Baladi Red Research Articles

Mitochondrial D-loop sequences and haplotypes diversity in Egyptian rabbit breeds

Rabbit breeds in Egypt are local and adapted foreign breeds that have been imported since the middle of the last century. Stressful environmental conditions including climatic changes, exposure to diseases and breeding selection have an influence on how gene flow has shaped the genetic diversity of the breeds. Mitochondrial DNA D-loop is a genetic marker used to trace the geographic distribution of genetic variation for the investigation of expansions, migrations and other gene flow patterns. The study aimed to determine the genetic diversity of the mitochondrial DNA D-loop (mtDNA D-loop) in Black Baladi, Red Baladi, Gabali, APRI line and New Zealand breeds to gather the scientific data required to create a proper conservation and sustainable management plan. Blood samples were taken from animals unrelated to each other. A 332-bp of mtDNA D-loop was successfully amplified and alignment sequences were deposited in the GenBank database. The results detected six haplotypes in the five breeds. Haplotype diversity within individual breeds varied from 0 (Red Baladi) to 0.551±0.114 (Gabali). The nucleotide diversity (π) value was relatively low (0.001-0.006), with greater values in APRI and New Zealand. Pairwise distances between breeds yielded varying values ranging from 0 to 0.254, and the values between the Red Baladi and other breeds were comparatively high, with pairwise distances from 0.172 to 0.254. The phylogenetic analysis involved 74 nucleotide sequences of the Egyptian rabbit and thirty-one sequences retrieved from GenBank of the reference samples of different haplogroups. The results of the phylogenetic analysis correlated to the reference mtDNA GenBank database showed that the five Egyptian rabbit breeds were grouped into haplotypes A, B and K. The results of the genetic diversity using mtDNA shed light on the importance of the local breed’s genetic diversity information and revealed unique mtDNA haplotypes, which is an important finding for breeding strategies designed to conserve genetic variants and provide sustainable management.

Association between IRS-1, PPAR-γ and LEP genes polymorphisms and growth traits in rabbits

Single nucleotide polymorphisms are commonly associated with changes in quantitative traits, and have been considered useful markers for improving different traits in livestock. The current study aimed to explore the effect of three SNPs located in Insulin receptor substrate (IRS-1), Peroxisome proliferator-activated receptor γ (PPAR-γ), and Leptin (LEP) genes on the growth traits of rabbits. Individuals from three rabbit breeds were genotyped using RFLP-PCR. The IRS-1 variant (c.189T > G) was associated with post-weaning body weight, and body weight gains, However, the effect on growth rates was insignificant in Baladi Red and V-line rabbits. The PPAR-γ variant (c.207A > C) was significantly associated with 8-wk body weights in V-line rabbits, 10-wk body weights, and growth rates from 8 to 10 weeks of age in New Zealand rabbits. However, the differences between genotypes were insignificant for body weight gains and average daily gain. The LEP gene mutation (g.16079636C > G) had significant effects on body weights at 6 and 8 weeks of age in New Zealand White rabbits and 8 weeks of age in Baladi Red rabbits were associated with the presence of the C allele. Concludingly, the results stressed the importance of the IRS-1 gene in post-weaning growth and suggested the existence of breed-specific effects for PPAR-γ and LEP.

Using Linear Discriminant Analysis to Characterize Novel Single Nucleotide Polymorphisms and Expression Profile Changes in Genes of Three Breeds of Rabbit (Oryctolagus cuniculus).

The objectives of this study were to investigate polymorphisms and changes in expression patterns of the genes FGF5, PGAM2, TLR2 and IL10 in V-line, Baladi Black and Baladi Red rabbits. Blood samples were collected from 180 healthy rabbits (n = 60 for each breed) for DNA extraction and DNA sequencing. At 3 mo of age, 20 randomly selected females from each breed were euthanized for gene expression quantification in muscle and spleen samples. PCR-DNA sequencing revealed single nucleotide polymorphisms (SNPs) among the 3 breeds that provided a monomorphic pattern for 3 of the 4 genes analyzed. Linear discriminant analysis (LDA) was used to classify the SNPs of these genes in the 3 breeds. The overall percentage of correctly classified cases for the model was 75%, with percentages of 100% for FGF5, 63% for IL10, and 100% for TLR2. Breed was a significant predictor for gene classification with estimation (1.00). Expression profiles of the genes were higher in V-line as compared with Baladi Black or Baladi Red. The LDA discriminated the 3 breeds using results of the gene expression profile as predictors for classification. Overall, 73% of the cases were correctly classified by gene expression. The identified SNPs, along with changes in mRNA levels of FGF5, PGAM2, TLR2, and IL10, could provide a biomarker for efficient characterization of rabbit breeds and could thus help develop marker assisted selection for growth and immune traits in rabbits.

EFFECT OF L-ARGININE SUPPLEMENTATION IN DRINKING WATER ON PERFORMANCE OF GROWING RABBIT MALES DURING SUMMER CONDITIONS

The present study aimed to determine the effect of L-arginine (L-Arg) supplementation in drinking water on the productive performance, biochemical traits, antioxidant status, carcass traits and economic efficiency of growing rabbit during summer conditions from July to September, 2020. Sixty male Baladi Red growing rabbits (35 days), were individually weighed and randomly divided into four equal treatment groups with five replicates (3 rabbits each). Rabbits were fed same pelleted ration ad-libitum. Each experimental group was supplied with drinking water from a separate container. The first group served as control (unsupplied), while the second, third and fourth groups supplemented with L-Arg in drinking water by levels 1, 2 and 3 g / L, respectively, during the experimental period (35 – 90 days of age). The results indicated that the group supplemented with 2 g L-Arg/L in drinking water had significantly improved body weight, body weight gain, performance index, relative growth rate percentage and feed conversion ratio at the end of the experimental period (90 day of age). The relative weights of pre-slaughter weight and total edible parts were significantly increased for the groups supplied with 1 and 2 g of L-Arg/L compared with other experimental groups. Triglyceride and high density lipoprotein concentrations for the group supplied with 2g L-Arg/L in drinking water recorded the significantly lowest values compared with the other groups and statistically equals with control group. Results of IgG, IgM, TAC and MDA for the group supplied with 2 g L-Arg/L were significantly improved compared with other experimental groups. In conclusion, supplementation growing rabbit males by 2 g L-Arg/ L in drinking water could improve productive performance, immunity and economic efficiency under summer conditions.

Status and origin of Egyptian local rabbits in comparison with Spanish common rabbits using mitochondrial DNA sequence analysis

<p>Mitochondrial DNA (mtDNA) and cytochrome b (cyt b) gene sequences were used to determine the status of genetic diversity and phylogeny for 132 individuals from local rabbit breeds in Egypt and Spain. The Egyptian local rabbit breeds were Egyptian Red Baladi (ERB), Egyptian Black Baladi (EBB) and Egyptian Gabali Sinai (EGS). However, the Spanish local rabbit breed was Spanish common rabbit (SCR). Previous breeds were compared with European Wild Rabbit taken from Albacete, Spain (EWR). A total of 353 mutations, 290 polymorphic sites, 14 haplotypes, 0.06126 haplotype diversity and -1.900 (<em>P</em><0.05) for Tajima’s D were defined in this study. Haplotype A mostly occurred in 83.3% of Egyptian rabbits and 11.7% of EWR, while haplotype B occurred in 63.8% of Spanish rabbits and 36.2% of the EGS breed. A total of 47 domestic and wild <em>Oryctolagus cuniculus</em> published sequences were used to investigate the origin and relation among the rabbit breeds tested in this study. The most common haplotype (A) was combined with 44.7% of published sequences. However, haplotype B was combined with 8.5%. Haplotypes of Egyptian, SCR and EWR were scattered in cluster 1, while we found only one EGS haplotype with two haplotypes of EWR in cluster 2. Our results assumed that genetic diversity for ERB, EBB and SCR was very low. Egyptian breeds and SCR were introduced from European rabbits. We found that ERB and EBB belong to one breed.</p>

ESTIMATION OF GENETIC DIFFERENCES BETWEEN RABBIT BREEDS USING MICROSATELLITE LOCI ON CHROMOSOMES 5, 7 AND 19

The objective of this study was to differentiate between five rabbit breeds at four microsatellite loci on autosomal chromosomes 5, 7 and 19, and to assess the association between detected microsatellite alleles and some economical traits. The breeds were Baladi White (BWH) and Baladi Red (BR) as native Egyptian breeds, and New Zealand White (NZW), American Rex (AR) and Chinchilla (CH) as exogenous breeds. Genomic DNA was extracted from nine individuals/breed, and screened by four pairs of microsatellite markers (Sat5, D7Utr4A, D7Utr4B and D19Utr4B). A total of 26 alleles was detected, with an average of 6.5 alleles per locus. The within-breed genomic variability was in general high, and was not significantly differed between breeds. The expected heterozygosity was also high and ranged from 0.769 in NZW to 0.826 in CH, with no significant differences between the breeds. The average polymorphism information content (PIC) varied from 0.286 in BWH to 0.593 in CH. The genetic distance indices revealed close genetic relationship between BWH and CH and averaged 2.629, however the genetic distance between AR and NZW averaged 3.355. Many alleles were found to associate many growth and reproduction traits. D7utr4A`4 showed significant association with body weight and chest circumference at 8 weeks of age and body length at 8 and 10 weeks of age. The microsatellite locus D7Utr4B on chromosome 7 showed significant association with parity.

Molecular genetic diversity and conservation priorities of Egyptian rabbit breeds

<p>The limited rabbit resources in Egypt are threatened by the danger of extinction, whereas genetic diversity studies of native breeds could play a vital role in conservation and improvement of these breeds. In this study, 3 native rabbit breeds: Gabali (G), Baladi Red (BR) and Baladi Black (BB), in addition to New Zealand White (NZW), were genotyped using 12 microsatellite markers. All the typed microsatellites were polymorphic by average number of alleles 5.25 per locus. Observed and expected heterozygosity per locus averaged 0.62 and 0.68, respectively. The average polymorphic information content was 0.71 and the highest polymorphic information content was recorded in locus SOL33 by 0.85. All the studied loci except SAT7 and SAT2 showed deviation from Hardy-Weinberg equilibrium with significant level. The inbreeding coefficient of the individuals relative to the total population was 0.07. The within-population heterozygote deficit averaged 0.07 and ranged from 0.141 in BR to 0.015 in BB breeds. The highest pairwise differentiation among the populations was recorded between BB and NZW (0.071), while the lowest value was recorded between BR and both of G (0.038) and BB (0.039). The lowest pairwise Nei’s genetic distance was recorded between BR and BB (0.190), while the highest was recorded between NZW and BB breeds (0.409). BR and G populations were clustered together forming an admixed mosaic cluster. BR recorded the highest contribution in the aggregate genetic diversity based on the three prioritisation methods used.</p>

Antioxidant and developmental capacity of retinol on the in vitro culture of rabbit embryos.

SummaryOxidative stress is a major cause of defective embryo development during in vitro culture. Retinoids are recognized as non-enzymatic antioxidants and may have an important role in the regulation of cell differentiation and vertebrate development. However, there are not enough reports discussing the antioxidant and developmental capacity of retinoids, including retinol (RT), on the in vitro development of embryos recovered from livestock animals, particularly in rabbit species. Therefore, morula embryos obtained from nulliparous Red Baladi rabbit does were cultured for 48 h in TCM199 medium in the absence of RT (control group) or in the presence of RT at concentrations of 10, 100 and 1000 nM. The developmental capacity to the hatched blastocyst stage, the antioxidant biomarker assay and the expression of several selected genes were analyzed in each RT group. The data show that RT significantly (P<0.001) promoted the embryo hatchability rate at the concentration of 1000 nM to 69.44% versus 29.71% for the control. The activity of malondialdehyde (MDA) level was significantly (P<0.05) lower in the RT groups than in the control group, while the total antioxidant capacity (TAC), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were significantly (P<0.05) higher following treatment with RT. Furthermore, RT treatment considerably upregulated the relative expression of gap junction protein alpha 1 (GJA1), POU class 5 homeobox 1 (POU5F1) and superoxide dismutase 1 (SOD1) genes compared with the control group. The current study highlights the potential effects of RT as antioxidant in the culture medium on the in vitro development of rabbit embryos.

In vitro development rate of preimplantation rabbit embryos cultured with different levels of melatonin

This study aimed to investigate the effect of melatonin supplementation at different levels in culture medium on embryo development in rabbits. Embryos of 2-4 cells, 8-16 cells and morula stages were recovered from nulliparous Red Baladi rabbit does by laparotomy technique 24, 48 and 72 h post-insemination, respectively. Normal embryos from each stage were cultured to hatched blastocyst stages in either control culture medium (TCM-199 + 20% fetal bovine serum) or control supplemented with melatonin at 10(-3) M, 10(-6) M or 10(-9) M. No effect of melatonin was found on development of embryos recovered at 24 h post-insemination. The high level of melatonin at 10(-3) M adversely affected the in vitro development rates of embryos recovered at 48 h post-insemination (52 versus 86, 87 and 80% blastocyst rate; 28 versus 66, 78 and 59% hatchability rate for 10(-3) M versus 10(-9) M, 10(-6) M and control, respectively, P< 0.05). At the morula stage, melatonin at 10-3 M significantly increased the in vitro development of embryos (92% for 10(-3) M versus 76% for control, P < 0.05), while the hatchability rate of these embryos was not improved by melatonin (16-30% versus 52% for melatonin groups versus control, P < 0.05). Results show that a moderate level of melatonin (10(-6) M) may improve the development and hatchability rates of preimplantation rabbit embryos. The addition of melatonin at a 10-3 M concentration enhances the development of rabbit morulae but may negatively affect the development of earlier embryos. More studies are needed to optimize the use of melatonin in in vitro embryo culture in rabbits.

Haematological and biochemical observations in four pure breeds of rabbits and their crosses under Egyptian environmental conditions.

&lt;span style="font-size: small;"&gt;&lt;span style="font-size: 13px; line-height: 14px;"&gt;The present study was conducted to evaluate 16 crosses between 4 breeds of rabbits from a physiological point of view. The breeds tested were Baladi Red (BR), Chinchilla Giganta (ChG), French Giant Papillon (FGP) and Simenwar (S). A total number of 6144 blood samples were collected to detect the effect of crossing, age of kits, month of kindling and sex effects. The traits evaluated were: haematological parameters; red blood cell count (RBCs), haemoglobin concentration (Hb), haematocrit value (Ht%), biochemical parameters of plasma; total protein (TP), albumin (Alb), globulin concentration (Glo), albumin/globulin ratio (Alb/Glo) and triglycerides (TG). BR or its crosses, using BR sires or BR dams, showed the highest value of RBCs, Hb and Ht%. Crossbred rabbits obtained from mating BR and FGP rabbits had the highest Glo values. Rabbits which were born in May-June months had the highest values of TP and its fractions (Alb and Glo). Age of kits had a highly significant effect (P&amp;lt;0.001) on RBCs, Hb, Ht%, TP and TG. Moreover, Glo and Alb/Glo ratio (P&amp;lt;0.01) and Alb (P&amp;lt;0.05) were also significantly affected. Sex had no significant effect on all studied parameters. Significant positive correlations were found between TP and each final body weight, total weight gain, total feed intake, carcass weight and dressing percentage, while significant negative correlation was found with feed conversion.&lt;/span&gt;&lt;/span&gt;

PERFORMANCE OF 3 RABBITS STRAINS AND THEIR RECIPROCAL CROSSES IN EGYPT DURING SUMMER.

The present work was conducted to study the performance of 3 rabbits strains: New Zealand White (NZW), Baladi Black (BB) and Baladi Red (BR) and 4 of the reciprocal crosses between NZW and Baladi rabbits, during hot summer of Egypt. Values of litter size at birth, weaning (28 days) and marketing ages (84 days) did not differ significantly as affected by genotype, sex or the interaction between them. Mortality values of offspring from birth to weaning age differed significantly (P<0.01) among the 7 genetic types and NZWxNZW showed the lower value (5.4%), while BRxBR showed the highest value (41.1 %). They were no significant differences for mortality from weaning to marketing age due to the effect of genotype, sex or interaction between them. Kit weight at birth was significantly higher (P<0.05) for crossbreds (72 to 78g) than purebreds (48 to 54g), the same trend was realized at marketing age, except for BBxBB group. Significant (P<0.05) interaction between genotype and sex was shown for kit weight at birth, females of BBxNZW cross showed the highest kit weight at birth (80 g). Male kits significantly (P<0.05) surpassed the female kits in marketing live weight at 12 weeks of age (1420 vs 1357 g). The difference between purebred and crossbred groups in the average daily gain was statistically significant (P<0.05) from birth to weaning age (0-28 daY.s). Reciprocal crosses between NZW and BB were of heavier da1ly gain than that of the reciproca! crosses between NZW and BR. From weaning to marketing age (28-84 days), daily gain of the crossbred groups was superior (17.5 to19.4g/day) and the liveweight heavier than that of the purebred ones (14.1 to 16.4g/day). Positive superiority for the studied crosses was observed for the litter size at weaning, mortality rate from birth to weaning, live weight at birth and weight gain from weaning to marketing age.

HETEROSIS, MATERNAL AND DIRECT GENETIC EFFECTS FOR LITTER PERFORMANCE AND REPRODUCTIVE INTERVALS IN RABBIT CROSSES

A crossbreeding experiment was carried out in Egypt involving a local breed (Baladi Red, BR) was and an exotic one (New Zealand effects White, and N ) to estimate direct heterosis, maternal additive effects and direct additive effects on some litter traits and reproductive intervals in doe rabbits. Litter traits included litter size and weight and mean yourg weight (at birth, 21 days and at weaning), number bom alive and preweaning litter gain and mortality, while reproductive intervals included days open (interval from kindling to next conception) and kindling interval (period between two consecutive parturitions). Data were analysed using a linear mixed model. Winter kindlings recorded the largest litter size and the heaviest weight and gain of litter weight up to weaning along with the lowest preweaning mortality compared to autumn and spring kindlings. Heterosis was found at weaning on litter size and weight at weaning and on some interval traits but not on litter size at birth, where negative values are found. Crossbred litters obtained from mating BR bucks with NZ does were generally associated with superiority compared to those litters obtained from the reverse mating. Maternal additive effects on all letter traits were in favor of NZ breed, although the differences between the two breeds were not significant. In terms of reproductive intervals, BR-mothered litters. For all litters traits and reproductive intervals, the direct additive effect was not significant. NZ-sired litters had higher direct additive effects compared to BR-sired litters, while BR-sired litters recorded shorter reproductive intervals relative to NZ-sired litters.

Crossbreeding effects for post-weaning growth traits in a project of Spanish V-line with Baladi Red Rabbits in Egypt

A four-year crossing scheme involving Spanish V line (V) and Egyptian Baladi Red (B) rabbits was carried out to produce five genetic groups: V, B, 1/2B1/2V(F 1), (1/2B1/2V) 2(F 2), and ((1/2B1/2V) 2) 2. The last genetic group was considered a new line, named APRI. Body weights (BW) and daily gains in weight (DG) from four to twelve weeks were evaluated for 13,383 rabbits produced by 330 sires and 1074 dams. An animal model was used to estimate heritabilities and common litter effects and a generalized least squares procedure was used to estimate direct additive effects, and direct and maternal heterosis. Heritabilities for growth traits were mostly moderate, ranging from 0.075 to 0.240 for BW and from 0.020 to 0.104 for DG. The V line was heavier and had better gains at each weighing than B rabbits. The F 2 and APRI were also lower in most post-weaning growth performance measures than V line rabbits. APRI rabbits were significantly lighter by 39, 26, 46, 64, and 50 g at ages of 4, 6, 8, 10, and 12 weeks, respectively, relative to the purebred V line, while APRI was significantly heavier by 36 and 127 g relative to the B line at 4 and 12 weeks. The V line, in general, had a higher DG than B line. The differences were 3.15, 7.91 and 1.95 g/d at age intervals of 8–10, 10–12 and 4–12 weeks. Differences in direct additive effects between the two lines were in favor of V line rabbits reaching 15.0% (76 g) at 4 weeks and 13.3% (195 g) at 12 weeks. Direct additive effects for DG were significant during most age intervals reaching 35.7% (7.19 g/d) in the interval of 10–12 weeks. All estimates of direct heterosis were positive and ranged from 4.9 to 16.7% for BW and 14.4 to 29.5% for DG, but the estimates for maternal heterosis were, in most cases, significantly negative and ranging from − 4.5 to − 15.2% for BW and from 20.6 to − 36.9% for DG. If the results are confirmed at commercial farms, the APRI line could be reared in heat stress conditions.

Diazinon toxicity affects histophysiological and biochemical parameters in rabbits

Diazinon is a widely used pesticide in agriculture. So, the current work aimed to investigate the effects of diazinon exposure on some physiological and biochemical parameters, as well as, histopathological changes and histochemical acetyl-cholinesterase activity (AChE). The red Baladi rabbits were dipped into water (Control Group), diazinon at low concentrations of 0.6 mg diazinon low concentration (DLC) or high concentration of 3 mg diazinon high concentration (DHC) dissolved in 1 l of water for 10 s. Treatment was repeated after 10 days and animals were sacrificed between 0 and 21 days after the second treatment. Blood analysis revealed that Red blood cells (RBC's), hemoglobin (Hb) and plasma total protein (TP) were significantly decreased in both diazinon concentrations ( P<0.01), ( P<0.05), ( P<0.01) respectively. Cholesterol and microsomal protein were increased ( P<0.01), while, liver/ body weight and cytochrome P-450 were decreased in both concentrations ( P<0.01). Also there was a highly significant effect of concentration X day interaction on all parameters ( P<0.01). Histopathological changes of liver, kidney and brain were observed after DHC dipping. Glycogen content was decreased in liver and increased in kidney Bowman's capsule. Furthermore, AChE activity was inhibited in brain tissue, decreased in liver cells, but gradually increased in kidney glomerular cells. Therefore, kidney and brain were highly affected by diazinon exposure compared with the liver. Exposure of animals to diazinon caused extensive changes in physiological, biochemical, and histopathological parameters as well as histochemical AChE. So, contact exposure of diazinon leads to negative response on animal health.

Changes in sources of shared variability of body size and shape in Egyptian local and New Zealand White breeds of rabbits during growth

Abstract. Correlations between body weight and measurements (body length, thigh circumference, shank length and chest width) at 6, 8, 10 and 12 weeks of age in New Zealand White (NZW), Red Baladi (RB), Black Baladi (BB) breeds of rabbits were studied by factor analysis to disclose the main sources of shared variability, to deduce the factors that describe these characteristics and to quantify breed differences in morphometric size and shape variation during growth. Differences and similarities between NZW and Egyptian rabbit breeds in factors describing variations in size and shape characters are discussed. At marketing age, compared with local breeds (RB and BB), NZW had higher communality (proportion of variance for a variable that is shared in common by other variables) for chest width and lower communality for body weight and other body shape characters. Compared with NZW, Egyptian breeds varied more in size and less in shape characters. Finding indicated that most of the common variability in live performance traits could be accounted for by two factors with the influence of general factor preponderating. Irrespective of breed, the first factor at various ages was interpreted as a general size factor. The second factor varies with breed and stage of development. In NZW, this factor at all ages (6 to 12 weeks) was described as chest width factor. The second factor in RB was designated to chest width (at 6 and 8 weeks) and a shank length at 10 and 12 weeks. In BB, the second factor was designated to chest width (at 6 weeks), a shank length (at 8 and 10 weeks) and to thigh circumference (at 12 weeks). The importance of the general size factor in relation to the second factor (shape) changes with age. The contribution of the general size factor to the total variance decreased with age in both NZW and RB, but it showed irregular pattern in BB. While that of the second factor increased with advancing age from 6 to 12 weeks in RB and from 6 to 10 weeks in NZW.

Sources of shared variability among body shape characters at marketing age in new zealand white and egyptian rabbit breeds

Body measurements (body length, thigh circumference, shank length and chest width) of 311 rabbits representing three breeds, New Zealand White (NZW), Red Baladi (RB) and Black Baladi (BB) purebreds were subject to factor analysis. The objectives of this study were (a) to disclose the main sources of shared variability among body shape characters, (b) deduce the factors that describe these traits, (c) quantify the breed differences in size and shape and (d) predict live weight at marketing age from orthogonal body shape characters. Body conformation 'shape' appeared to be controlled by common and unique factors. The communalities ranged from 0.80 for chest width to 0.99 for thigh circumference and uniqueness (special factors) made the balance. Compared with local breeds (RB and BB), NZW had higher communality (proportion of variance for a variable that is shared in common by other variables) for chest width and lower communality for thigh circumference and body length. Our findings indicated that most of the common variability in NZW body dimensions could be accounted for by factors representing general size and chest width. Corresponding factors in RB were general size and shank length and those in BB were general size and thigh circumference. Independent body shape characters derived from factor analysis accounted for 83.4%, 87.9% and 90.8% of the variation in live body weight in New Zealand White, Red Baladi and Black Baladi, respec- tively. New Zealand White rabbits / Egyptian rabbits / body dimensions / multicollinearity / factor analysis / shared variability

Rabbit genetic resources of Egypt

SummaryIn Egypt, there are three breeds of rabbits, Giza White, Baladi and Gabali. For Baladi rabbits, there are three strains; Baladi Red, Baladi White and Baladi Black, while Sinai Gabali and Desert Gabali are considered the two strains of Gabali rabbits. Giza White rabbits are usually called improved Giza or El-Giza El-Mohassan. These Egyptian rabbits are medium-sized breeds and used mainly for meat production. Giza White and Baladi rabbits are docile, while Gabali rabbits are moderately tractable. Origin, physical description, and census data for these Egyptian genetic resources were described. Also, they were characterized with regard to their performance (e.g. reproductive efficiency, lactational and maternal abilities, growth rate, feed conversion ratio, carcass traits and meat composition, hair and fur quality, etc.) and adaptability to heat stress.

Factors influencing the weight of the doe during pregnancy in different breeds of rabbits

The effect of breed, year of production, age of doe at conception, season of conception and parity on doe's weight at conception, at the 1st, 2nd, 3rd and 4th week of gestation, after kindling and on doe's total weight gain during gestation were studied using data from 250 pregnant does from five breeds of rabbits: Bauscat, Giza White, Baladi Red, Gray Giant Flander and Baladi White. Breed and year of production were the most important factors affecting doe's weight during pregnancy and after kindling while the other factors were of minor influence. Age of doe at conception was not significant for all the weights and total weight gain recorded. Season of conception was the most important factor affecting doe's total weight gain during gestation while all the other factors were of minor importance. The effect of parity was significant for doe's weight at the 4th week of gestation, otherwise it was not significant for the weights and total weight gain recorded. Breed rank for doe's weight at different stages of gestation differed from that for doe's total weight gain during pregnancy. Weights and total weight gain of pregnant does recorded during 1978/79 were higher than those recorded during 1977/78.