Four new alleles at the mannose-6-phosphate isomerase locus in rabbit

Four new alleles at the rabbit ( Oryctolagus cuniculus ) mannose-6-phosphate isomerase (E. C. 5. 3. 1. 8, MPI) locus are proposed to account for phenotypes observed after starch gel electrophoresis and enzymatic staining of red cell lysates and tissues. Population data from various wild and domestic rabbit populations are presented.     

Genetic polymorphism of delta-aminolaevulinic acid dehydratase (E.C. 4.2.1.24, ALAD) in the domestic rabbit

A genetic polymorphism of delta-aminolaevulinic acid dehydratase (ALAD) in the domestic rabbit, Oryctolagus cuniculus, was detected by starch gel electrophoresis. Family data (15 matings with 49 offspring) support the genetic model of two common codominant alleles at an autosomal locus. Gene frequencies were calculated in a random sample of 55 mixed breed, unrelated domestic rabbits: ALAD1 = 0.31 and ALAD2 = 0.69.     

Biochemical and genetic studies on rabbit hemoglobin. I. Electrophoretic polymorphism of theβ chain

A genetic polymorphism of beta-chain rabbit (Oryctolagus cuniculus) hemoglobin is demonstrated by means of acid starch gel electrophoresis. The biochemical evidence presented suggests that a previously reported substitution of a neutral amino acid for a histidine is responsible for the detected genetic variation. Segregation analysis was performed in a sample of 15 matings with 49 offspring and confirmed the genetic hypothesis: two common alleles at an autosomal locus. The calculated gene frequencies in a random sample of 125 individuals are HBB*1 = 0.48 and HBB*2 = 0.52.     

The oxygen affinity of mammalian hemoglobins in the absence of 2,3-diphosphoglycerate in relation to body weight

We studied the oxygenation of mammalian hemoglobins: mouse (Mus musculus molossinus), rabbit (Oryctolagus cuniculus domesticus), Japanese monkey (Macaca fuscata), man (Homo sapiens), sheep (Ovis aries), llama (Lama glama), pig (Sus scrofa domesticus), cow (Bos taurus domesticus) and horse (Equus caballus), in the absence of 2,3-diphosphoglycerate (DPG) and compared their oxygen affinity in relation to the body weight. The negative correlation between body weight and the oxygen affinity of the whole blood, observed by Schmidt-Nielsen and Larimer (1958), was not observed in the absence of DPG. Our results indicated that an adaptive evolution proposed for hemoglobin in terms of its oxygen affinity vs body weight of the animal can only be appreciated with DPG.     

Lymphosarcoma with lymphoblastic leukemia in a New Zealand white rabbit.

An 8 to 10-week-old female New Zealand white rabbit, Oryctolagus cuniculus, which exhibited clinical signs of anorexia, depression, and torticollis was found to have lymphosarcoma with lymphoblastic leukemia. The multiple visceral involvement with neoplastic lymphoid cells observed in this animal was similar to previously reprted cases of lymphosarcoma in the rabbit. An unusual finding was the occurrence of lymphoblastic leukemia since lymphosarcoma in the rabbit has previously been reported as aleukemic.     

The incidence of Encephalitozoon cuniculi in a commercial barrier-maintained rabbit breeding colony.

Between 1982 and 1987 sera from 4952 New Zealand White rabbits (Oryctolagus cuniculus) obtained from a single commercial supplier were tested for the presence of antibodies to Encephalitozoon cuniculi. A commercially available carbon immunoassay test kit was used. Initially 32.9% of the rabbits were seropositive with the number progressively decreasing to 2.3% by 1987. The reason for the significant decline in the incidence of infection was most likely due to a selection process for breeding stock instituted by the supplier based upon productivity, posture and weight of each animal.     

Comparative population dynamics of the bug Mepraia spinolai, a sylvatic vector of Chagas' disease, in different hosts

Abstract.  The aim of this work was to determine the impact of specific hosts on a population of Mepraia spinolai (Porter) (Hemiptera, Reduviidae), a sylvatic vector of Chagas' disease in Chile. We assessed whether a recently introduced host could be an important epidemiological factor in maintaining Chagas' disease in Chile. The study stressed the variations in survival, individual weight and fecundity in the insect population when the vector was raised with a species-specific food supply. The study compared the European rabbit Oryctolagus cuniculus , introduced in Chile ≤ 150 years ago, with a wild endemic rodent, Octodon degus . Hosts were placed separately in experimental glass chambers. Groups of insects maintained with rabbits had greater fecundity than those raised with rodents, but both groups had similar survival times and average weights. Both O. degu s and the European rabbit appear to be suitable hosts for M. spinolai , but the rabbit is better than the rodent. Additional research is needed to determine which factors of O. cuniculus produce the observed results.     

Hematology and serum chemistry values of adult, pregnant and newborn New Zealand rabbits (Oryctolagus cuniculus)

Hematological and serum chemistry values were determined in adult female and pregnant New Zealand rabbits (Oryctolagus cuniculus) and their newborn at delivery. No significant difference was found between adult and pregnant hematological profiles. In the newborn, RBC were significantly lower and WBC, MCV and MCH higher than in their mother and adults. A characteristic protein profile was observed for the serum of each animal group, as well as for amniotic fluid. Lipoprotein pattern of the newborn was close to that of the dam, which differed from the adult female rabbit profile. The serum biochemical patterns are close to those of humans, suggesting that the New Zealand rabbit could be a reliable animal model for studies in the perinatal field involving monitoring of selected variables.     

Testing the threat-sensitive predator avoidance hypothesis: physiological responses and predator pressure in wild rabbits

Predation is a strong selective force with both direct and indirect effects on an animal’s fitness. In order to increase the chances of survival, animals have developed different antipredator strategies. However, these strategies have associated costs, so animals should assess their actual risk of predation and shape their antipredator effort accordingly. Under a stressful situation, such as the presence of predators, animals display a physiological stress response that might be proportional to the risk perceived. We tested this hypothesis in wild European rabbits (Oryctolagus cuniculus), subjected to different predator pressures, in Doñana National Park (Spain). We measured the concentrations of fecal corticosterone metabolites (FCM) in 20 rabbit populations. By means of track censuses we obtained indexes of mammalian predator presence for each rabbit population. Other factors that could modify the physiological stress response, such as breeding status, food availability and rabbit density, were also considered. Model selection based on information theory showed that predator pressure was the main factor triggering the glucocorticoid release and that the physiological stress response was positively correlated with the indexes of the presence of mammalian carnivore predators. Other factors, such as food availability and density of rabbits, were considerably less important. We conclude that rabbits are able to assess their actual risk of predation and show a threat-sensitive physiological response.     

Feeding responses of the red fox (<Emphasis Type="Italic">Vulpes vulpes</Emphasis>) to different wild rabbit (<Emphasis Type="Italic">Oryctolagus cuniculus</Emphasis>) densities: a regional approach

We investigate the feeding responses of the red fox (Vulpes vulpes) at a regional scale to different densities of European wild rabbit (Oryctolagus cuniculus) in central–southern Spain. Rabbit abundance indices were obtained in 86 localities during summer 2002. The diet of the fox was studied by analysis of 114 scats collected in 47 of these localities. The feeding response of the fox was examined by a representation of the dry weight percent of rabbit in the diet as a function of the abundance of rabbits; this used data only from those localities where at least 3 scats were collected (70 fox scats from 18 localities). We evaluated the relationship between rabbit abundance and the diversity of the diet of the fox. The feeding patterns of red foxes approximated to Holling’s type III functional response, typical of opportunistic predators. There was a negative relationship between the diversity of the fox’s diet and the abundance of rabbits. Therefore, the fox apparently behaves as a facultative predator, feeding on rabbits when they are abundant and shifting to other prey (and hence a more diverse diet) when rabbits are scarce. These findings are the first step towards understanding the potential role of red foxes in regulating rabbit populations in central–southern Spain.     

Age-dependent changes in the multiple forms of the soluble 17 beta-hydroxysteroid dehydrogenase of female rabbit liver.

The soluble NADP-dependent 17 beta-hydroxysteroid dehydrogenase activity of female rabbit liver increases with the age of the animal, the specific activity of the enzyme in the 56-day-old rabbit being 3 times that of the 28-day-old animal. The increase in activity is accompanied by a change in the molecular heterogeneity of the enzyme. Three forms (enzymes I, II and III) were identified in the liver cytosol of the 56-day-old female rabbit, whereas only one major form (enzyme IIIY) was present in the 28-day-old animal. Peptide maps of the four purified enzymes showed that there were minor differences in structure. The enzyme present in the liver of the 28-day-old rabbit was distinct from the three enzymes of the 56-day-old animal. All of the enzymes exhibited bifunctional activity, having 17 beta-hydroxysteroid dehydrogenase activity towards androgen and oestrogen substrates and 3 alpha-hydroxysteroid dehydrogenase activity towards androgens of the 5 beta-androstane series. The differences in substrate specificity of the enzymes paralleled their differences in structure. The data suggest that one enzyme (enzyme III) may have a special role in steroid metabolism during development in the female rabbit.     

Experimental infection of wild‐caught European rabbits (Oryctolagus cuniculus) with Sarcoptes scabiei from a naturally infected wild rabbit

Scabies was recently reported for the first time in the European wild rabbit, Oryctolagus cuniculus (Lagomorpha: Leporidae). We experimentally exposed 10 seronegative wild‐caught rabbits to skin from a mangy wild rabbit. Serological, physiological, parasitological and histopathological changes were recorded. Three rabbits developed antibodies at 2–5 weeks post‐infection (w.p.i.), two of which then developed lesions at 7 w.p.i. One of these had a small area of alopecia on the hind limb that healed naturally within 1 week; the other developed more extensive lesions restricted to the hind limbs (as typically observed in wild rabbits) that lasted until the rabbit died (12.5 w.p.i.). The third rabbit died of trauma 5 w.p.i. before developing any lesions. Antibodies in the healed rabbit disappeared from serum at 8 w.p.i., whereas antibody levels in the sick rabbit increased until its death. Disseminated intravascular coagulation and hepatic necrosis, probably arising from a concomitant infection with rabbit haemorrhagic disease virus, were the likely final cause of death in this rabbit. The mangy rabbit that served as a donor died of a multifocal fibrinosuppurative pneumonia that may have been secondary to the skin bacterial pyoderma.     

The Goat (Capra hircus) Mammary Gland Mitochondrial Proteome: A Study on the Effect of Weight Loss Using Blue-Native PAGE and Two-Dimensional Gel Electrophoresis

Seasonal weight loss (SWL) is the most important limitation to animal production in the Tropical and Mediterranean regions, conditioning producer’s incomes and the nutritional status of rural communities. It is of importance to produce strategies to oppose adverse effects of SWL. Breeds that have evolved in harsh climates have acquired tolerance to SWL through selection. Most of the factors determining such ability are related to changes in biochemical pathways as affected by SWL. In this study, a gel based proteomics strategy (BN: Blue-Native Page and 2DE: Two-dimensional gel electrophoresis) was used to characterize the mitochondrial proteome of the secretory tissue of the goat mammary gland. In addition, we have conducted an investigation of the effects of weight loss in two goat breeds with different levels of adaptation to nutritional stress: Majorera (tolerant) and Palmera (susceptible). The study used Majorera and Palmera dairy goats, divided in 4 sets, 2 for each breed: underfed group fed on wheat straw (restricted diet, so their body weight would be 15–20% reduced by the end of experiment), and a control group fed with an energy-balanced diet. At the end of the experimental period (22 days), mammary gland biopsies were obtained for all experimental groups. The proteomic analysis of the mitochondria enabled the resolution of a total of 277 proteins, and 148 (53%) were identified by MALDI-TOF/TOF mass spectrometry. Some of the proteins were identified as subunits of the glutamate dehydrogenase complex and the respiratory complexes I, II, IV, V from mitochondria, as well as numerous other proteins with functions in: metabolism, development, localization, cellular organization and biogenesis, biological regulation, response to stimulus, among others, that were mapped in both BN and 2DE gels. The comparative proteomics analysis enabled the identification of several proteins: NADH-ubiquinone oxidoreductase 75 kDa subunit and lamin B1 mitochondrial (up-regulated in the Palmera breed), Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-2 (up-regulated in the Majorera breed) and cytochrome b-c1 complex subunit 1, mitochondrial and Chain D, Bovine F1-C8 Sub-Complex Of Atp Synthase (down-regulated in the Majorera breed) as a consequence of weight loss.     

Monomorphism of isozyme loci in natural and cultivated amaranth (<Emphasis Type="Italic">Amaranthus</Emphasis> L.) populations

Electrophoretic spectra of alcohol dehydrogenase (ADH), glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH), and malic enzyme (ME) in different amaranth populations has been studied using a starch gel electrophoresis. 93 populations and 4 cultivars of amaranth have been analyzed. Some populations have been proved to be polymorphic that provided a possibility of a genetic control of the above-mentioned enzymes. The isozyme variability of the studied amaranth populations is low; all studied loci are found to be monomorphic for 73 populations and 4 cultivars. Some populations demonstrate a polymorphism in separate loci (Adh, Mdh 2, Gdh, Idh 1, Idh 2, and Mod 2). The obtained results evidence the presence of a genetic monomorphism in amaranth concerning the loci studied.     

Allotypy of the rabbit kappa 2 light chain: evidence that the kappa 2 isotype is expressed by all members of the rabbit species

The rabbit kappa 2 light chain subtype was described after isolation of the Basilea mutant strain, which does not express the kappa 1 subtype; antibodies raised in domestic rabbits against the Basilea kappa 2 chain recognized antigenic determinants present in Basilea strain rabbits and in some wild Oryctolagus cuniculus individuals. Some authors have proposed that the kappa 2 isotype is expressed in some individuals and is silent in others. The results presented here provide immunochemical and genetic evidence that the kappa 2 isotype presents at least two allotypic forms, bas 1 (equivalent to bas+) and bas 2 (equivalent to the so-called bas-), which are expressed in low levels in all members of the rabbit species. In addition, preliminary data on the expression of the bas 2 allotype in some hares (Lepus capensis) are reported. On the basis of these results, the rules guiding the selection of kappa 1 and kappa 2 isotypic light chain expression in this species may now be approached.     

High‐throughput SNP discovery in the rabbit (Oryctolagus cuniculus) genome by next‐generation semiconductor‐based sequencing

The European rabbit (Oryctolagus cuniculus) is a domesticated species with one of the broadest ranges of economic and scientific applications and fields of investigation. Rabbit genome information and assembly are available (oryCun2.0), but so far few studies have investigated its variability, and massive discovery of polymorphisms has not been published yet for this species. Here, we sequenced two reduced representation libraries (RRLs) to identify single nucleotide polymorphisms (SNPs) in the rabbit genome. Genomic DNA of 10 rabbits belonging to different breeds was pooled and digested with two restriction enzymes (HaeIII and RsaI) to create two RRLs which were sequenced using the Ion Torrent Personal Genome Machine. The two RRLs produced 2 917 879 and 4 046 871 reads, for a total of 280.51 Mb (248.49 Mb with quality >20) and 417.28 Mb (360.89 Mb with quality >20) respectively of sequenced DNA. About 90% and 91% respectively of the obtained reads were mapped on the rabbit genome, covering a total of 15.82% of the oryCun2.0 genome version. The mapping and ad hoc filtering procedures allowed to reliably call 62 491 SNPs. SNPs in a few genomic regions were validated by Sanger sequencing. The Variant Effect Predictor Web tool was used to map SNPs on the current version of the rabbit genome. The obtained results will be useful for many applied and basic research programs for this species and will contribute to the development of cost‐effective solutions for high‐throughput SNP genotyping in the rabbit.     

Monitoring of blood gas parameters and acid-base balance of pregnant and non-pregnant rabbits (Oryctolagus cuniculus) in routine experimental conditions.

Blood gas parameters and acid-base balance values were determined in adult pregnant New Zealand rabbits (Oryctolagus cuniculus) in standard laboratory housing conditions and during anaesthesia with an association of ketamine-chlorpromazine, administered before surgical procedures. All the variables were also studied in adult non-pregnant female, used as controls. No differences in pH, sO2c, O2Hb, COHb, sO2m and a-vDO2 were found between pregnant and non-pregnant rabbits in physiological conditions and during anaesthesia. Ketamine-chlorpromazine and pregnancy seemed to change the other parameters used to assess the acid-base balance and the oxygenation conditions. Anaesthesia affected only Hb, O2Ct, O2Cap, CcO2 and P50. The additive effect of pregnancy and anaesthesia modified pCO2, pO2, HCO3-, TCO2, BEb, SBC, BEecf, A-aDO2, RI, MetHb, RHb, CaO2 and CvO2. The patterns described are close to those of other species, suggesting the New Zealand rabbit might be a reliable animal model for monitoring selected variables.