Commercial Rabbit Research Articles

Clinical Management of Sarcoptic Mange in Rabbits

Dermatological problems are one of the most common clinical entities in domestic pets and fur bearing animals (Deshmukh et al., 2010). Amongst them, sarcoptic mange is one of the most common and major constraint in commercial rabbit production in India (Darzi et al., 2007). Sarcoptic mange is the most obstinate, resistant and contagious disease with zoonotic importance (Kumar et al., 2002). It is mainly characterized by pruritis, alopecia and in prolonged illness; the animal becomes emaciated and mayeven die due to cachexia (Roy et al., 2001). Being a contagious parasitic skin disease, mites are generally spread by direct contact between infected and healthy rabbits (Panigrahi and Gupta, 2013). Sarcoptic mange, if left untreated may cause significant morbidity and economic loss in the livestock. Moreover, high costs are associated with acaricides used in infested livestock (Rehbein et al., 2003 and Walton et al., 2004). The avermectin compounds can be used to treat rabbits which are naturally infected with scabies (Kachhawa et al., 2013 and Eraslan et al., 2010). The present communication reports the successful management of sarcoptic mange in rabbits.

Comparison of the fecal microbiota of domestic commercial meat, laboratory, companion, and shelter rabbits (Oryctolagus cuniculi)

BackgroundRabbits are cecotrophic, hindgut-fermenters that rely heavily on their gastrointestinal microbiota for optimal digestion of plant-based diets. Dysbiosis, caused by disruption of the gastrointestinal microbiota, is known to predispose rabbits to rabbit enteritis complex (REC), a major cause of morbidity and mortality. The objectives of this study were to describe the fecal microbiota of domestic rabbits from a variety of settings (commercial meat, companion, laboratory, and shelter) and to identify how factors such as age, season, and routine antimicrobial use affect the fecal microbiota composition.ResultsA total of 86 pooled commercial meat, 54 companion, 14 pooled laboratory, and 14 shelter rabbit fecal samples were evaluated using 16S rRNA gene sequencing of the V4 region. In all sample types, the predominant bacterial phylum was Firmicutes. Other commonly identified phyla (composing ≥ 1% of the total microbiota composition) were Verrucomicrobia, Proteobacteria, and Bacteroidetes. Significant differences in composition were noted between commercial, companion, laboratory, and shelter rabbit samples for proportions of Verrucomicrobia (P < 0.01), Proteobacteria (P < 0.01), and Lentisphaerae (P = 0.01) within the total microbiota. Within the commercial meat rabbit samples, significant differences between the microbiota composition of growers (n = 42) and does (n = 44) were limited to one unclassified Firmicutes (P = 0.03) and no differences were identified at the phylum level. Significant differences were present between fecal samples taken from rabbits during the summer (n = 44) compared to the winter (n = 42), with Firmicutes (P = 0.04), Verrucomicrobia (P = 0.03), Proteobacteria (P = 0.02), Deinococcus-Thermus (P = 0.04), Armatimonadates (P = 0.003), and Actinobacteria (P = 0.03) forming significantly different proportions of the microbiota. The only significant difference in composition between those farms that routinely reported antimicrobial use and those that did not was in one unclassified Bacteroidetes (P < 0.05) and no differences were identified at the phylum level.ConclusionsRabbit husbandry and diet, in addition to season, significantly influence the fecal microbiota composition of domestic rabbits, while age of the rabbit post-weaning has minimal impact.

Discovery and description of a new serogroup 7 Streptococcus pneumoniae serotype, 7D, and structural analysis of 7C and 7D

Streptococcus pneumoniae is characterised into 92 serotypes based on antigenic reactions of commercial rabbit sera to the capsular polysaccharides. During development of a bioinformatic serotyping tool (PneumoCaT), an isolate exhibited a novel codon at residue 385 of the glycosyltransferase gene wcwK encoding a distinct amino acid, which differentiates genogroup 7. Investigation by repeat serotyping and Quellung reaction revealed a novel pattern of factor sera with the isolate reacting very strongly with 7f, but also with 7e factor sera. The structure of the capsular polysaccharide was determined by NMR spectroscopy to be an approximately 5:1 combination of the structures of 7C and 7B, respectively, and the structure of 7C was also elucidated. All data from whole genome sequencing, NMR spectroscopy, production of antisera and serotyping of the novel 7 strain shows that it is a new serotype, which will be named in the Danish nomenclature as 7D.

Green, Hydrothermal Synthesis of Fluorescent Carbon Nanodots from Gardenia, Enabling the Detection of Metronidazole in Pharmaceuticals and Rabbit Plasma.

Strong fluorescent carbon nanodots (FCNs) were synthesized with a green approach using gardenia as a carbon source through a one-step hydrothermal method. FCNs were characterized by their UV-vis absorption spectra, photoluminescence (PL), Fourier transform infrared spectroscopy (FTIR) as well as X-ray photoelectron spectroscopy (XPS). We further explored the use of as-synthesized FCNs as an effective probe for the detection of metronidazole (MNZ), which is based on MNZ-induced fluorescence quenching of FCNs. The proposed method displayed a wide linear range from 0.8 to 225.0 µM with a correlation coefficient of 0.9992 and a limit of detection as low as 279 nM. It was successfully applied to the determination of MNZ in commercial tablets and rabbit plasma with excellent sensitivity and selectivity, which indicates its potential applications in clinical analysis and biologically related studies.

A study on Pasteurellosis in a commercial rabbit unit

This paper studies Pasteurellosis in a commercial rabbit unit, one of the most important and common diseases of rabbits. The morbidity within the 2216 animals of the unit was 8,1%, while the mortality was 58,8%. The percentage of the morbidity tended to increase along with the age of the animals, but this was not statistically significant. It was 11,6% at the age of weaning and 15,48% at the age of fattening. The morbidity of the breeding animals was 10,5%. The clinical findings of the infected rabbits included rhinitis, keratoconjunctivitis, otitis media, pneumonia, enteritis, metritis and subcutaneous abscesses. Thirty seven rabbits were subjected to postmortem examination and the characteristic lesions of Pasteurellosis were observed. Samples of the organs of infected rabbits were used for microbiological examinations by which Pasteurella multocida was isolated.

Effect of genotype and some non-genetic factors on weaning weight in rabbits

The rabbit meat producers have a strong desire to improve productivity in order to maximize on financial gains. There has been a deliberate move to target improved weaning weight, which is thought to be a critical component in influencing total meat yield and economic returns. However, it has been acknowledged that weaning weight is partly influenced by individual kit genetic potential at the same time its overwhelmed by various non genetic factors. In this respect, weaning weights a complex character which reflects the influence of many biological processes namely fertility, maternal instinct, growth and viability. For the purpose of increasing production, it is reasonably to suggest that the complex inter-relationship among known various non genetic factors that influence weaning weight and the degree of their interactive effects need to be ascertained and understood in different production systems. While, genotype is a major contributor to weaning weight, environmental, nutritional and management practices also play significant roles in influencing weaning weight. There are several known environmental factors that influence weaning weight and these include feeding practices, birth weight, parity order, sex of kits, management, etc. The rabbit producers’ attention to the aforementioned factors is likely to improve weaning weight at enterprise level. It is important to note that selection for increased litter size have an adverse effect on average litter birth weight which subsequently reflects on weaning weight. The enhanced prolificacy in does has resulted in an increase in within litter variation and a larger number of kits born light. From the farmer’s performance point of view, genetic diversity utilization in crossbreeding has been the focus in improving weaning weight in commercial rabbit meat production. However, the complementary role played by nutritional status in optimization of performance in selected genotypes has been tremendous in the past two decades. Crossbreds have performed at levels consistent with different targeted rabbit meat market expectations. Generally, it is pronounced that improved nutritional regime and patterns for lactating does and their suckling kits had a positive effect on weaning weight. On the other hand, unbalanced parity structure and distribution in rabbit enterprise results in unreasonable variation in weaning weight, which impacts negatively on subsequent kits management after weaning. The purpose of this review is to discuss the influence of genotype and some non-genetic factors (litter size, birth weight, parity) on weaning weight in rabbits.

Use of non-classical feed resources and their influence on some performance indicators in rabbits

Generally, it has been pronounced that the demand for animal products worldwide will drastically increase due to population boom in turn putting pressure on animal production systems. In view of meeting animal protein demand, suggestions have been put forward to the effect that mini-livestock production, which include rabbits should be part of the mainstream animal production strategies. However, it has been noted that commercial rabbit production has been adversely affected by the high cost of feeding and use of traditional feed stuff (grain and soya bean) that have direct competition with humans for food. There has been an unbearable continued increase in the cost of traditional feed resources (soya been, maize, millet, groundnut, fish meal etc.) in the past decade, which in turn has led to exorbitant rabbit feed prices and consequently expensive rabbit meat and their products. This on the backdrop that feeding is a very critical aspect of rabbit production enterprise that influence overall performance (growth, mortality, reproduction, carcass and meat quality) in rabbits. In this aspect, it has been recommended to explore non-classical (alternative or non-traditional or non-conventional) feed resources to depart from exorbitant cost of feeding and the cost related influence of feed resources due to direct competition between rabbits and humans for food, while maintaining improved rabbit productivity. A series of studies have been carried out targeted on some local non-classical feed resources on account of their nutritional values, as energy and protein sources in rabbits’ diets. The inferiority and unbalance nutritive quality of some of the non-classical feed resources is a major challenge which restrict their successful use in rabbit production. Initial assessment of some non-classical feed resources has reported low nutritive value that distinctly depress voluntary feed intake and nutrient digestibility which in turn adversely affect weight gain in rabbits. However, some non-classical feed resources tested have shown marked potential as energy and protein substitute sources in rabbits’ diets to enhance production. This point to the fact that successful use of non-classical feed resources can mitigate the current high cost and shortage of traditional feedstuffs, and also lessen the potential high competition between rabbits and humans on food. The purpose of this review is to discuss the use of non-classical feed resources and their influence on some performance indicators.

Some animal-related factors affecting pre-weaning mortality in rabbits

Pre-weaning mortality is one of the dominant aspect that impact negatively on productive and reproductive components in a commercial rabbit enterprise. This review article looks at some animal-related factors such as litter size and birth weight in influencing pre-weaning mortality in rabbits. There are several factors that influence pre-weaning mortality in rabbit production. Therefore, understanding of these factors may reduce production losses and maximize profits. Pre-weaning mortality restrict the output of any rabbit enterprise culminating in reduced income earned from rabbit production. A complicated interconnection between the doe, the kit and the environment influence pre-weaning mortality. A negative association between birth weight and litter size has been demonstrated in rabbits which implied that large litter resulted in individual low birth weight consequently increased pre-weaning mortality. Birth weight and litter size can be manipulated to the producers’ advantage and improve rabbits’ performance in the long run. A positive association of litter size and mortality has been reported in rabbits. The larger the litter the greater the mortality rate. The smaller the weight at birth of kits the less the chances of survivability. Mothers should be selected for good maternal attributes and reasonable litter size in order to curtail pre-weaning mortality. The present discussion will focus on litter size and birth weight as some of the major factors that influence pre-weaning mortality.

Effect of restricted feeding under rearing on reproduction, body condition and blood metabolites of rabbit does selected for growth rate

Young rabbit females selected for growth rate can have nutritional needs which may not be met by the common practice of feed restriction during rearing in commercial rabbit production. The aim of this study was to analyse the effect of two different feeding programmes: restricted and ad libitum feeding, applied in young rabbit females for one month at the end of rearing, on reproductive performance, body condition and circulating metabolic hormones and metabolites in a rabbit line selected by growth rate in 3 consecutive reproductive cycles. Thus, twenty-four 16-week-old does were randomly assigned to a group in which the daily recommended nutrient intakes were satisfied (fed restricted: 130 g/day, n=13) or a group fed to satiety (ad libitum: 235.5 g/day, n=11) during one month. Then, all does were inseminated in 3 consecutive cycles using a 42-day reproductive cycle. Measurements of does’ body weight, perirenal fat thickness and plasma leptin, non-esterified-fatty-acids (NEFA), beta-hydroxybutyrate (BOHB) and fructosamine were performed at artificial insemination (AI), parturition and weaning time in 3 consecutive cycles. Reproductive performance of does was evaluated based on fertility, litter size at parturition, prolificacy and productivity. Differences in body weight were found only in the 1&lt;sup&gt;st&lt;/sup&gt; cycle, ad libitum fed females being heavier than restricted ones. Nevertheless, body weight variances disappeared in later cycles. No differences were found in perirenal fat thickness. Finally, in ad libitum fed females slight differences were found in plasma levels of NEFAs (452 vs. 258 μekv/L and 527 vs. 306 μekv/L for 1&lt;sup&gt;st&lt;/sup&gt; and 2&lt;sup&gt;nd&lt;/sup&gt; cycles) and BOHB (0.26 vs. 0.03 mM for 2&lt;sup&gt;nd&lt;/sup&gt; cycle), but disappeared in the 3&lt;sup&gt;rd&lt;/sup&gt; reproductive cycle. Fertility, prolificacy and productivity was not significantly affected by the feeding programme. Nevertheless, total litter size showed to be higher in ad libitum fed females at second parturition (8.7 vs. 5.9 kits). Therefore, the evaluated feeding programmes until first AI in females selected by growth rate had no effect on their reproductive outcomes, as the global reproductive performance was not affected.

Efficacy of Blunt Force Trauma, a Novel Mechanical Cervical Dislocation Device, and a Non-Penetrating Captive Bolt Device for On-Farm Euthanasia of Pre-Weaned Kits, Growers, and Adult Commercial Meat Rabbits.

Simple SummaryDeveloping effective and humane on-farm euthanasia methods is essential for all livestock industries to ensure that animals do not suffer and are killed humanely. Approved methods are lacking for commercial meat rabbits, potentially leading to poor welfare. We assessed several methods of on-farm killing of cull rabbits of different ages to determine which methods were most effective and humane. These included blunt force trauma (the most commonly used method on rabbit farms), a novel mechanical cervical dislocation device, and a non-penetrating captive bolt device. We evaluated method effectiveness by examining animal reflexes and behaviours after applying the method as well as by examining radiographs of rabbit heads for signs of skull damage, and by assessing the degree of trauma to the brain through dissection and microscopy, because more trauma is generally correlated with enhanced method effectiveness and irreversibility. We found that blunt force trauma resulted in an unacceptably high failure rate, particularly in mature rabbits, whereas the mechanical cervical dislocation and non-penetrating captive bolt devices were both highly effective for killing rabbits humanely and irreversibly. The non-penetrating captive bolt device was the most effective with a 100% success rate and could be used on all rabbits weighing more than 150 g.The commercial meat rabbit industry is without validated on-farm euthanasia methods, potentially resulting in inadequate euthanasia protocols. We evaluated blunt force trauma (BFT), a mechanical cervical dislocation device (MCD), and a non-penetrating captive bolt device (NPCB) for euthanasia of pre-weaned kits, growers, and adult rabbits. Trials were conducted on three commercial meat rabbit farms using 170 cull rabbits. Insensibility was assessed by evaluating absence of brainstem and spinal reflexes, rhythmic breathing, and vocalizations. Survey radiographs on a subsample of rabbits (n = 12) confirmed tissue damage prior to gross dissection and microscopic evaluation. All 63 rabbits euthanized by the NPCB device were rendered immediately and irreversibly insensible. The MCD device was effective in 46 of 49 (94%) rabbits. Method failure was highest for BFT with euthanasia failures in 13 of 58 (22%) rabbits. Microscopically, brain sections from rabbits killed with the NPCB device had significantly more damage than those from rabbits killed with BFT (p = 0.001). We conclude that BFT is neither consistently humane nor effective as a euthanasia method. MCD is an accurate and reliable euthanasia method generally causing clean dislocation and immediate and irreversible insensibility, and the NPCB device was 100% effective and reliable in rabbits >150 g.

Epizootic rabbit enteropathy - Current data and control

Epizootic Rabbit Enteropathy (ERE) is an important syndrome that occurred in European rabbit farms the last ten years and is linked to massive deaths, mainly during the fattening period. ERE was first observed in France, in 1997, and was quickly spread in all rabbit-breeding European countries, e.g. Italy, Spain, Portugal, Belgium, Netherlands, Hungary, Germany, Great Britain and Greece. In Greece, ERE has been clinically identified since 2003 in several commercial rabbit farms, causing severe economic loss in country's rabbit farming sector. In other continents no ERE cases have been reported up to today. ERE is characterized by very high mortality, reaching up to 30-80%. The exact etiology of the syndrome is still unclarified, although in several cases, various known pathogens have been isolated, e.g. coccidia, E. coli, Clostridium spp., Enteroviruses, Rota, virus. Treatment is only symptomatic and is mainly based on the use of antibiotics. Prescribed antibiotics against ERE are thiamouline and tylozine. But, the antibiotic of choice is the water soluble bacitracin, which is exclusively permitted only for use in rabbit farms.

Prevalence of antimicrobial resistance in fecal Escherichia coli and Salmonella enterica in Canadian commercial meat, companion, laboratory, and shelter rabbits (Oryctolagus cuniculus) and its association with routine antimicrobial use in commercial meat rabbits

Antimicrobial resistance (AMR) in zoonotic (e.g. Salmonella spp.), pathogenic, and opportunistic (e.g. E. coli) bacteria in animals represents a potential reservoir of antimicrobial resistant bacteria and resistance genes to bacteria infecting humans and other animals. This study evaluated the prevalence of E. coli and Salmonella enterica, and the presence of associated AMR in commercial meat, companion, research, and shelter rabbits in Canada. Associations between antimicrobial usage and prevalence of AMR in bacterial isolates were also examined in commercial meat rabbits. Culture and susceptibility testing was conducted on pooled fecal samples from weanling and adult commercial meat rabbits taken during both summer and winter months (n=100, 27 farms), and from pooled laboratory (n=14, 8 laboratory facilities), companion (n=53), and shelter (n=15, 4 shelters) rabbit fecal samples. At the facility level, E. coli was identified in samples from each commercial rabbit farm, laboratory facility, and 3 of 4 shelters, and in 6 of 53 companion rabbit fecal samples. Seventy-nine of 314 (25.2%; CI: 20.7-30.2%) E. coli isolates demonstrated resistance to >1 antimicrobial agent. At least one E. coli isolate resistant to at least one antimicrobial agent was present in samples from 55.6% of commercial farms, and from 25% of each laboratory and shelter facilities, with resistance to tetracycline being most common; no resistance was identified in companion animal samples. Salmonella enterica subsp. was identified exclusively in pooled fecal samples from commercial rabbit farms; Salmonella enterica serovar London from one farm and Salmonella enterica serovar Kentucky from another. The S. Kentucky isolate was resistant to amoxicillin/clavulanic acid, ampicillin, cefoxitin, ceftiofur, ceftriaxone, streptomycin, and tetracycline, whereas the S. London isolate was pansusceptible. Routine use of antimicrobials on commercial meat rabbit farms was not significantly associated with the presence of antimicrobial resistant E. coli or S. enterica on farms; trends towards resistance were present when resistance to specific antimicrobial classes was examined. E. coli was widely prevalent in many Canadian domestic rabbit populations, while S. enterica was rare. The prevalence of AMR in isolated bacteria was variable and most common in isolates from commercial meat rabbits (96% of the AMR isolates were from commercial meat rabbit fecal samples). Our results highlight that domestic rabbits, and particularly meat rabbits, may be carriers of phenotypically antimicrobial-resistant bacteria and AMR genes, possibly contributing to transmission of these bacteria and their genes to bacteria in humans through food or direct contact, as well as to other co-housed animal species.

On-farm euthanasia practices and attitudes of commercial meat rabbit producers

Appropriate and timely on-farm euthanasia is the responsibility of the producer, working together with their herd veterinarian. Unfortunately, validated methods for euthanasia of commercial meat rabbits are lacking and there...

Prevalence of lapine rotavirus, astrovirus, and hepatitis E virus in Canadian domestic rabbit populations

Lapine rotavirus and astrovirus have been associated with disease in rabbits, and there is strong evidence of zoonotic transmission of lapine hepatitis E virus (HEV). Outbreaks of enteritis are common on commercial meat farms, resulting in poor welfare, high rabbit mortality, and significant financial losses for rabbit producers. Currently, none of these viruses are routinely tested by diagnostic laboratories. In this study, we assessed the prevalence of rotavirus, astrovirus, and HEV RNA in 205 pooled and individual fecal samples from healthy Canadian laboratory, companion, shelter and commercial meat rabbit populations. Viral RNA were extracted and amplified via RT-PCR using virus-specific primers. Positive samples from the first cohort of samples tested were sequenced and aligned to previously identified viruses to confirm the products. Almost 45% (13/29) of the surveyed commercial rabbit farms were astrovirus-positive. Three commercial meat rabbit samples were positive for rotavirus, and either astrovirus or HEV RNA was also detected. Three companion rabbit samples also tested positive for lapine HEV. Samples from specific pathogen-free laboratory animals were negative for all viruses. Sequencing results showed highest identity to rotavirus A strain 30–96, lapine astrovirus strain 2208 and lapine HEV strain CMC-1. These results permit a better understanding of the prevalence of rotavirus, astrovirus, and hepatitis E virus in Canadian domestic rabbit populations, and continued screening for viruses may help to reduce risk of zoonotic agent transmission as well as providing a better understanding of potential causative agents of rabbit enteritis.

Baccaurea angulata fruit juice reduces atherosclerotic lesions in diet-induced Hypercholesterolemic rabbits

BackgroundAtherosclerosis is the most common disease of large and medium-sized arteries linked to oxidative stress, dyslipidemia as well as chronic inflammation. The aim of this study was to evaluate the potential health benefits of Baccaurea angulata (BA) fruit juice on the aorta of diet-induced hypercholesterolemic rabbits, to detect an accumulation of fatty streak and evaluate the percentage of atherosclerotic lesion accrued.MethodsThirty-five healthy male adults New Zealand White rabbits were assigned to seven different groups. Four groups were fed 1% cholesterol diet and 0, 0.5, 1.0, and 1.5 mL of BA fruit juice per kg of rabbit daily (atherogenic groups), while the other three groups were fed commercial rabbit pellet and 0, 0.5, and 1.0 mL of juice per kg of rabbit daily (normocholesterolemic groups) for 90 days. The thoracic and abdominal aorta between the heart origin and bifurcation into iliac arteries of all the rabbits were carefully removed and analyzed accordingly.ResultsThe supplementation of the high-cholesterol diet of hypercholesterolemic rabbits with only 0.5 mL BA/kg rabbit per day significantly (p < 0.001) improved aortic lipid profile, attenuated aortic fatty streak development and reduced intima thickening. Higher BA doses used (1.0 and 1.5 mL/kg rabbit per day) also significantly (p < 0.001) decreased further the development of aortic fatty streaks, reduced the thickening of the tunica intima layer and preserved endothelial healing following arterial injury.ConclusionTherefore, BA fruit is a potential novel functional food with effective anti-inflammatory, anti-atherogenic and hypocholesterolemic activities.

EFFECT OF DIETARY ARAK (Salvadora persica) AND SEASON INTERACTION ON PERFORMANCE OF PRE AND POST-SEXUAL MATURITY OF RABBIT MALES

The present study aimed to evaluate the interaction effects of Arak (Salvadora persica) as feed additive and season on performance of pre- and post-sexual maturity of rabbit males. Ninety-six weaned New Zealand White (NZW) male rabbits aged 30 days with weighing average 586.4 gm (48 in each season) were used during winter and summer seasons. Within each season, two groups were used (24 in each group); the first group fed to ad libitum with commercial rabbit pellets and kept as control group, while the second group fed the same diet supplemented with 0.2% dried Arak powder. Body weight, daily gain, daily feed intake and feed conversion were recorded from weaning up to 70 days of age. Whereas, four rabbits from each group were slaughtered and genitalia were immediately taken and dissected. Blood samples were collected at 150 days of age from five bucks from each group. At maturity age, several reproductive traits were recorded. Results showed that final body weight, daily weight gain, feed intake, feed conversion and weights of genital organs at 70 days of age significantly (P≤0.05) increased with dietary of Arak supplementation. Serum testosterone concentration at 150 days of age (maturity) significantly (P≤0.01) increased with Arak inclusion during winter and summer seasons. The minimum maturity age was obtained by 0.2% Arak inclusion during summer season (151 days). Sexual desire, mating activity, semen-ejaculate volume, advanced-sperm motility%, sperm-cell concentration and total-sperm output were significantly (P≤0.01) affected by Arak inclusion, season and their interactions. Conclusively, from these results could be concluded that the addition of 0.2% Arak (Salvadora persica) to growing NZW male rabbit diets till sexual maturity age under winter and summer season improved growth and reproductive capabilities.

Efficacy of a commercial vaccine against different strains of rabbit haemorrhagic disease virus

This study investigated the ability of a commercial rabbit haemorrhagic disease virus (RHDV) vaccine (Cylap®) to protect rabbits from disease caused by two different strains of the virus (v351 and K5) that are used or proposed to be used for wild rabbit control in Australia. These strains of the RHDV1 genotype belong to the 'classical RHDV' and 'antigenic variant RHDVa' subtypes, respectively. Vaccinated rabbits were exposed to very high doses of the virus either by direct oral dosing or by exposure to infected rabbit livers. All vaccinated rabbits were protected against rabbit haemorrhagic disease, indicating that the Cylap® vaccine is effective against both strains of the virus under experimental conditions.

In this issue – July 2017

In this issue – July 2017

Feed restriction regime in a rabbit line selected for growth rate alters oocyte maturation manifested by alteration in MSY2 gene expression.

Young rabbit females selected for growth rate may have nutritional needs, which may not be met with the common practice of feed restriction during rearing in commercial rabbit production. The aim of this study was to analyse whether two different feeding programmes: ad libitum or restricted (130g/day) feeding, applied in young rabbit females for 1month at the end of rearing, could modulate the origin of ovulation process and the quality of the oocytes. At 16weeks of age, 34 females were randomly assigned to restricted or ad libitum feeding, maintaining these conditions for a month. Then, in an initial experiment, transcriptional profiling of hypothalamus-hypophysis tissue was performed to assess failure to ovulate. In the second experiment, the gene expression analysis of some candidate genes related to oocytes quality was performed. Our results demonstrated that neither of the two feeding programmes modified the transcription of hypothalamus-hypophysis tissue, while the only differences in MSYR expression were found in in vivo mature oocytes ready for successful fertilization. Specifically, MSYR was over-expressed in oocytes from females fed ad libitum. MSYR is one of the most abundant proteins in the oocyte and has proven to be a key regulator of maternal RNA transcription and translation. This finding suggests that MSYR gene is a promising gene in our understanding of the relationship between high growth rate and reproductive performance decline.

Baccaurea angulata fruit juice ameliorates altered hematological and biochemical biomarkers in diet-induced hypercholesterolemic rabbits

Hypercholesterolemia is an important risk factor linked to the alteration of blood hematology and clinical chemistry associated with the development and progression of atherosclerosis. Previous studies have demonstrated the safety and potential health benefits of Baccaurea angulata (BA) fruit. We hypothesized that the oral administration of BA fruit juice could ameliorate the alteration in the hematological and biochemical biomarkers of diet-induced hypercholesterolemic rabbits. The aim of this study was to investigate the effects of different doses of BA juice on the hematological and biochemical biomarkers in normo- and hypercholesterolemic rabbits. Thirty-five healthy adult New Zealand White rabbits were assigned to seven different groups for 90days of diet intervention. Four atherogenic groups were fed a 1% cholesterol diet and 0, 0.5, 1.0, and 1.5mL of BA juice per kg of rabbit daily. The other three normal groups were fed a commercial rabbit pellet diet and 0, 0.5, and 1.0mL of BA juice per kg of rabbit daily. Baseline and final blood samples after 90days of repeated administration BA juice were analyzed for hematological parameters while serum, aortic and hepatic lysates were analyzed for lipid profiles and other biochemical biomarkers. The alteration of the hemopoietic system, physiological changes in serum and tissues lipid profiles and other biochemicals resulting from the consumption of a high-cholesterol diet were significantly (P<.05) ameliorated by the administration of BA juice. Improvements of the biomarkers in rabbits were dose-dependent, markedly enhanced at the highest dose of juice (1.5mL/kg/day). The results suggest potential health benefits of the antioxidant-rich BA fruit juice against hypercholesterolemia-associated hematological and biochemical alterations in the rabbit.