a mean BCS (5/9): PR = 79.3%. We may infer that the optimum BCS for reproduction is 6/9, rather than 5/9. Some changes in female rabbit health and husbandry to improve reproductive performance and welfare are highlighted. [ABSTRACT FROM AUTHOR]

Simple Summary: The rabbit is one of the genetically most diverse farm animals, where domestication has resulted in a change primarily in the genes responsible for behavior. The elements of intensive production technology (e.g., nursing, change of nest material) can have a significant effect on maternal behavior. Its individual variability is evident in the timing of nest building and nest composition. As a result that the hormone progesterone strongly influences the steps of nest building, we investigated the association of genetic mutations in the progesterone receptor gene with nest-building behavior in wild-type rabbit does. In addition to the already described point mutations in domesticated lines, we detected a new mutation in our wild type rabbits. However, the timing of nest building (hay carrying) was related to an already described point mutation. The heritability of this trait was low, but it confirms the genetic determination of the behavior besides the environmental factors. One of the genotypes was responsible for the two days earlier initiation of the hay carrying behavior. The early initiation of this process allows animals to construct a high-quality nest resulting in better survival of the offsprings in nature. Once a day, nursing and absentee mothering make the wild rabbit (Oryctolagus cuniculus) an ideal model animal for measuring differences in maternal behavior. Behavioral events and their hormonal regulation leading to parturition are well documented; however, the genetic background behind individual differences in this complex process is unknown. Decreased progesterone hormone level and the reduction of progesterone receptor activity are crucial to initiating the collection of nest material. The progesterone receptor gene is a likely candidate affecting nest-building behavior. In addition to several known point mutations in the progesterone receptor gene of the European wild rabbit, we have found a new mutation in the promoter region of the gene at 2682 T > C. Although this new single nucleotide polymorphism (SNP) was not involved in the formation of the nest-building behavior, an SNP (2464G > A) already described in the promoter region showed an association with individual differences in the initiation of hay carrying. The distribution of this SNP delivered an opposite result compared to domestic rabbits. Genotype (GG) with high uterine capacity was most frequent; the hereditary value of the trait was h2 = 0.10. Thus, progesterone receptor gene polymorphism may manifest in individual differences affecting breeding success in this species. [ABSTRACT FROM AUTHOR]

Simple Summary: Staphylococcosis is a major disease in both human and veterinary medicine. In commercial rabbit production, highly virulent variants cause significant economic losses. This study describes the comparative analysis of the whole genome of 51 strains sequenced by our group, and 12 sequences derived from online repositories. The investigation was based on whole-genome sequencing and whole-genome multilocus sequence typing. The typical highly virulent strains showed great similarity with ST121/t645 isolates from Italy, Spain and the UK. The most prevalent genotype in Hungary was an atypical highly virulent variant; these strains form a novel sequence type (ST5993), and belong to three different spa types (t4770, t711 and t2407). Low virulence (LV) strains grouped into two main clusters, two ST1 LV strains formed a separate cluster from the majority forming a clone-like group, despite the five different multilocus sequence typing (MLST) patterns and seven different spa types. Some strains in this survey showed genetic polymorphism on more than 50% of the examined loci, however, even within the same MLST ST group, hundreds of loci showed polymorphism, which could facilitate the very fine differentiation of the strains. Staphylococcosis is one of the most important infectious diseases in rabbit medicine, especially in commercial farming. Previous studies revealed the existence of virulent variants adapted to rabbits. Typical and atypical, highly virulent as well as low virulent variants have been isolated and reported from industrial units in all major rabbit-meat-producing countries. Preceding the research focused on detecting defined nucleotide sequences, the genome of these organisms as a whole was rarely subjected to scientific investigations. The authors sequenced 51 Staphylococcus strains originating from industrial rabbit farms in Hungary. Another 12 draft genomes of rabbit isolates were constructed from read sequences available in digital repositories, and were compared based on whole-genome multilocus sequence typing. The clonal origin of highly virulent variants is confirmed, the strains from Hungary were closely related with the strains isolated in the UK, Italy, and Spain. Atypical highly virulent strains are the most prevalent in Hungary, they form a separate clonal cluster. The low virulent strains were genetically similar, but more heterogeneous than the highly virulent (HV) and aHV strains even by the traditional MLST typing scheme. Other "non-aureus" Staphylococcus species were also identified. [ABSTRACT FROM AUTHOR]

Simple Summary: Hare coursing is a widespread and controversial activity in the Republic of Ireland in which the speed and agility of greyhounds are measured against that of a hare. Every year, several thousands of hares are taken from the wild by coursing clubs under licenses issued by the National Parks and Wildlife Service. While the majority are returned to the wild at the end of the coursing season, no research has been done on the impact of hare coursing on the welfare of individual hares. Despite greyhounds in licensed coursing events being muzzled since 1993, hares may be pinned to the ground by the dogs and killed or so severely injured that they have to be euthanized by a veterinary practitioner. In addition to animal welfare concerns, the recent emergence in Ireland of rabbit haemorrhagic disease (RHD2) has led to calls for licensed hare coursing to be prohibited on animal welfare, disease control, conservation and ethical grounds. In this paper, publicly available information provided by licensed hare coursing clubs on the number of hares captured, used for coursing events, killed or injured and the percentage returned to the wild, over four coursing seasons is reviewed. A reported 19,402 hares were taken from the wild over the four coursing seasons. Whilst 19,080 hares (98%) were returned to the wild, 75 were killed by greyhounds or had to be euthanized due to their injuries. Policy makers should take animal welfare, disease control, conservation, ethics and public opinion into account and fund independent research where gaps in knowledge are identified. Hare coursing is legal in the Republic of Ireland under licenses issued to coursing clubs but is illegal in other jurisdictions in the British Isles including Northern Ireland. Supporters of coursing maintain that coursing contributes to the conservation of the hare whilst opponents claim that coursing is cruel and the welfare of the hares is compromised. However, while the contribution of coursing to conservation has been considered, the impact of coursing on hare welfare has not been investigated. This paper reviews publicly available information from licensed hare coursing clubs over four coursing seasons, including the number of hares taken from the wild, numbers coursed, and numbers pinned to the ground by dogs, killed or injured during coursing events. In total, 19,402 hares were taken from the wild—98% of which were subsequently released back to the wild at the end of the coursing season. Almost 600 hares were pinned by greyhounds during coursing events and 75 were either killed or had to be euthanized as a result of their injuries. While the number of hares killed or injured is relatively small compared to the number caught, the welfare of all captured hares will have been compromised and has not been investigated. Policy makers must fill this knowledge gap or take a precautionary approach and further regulate or indeed prohibit the capture of hares which are otherwise fully protected. [ABSTRACT FROM AUTHOR]

Simple Summary: Domestic and wild lagomorphs, especially rabbits and hares, are important from an economic, ecological and public health point of view. Both rabbits and hares are susceptible to a wide variety of pathological disorders, so that the knowledge of the different risk factors, causes of death or disease and prevalence rates is relevant from a health, economic and welfare perspective. Despite the accumulation of information on lagomorph medicine and pathology, comprehensive published compilations of diagnostic cases in rabbits and hares are scarce. Between 2000 and 2018, 325 lagomorphs (rabbits and hares) from northern Spain were necropsied. A wide variety of conditions were identified. The health problems most frequently diagnosed were related to parasitic conditions (n = 65; 24.34%), bacterial diseases (n = 56; 20.97%), nutritional and metabolic disorders (n = 48; 17.97%), viral infections (n = 31; 11.61%), miscellaneous causes (n = 31; 11.61%), neoplasms (n = 12; 4.49%), toxicoses (n = 11; 4.11%), trauma-related injuries (n = 9; 3.37%) and finally, congenital diseases (n = 4; 1.49%). The species, sex, age and time of the year were predisposing factors in many of the conditions identified. The frequency of presentation and main pathological findings of these disorders were consistent with the most important lagomorph diseases reported in other European countries and other referenced studies. In this study we determined the causes of mortality and disease in a total of 325 lagomorphs (rabbits and hares) in northern Spain between 2000 and 2018. Risk factors such as the species, age, sex, time of year and origin were also considered. Clinical signs, gross and histopathological findings and ancillary test results were the basis for the final diagnoses that were reviewed to classify and identify the different disorders. A total of 26 different conditions were identified. A single cause of death or illness was detected in 267 animals. They were grouped into parasitic conditions (n= 65; 24.34%) represented by encephalitozoonosis, hepatic coccidiosis, hepatoperitoneal cysticercosis, intestinal coccidiosis, parasitic gastritis and cutaneous ectoparasitosis; bacterial diseases (n = 56; 20.97%) including pseudotuberculosis, blue breast, skin abscesses, tularemia, pneumonic pasteurellosis and staphylococcal infections; nutritional and metabolic diseases (n = 48; 17.97%) with epizootic rabbit enteropathy, hepatic steatosis and pregnancy toxemia as prominent diseases; viral infections (n= 31; 11.61%) comprising rabbit hemorrhagic disease and myxomatosis and miscellaneous causes (n = 31; 11.61%) where rabbit enteritis complex, renal conditions (nephrosis), heat stroke, and arterial bone metaplasia were included; neoplasms (n = 12; 4.49%) represented by uterine adenocarcinoma, mammary adenocarcinoma, cutaneous fibroma, intestinal lymphoma and hepatic cholangiocarcinoma; toxicoses (n = 11; 4.11%); trauma-related injuries (n = 9; 3.37%) and finally congenital diseases (n = 4; 1.49%). In 58 animals of the study, some of these conditions were presented jointly. We discuss the detection frequency, possible causes or associated factors of the different pathologies as well as the importance of the different variables considered. [ABSTRACT FROM AUTHOR]

Simple Summary: The rabbit nose has a very complex structure. How this structure accomplishes functions such as olfaction and the filtration of nanoparticles is not well understood. Moreover, rabbits often sniff; how this sniffing helps them smell better is still a myth. In this study, we examined the anatomy of a New Zealand white (NZW) rabbit nose, especially the spiral-shaped vestibule. Based on its high flow resistance, we hypothesized that the vestibule plays a pivot role in regulating flow ventilation to the olfactory region through sniffing. We observed that this expanding vestibule increased the nanoparticle deposition in the olfactory region, and that particles depositing in the olfactory region only came from a specific area of the nostril. The rabbit nose's ability to filter out inhaled agents is directly related to its defense to infectious diseases. The knowledge of the rabbit nose anatomy is essential to appreciate its functions in ventilation regulation, aerosol filtration and olfaction. The objective of this study is to numerically simulate the inhalation and deposition of nanoparticles in a New Zealand white (NZW) rabbit nose model with an emphasis on the structure–function relation under normal and sniffing conditions. To simulate the sniffing scenario, the original nose model was modified to generate new models with enlarged nostrils or vestibules based on video images of a rabbit sniffing. Ventilations into the maxilloturbinate and olfactory region were quantified with varying nostril openings, and deposition rates of inhaled aerosols ranging from 0.5 nm to 1000 nm were characterized on the total, sub-regional and local basis. Results showed that particles which deposited in the olfactory region came from a specific area in the nostril. The spiral vestibule played an essential role in regulating flow resistance and flow partition into different parts of the nose. Increased olfactory doses were persistently predicted in models with expanded nostrils or vestibule. Particles in the range of 5–50 nm are more sensitive to the geometry variation than other nanoparticles. It was also observed that exhaled aerosols occupy only the central region of the nostril, which minimized the mixing with the aerosols close to the nostril wall, and potentially allowed the undisruptive sampling of odorants. The results of this study shed new light on the ventilation regulation and inhalation dosimetry in the rabbit nose, which can be further implemented to studies of infectious diseases and immunology in rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: Myxomatosis has affected the European domestic rabbit in Spain since the end of 1953; and rabbit haemorrhagic disease (RHD) since mid-1988. In this study, we describe the occurrence of myxomatosis; and RHD; on commercial rabbitries visited in Spain; between 1988 and 2018. Annual occurrence of myxomatosis decreased over 30 years. Cases of myxomatosis were detected most frequently between August and March; more cases occurring in September and fewer in June. Two important RHD epidemics occurred; the first in 1988–1989 due to classic RHD virus (RHDV), and the second from 2011 to 2013 due to new calicivirus (RHDVb/RHDV2). Monthly occurrence of RHD in 2011–2018 was higher from April to August. Despite seasonal variations of these diseases; we recommend that young breeders and adults should be protected by vaccination all year round; and on-farm hygiene measures implemented In this retrospective study, we describe the relative occurrence of clinical myxomatosis, and rabbit haemorrhagic disease (RHD), on 1714 commercial farms visited in Spain, between 1988 and 2018. We determined the annual prevalence based on 817 visits to 394 farms affected by myxomatosis. Myxomatosis was more prevalent from August to March, being lowest in June (3%) and highest in September (8.9%). With regard to RHD, we assessed 253 visits to 156 affected farms. We analyzed mean annual and monthly incidence. Two important RHD epidemics occurred; the first in 1988–1989 due to RHDV GI.1 (also known as RHDV), and the second from 2011 to 2013 due to RHDV GI.2 (RHDV2 or RHDVb). These epidemics occurred at times when effective vaccination had not been carried out. Relative monthly incidence in 2011–2018 was higher from April to August (p < 0.001). The results we obtained from 1404 necropsies on 102 farms did not clearly relate serosanguinous nasal discharge in rabbits with disease caused by GI.2 infection. We also assessed vaccination schedules used on 200 doe farms visited from the end of 2014 to 2018; 95.5% vaccinated against myxomatosis and 97.5% against RHD. Both diseases remain prevalent; however, effective vaccination has produced a steady decline in myxomatosis and RHDV GI.1 and GI.2 on-farm detection. The maintenance of high hygienic standards will be needed to continue and improve this control. However, further studies are required to investigate the causes of sustained virus presence and vaccine breaks. [ABSTRACT FROM AUTHOR]