World Rabbit Science

Genome wide association study of growth and feed efficiency traits in rabbits

2023-09-28T12:52:07+02:00

Feed efficiency is a major production trait in animal genetic breeding schemes. To further investigate the genetic control of feed efficiency in rabbits, we performed a genome-wide association study (GWAS) for growth and feed efficiency on 679 rabbits genotyped with the Affimetrix Axiom Rabbit 200K Genotyping Array. After quality control, 127 847 single-nucleotide polymorphisms (SNP) were retained for association analyses. The GWAS were performed using GEMMA software, applying a mixed univariate animal model with a linear regression on each SNP allele. The traits analysed were weight at weaning and at 63 days of age, average daily gain, total individual feed intake, feed conversion ratio and residual feed intake. No significant SNP was found for growth traits or feed intake. Fifteen genome-wide significant SNPs were detected for feed conversion ratio on OCU7, spanning from 124.8 Mbp to 126.3 Mbp, plus two isolated SNP on OCU2 (77.3 Mbp) and OCU8 (16.5 Mbp). For residual feed intake, a region on OCU18 (46.1-53.0 Mbp) was detected, which contained a putative functional candidate gene, GOT1.

The FRZB gene regulates hair follicle development in rabbits via the Wnt/β-catenin signaling pathway

2023-09-28T12:52:25+02:00

To explore the mechanism of the FRZB gene in hair follicle development by regulating the Wnt/β-catenin signalling pathway, Angora rabbits were selected to collect back skin samples for the experiment. The action mechanism is understood by cell culture and transfection, apoptosis and proliferation assays and TOP/FOP Flash Wnt Reporting System methods. The results showed that the interference and overexpression of the FRZB gene in rabbit dermal papilla cells indicated that overexpression could inhibit the expression of SFRP2, BMP4, and WNT2 genes (P<0.05). On the contrary, the expression of Wnt signalling pathway-related genes LEF1, CCND1, DKK1, and TCF7 was significantly up-regulated (P < 0.05). Further examination of the luciferase reporter system TOP/FOP revealed that pcDNA3.1-FRZB inhibits Wnt activity. PcDNA3.1-FRZB was found to promote the level of apoptosis in DP cells, whereas si-FRZB inhibited DP cell proliferation. Therefore, it is concluded that FRZB inhibits hair follicle development in long-haired rabbits by regulating the Wnt/β-catenin signalling pathway.

Respiratory disorders of farmed rabbits: occurrence and risk factors

2023-09-28T12:51:53+02:00

In this study, we focused on the occurrence of respiratory disorders in rabbit farms, as well as several risk factors. We based the assessment on 11 217 visits to 1288 commercial farms in Spain and Portugal from 1996 to 2020. There was a sub-set of 307 visits due to respiratory system issues on 172 farms; the main causes were high prevalence of rhinitis in does and high mortality risk in weaned rabbits. During the 25-yr observational study, we physically examined 29 000 males and 200 000 lactating does to monitor their sanitary status on 894 farms. The mean annual prevalence of clinical rhinitis (CR) and 95% binomial confidence interval (CI) in does was 19.9% (95% CI [19.7-20.1%]). We observed an improvement as prevalence of annual CR fell from 29.6% in 1996 to 15.2% in 2020. The main risk factor for rhinitis was the rabbit line, followed by gender (males become sick more than females) and age of females. The median age of farmed does was 5 parities (minimum to maximum: 1-39). The enabling risk factors were year, season (more often affected in summer) and service timing (lowest prevalence when does were served ≥32 d postpartum). In a sub-set of 208 farms, we determined the prevalence of apparent atrophic rhinitis, which was 0.04% in females and 0.11% in males. Concerning bacteriological studies with 444 samples from 153 farms, Pasteurella multocida and Staphylococcus aureus were the main agents isolated from cases of pneumonia, rhinitis and other issues. We may infer that much work is required to determine in greater detail the factors linked to the farm environment and apply this knowledge in practice.

Non-cruelty eradication of european rabbit (Oryctolagus cuniculus) from a small mediterranean island (Isola delle Femmine, Italy)

2023-09-28T12:51:38+02:00

European rabbit is, among mammals, one of the most widespread species almost worldwide, introduced on over 800 islands. In microinsular habitats, the introduction of alien species represents a major threat to biodiversity, and the European rabbit is included in the IUCN published list of the 100 worst invasive species. In 2008, an eradication plan was launched on “Isola delle Femmine”, a small and uninhabited island of about 14.5 ha, located in the Mediterranean basin and established as a nature reserve in 1997 to protect its flora and vegetation. The present work was conducted to evaluate the effectiveness of a non-cruelty intervention through the trapping and translocation of live animals, avoiding the use of poisons or hunting in a sensitive microinsular habitat. The European rabbit eradication plan began in December 2007 and ended in 2016, with the complete eradication of the species achieved in 2012. During the 5 yr in which trapping took place on the island, a total of 799 rabbits were trapped and translocated. A significant positive correlation (r=0.986; P=0.014) was observed between the number of catches made during the year and the estimated rabbit density in July (considered the highest of the year). The method used showed considerable efficacy for the management of rabbit populations in microinsular environments, highlighting the possibility of intervention with these methods when control using poison or direct culling is impractical or inadvisable.

Role of housing system and season on the carcass and meat quality traits of growing rabbits reared in Italian commercial farms

2023-09-28T12:50:42+02:00

The aim of this study was to compare the carcass traits and meat quality of growing rabbits reared in four types of commercially available housing systems (i.e. bicellular cages, dual-purpose cages, enriched cages and elevated pens) across three production cycles covering different seasons (i.e. autumn, winter and summer) under field conditions. The rabbits originated from 12 commercial farms (three farms per housing system) located in the Northeast of Italy and were slaughtered in five commercial slaughterhouses at a slaughter age from 71 to 90 d. Twenty carcasses per farm and cycle were randomly selected at the slaughterhouse and carcass and meat quality traits were evaluated 24 h post-mortem. The heaviest carcass weights were found in rabbits reared in enriched cages, followed by those in parks, while the lightest carcasses were found in rabbits from bicellular cages. Carcass fat and longissimus lumborum proportions were higher and hind legs proportion lower in carcasses of rabbits kept in enriched cages compared to those from the other systems. Based on significant differences for meat quality traits (i.e. pH, L*, thawing losses and shear force) among housing systems, ante-mortem stress was likely lower in rabbits from enriched cages and parks than in those from bicellular and dual-purpose cages. Nevertheless, these differences were not translated into noticeable changes in meat quality because of the small variations among housing systems. Overall, the observed differences could not be strictly and exclusively related to the enclosure in which the animals were housed, but also to other production and ante-mortem factors. The rearing season significantly affected slaughter traits, with lower slaughter and carcass weights in summer compared to winter and autumn. Despite the limit in the sample size of investigated farms, this study highlighted that under field conditions the final product quality of rabbits is not clearly distinguishable based on the housing system per se.

Improvement of the quality of cured rabbit meat product (Chan Si Tu) using Staphylococcus xylosus as starter culture

2023-09-28T12:50:59+02:00

Starter cultures can help improve the quality and safety of traditional fermented meat products. This work was conducted to evaluate the effects of the inoculum of Staphylococcus xylosus on the quality characteristics of a Sichuan cured rabbit product (Chan Si Tu). Physicochemical analyses showed that meats inoculated with S. xylosus had a significant increase in lightness, redness, cohesiveness and chewiness (P<0.05). In addition, a lower content of nitrite, diethylnitrosamine and histamine, was observed in the inoculated samples (P<0.05). The thiobarbituric acid reactive substances (TBARS) value in the S. xylosus incubation group was 0.108±0.004 mg/kg, which was significantly lower than that in the control group (P<0.01). Interestingly, a lower TBARS value was observed in the incubation samples through storage. Furthermore, solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified a total of 73 volatiles, and the species and abundance of theses volatile compounds were higher in the samples with added S. xylosus, and 12 with odour activity value>1 were proposed as the most odouractive compounds that enhanced the complexity of the product. Thus, inoculation with S. xylosus in the cured rabbit meat product (Chan Si Tu) can effectively enhance the product quality.

Abstracts of the 47th Symposium on Cuniculture, ASESCU

2023-06-22T12:46:22+02:00

The 47^th Congress of the Spanish Association of Cuniculture (ASESCU) was held in León (Castile and Leon, Spain) on the 31^st of May and 1^st of June. The event was organised by ASESCU and the Faculty of Veterinary Medicine at the University of León. Four main lectures were delivered. The first two of these lectures delved into the past, present and future perspectives of cuniculture in Castile and Leon. The third talk focused on the use of state-of-theart technologies in animal production for precision livestock farming. Lastly, the fourth lecture provided an overview of the current status of Staphylococcus aureus studies and introduced novel tools for its control. Moreover, two round tables were conducted to examine the current state of sustainability in rabbitries, as well as the effects of implementation of the new antimicrobial laws. Throughout the congress, a total of 21 oral communications and two posters were presented in working sessions on genetics, sustainability, nutrition, reproduction, pathology, welfare and products. The event was attended by approximately 160 participants from different European and American countries. The abstracts of contributions are reported below.