Rabbit Carcass Research Articles

Compost-sourced substances (SBO) as feedstuff additives in rabbit production

Acid soluble bio-organic (SBO) substances have been extracted from plant bio-waste. The SBOs have been tested as feed additives for reared animals. Two trials (T1 and T2, lasting 63 and 56 days, respectively) were carried out to evaluate the effect of different doses of SBOs as feed additives in diets for fattening rabbits (131 and 120 animals from 35 days of age, respectively) and as binders for the manufacturing of diet pellets to improve their physical properties. The effect of different SBO doses (0, 0.5, 2.5g/kg for T1 and 0, 5, 10g/kg for T2) on the growth performance, health status, diet digestibility, carcass and meat traits of rabbits was studied. The aggregating effect of SBOs on feed particles during pelleting was studied by adding 50 and 100g/kg of SBOs to a feed, and then measuring the shear and compression force on the pellets. The results have shown that SBO supplementation of rabbit diets at a concentration of 0.5–10g/kg does not affect the live and slaughtering performances, except for the intestinal tract absorption area (higher in the intestines of rabbits fed with a high supplementation of SBO; P<0.05) or the dry matter, organic matter, ether extract, fibre and gross energy apparent digestibility of the feed (lower in diets with low or no supplementation of SBO; P<0.05). The rabbits fed with the lower SBO dose showed higher values of total anaerobic bacteria and Bacteroides (P<0.05) and a higher cadmium meat content (P<0.05) in T1 and T2 than all others groups. SBOs included at concentrations of 10 and 20% were also found to affect the physical properties of the pelleted feed. These pellets are more resistant to shear (P<0.05) and compression force (P<0.01) in the presence of added SBO. It can be concluded that SBO may be used as a feed additive for rabbits, without any adverse effects on animal productivity and health, as well as to improve the physical properties of pelleted feeds.

Dietary supplementation of a bacteriocinogenic and probiotic strain of Enterococcus faecium CCM7420 and its effect on the mineral content and quality of Musculus longissimus dorsi in rabbits

The effect of freeze-dried bacteriocinogenic and probiotic strain Enterococcus faecium CCM7420 on the mineral content and carcass quality of rabbits was investigated. Significant increase in iron content in the carcass samples was recorded during the probiotic treatment, whereas the concentrations of calcium and copper decreased in the experimental groups compared with the Control. The treatment did not have a negative influence on the pH, colour, water-holding capacity, protein and fat contents or energetic value of the rabbit carcass. Inferring from the higher iron content we conclude that the diet supplementation with bacteriocinogenic and probiotic strain E. faecium CCM7420 may enhance the mineral quality of rabbit meat.

Blowfly Larval Tissues as a Secondary Detector for Determining Paraquat‐Related Death in Rabbit Carcass

Paraquat poisoning is commonly associated with suicide or homicide in Malaysia. In a case involving advanced body decomposition, pathological analysis regarding the cause of death may become difficult or almost impossible. Insects serve as common alternative matrix for poison detection in forensic analysis. Paraquat detection via secondary bioaccumulation in fly larvae tissue has never been reported. In this study, tissues from blowfly larvae collected from a rabbit carcass with paraquat poisoning were analyzed for secondary bioaccumulation. Larvae samples were collected and analyzed using liquid-liquid extraction. The detection was performed via reduction of quaternary ammonium presence in paraquat and analyzed using gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring mode (SIM mode). GC-MS showed the elution of reduced paraquat was at retention time 12.8min. Blowfly larvae tissue has proven useful as a secondary detector in paraquat-related deaths.

Experimental study of bone modification by captive caracal (Caracal caracal); a model for fossil assemblage analysis

Medium-size animals such as rabbits and hares are common occurrences in fossil assemblages, and make up a large part of the diet of many carnivores. However their mode of accumulation, especially in African localities is poorly understood. This investigation undertook experimental feeding of domestic rabbit carcasses to captive caracal (Caracal caracal), in order to create a taphonomic model of bone modifications that can be applied to fossil assemblages. We investigated the modification patterns of both the feeding refuse (non-ingested) and the scatological remains. The anatomical composition, breakage patterns, digestive modifications and tooth marks are described. The caracals preferentially fed on high yield parts of the rabbit carcass and discarded low yield parts like the cranium and feet, a pattern that has been observed in wild and captive coyotes when food resources are abundant. Rabbit remains from the caracal displayed poor survival, relative to other small carnivores. Fragmentation in the scat assemblage was high. Bones were extensively but lightly digested and carnivore tooth marks were frequent. This investigation provides a model of bone modification in a carnivore that while common in fossil localities has received little taphonomic attention. The study also exhibits how detailed actualistic investigations can provide information that may aid palaeoecological interpretations.

Effect of dietary supplementation of spirulina (Arthrospira platensis) and thyme (Thymus vulgaris) on carcass composition, meat physical traits, and vitamin B12 content on growing rabbits

The aim of this study was to compare the effect and duration of dietary inclusion of 5% spirulina (Arthrospira platensis) and/or 3% thyme (Thymus vulgaris) on growing rabbit carcass composition, meat and bone rheological traits, and the vitamin B12 content of Longissimus dorsi (LD) meat. The study involved 294 maternal line growing rabbits from the Pannon breeding programme. At weaning (5 wk), animals were randomly divided by dietary treatment into 7 groups of 42 rabbits each. A control group (C-C) received a pellet with no supplementation throughout the trial (5-11 wk of age), whereas the other groups were fed diets supplemented with 5% spirulina (S), 3% thyme (T) or with both ingredients (ST) for either the entire growing period (5-11 wk of age; groups: S-S, T-T, ST-ST, respectively), or its final part only (8-11 wk of age; groups: C-S, C-T, C-ST, respectively). Results showed that regardless of the duration of supplementation, spirulina and thyme provided no effect on the traits examined, except for scapular fat content, whose value was higher in the S-S group than in the C-T group (P&lt;0.05). Spirulina was confirmed as a rich source of vitamin B12 that was successfully transferred into LD meat, thus demonstrating its value as an effective natural supplement in producing food fortified with this vital element. Further studies are necessary to clarify the effect of spirulina on carcass fat deposition, bone development, and mineralisation.

Bicellular cage vs. collective pen housing for rabbits: Growth performance, carcass and meat quality

The aim of this study was to compare the growth performance, slaughter results, and carcass and meat quality of rabbits reared in different housing systems. To this purpose, 456 Hyplus crossbred rabbits were reared from weaning (35d of age) until slaughter (77d) in 40 bicellular wire net cages (28×40×28cm3; 2 rabbits/cage; 18animals/m2); 4 small collective pens (1.40×1.20m2) at low stocking density (20 rabbits/pen; 12animals/m2); 4 small collective pens at high stocking density (27 rabbits/pen; 16animals/m2); 2 large collective pens (1.40×2.40m2) at low stocking density (40 rabbits/pen; 12animals/m2); and 2 large collective pens at high stocking density (54 rabbits/pen; 16animals/m2). The housing of rabbits in collective pens decreased final live weight (2839 vs. 2655g; P<0.01), daily weight gain by 10.0% (P≤0.01), and feed intake by 10.7% (P=0.001), compared with rabbits housed in bicellular cages, without affecting feed efficiency. At slaughter, the rabbits from collective pens showed lower live weight, carcass weight, dressing percentage (60.5% vs. 59.5%), dissectible fat proportion (3.0% vs. 2.1%), and hind leg muscle-to-bone ratio (7.53 vs. 6.63) compared with those from bicellular cages (P<0.001); the former rabbits had shorter (P<0.05) and thicker femurs (P=0.01). Within the collective pens, the increase in the stocking density from 12 to 16 rabbits/m2 increased only the slaughter dressing percentage (59.4% vs. 59.8%; P=0.05) and the femur resistance to fracture (39.9kg vs. 45.5kg; P<0.01). Pen size affected meat quality: meat pH was lower (5.72 vs. 5.76 for Longissimus lumborum muscle; 5.98 vs. 6.00 for Biceps femoris muscle; P=0.05) and cooking losses were higher (L. lumborum: 30.0% vs. 28.8%; P<0.01) for rabbits reared in small pens compared with those in large pens. Additionally, femur maximum diameter was lower in rabbits kept in small pens compared to those in large pens (P=0.05). In conclusion, rearing rabbits in collective pens impaired growth performance and slaughter results compared to rabbits kept in bicellular cages, regardless of stocking density or pen size. However, the skeletal development of the animals improved in collective systems, whereas meat quality was only slightly affected by the housing system.

Carcass and meat quality traits of rabbits under heat stress

Rabbits are very sensitive to heat stress because they have difficulty eliminating excess body heat. The objective of the current study was to evaluate the effects of heat stress on slaughter weight, dressing percentage and carcass and meat quality traits of rabbits from two genetic groups. Ninety-six weaned rabbits were used: half were from the Botucatu genetic group and half were crossbreds between New Zealand White sires and Botucatu does. They were assigned to a completely randomized design in a 2 × 3 factorial arrangement (two genetic groups and three ambient temperatures: 18°C, 25°C and 30°C) and kept under controlled conditions in three environmental chambers from 5 to 10 weeks of age. Slaughter took place at 10 weeks, on 2 consecutive days. Meat quality measurements were made in the longissimus muscle. Actual average ambient temperature and relative humidity in the three chambers were 18.4°C and 63.9%, 24.4°C and 80.2% and 29.6°C and 75.9%, respectively. Purebred rabbits were heavier at slaughter and had heavier commercial and reference carcasses than crossbreds at 30°C; however, no differences between genetic groups for these traits were found at lower temperatures. No genetic group × ambient temperature interaction was detected for any other carcass or meat quality traits. The percentages of distal parts of legs, skin and carcass forepart were higher in crossbred rabbits, indicating a lower degree of maturity at slaughter in this group. The percentage of thoracic viscera was higher in the purebreds. Lightness of the longissimus muscle was higher in the purebreds, whereas redness was higher in the crossbreds. Slaughter, commercial and reference carcass weights and the percentages of thoracic viscera, liver and kidneys were negatively related with ambient temperature. Commercial and reference carcass yields, and the percentage of distal parts of legs, on the other hand, had a positive linear relationship with ambient temperature. Meat redness and yellowness diminished as ambient temperature increased, whereas cooking loss was linearly elevated with ambient temperature. Meat color traits revealed paler meat in the purebreds, but no differences in instrumental texture properties and water-holding capacity between genetic groups. Purebred rabbits were less susceptible to heat stress than the crossbreds. Heat stress resulted in lower slaughter and carcass weights and proportional reductions of organ weights, which contributed to a higher carcass yield. Moreover, it exerted a small, but negative, effect on meat quality traits.

Effects of water restriction on growth performance, feed nutrient digestibility, carcass and meat traits of rabbits

The study investigates the effects of a post-weaning water restriction on performance, nutrient digestibility, carcass traits and meat quality of 84-day-old rabbits. A total of 1388 weaned rabbits (35 days) were randomly divided into two groups on the basis of BW and sex. The two groups were fed the same diets ad libitum both in the post-weaning (35 to 60 days) and fattening (61 to 84 days) periods. In the post-weaning period, one group (AL) also received drinking water ad libitum, whereas the other (WR) had a water restriction from 35 to 41 days 2 h/day; from 42 to 48 days 2.5 h/day; from 49 to 55 days 3 h/day; and from 56 to 60 days 4 h/day. During the fattening period, both groups had water-free access. Individual live weights and feed intake per cage were recorded weekly for 32 cages randomly chosen per group (64 rabbits) to calculate the BW gain, feed intake and feed conversion ratio (FCR). The apparent digestibility values of nutrients were measured using acid-insoluble ash. Carcass data were collected from 16 rabbits (8 males and 8 females) per group selected for similar final BW in both groups. Mortality from 35 to 60 days was higher in the AL group (10.1% v. 5.2%, for AL and WR, respectively, P < 0.0001). BW gain was higher for the AL group during both the post-weaning (+22.4%, P < 0.01) and the entire period (+7.5%, P < 0.05). Water restriction reduced feed intake both in the post-weaning (−17.4%, P < 0.0001) and in the entire period (−9.9%, P < 0.05). During the fattening period, FCR was lower for the WR group (5.15 v. 5.75 g/g, for WR and AL, respectively, P < 0.05). The apparent digestibilities of dry matter, organic matter, NDF, ADF and cellulose were greater in the restricted rabbits (+4.7%, +4.5%, +10.2%, +18.8% and +12.8%, P < 0.01, P < 0.01, P < 0.05, P < 0.01, P < 0.05, respectively). Perirenal and scapular fat percentages were higher in the AL rabbits (+30.7% and +116.6%, P < 0.01 and P < 0.001, respectively). Water restriction increased saturated fatty acids (C16:0, +12.9%, P < 0.05), lauroleic acid (C12:1, +75.0%, P < 0.01), n-3 polyunsaturated fatty acids (C20:5, +50.0%, P < 0.01 and C22:5, +16.6%, P < 0.05) and the n-3/n-6 ratio (+28.6%, P < 0.05). The applied water restriction between 35 and 60 days executed during the winter months improved the digestive health of rabbits, with no negative effects on carcass traits, or physical and chemical meat characteristics. However, from the animal welfare point of view, a water restriction can be criticized as a method to restrict feed intake.

Real-time ultrasound to predict rabbit carcass composition and volume of longissimus dorsi muscle

Real-time ultrasonography (RTU) was used to measure the longissimus dorsi muscle (LM) volume in vivo and to predict the carcass composition of rabbits. For this, 63 New Zealand White × Californian rabbits with 2093±63 g live weight were used. Animals were scanned between the 6th and 7th lumbar vertebrae using an RTU equipment with a 7.5 MHz probe. Measurements of LM volume were obtianed both in vivo and on carcass. Regression equations were used for the prediction of carcass composition and LM volume using the LM volume measured obtained with RTU (LMVU) as independent variable. Carcass meat, bone and total dissectible fat weights represented 780, 164 and 56 g/kg of the reference carcass weight, respectively. Regression equations showed a strong relationship between LMVU and the correspondent volume in carcass. Furthermore, LMVU was also useful in predicting the amounts of carcass tissues. It is possible to predict LM volume in the carcass using the LM volume measured in vivo by RTU. The amount of carcass tissues can be predicted by the LM volume measured in vivo by RTU.

Abstracts of the XXXVI Symposium de cunicultura de ASESCU, 2011

The annual Congress of the Spanish Association of Cuniculture (ASESCU) was held in Peñíscola (province of Castellón, autonomous community of Valence) on 12-13th May of 2011. The 36th edition was devoted to analyse the actual situation of the rabbit sector. It was presented an overview of the situation of the rabbit farming in the province of Castellón, an analysis of the factors that determine the final price of the rabbit meat in the market. Moreover, a special session devoted to the rabbit farmers studied the environmental control in the farms and the main factors influencing the profitability in the rabbit farming. Main papers related to coccidiosis, mixomatosis and, and a summary of the norm extension carried out by the Spanish Rabbit Interprofessional (INTERCUN) were also presented in three different conferences. Furthermore, a total of 32 communications were presented in seven working sessions. Nutrition session analysed diet digestibility in lactating does, the increasing of soluble fibre and starch in diets for growing rabbits, the effect of a feed restriction in fattening rabbits, pre-weaning feeding management of growing rabbits and does, the inclusion of palm kernel meal in diets for growing rabbits, and the digestibility of Lablab purpureus and Stizolobium niveum. Technico-economic management session studied concepts for improving profitability of farms. Genetics session evaluated several maternal lines and cross does for longevity, and studied doe genetic origin, environmental conditions during lactation and kit survival during the fattening period. Ethology session analysed aggressiveness in breeding does, the effect of type of cage on does behaviour, and evaluated sampling techniques for assessing does behaviour. Reproduction and Body Composition session studied several aspects related to the body composition of does, the application of biolectrical impedance for its assessment, the effect of different treatments of ovulation induction, and the relation between the performance of the does and plasma concentration of non-esterified fatty acids. Carcass Quality session analysed the prediction of intramuscular fat and fatty acid content in rabbit meat by near infrared spectroscopy, the nutritional quality of rabbit meat fed with a feed enriched in Omega 3, risk factors related to rabbit digestive pathologies on carcass classification, the anatomical assessment and meat quality, and prediction of rabbit carcass composition using visual image analysis. Pathology section studied the use of the Pheneplate System for autovaccine design, the effect of heat stress on the immune system of rabbit does, the characterization of nasal carried Staphylococcus aureus strains, the pharmacokinetic of marbofloxacin and several fluoroquinolones, and the development of a subunit vaccine against rabbit hemorrhagic disease virus.

Carcass and Non-carcass Traits of Local Rabbits Fed Different Sources of Fodder in Sudan

Carcass and Non-carcass Traits of Local Rabbits Fed Different Sources of Fodder in Sudan

Effect of dietary type and level of fibre on rabbit carcass yield and its microbiological characteristics

The aim of this trial was to study the effect of level and type of fibre during the last week of the fattening period on carcass characteristics. A total of 6602 rabbits (New Zealand×Californian) were divided in three groups and fed with three different diets: HFBP diet (39.6% NDF, 10% beet pulp), HFS diet (39.4% NDF, 8% straw) and LFS diet (37.2% NDF, 4% straw). Feed intake was measured collectively by weighing the feed consumed during the whole experimental period. Thirty two cages were assigned to each replicate that housed around 300 animals, resulting in 7, 7 and 6 replicates for HFBP, HFS and LFS, respectivley. Twenty eight animals per diet, except for the LFS diet with 24 animals, were selected at random to determine the individual carcass yield and the weight of anatomical parts of the digestive tract. Samples of caecal content, the Longissimus dorsi, and Biceps femoris were taken (12 or 14 rabbits per treatment) to determine microbiological counts. The evolution of bacteriological count on the carcass was measured on days 1, 7 and 11 after slaughter. Temperature and pH in Biceps femoris were measured 24h post mortem (12 or 14 rabbits per treatment). Animals fed with the lowest dietary fibre content (LFS) had higher carcass yield (2.7%; P=0.005) and lower bacteriological counts on the carcass (P<0.05) than animals fed HFS or HFBP diets. The type of fibre (beet pulp or straw) did not affect carcass yield but the temperature was higher (0.63°C; P=0.016) and the Enterobacteriaceae and coliform counts were higher in the muscles of the animals fed the HFS diet (P<0.05). A gradual increase with time in storage at 4°C was observed in the microorganism content of the carcass. The highest values were reached at last day of measurement at 11days after slaughter (P<0.001), especially for coagulase-positive Staphylococci in animals fed HFS diet. From these results, it may be concluded that a decrease of dietary fibre (from 39 to 37% NDF) when insoluble fibrous sources (straw) are included, enhances the carcass yield and the carcass microbiological quality. For the same level of fibre, the inclusion of a moderate amount of beet pulp, improved the microbiological characteristics without impairment of carcass yield.

XXXV Symposium de Cunicultura de ASESCU

The annual Congress of the Spanish Association of Cuniculture (ASESCU) was held in Segovia (Castilla y Le&oacute;n) on 27-28th May of 2010. The 35th edition was devoted to analyse the actual situation of the rabbit sector. It was presented an overview of challenges for the future of the Spanish rabbit farms, a review of the competitive factors that affect the rabbit production, and the management systems to ensure food safety in rabbit farms. Moreover, the Technology Platform for Sustainable Agriculture, and a summary of the actions for the promotion of the rabbit meat consumption carried out by the Spanish Rabbit Interprofessional (INTERCUN) were presented in two different conferences. Furthermore, a total of 20 communications were presented in five working sessions. Pathology session analysed a vaccine candidate against RHD, blood lymphocyte populations in multiparous does, the efficacy of Timilcosin, and serological test of blood samples collected in filter paper. Reproduction session studied a new method for artificial insemination, the effect of sperm DNA fragmentation on fecundation ratio, and the effect of development on seminal parameters in bucks. Management and Welfare session included references about the need to carrying technical-economic management in the farms and the link between cage height and welfare. Nutrition session analysed feeding costs, the effect of birth weight and rearing diet on the reproduction of does, the effect of feeding restriction on the productive and pathological parameters of fattening rabbits, the use of barley and lucerne hay on performance of growing rabbits, the effect of dietary short-chain organic acids on performance of growing rabbits, and the influence of a liquid alimentary supplement on fattening rabbits. Morphophysiology and Body Composition session studied intestinal barrier mechanisms and bone content of wild rabbit carcass. &nbsp

Heterosis, direct and maternal additive effects on rabbit growth and carcass traits from a Canadian experiment

A total of 479 male and female rabbits from the Californian (CA), American Chinchilla (CH) and New-Zealand White (NZ) breeds and nine crosses between them were used in this experiment. This study aimed to estimate heterosis and direct and maternal additive effects as well as some non genetic effects on rabbit growth and carcass traits in order to identify the most appropriate crossbreeding plan to use for rabbit meat production under Quebec conditions. Each rabbit was identified and weighed individually at weaning (35 d) and at slaughter (63 d). Rabbits were slaughtered after an 18 h fasting period from feed only. Statistical analyses were performed solving fixed models that allow different variances between genetic types. Significant statistical differences were obtained between genetic types for rabbit growth performance. Rabbits from purebred NZ females mated to CA and NZ males or from CA×NZ and NZ×CH crossbred females mated to NZ males ranked first for live weight at 35 and 63 d body weight and for average daily gain (ADG). ADG of NZ×NZ, NZ×(NZ×CH) and NZ×(CA×NZ) rabbits reached around 50 g/d and their feed conversion ratio was about 3.4. Significant differences between genetic types were observed for all carcass traits except for meat/bone ratio. Rabbits from CH, NZ, CA×NZ and NZ×CH does mated to NZ males, and from NZ does mated to CA males had the highest commercial carcass weight and the lowest commercial carcass yield (CCY), whereas CH×CA rabbits ranked first with a CCY higher by 4 to 8% than rabbits from other genetic types. The highest hind part yields were obtained with CH×CH, CH×NZ and NZ×CH rabbits. Concerning the intermediate part percentages, the highest values corresponded to the highest CCY. The CH breed had unfavourable direct effects but favourable maternal effects on growth traits. The CA breed had negative maternal effects on weight traits from weaning to slaughtering. The CA and CH breeds had positive direct and negative maternal effects on intermediate part yield of the carcass compared to NZ. Direct heterosis effects were found for body weight traits, particularly in the crosses involving the NZ breed, with a magnitude ranging from 5 to 10% of the parental mean.

Participation of main parts and internal organs in rabbit meat

This study shows the results of examination of main rabbit carcass parts and internal organs. A total of 22 rabbits of mixed breed (Californian and New Zealand rabbits) were examined. The average live mass of the rabbits was 2.467 g varying from 2.000 g to 2.800 g, while the hide participated with 428 g varying from 385 g to 480 g. The head participated with 5.93%, the forelegs and hinde legs participated with 0.8% and 1.94%, and the internal organs participated with 0.51% (lungs) and 17.61% (bowels).

Effect of nutritional status of rabbit kits on their productive performance, carcass and meat quality traits

The effect of nutrient supply at foetal, suckling and growing ages on productive, carcass and meat quality traits of rabbits was studied. New-born rabbits were divided into three groups according to their birth weight (low/L/: 35–50 g, medium/M/: 58–62 g and high/H/: 70–88 g). Half of the litters were nursed by one doe (O) and the other half by two does (T). The kits were weaned at 3 weeks. From the age of 4 weeks, half of the rabbits were fed ad libitum (A), or on a restricted regime (R) (85–90% of the ad libitum feed intake level). Rabbits were slaughtered at 11 weeks of age. Difference in average feed intake between groups L and H, groups O and T and between R and A was 11.2%, 7.8% and 11.7%, respectively; in all cases, the latter groups had the highest intakes. Body weight gain between 3 and 11 weeks was significantly affected by birth weight and feeding regime. Body weight at slaughter of L rabbits was 124 g lower than that of M rabbits and 255 g lower than that of H rabbits (P < 0.05). Group L had the highest dressing out percentage (58.0%), whereas M rabbits had the lowest dressing out percentage (57.3%) (P < 0.05). Ratio of hind part of the reference carcass was higher in group H (39.0%) than in group L (38.1%) (P < 0.05). Percentage of perirenal fat was the highest in L rabbits (2.10%) and the lowest in group H (1.64%) (P < 0.05). Slaughter weight of T rabbits was 198 g higher (P < 0.001) than that of group O. Chilled carcass weight and dressing out percentage were 16 g (P = 0.006) and 0.7% (P = 0.002) lower, respectively, in T rabbits. In consequence of feed restriction slaughter weight, chilled carcass weight and dressing out percentage decreased by 141 g (P < 0.001), 22 g (P < 0.001) and 0.8% (P = 0.001), respectively, while the ratio of liver and kidneys to liveweight increased by 0.57% (P < 0.001) and 0.05% (P < 0.001). Cooking loss of musculus longissimus dorsi (MLD) was 1.8% lower (P < 0.05) in H rabbits compared with L and M animals. Cooking loss was 1.6% lower (P = 0.003) in group T than in group O. Due to the restriction, slaughter weight and dressing out percentage decreased by 141 g (P < 0.001) and 0.8% (P = 0.001), respectively. Feeding regime influenced all meat quality parameters except the b* value of meat colour. Rabbits in R group had 0.08 (P < 0.001) lower pH, while 1.1 (P < 0.001) higher L* and 0.7 (P = 0.008) lower a* values resulted lighter colour of MLD. The cooking loss of MLD of R rabbits was 1.2% higher (P = 0.028). Results show that the foetal and suckling nutrient supply exert a long-term effect, affecting also carcass traits and meat quality.

Evaluation of the House Fly Musca domestica as a Mechanical Vector for an Anthrax

Anthrax is a disease of human beings and animals caused by the encapsulated, spore-forming, Bacillus anthracis. The potential role of insects in the spread of B. anthracis to humans and domestic animals during an anthrax outbreak has been confirmed by many studies. Among insect vectors, the house fly Musca domestica is considered a potential agent for disease transmission. In this study, laboratory-bred specimens of Musca domestica were infected by feeding on anthrax-infected rabbit carcass or anthrax contaminated blood, and the presence of anthrax spores in their spots (faeces and vomitus) was microbiologically monitored. It was also evaluated if the anthrax spores were able to germinate and replicate in the gut content of insects. These results confirmed the role of insects in spreading anthrax infection. This role, although not major, given the huge size of fly populations often associated with anthrax epidemics in domestic animals, cannot be neglected from an epidemiological point of view and suggest that fly control should be considered as part of anthrax control programs.

Effect of dietary betaine supplementation on growth, carcass and immunity of New Zealand White rabbits under high ambient temperature

The objective of this study was to determine the effects of dietary betaine supplementation on growth performance, carcass characteristics, rectal temperature, respiration rate and immune response of growing rabbits under high ambient temperature. A total of 120 weaned New Zealand White male rabbits, 6 weeks old, were randomly divided into five experimental treatments (24 each). Animals were fed ad libitum the basal diet supplemented with 0 (control), 250, 500, 750 and 1000 mg betaine/kg diet from 6 to 12 weeks of age. Animals were provided with water freely. The average daily temperature and relative humidity inside the rabbitry were 30.3 ± 0.9 °C and 76.2 ± 2.5%, respectively. Under heat stress conditions, diet significantly increased the body weight and hot carcass weight and significantly reduced the feed conversion. Dietary 1000 and 750 mg betaine/kg increased ( P < 0.05) final body weights (2529.1 and 2418.5 g, respectively) compared with the control (2110.3 g). Betaine supplementation ameliorated some of the adverse effects of heat stress on immune responsiveness, rectal temperature and respiration rate. Dietary 250, 500, 750 and 1000 mg betaine/kg led to a decrease in rectal temperature (40.03, 39.85, 39.63 and 39.53 °C, respectively) compared with the control (40.20 °C). The inclusion of 1000 mg betaine/kg in the growing rabbits' diets nearly doubled the humoral and immune responses compared to the controls ( P < 0.05) and significantly reduced rectal temperature and respiration rate. Serum T3, T4, total protein, globulin and total lipids were significantly increased while serum glucose concentration was significantly decreased due to dietary betaine. In conclusion, supplemental dietary betaine enhanced growth performance and humoral and cell-mediated immunity as well as reduced rectal temperature and respiration rate in growing rabbits subjected to heat stress. From an economic point of view, high levels of betaine are not recommended because betaine is reasonably effective at lower, less expensive, doses.

Abstracts of 2nd Iberic Rabbit Congress. VILA REAL PORTUGAL JUNE 2007

s of the “2ND IBERIC RABBIT CONGRESS” ASESCU Vila Real, Portugal. 5 6 June, 2007 Meat quality and body composition WATER HOLDING CAPACITY AND PH OF THE HUNTED WILD RABBIT MEAT. GO N Z A L E ZREDONDO P., CAMACHO T., ALCALDE M.J. Dpto. Ciencias Agroforestales, EUITA, Univ. de Sevil la, Sevilla, pedro@us.es Percentage of released water (PRW) of the Longissimus dorsi (LD) and pH of the LD and Biceps femoris (BF) muscles were measured in 53 (49% males) wild rabbits (Oryctolagus cuniculus cuniculus). The pH of LD and BF muscle were 5.96 and 6.03, respectively. Both pH values were positively correlated (r=0.861; P<0.001), being the pH of BF muscle higher (P=0.001). There were no differences between sexes in the pH of both muscles. There were negative correlations between the eviscerated weight of the rabbits and the pH of the LD and BF muscles (r=0.322; P=0.019). PRW from LD muscle was 17.98%, without differences neither between sexes nor due to the eviscerated weight of the rabbits. PRW and pH of LD muscle show a negative correlation (r=-0.433; P=0.001). Both muscles pH values, mainly the one of LD muscle, and PRW of LD muscle, that is described in this paper for the fist time in wild rabbits, were higher in wild rabbits than the described for meat breeds in the literature. These parameters showed comparatively the same tendencies between them, and showed the same influence of the sex and weight that those described for meat breeds in the literature. _______________________________________________________________________________________ RABBIT CARCASS CHEMICAL COMPOSITION PREDICTED BY REAL TIME ULTRASONOGRAPHY. SILVA S.R., GUEDES C., MOURAO J., PINHEIRO V. CECAVUniv. de Tras-os-Montes e Alto Douro, Dpt. Zootec., VilaReal, Portugal. ssilva@utad.pt Ultrasonic measurements were taken on 52 rabbits using a real time ultrasound (RTU) machine equipped with a 7.5 MHz. Measurements of area, depth, width and perimeter Longissimus thoracis et lumborum muscle were taken at the 5th lumbar vertebra to estimate rabbit chemical carcass composition. Estimates based on RTU muscle measurements allow to explain a large amount of variation (r2 between 0.51 and 0.94; P<0.001) of carcass chemical composition. The results suggest that is possible to estimate rabbit carcass composition from in vivo RTU measurements. _______________________________________________________________________________________ STUDY OF BODY COMPOSITION OF RABBIT DOES BY MEANS OF BIOELECTRICAL IMPEDANCE. PART I: BODY COMPOSITION AND IMPEDANCE RESULTS. PEREDA 1 N., REBOLLAR1 P.G., SCHWARZ1 B.F., ARIAS-ALVAREZ2 M., REVUELTA2 L., LORENZO2 P.L., NICODEMUS1 N. 1Dpt. Prod. Animal, ETSIA, Univ. Poli tecnica de Madrid. 2Dpt. Fisiologia Animal, Fac. de Veterinaria, Univ. Complutense de Madrid, Madrid. pilar.grebollar@upm.es. The aim of this experiment was to evaluate the bioelectrical impedance technique (BIA) to estimate in vivo body composition of reproductive rabbit does. Eighty seven female rabbits (New Zealand x Californian, weight range: 3173-5736 g) at different physiological states were used: Pregnant and lactating (GL), pregnant and not lactating (GNL), lactating and not pregnant (LNG), not pregnant and not lactating (NGNL) and nulliparous (NUL). A four terminal body composition analyser (model Quantum II, Q 1174 II, RJL Systems, Clinton Twp. MI USA) was used to determine resistance and reactance values. After BIA assessment (five times), animals were slaughtered and stored at -20o C

Growth, carcass and meat quality traits of straightbred and crossbred botucatu rabbits

The objective was to evaluate the effects of genetic group and age on growth, carcass, and meattraits of rabbits. A total of 144 straightbred Botucatu and White German Giant × Botucatu crossbred rabbitswere involved. Rabbits were weaned at 35 d and sequentially slaughtered, four per genetic group × sexcombination, at: 42, 49, 56, 63, 70, 77, 84 and 91 d. A 2×2 factorial arrangement was employed in a completelyrandomized design with repeated measures for growth traits, and a split-plot for carcass and meat traits.Crossbred rabbits were heavier (2032 vs. 1962 g; P<0.01), consumed more feed (143.5 vs. 131.0 g/d; P<0.01),and presented higher slaughter weight (2169 vs. 2093 g; P=0.02) and dressing percentage (59.0 vs. 58.2%;P=0.07) than straightbreds throughout the experiment. No difference between genetic groups was detectedfor feed conversion and empty gastrointestinal weight corrected for slaughter weight (SW). Crossbredsshowed higher skin weight (308.2 vs. 299.7 g; P=0.06) and distal parts of leg weight (75.7 vs. 71.4 g; P<0.01),both corrected for SW. No genetic group effect was detected on dissectible fat and hind part weights. Chilledcommercial carcass (1284 vs. 1229 g; P=0.02), chilled reference carcass (1036 vs. 1000 g; P=0.06), fore part(297.9 vs. 283.3 g; P=0.01) and loin (308.7 vs. 295.5 g; P=0.05) were heavier in crossbreds than in straightbreds,but these differences were attributed to differences in SW. Uncorrected weights of head, kidneys, liver andthoracic viscera were higher in the crossbred group, but only head (116.6 vs. 113.6 g; P=0.06) and thoracicviscera (30.4 vs. 28.6 g; P=0.01) were, in fact, proportionately heavier in crossbreds than in straightbreds. Noeffect of genetic group was detected on meat to bone ratio, muscle ultimate pH and chemical composition of theLongissimus dorsi muscle. All traits, except for ash and fat contents of the Longissimus muscle, showed ageeffects (P<0.01). Crossbreeding may be recommended for the production of whole commercial carcasses, butit is not clearly advantageous for the production of retail cuts. Slaughter should take place between 63 and 70d of age for both genetic groups.