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A FEEDING PROGRAMME FOR YOUNG RABBIT DOES BASED ON LUCERNE
(World Rabbit Science. ICTA. UPV, 2002) Pascual Amorós, Juan José; Cervera, C.; Fernández-Carmona, J.; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Educación y Cultura
[EN] A feeding programme for young rabbit does based on a high fibrous diet was evaluated in the present work, using 46 crossbred does of 70 days of age. Two diets, control (C) and a high fibre diet (F) formulated almost exclusively with luceme (96%), were compared. Young does in F group received F diet ad libitum until first parturition, while does in e group received e diet ad libitum until 3 kg live weight and then were restricted to 150 g per day. As of parturition, C diet was offered ad libitum to both groups until the end of the experiment. Up to 3 kg live weight, does given C diet had higher DE (P<0.001) intake and greater daily weight gain (P<0.001) than those fed F diet. C does weighed 3 kg and had the first parturition earlier than F does (18 and 7.6 days, respectively). F does ingested more food (P<0.001) during lactation, produced more milk (P<0.01) and weaned heavier litters (P<0.01) than C does, but litter size at birth and the number of pups replaced during lactation was not affected by diet. Maintaining these two groups for two years with the same reproduction schedule, no significant differences were detected in parturition interval, litter size at birth and litter size and weaning between them, although the figures related to F group were in general slightly better.
A method to estimate endogenous losses of nitrogen and amino acids at the ileal level in growing rabbits
(Universitat Politècnica de València, 2024-03-28) Marín-García, Pablo Jesús; Rodríguez, Mireia; Ródenas, Luís; Moya Salvador, Vicente Javier; Martínez Paredes, Eugenio Melchor; López-Luján, María del Carmen; Cambra López, María; Pascual Amorós, Juan José; Blas, Enrique; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital, Generalitat Valenciana
[EN] Apparent ileal digestibility can be corrected to give the true ileal digestibility of the nitrogen and amino acids provided by the diet, by determining the flow of endogenous nitrogen and amino acids (from desquamated epithelial cells of gastrointestinal mucosa, mucins and digestive enzymes). This flow of nitrogen and amino acids has been studied in adult rabbits fitted with a T-cannula, but remains unknown for growing rabbits. The aim of this work was to propose a method to estimate endogenous nitrogen and amino acid losses in the ileum of growing rabbits slaughtered at 64 d of age from 20:00 h. For this purpose, two experiments were carried out. The first was performed with 10 weaned rabbits fed with a diet with casein as the only source of protein (whose ileal digestibility is 100%) and labelled with ytterbium. This experiment allowed us to identify the relationship between the ileal flow of endogenous nitrogen (IFEN) and the dry matter intake in the last 24 h before slaughter (DMI), which fits the equation: IFEN (mg/d)=5.99 DMI (g/d) +133; (R2=0.778, residual standard deviation=138, P<0.001, n=10). The second experiment was carried out with 36 rabbits fed the same diet but without ytterbium, with whose ileal content 9 pools were constituted to determine the amino acid profile of endogenous nitrogen, which was found to be rich in glutamic acid, serine, aspartic acid, glycine, valine and threonine (15.97±1.33; 8.00±0.80; 7.06±0.72; 6.24±0.77; 5.48±0.51 and 4.97±0.47 g/16 g of N, respectively) and poor in methionine and histidine (1.05±0.06 and 1.34±0.16 g/16 g of N, respectively). Knowing the DMI of a certain growing rabbit in the 24 h prior to slaughter, the combined use of the equation and the amino acid profile obtained makes it possible to estimate the ileal endogenous losses of each amino acid.
Book Review. Rabbit Production. 9th Edition. J.I. McNitt, S.D. Lukefahr, P.R. Cheeke, H.M. Patton
(Editorial Universitat Politècnica de València, 2013-10-01) Pascual Amorós, Juan José; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural
[EN] Book review. Rabbit Production. 9th Edition. J.I. McNitt, S.D. Lukefahr, P.R. Cheeke, H.M. Patton. CABI Wallingford and Boston, (2013). 300 pp. Hardcover.
Challenges in rabbit doe feeding, including the young doe
(Universitat Politècnica de València, 2022-03-31) Martínez Paredes, Eugenio Melchor; Nicodemus, Nuria; Pascual, Juan José; García, Javier; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal
[EN] In this review is summarized the last knowledge on rabbit doe nutrition, to complement the current nutritional requirements and strategies for the young and adult rabbit does, considering the production, health, and welfare issues. The rabbit doe must reach an adequate maturity level (body condition) at first artificial insemination (AI) to face its productive life with minimal guarantees (around 7.0 mm of perirenal fat thickness, 2.8 ng/mL of plasma leptin concentration and around 18% and 15-20% of body protein and fat, respectively). This goal can be achieved by restricting feed intake from 12 weeks of age until first AI or feeding ad libitum with a fibrous diet (<10.5 MJ digestible energy/kg) from 60 d of age to first parturition. Once the doe is reproducing, the increase of the n-3 fatty acids (or reduction of the n-6/n-3 ratio), soluble fibre (under epizootic enteropathy) and the Arg/Lys and Gln/Lys ratios may help to improve the reproductive traits of rabbit does, although their optimal level of inclusion remain to be identified. It is recommended to limit an excessive negative energy balance before parturition, and the supplementation of glucose precursors to reduce the ketosis incidence could be useful. The formulation of different diets for the doe and the litter to fit better their requirements and assuring their health would be an option to consider when it would be applicable in the farm. The influence of the mother on the litter microbiota and immune status and its potential modulation through the diet open a new research area that will deserve more studies in the next future.
Characterization of the indoor environment and gas emissions in rabbit farms
(World Rabbit Science. ICTA. UPV, 2011) Calvet Sanz, Salvador; Cambra López, María; Estellés Barber, Fernando; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Ciencia e Innovación
[EN] There is a need to characterize gas concentrations and emissions from rabbit production. A study was conducted in order to determine ammonia, nitrous oxide and carbon dioxide concentrations and emissions in three rabbit farms in the Spanish Mediterranean area. Gas emissions were measured for 187 days in two different production stages (reproductive does and fattening rabbits). Gas concentrations were measured every two hours. Indoor temperature, relative humidity and ventilation flow were measured hourly. As a result, indoor temperature and relative humidity varied throughout the year, following a sinusoidal daily variation pattern. Maximum gas concentrations (14.3 mg/m3 of NH3, 7041 mg/m3 of CO2 and 5.10 mg/m3 of N2O) did not exceed the maximum recommended thresholds considering human health and animal welfare. Ammonia emissions were on average 55.9 and 10.2 mg/h per reproductive doe and fattening rabbit, respectively, and they were affected by temperature and relative humidity. The average carbon dioxide emission was 12588 mg/h per animal for does and 3341 mg/h for fattening rabbits. Nitrous oxide emission from does was 10.3 mg/h per animal, whereas for fattening rabbits the emission was negligible. Daily variation patterns of all measured parameters were observed and characterised in this study.
Comparison of degrees of maturity of rabbit lines selected for different traits
(Editorial Universitat Politècnica de València, 2015-09-30) Pascual, M.; Calle Ayma, Eddy Wilfredo; Blasco Mateu, Agustín; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Economía, Industria y Competitividad
[EN] The aim of this work was to study whether commercial nucleus lines of rabbits selected for different traits, and experimental lines having commercial purposes, have the same degree of maturity when compared at the same slaughter age. The study was carried out with 17897 rabbits from Universitat Politècnica de València. Rabbits came from the maternal lines A (3902 rabbits; 44th generation), V (4238 rabbits; 39th generation) and LP (6115 rabbits; 9th generation), selected for litter size at weaning; the paternal line R (2023 rabbits; 25th generation), selected for growth rate between 28 and 63 days of age; the maternal line OR (586 rabbits; 11th generation) selected for ovulation rate; and the lines High (503 rabbits; 5th generation) and Low (530 rabbits; 5thgeneration) lines, from a divergent selection for high and low intramuscular fat, respectively. Rabbits were weighted at 28 (W28) and 63 (W63) days of age. Rabbit does (42, 25, 39, 94, 14, 32 and 22 from lines A, V, R, LP, OR, High and Low, respectively) were weighed between 30 and 80 wk of age to determine adult weight (AW). Line R had higher W28 and W63, growth rate between 28 and 63 d of age and AW than lines A, V and LP (5802 g vs. 4410, 4222, and 4391 g for AW, respectively). No relevant differences between lines in degrees of maturity at 28 and 63 d of age and time to reach 40% of degree of maturity (percentage of weight compared to AW) were found between lines A, V, R and LP, but the degree of maturity at 2000 g and the time taken to reach that weight were lower in line R (34.7% and 55.2 d) than in lines A (45.5% and 71.1 d), V (47.4% and 69.6 d), and LP (45.8% and 68.0 d). No relevant differences were found between lines OR, High and Low in the traits analysed. A robustness analysis showed that results can be extrapolated to other commercial lines and other slaughter weights. In conclusion, comparison of lines at similar slaughter age could be considered a valid approach for comparisons at the same maturity stage.
COMPARISON OF DIFFERENT IN VITRO DIGESTIBILITY METHODS FOR NUTRITIVE EVALUATION OF RABBIT DIETS
(World Rabbit Science. ICTA. UPV, 2000) Pascual Amorós, Juan José; Cervera, C.; Fernández-Carmona, J.; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural
[EN] Seven simplified experimental diets for rabbits with a wide range of acid detergen! fibre content (87 to 525 g kg-1 dry matter) were used to compare three different in vitro techniques for evaluating their dry matter and organic matter digestibilities, based on the use of multienzyme, caecal or faecal inocula. The multienzyme method always resulted in higher in vitro dry matter digestibility values (P<0.001) !han those methods based on the use of digestive trae! inocula. The prediction equations for dry matter digestibility obtained with the multienzyme and caecal in vitro techniques showed higher precision (r2 = 0.95 and 0.88, respectively) and lower variability (se: 4.32 and 6.58, respectively) !han that based on the chemical composition (r2 = 0.80 and se = 8.34), while the method using faecal inocula showed lower precision and variability (r2 = 0.68 and se = 10.64). Repeatability was good for the three techniques (0.38 to 1.05), although !he multienzyme method was significantly better (P<0.05). However, the caecal and faecal in vitro methods showed clearly poorer results for reliability (P<0.001) !han the multienzyme technique (2.61, 2.65 and 0.71 for dry matter digestibility prediction, respectively).
Determination of enzyme activity in rabbit seminal plasma and its relationship with quality semen parameters
(Editorial Universitat Politècnica de València, 2015-12-23) Viudes de Castro, M.P.; Casares-Crespo, L.; Monserrat-Martínez, A.; Vicente Antón, José Salvador; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria
[EN] The objective of this study was to determine rabbit seminal plasma enzyme activity. Furthermore, correlations between semen parameters and enzyme activity and male age were examined. The study was performed using 17 New Zealand White males from 5 to 9 mo old. Overall, 252 semen samples were collected from bucks from May to September. Semen characteristics were analysed and the seminal plasma was obtained by centrifugation. The activities of alanyl aminopeptidase (APN), aspartate transaminase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALKP) in the seminal plasma fluid were measured. Significant differences between males were found in APN, GGT, LDH, ALKP and ALT activities (P<0.05). No significant differences between enzyme activity and male age were found. We also observed significant positive correlations between male age and sperm concentration (r=0.26), progressive motility (r=0.17) and amplitude of lateral head displacement (r=0.21), and negative ones between male age and average path velocity (r=–0.56), velocity of the sperm head along its actual curvilinear path (r=–0.61), straight line velocity (r=–0.50), linearity index (r=–0.13), and cytoplasmic droplet (r=–0.33). Furthermore, a significant negative correlation between APN activity and the status of the acrosome (r=–0.20) and significant positive correlations between APN activity and the sperm abnormalities (r=0.21), GGT activity and sperm concentration (r=0.34) and the status of the acrosome (r=0.31), and ALKP activity and sperm concentration were observed (r=0.41). In our study, APN and GGT seem to be the most predictive enzymes for rabbit semen quality.
Diet digestibility in growing rabbits: effect of origin and oxidation level of dietary fat and vitamin e supplementation
(World Rabbit Science. ICTA. UPV, 2010) Casado, C.; Moya, V.J.; Fernández, C.; Pascual Amorós, Juan José; Blas, E.; Cervera, C.; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Ciencia y Tecnología
[EN] The effects of the dietary inclusion of fats with different origin (lard or vegetal oil), fatty acid profile (linseed or sunflower), oxidation level (fresh, peroxidised: 11 d at 55ºC or oxidised: 31 h at 140ºC) and vitamin E supplementation (0 or 100 ppm) on the rabbit diet apparent digestibility were studied. Digestibility coefficients of dry matter, organic matter, crude protein, ether extract and gross energy were determined in eight diets using 58 rabbits aged 49 d. Contrast analysis between groups of diets showed that lard, characterised by a greater saturated fatty acid content, compared with vegetal oils, rich in unsaturated fatty acid, reduced the apparent digestibility of ether extract (62.3 vs. 68.4%; P=0.0329). However, there were no significant differences in the nutrient digestibility when linseed or sunflower oils (rich in [omega]-3 or in [omega]-6 polyunsaturated fatty acids, respectively) were compared. The oxidation degree of the sunflower oil and the supplementation with 100 ppm of vitamin E to the diets did not modify the apparent digestibility values of any dietary fraction.
Digestive efficiency in rabbit does according to environment and genetic type
(Editorial Universitat Politècnica de València, 2012) Savietto, Davi; Blas Ferrer, Enrique; Cervera Fras, Mª Concepción; Baselga Izquierdo, Manuel; Friggens, Nicolas C.; Larsen, Torben; Pascual Amorós, Juan José; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Ciencia e Innovación
[EN] Ninety lactating rabbit does of three different genetic types [2 from a line differentiating 20 generations by selection for litter size at weaning (lines V16 and V36) and 1 from a line founded under reproductive longevity criteria and then selected by litter size at weaning (line LP)] were subjected to three environmental conditions: NC, females housed under normal conditions (14 to 20oC) and fed with a control diet (333 g NDF/kg DM); HC, females housed under heat conditions (25 to 35oC) and fed with the control diet; or NF, females housed under normal conditions and fed with a fibrous diet (443 g NDF/kg DM). The apparent digestible coefficients of dry matter (DMd), organic matter, crude protein (CPd), gross energy, NDF (NDFd) and acid detergent fibre, as well as the daily intake of dry matter (DM), digestible protein (DP) and digestible energy (DE), were determined (14 to 18 d post-partum). The environment affected all variables analysed. In general, heat conditions reduced the daily feed intake (around -30%; P<0.05) and increased main apparent digestible coefficients (+4.5 percentage points for DMd). In contrast, the use of a fibrous diet led to lower DE intake (-217 kJ/d; P<0.05) and main apparent digestibility coefficients (-13.5 percentage points for DMd). Females from line V, regardless of generation, showed lower daily DM intake (-19.2 g/d; P<0.05) and NDFd (-1.5 percentage points; P<0.05) than line LP. Interactions between genetic type and environment were found for daily DM intake, NDFd and CPd. When receiving fibrous diet, LP females showed a higher increment in daily DM intake (65.6 g/d; P<0.05) than V36 females, compared to control. Under heat conditions, NDFd obtained for LP females were higher to those in normal conditions (+3.14 percentage points), while V females showed similar NDFd. In addition, the increase in CPd observed under heat conditions was higher for LP (+9.87 percentage points) and V36 (+8.74 percentage points) than V16 females (+3.84 percentage points). In conclusion, rabbit females from a line founded for reproductive longevity seem to show a higher flexibility in their digestive capacity under constrained conditions.
EARLY WEANING OF YOUNG RABBITS : A REVIEW
(World Rabbit Science. ICTA. UPV, 2001) Pascual Amorós, Juan José; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural
[EN] In the present work, the main recen! literature concerning early weaning of young rabbits was reviewed. Available information about the possible effect of early weaning practice on reproductive females (corporal condition and health status), weaned kits (changes of caecum fermentation and digestive enzymatic activities) and growing rabbits (performance and health status) was revised. Early weaning at 21-25 days seems to be a feasible practice that could have interesting possibilities from a productive point of view. This practice should decrease the usual reserve mobilization of does during the last days of lactation and could allow a specific and more adequate nutrition of kits around weaning time. However, more information about the positive or negative effects of early weaning on the performance and pathology incidences is need. At this respect, a higher effort on the study of adequate management systems and weaning diets should be required in the future.
Effect of divergent selection for uterine capacity on embryonic survival and development at 30 h post-mating in unilaterally ovariectomized rabbit females
(Editorial Universitat Politècnica de València, 2015-12-23) Peiró Barber, Rosa María; Gallego, M.; Blasco Mateu, Agustín; Santacreu Jerez, María Antonia; Dpto. de Ciencia Animal; Dpto. de Biotecnología; Instituto Universitario de Conservación y Mejora de la Agrodiversidad Valenciana; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Ciencia e Innovación; Ministerio de Educación y Ciencia
[EN] Uterine capacity has been proposed as an indirect way to increase litter size. The aim of this work is to study the effect of a divergent selection for uterine capacity (UC) on reproductive traits at 30 h post mating in unilaterally ovariectomized (ULO) females. A total of 62 ULO females from the high line (selected to increase UC) and 39 ULO females from the low line (selected to decrease UC) were used. Ovulation rate was estimated as the number of corpora haemorrhagica and early embryonic survival was estimated as the ratio between number of embryos and ovulation rate. No differences in ovulation rate and early embryonic survival at 30 h post mating were found between high and low lines. Selection for UC did not change the embryonic stage of development either, the majority of embryos being at 4-cell stage. Additionally, the embryos were evaluated according to morphological criteria and more than 95% of the embryos were evaluated as good or fair quality. No differences in embryonic morphological criteria between high and low lines were found either. Thus, selection for UC did not modify the early embryonic survival and development in ULO females at 30 h post mating.
Effect of gestational and lactational exposure to heat stress on performance in rabbits
(Universitat Politècnica de València, 2017-03-30) Marco Jiménez, Francisco; García Diego, Fernando Juan; Vicente Antón, José Salvador; Dpto. de Física Aplicada; Dpto. de Ciencia Animal; Escuela Técnica Superior de Ingeniería Industrial; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Centro de Investigación en Acuicultura y Medio Ambiente; Ministerio de Economía y Competitividad
[EN] Reproductive performance is greatly affected by environmental factors such as temperature. Heat stress (HS) during pregnancy and lactation can influence not only foetal growth but also postnatal development of kits. The aim of this study was to test the effect of HS during gestation and lactation on postnatal growth till Spanish commercial liveweight. To investigate this, 32 primiparous non lactating rabbit does were exposed to 1 of 2 environmental treatments: high temperature (between 25 and 36°C, HS group; n=16) or thermoneutral conditions (between 14 and 20°C, TN group; n=16). Does were allowed to acclimate 30 d before the artificial insemination. At birth, kits were allocated into 4 groups: HS was only applied during gestation (G group; n=54); HS was applied during gestation and lactation period (GL group; n=85); HS was only applied during lactation period (L group; n=60); and TN was applied during gestation and lactation period (C group; n=77). All litters were kept under each experimental environment until weaning at day 30. Then, litters were moved to TN temperatures until slaughter at day 63. Compared with TN does, the HS does presented lower litter size (9.7 and 11.4; P<0.05), litter weight (503.0 vs. 630.5 g; P<0.05) and kit weight at birth (56.6 vs. 61.4 g; P<0.05), as well as a higher stillborn rate (25.4 vs. 9.9%; P<0.05). The kits from does subjected to HS during gestation (G group) had similar postnatal growth compared to offspring from does gestated in TN conditions (C group), whereas kits from does that experienced HS during gestation and lactation (GL group) and during their lactation (L group) presented decreased postnatal growth. Together, these results demonstrate that kits from does that underwent HS during gestation did not alter postnatal growth until Spanish commercial liveweight, whereas HS during lactation resulted in decreased postnatal growth.
Effect of increased ovulation rate on embryo and foetal survival as a model for selection by ovulation rate in rabbits
(Editorial Universitat Politècnica de València, 2016-06-29) Badawy, A.Y.; Peiro, R.; Blasco Mateu, Agustín; Santacreu Jerez, María Antonia; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Generalitat Valenciana; Ministerio de Ciencia e Innovación
[EN] Selection for ovulation rate in prolific species has not improved litter size, due to an increase in prenatal mortality, with most mortality observed in the foetal period. The aim of this study was to investigate the magnitude and timing of embryo and early foetal survival in females with high ovulation rate using hormonal treatment as a model for selection by ovulation rate. Two groups of females (treated and untreated) were used. Treated females were injected with 50 IU equine chorionic gonadotropin 48 h before mating. Females were slaughtered at 18 d of gestation. Ovulation rate (OR), number of implanted embryos (IE), number of live foetuses at 12 and 18 d (LF12 and LF18, respectively) were recorded. In addition, embryo survival (ES=IE/OR), foetal survival at 18 d of gestation (FSLF18=LF18/IE), foetal survival between 12 and 18 d of gestation (FSLF18/LF12=LF18/LF12) and prenatal survival (PSLF18=LF18/OR) were estimated. For each female, the mean and variability of the weight for live foetuses (LFWm and LFWv, respectively) and their placentas (LFPWm and LFPWv, respectively) were calculated. Treated females had a higher ovulation rate (+3.02 ova) than untreated females, with a probability of 0.99. An increase in the differences (D) between treated and untreated females was observed from implantation to 18 d of gestation (D=–0.33, –0.70 and –1.28 for IE, LF12 and LF18, respectively). These differences had a low accuracy and the probability that treated females would have a lower number of foetuses also increased throughout gestation (0.60, 0.70 and 0.86 for IE, LF12 and LF18, respectively). According to the previous results for OR and LF18, treated females showed a lower survival rate from ovulation to 18 d of gestation (D=–0.12, P=0.98 for PSLF18). Treated females also had lower embryo and foetal survival (D=–0.10 and P=0.94 for ES and D=–0.08 and P=0.93 for FSLF18). Main differences in foetal survival appeared from 12 to 18 d of gestation (D=–0.09 and P=0.98 for FSLF18/LF12). Unexpectedly, treated females showed similar foetus weight and higher foetal placenta weight than untreated females (D=0.25 g, P=0.98) and lower variability for these traits (D=–0.02 g, P=0.72 for LFWv and D=–0.05 g, P=0.83 for LFPWv). These results are not related to a lower number of IE or LF18. Thus, the effect of increasing by three ova in rabbits leads to a lower embryo and early foetal survival. There seems to be no relationship between foetal mortality and foetus weight.
Effect of oxidation state of dietary sunflower oil and dietary zinc and [alfa]-tocopheryl acetate supplementation on performance of fattening rabbits
(Editorial Universitat Politècnica de València, 2011) Casado, Cristina; Moya Salvador, Vicente Javier; Pascual Amorós, Juan José; Blas Ferrer, Enrique; Cervera Fras, Mª Concepción; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Ciencia y Tecnología
[EN] Twelve diets were formulated using the same raw materials and including 3% of sunflower oil at 3 different oxidation levels [fresh (F), peroxidised (P; 55ºC for 11 d; 83 meq O2/kg oil) and highly-oxidised (O; 140ºC for 31 h; [Ro]-anisidine value of 125)], with 2 levels of [ALFA]-tocopherol supplementation (0 and 100 ppm), and 2 levels of Zn supplementation (0 and 200 ppm). A growing trial with 900 twenty eight d old rabbits was carried out in order to study the effect of the oxidation and protection level of supplemented oil on the performance of animals from weaning (28d) to 63 d of age. Another coetaneous trial was performed to study the effect of the oxidation level of sunflower oil (F, P and O) on caecal activity around weaning, using 120 suckling rabbits randomly re-allocated into 12 litters of 10 kits (4 litters per diet) from 17 to 44 d of age. Four rabbits per litter were slaughtered at 30 and 44 d (16 rabbits/treatment and age). Full gastro-intestinal tract and caecum were weighed and pH, dry matter (DM), ammonia nitrogen (NH3) and volatile fatty acids concentration (VFA) values in caecal content were measured. No effect was observed either in the mortality rate, body weight gain, feed intake or conversion rate throughout the growing period when peroxidised or oxidised oils were included in the diet, being on average 32%, 45.1 g/d, 107.6 g DM/d and 2.44, respectively. Dietary supplementation with [alfa]-tocopherol and/or Zn had no effect on the mortality rate, feed intake and performance of rabbits during the fattening period. Daily weight gain just after weaning (28 to 30 d of age) was higher for kits receiving the diet supplemented with F and O diets than those with the P diet (55, 50 and 35 g/d, respectively; P<0.05), but no further effect on performance was observed. Young rabbits fed with the P diet showed lower DM percentage in caecum at 30 d of age (-9.5%; P<0.05) than those with F or O diets. Caecum of young rabbits fed with the O diet presented lower NH3 content at 30 d of age that those given F diet (-38%; P<0.05) and higher total VFA and acetic acid concentration (+36 and +34 %, respectively; P<0.05). Therefore, and although many questions are still open, oxidised oils could be considered as a possible energy source for rabbit nutrition.
Effects of rearing feeding programme on the young rabbit females’ behaviour and welfare indicators
(Editorial Universitat Politècnica de València, 2015-09-30) Martínez Paredes, Eugenio Melchor; Ródenas Martínez, Luis; Pascual Amorós, Juan José; Blas Ferrer, Enrique; Brecchia, G.; Boiti, C.; Cervera Fras, Mª Concepción; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Economía y Competitividad
[EN] Restriction of young rabbit females during rearing is a widespread management technique that could have negative consequences on their welfare and behaviour. In the present work, a total of 24 young rabbit females aged 9 wk were used to evaluate 3 rearing feeding programmes until first parturition: CAL, fed ad libitum with a control diet [C: 11.0 MJ digestible energy (DE) and 114 g digestible protein (DP) per kg dry matter (DM)]; CR, receiving the C diet restricted (140 g/d) from 12 wk of age; and F, fed ad libitum with a low energy/high fibre diet [F: 8.7 MJ DE and 88 g DP per kg DM]. F females presented lower body weight than CAL and CR females at week 18 (–0.4 kg and –0.2 kg; P<0.05), but differences in body weight disappeared at parturition. Feeding programme affected the daily feed intake of young females during rearing and gestation periods (on av. of 2 periods: 140, 127 and 179 g DM/d, for CAL, CR and F females, respectively; P<0.001). Blood levels of glucose and insulin decreased with the age of rabbits (from 97 to 73 mg/dL for glucose and from 11 to 6 μUI/mL for insulin at 13 and 20 wk, respectively; P<0.001). Concentration of non-esterified fatty acids was higher in the blood of CAL females (+0.13 mmol/L compared to F; P<0.05), while corticosterone was higher in F females (+0.7 μg/dL compared to CAL; P<0.05). The type of feeding schedule affected the lying still and eating behaviour (P<0.01) of CR females, especially before and after feeding supply, as well as their behavioural stressed indicators (stereotypies; P<0.01), which were more frequent in CR females before feeding supply at 20 weeks of age. Therefore, ad libitum use of a low energy/high fibre diet is an adequate feeding programme for young rabbit females, which does not alter their behavioural patterns.
Evaluation of calcium superphosphate as an additive to reduce gas emissions from rabbit manure
(Editorial Universitat Politècnica de València, 2014-12-22) Estellés Barber, Fernando; Cambra López, María; Jiménez Belenguer, Ana Isabel; Calvet Sanz, Salvador; Dpto. de Ciencia Animal; Dpto. de Biotecnología; Centro Avanzado de Microbiología de Alimentos; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Ciencia e Innovación
[EN] Techniques to reduce the emission of air pollutants from livestock production are demanded. In this study, the effect of an additive (calcium superphosphate) on gas emissions from rabbit manure was investigated and compared with a control where no additive was used. Calcium superphosphate was applied at a rate of 100 g/m2 per week in a manure pit during 2 cycles of growing rabbits. Manure samples were collected weekly and then chemically and microbiologically analysed. Gas emissions (ammonia, carbon dioxide, methane and nitrous oxide) were determined in 2 open flux chambers. No differences were observed in gas emissions between the treated and control samples except for ammonia emissions, which were reduced by 33% when the additive was applied (P<0.05). No statistical differences were obtained in the microbial content between control and treatment, as results showed a high variability. Dry matter content and pH were the most influential parameters on the emission of gases from manure. According to these results, the application of calcium superphosphate may be considered as an effective technique to reduce ammonia emission from rabbit manure. The additive may also be potentially effective in other species, but additional research is necessary to investigate its performance.
Evaluation of the sensory attributes along rabbit loin by a trained panel
(Universitat Politècnica de València, 2018-03-28) Martínez-Álvaro, Marina; Hernández Pérez, Maria del Pilar; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Economía y Competitividad
[EN] The aim of this study was to evaluate and quantify variation in sensory attributes along the Longissimus dorsi (LD) muscle in rabbits. A descriptive analysis was performed by a panel of 8 assessors previously trained in the evaluation of rabbit meat. Reference standards used in training for the evaluation of rabbit meat are also described. Sensory attributes rabbit and liver odour, rabbit and liver flavour, toughness, juiciness and fibrousness were assessed in 56 rabbits from a divergent selection experiment for intramuscular fat (28 slaughtered at 9 wk and 28 slaughtered at 13 wk). Immediately after cooking, loins were cut lengthwise into 4 equidistant pieces from caudal to cranial end (LD1, LD2, LD3 and LD4). Assessors were able to detect and quantify a longitudinal sensory variation in muscle LD. Caudal extreme LD1 was tougher and more fibrous than LD2, LD3 and LD4, and less juicy than LD3 and LD4. The greatest variation was found between caudal and cranial ends, with LD1 being 9% tougher (P=0.99), 11% more fibrous (P=1.00) and 12% less juicy (P=0.99) than LD4. Assessors found few variations along LD muscle in flavour and odour attributes. Location LD3 showed 9% greater rabbit odour (P=0.99) and flavour (P=0.97) than LD4, and 8% greater rabbit odour than LD2 (P=0.97). Our results highlight the importance of randomisation within muscle location in sensory studies on rabbit LD muscle, as there is considerable sensory variation along this muscle.
Experimental balance to estimate efficiency in the use of nitrogen in rabbit breeding
(World Rabbit Science. ICTA. UPV, 2008) Calvet Sanz, Salvador; Estellés Barber, Fernando; Hermida, B.; Blumetto, O.; Torres Salvador, Antonio Germán; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Educación y Ciencia
[EN] Defining the composition and properties of manure in livestock production is critical in order to minimise possible environmental impacts stemming from its management. In this study, a nitrogen balance was carried out during two identical fattening periods (Experiments 1 and 2) in growing rabbits from weaning (age 28 d and live weight about 0.6 kg) to slaughter (age 61 d and live weight about 1.8 kg). The breeding conditions were typical for Spanish rabbit production. The objectives were to quantify the total nitrogen excreted by the animals and to estimate the average efficiency in the use of this nutrient, in comparison to other species. Animal weight, feed intake, and the production of faeces and urine were monitored weekly in a set of eight cages with nine rabbits in each, performing weekly analyses for nitrogen content in feed, urine and faeces. The overall nitrogen excretion was 50.2 g N per animal in Experiment 1 and 46.9 g N per animal in Experiment 2, which corresponded to about 58% of the total nitrogen intake. Urine and faeces contributed to overall nitrogen excretion in approximately the same proportions. The nitrogen excretion ratio was 40 grams per kilogram of animal produced. According to this ratio, rabbit breeding is less efficient in the use of nitrogen than raising broilers, but more than fattening pigs.
FEEDING RYEGRASS HAY TO GROWING RABBITS, A NOTE
(World Rabbit Science. ICTA. UPV, 2001) Fernandez-Carmona, J.; Cervera, C.; Moya, J.; Pascual Amorós, Juan José; Dpto. de Ciencia Animal; Instituto Universitario de Ciencia y Tecnología Animal; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Educación y Cultura
[EN] Digestibility of ryegrass hay (18% crude protein and 18.9% crude fibre) was determined with 11 three-way crossbred New Zealand x Californian growing rabbits, using a 95% ryegrass die! +2% animal fat and 3% amino-acids, vitamins and minerals. Amino acids composition of diet and of the ryegrass was given. With the same diet, twenty-eight rabbits were used from 42 to 70 days of age to study the growth performance and carcass parameters. The ryegrass hay used in the present work showed high digestible energy (10.3 MJ kg·1 DM) and digestible protein (119 g kg·1 DM) contents. Avera~e daily gain, feed intake and live weight at 70 days were 36.7 g day" , 111 g DM day"1 and 2042 g, respectively. Sex did not affect any of the carcass values. Weights of full gastrointestinal trae!, liver and kidney fat were 504, 73 and 6.9 g. In conclusion, growth rate, feed conversion ratio (3.02 g g·1 DM) and dressing percentage (53.3%) were satisfactory when this high forage diet was used.

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