Reproductive performance of rabbit females from three paternal lines with a different potential for growth rate and resilience.

A total of 197 nulliparous rabbits (from three paternal lines) were used to test potential strategies to overcome the consequences on reproduction associated with the selection for high growth rate. The R line was selected for growth rate during the growing period for 37 generations, the RF line was founded through a high selection intensity of elite animals of the R line, and the RFLP line, which was obtained by backcrossing RF animals with the LP line (a long-lived productive maternal line, characterised by high resilience). BW, perirenal fat thickness, fertility, daily feed intake, milk yield and blood metabolites of females were controlled from 1st artificial insemination to 3rd parturition. Litter size, litter weight, individual weight and feed ingestion of kits were controlled from birth to weaning. Our results show that RF females were significantly lighter than R and RFLP females throughout the trial (-5.0%; P < 0.05). Furthermore, RF animals had a higher fertility rate than RFLP females, at first cycle (+10.5 percentage points; P < 0.05). However, RFLP had a higher fertility rate than RF females at second cycle (+21.5 percentage points; P < 0.01). On average, RFLP females had higher perirenal fat thickness than R females at parturition (+3.0%; P < 0.05) and higher daily feed intake than of R and RF females during gestation and late lactation (+9.7 and +8.7%, respectively; P < 0.05). RFLP females produced more milk than R and RF females in the two first lactations (+18.5%; P < 0.001). In the first three parturitions, R females delivered fewer kits born alive (-1.7 kits than RF and RFLP; P < 0.05). In addition, R females' blood had a higher concentration of glutamine and glutamate than RFLP (+24 and +22.7%, respectively; P < 0.05). RFLP litters were heavier than both R and RF litters throughout lactation. However, R kits were heavier at birth than RF and RFLP (+7.9%). Results suggest that the foundation of a paternal line using elite animals could generate females with better early reproductive performance. In addition, backcrossing the RF line with a maternal LP line resulted in a genetic line whose females had a different resource allocation strategy to foster reproduction during the studied period.

Pituitary cryptococcoma in an immunocompetent patient with panhypopituitarism: illustrative case.

BACKGROUND: Cryptococcosis is the most common mycosis of the central nervous system. It may develop in immunocompetent and immunocompromised patients, the latter representing most cases. The most common presentation of the disease is meningitis, whereas intra-axial lesions in the form of cryptococcoma are less frequent with a greater tendency to present in immunocompetent patients. The presentation of pituitary cryptococcoma is exceptional. To the best of the authors' knowledge, there is only one case published in the medical literature. OBSERVATIONS: The authors present the case of a 30-year-old male without a relevant medical history. He was referred to our center with a pituitary mass on magnetic resonance imaging and panhypopituitarism. The patient underwent endonasal endoscopic transsphenoidal tumor resection, and a histopathological diagnosis of pituitary cryptococcoma was made. Medical management included fluconazole and intravenous amphotericin. LESSONS: This case underscores the neurosurgical and medical management of an exceptional clinical presentation of pituitary cryptococcoma in an immunocompetent patient. To the best of the authors' knowledge, there is only one case published in the medical literature. This case provides an invaluable review of the clinical, imaging, and therapeutic considerations regarding this exceptional clinical entity.

Consequences of rearing feeding programme on the performance of rabbit females from 1st to 2nd parturition.

To evaluate how rearing programmes could affect resources allocation and reproductive performance of primiparous rabbit females, a total of 118 rabbit females were used to evaluate the effects of five rearing feeding programmes on their performance from 1st to 2nd parturition: CAL, fed ad libitum C diet (11.0 MJ digestible energy (DE), 114 g digestible protein (DP) and 358 g NDF/kg dry matter (DM) until 1st parturition; CR, fed ad libitum with C diet until 12 weeks of age and then C diet restricted (140 g/day) until 1st parturition; F, fed ad libitum with F diet (8.7 MJ DE, 88 g DP and 476 NDF/kg DM) until 1st parturition; FC, fed with F diet ad libitum until 16 weeks of age, and C diet ad libitum until 1st parturition; FCF, fed with F diet ad libitum until 16 weeks of age, then C diet ad libitum until 20 weeks and then F diet ad libitum until 1st parturition. From 1st parturition, C diet was ad libitum offered to all the experimental groups until 2nd parturition. CAL females presented lower feed intake than females of F, FC and FCF groups in the 1st week of lactation (on av. -16.6%; P<0.05). During 1st lactation, the perirenal fat thickness change in CAL females was not different from 0 (+0.02 mm), while in the other four groups it increased (on av. +0.44 mm; P<0.05). Plasma of females fed with F diet during rearing (F, FC and FCF) had lower non-esterified fatty acids content than those exclusively fed with C diet (-0.088 and -0.072 mmol/l compared to CAL and CR, respectively; P<0.05). FCF litters had higher weight than F litters at day 21 of lactation (+247 g; P<0.05), but FCF litter had significantly lower weight than FC litters at weaning (+170 g; P<0.05). CR females had the shortest average interval between the 1st and 2nd parturition (49 days) and FCF females the longest (+ 9 days compared to CR; P<0.05). At 2nd parturition, liveborn litters of F females were larger and heavier than litters of FCF females (+2.22 kits and +138 g; P<0.05), probably due to the lower mortality at birth of F litters (-16.5 percentage points; P<0.05). In conclusion, rearing females on fibrous diets seems to increase the ability of primiparous rabbit females to obtain resources, especially at the onset of lactation.

Long-term implications of feed energy source in different genetic types of reproductive rabbit females: I. Resource acquisition and allocation.

To achieve functional but also productive females, we hypothesised that it is possible to modulate acquisition and allocation of animals from different genetic types by varying the main energy source of the diet. To test this hypothesis, we used 203 rabbit females belonging to three genetic types: H (n=66), a maternal line characterised by hyper-prolificacy; LP (n=67), a maternal line characterised by functional hyper-longevity; R (n=79), a paternal line characterised by growth rate. Females were fed with two isoenergetic and isoprotein diets differing in energy source: animal fat (AF) enhancing milk yield; cereal starch (CS) promoting body reserves recovery. Feed intake, weight, perirenal fat thickness (PFT), milk yield and blood traits were controlled during five consecutive reproductive cycles (RCs). Females fed with CS presented higher PFT (+0.2 mm, P0.05), particularly for those fed with AF. Moreover, LP females fed with AF progressively increased PFT across the RC, whereas those fed with CS increased PFT during early lactation (+7.3%; P<0.05), but partially mobilised it during late lactation (-2.8%; P<0.05). Independently of the diet offered, LP females reached weaning with similar PFT. H females fed with either of the two diets followed a similar trajectory throughout the RC. For milk yield, the effect of energy source was almost constant during the whole experiment, except for the first RC of females from the maternal lines (H and LP). These females yielded +34.1% (P<0.05) when fed with CS during this period. Results from this work indicate that the resource acquisition capacity and allocation pattern of rabbit females is different for each genetic type. Moreover, it seems that by varying the main energy source of the diet it is possible to modulate acquisition and allocation of resources of the different genetic types. However, the response of each one depends on its priorities over time.

Iron reactivity in anoxic sediments in the Ría de Vigo (NW Spain).

The high sedimentation rates and high organic matter contents in the sediments of the Ría de Vigo (NW Spain) promote the development of anoxic conditions, determining the dynamics of elements like Fe and conditioning his speciation and reactivity. Four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. In order to understand the behavior of Fe in these complex environments different fractions of reactive iron were analyzed. The decrease in highly reactive iron and sulfide contents with depth showed the relationship between the iron and sulfur cycle in the middle and outer zones of the ría. In the inner zone, the apparition of shallow methane gas may cause the slower decrease of the highly reactive iron contents. In zones without methane, sediment layers enriched in iron -with a reactivity higher than in other sediment samples- were observed. An increase was observed in the dithionite and total reactive iron contents from the inner to the outer zone of the ría, according to the gas depth. Furthermore, a decrease in Fe (III)-bearing minerals contents with depth was observed in the outer and middle zones, but not in the innermost area where the gas is shallow. The high organic matter and sulfide contents, mainly in the inner zone of the ría, indicate that the most of the Fe (II) is FeS. Moreover, the high contents of total reactive iron and pH values (6.86-7.98) could contribute the formation of stable minerals like pyrite along the Ría de Vigo.

Modulation of the stress response during apoptosis and necrosis induction in cadmium-treated U-937 human promonocytic cells.

Treatment for 2 h with 200 microM cadmium chloride, followed by recovery, caused apoptosis and induced heat-shock protein 70 (HSP70) expression in U-937 promonocytic cells. However, pre-incubation with the GSH depleting agent L-buthionine-[S,R]-sulfoximine (BSO, 1 mM for 24 h) caused necrosis instead of apoptosis and failed to induce HSP70 expression. This failure was a consequence of necrosis instead of GSH depletion, since BSO allowed or even potentiated HSP70 induction when used in combination with heat shock (2 h at 42.5 degrees C) or with 50 microM cadmium, which caused apoptosis. The administration of N-acetyl-L-cysteine (NAC) at the beginning of recovery after BSO/200 microM cadmium treatment prevented the execution of necrosis and restored the execution of apoptosis, but did not restore HSP70 induction, indicating that the inhibition by BSO of HSP70 expression is an early regulated event. This contrasted with the capacity of NAC to prevent the alterations caused by BSO/200 microM cadmium in other proteins, namely the suppression of Bax expression and the increase in Bcl-2 and HSP-60 expression. Finally, it was observed that treatment with 200 microM cadmium rapidly increased the HSP70 mRNA level and stimulated heat-shock factor 1 (HSF1) trimerization and binding, and that these effects were prevented by pre-incubation with BSO. Taken together, these results indicate that the stress response is compatible with apoptosis but not with necrosis in cadmium-treated promonocytic cells. The suppression of the stress response is specifically due to the early inhibition of HSF1 activation.

The selection between apoptosis and necrosis is differentially regulated in hydrogen peroxide-treated and glutathione-depleted human promonocytic cells.

Treatment with 0.2 mM hydrogen peroxide (H(2)O(2)) or with 0.5 mM cisplatin caused caspase-9 and caspase-3 activation and death by apoptosis in U-937 human promonocytic cells. However, treatment with 2 mM H(2)O(2), or incubation with the glutathione suppressor DL-buthionine-(S,R)-sulfoximine (BSO) prior to treatment with cisplatin, suppressed caspase activation and changed the mode of death to necrosis. Treatment with 2 mM H(2)O(2) caused a great decrease in the intracellular ATP level, which was partially prevented by 3-aminobenzamide (3-ABA). Correspondingly, 3-ABA restored the activation of caspases and the execution of apoptosis. By contrast, BSO plus cisplatin did not decrease the ATP levels, and the generation of necrosis by this treatment was not affected by 3-ABA. On the other hand, while all apoptosis-inducing treatments and treatment with 2 mM H(2)O(2) caused Bax translocation from the cytosol to mitochondria as well as cytochrome c release from mitochondria to the cytosol, treatment with BSO plus cisplatin did not. Treatment with cisplatin alone caused Bid cleavage, while BSO plus cisplatin as well as 0.2 and 2 mM H(2)O(2) did not. Bcl-2 overexpression reduced the generation of necrosis by H(2)O(2), but not by BSO plus cisplatin. These results indicate the existence of different apoptosis/necrosis regulatory mechanisms in promonocytic cells subjected to different forms of oxidative stress.

OTX2 homeoprotein in the developing central nervous system and migratory cells of the olfactory area.

We analyzed the distribution of OTX2 during mouse development. OTX2 is a homeoprotein encoded by Otx2, a vertebrate homeobox gene expressed in the developing brain and anterior head regions. The protein is already detectable in pre-streak embryos, in nuclei of embryonic ectoderm or epiblast and primitive endoderm or hypoblast. Its distribution is uniform along the entire epiblast, while showing an antero-posterior gradient along the hypoblast at the time when primitive streak first forms. Between embryonic day 7 (E7) and E7.5 there is a progressive confinement of the protein to the anterior ectoderm corresponding to the forming headfold. At E7.5-E7.8, the protein is mainly confined in this region but is still present, though at lower level, in more posterior ectoderm. Starting from day 8 of development it is essentially confined to anterior neuroectoderm corresponding to presumptive fore- and midbrain. Its subsequent distribution in forebrain, midbrain, developing isthmo-cerebellum and posterior central nervous system is analyzed in detail. Of particular interest is the presence of OTX2 in nuclei of cells of the olfactory system starting from its origin in the olfactory placode. OTX2 protein is present in some cells of the olfactory epithelium, in both the major olfactory epithelium and the vomero-nasal organ, and in scattered migratory cells present in the mesenchyme outside it. These cells surround the axon bundles of the olfactory nerve along its path from the olfactory epithelium in the nasal cavities to the olfactory bulb in rostral telencephalon and include both ensheathing glial cells and luteinizing hormone-releasing hormone (LHRH)-positive cells.

EMX1 homeoprotein is expressed in cell nuclei of the developing cerebral cortex and in the axons of the olfactory sensory neurons.

We analyzed the distribution of EMX1 during mouse development. EMX1 is a homeoprotein encoded by Emx1, a regulatory homeobox gene expressed in the developing forebrain. Its distribution essentially overlaps the expression domains of Emx1 transcripts. The EMX1 protein is present in the developing dorsa telencephalon, that is in the cerebral cortex, olfactory bulb and hippocampus. In the cerebral cortex EMX1 is present in nuclei of proliferating, differentiating and most mature neurons belonging to all cortical layers. In the olfactory bulb it is present in all proliferating cells during development, whereas postnatally it is faintly expressed in some mitral cells. Non-cerebral localizations include a transient expression in branchial pouches, in the apical ectodermal ridge of the developing limbs and in the developing kidney. Of particular interest is the presence of EMX1 in the olfactory nerve from its first appearance during embryogenesis to birth. The protein is present in axons of olfactory sensory neurons along their entire length, including their terminals in spherical regions of neuropil in the olfactory bulb called glomeruli.

Pneumatosis cystoides intestinalis in a rabbit doe (Oryctolagus cuniculus).

Pneumatosis cystoides intestinalis (PCI) is an infrequent condition of animals characterized by the existence of numerous thin-walled, gas-filled cystic structures within the intestinal wall and adjacent lymph nodes. Microscopically, the cystic structures appear to be dilated lymphatics located in the lamina propria, submucosa, muscularis, subserosa, mesentery, and mesenteric lymph nodes. This report describes a case of pneumatosis cystoides intestinalis in a rabbit doe from an organic farm where 20 rabbit does were fed ad libitum with a natural diet consisting of whole barley, pea beans, alfalfa hay, and a pelleted vitamin-mineral blend. A combination of nutritional, bacterial, and other factors are hypothesized as possible predisposing factors in the development of PCI.

Redox processes in pore water of anoxic sediments with shallow gas.

The Ría de Vigo (NW Spain) has a high organic matter content and high rates of sedimentation. The microbial degradation of this organic matter has led to shallow gas accumulations of methane, currently distributed all along the ría. These peculiar characteristics favor the development of anoxic conditions that can determine the dynamics of iron and manganese. In order to study the role played by iron and manganese in the processes that take place in anoxic sediments with shallow gas, four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. Methane was present in two of them, below 90cm in the inner zone and below 200cm, in the outer zone. Pore water was collected and analyzed for vertical profiles of pH, sulfide, sulfate, iron and manganese concentrations. Sulfate concentrations decreased with depth but never reached the minimum detection limit. High sulfide concentrations were measured in all cores. The highest sulfide concentrations were found in the inner zone with methane and the lowest were in the outer zone without methane. Concentrations of iron and manganese reached maximum values in the upper layers of the sediment, decreasing with depth, except in the outer zone without gas, where iron and manganese concentration increased strongly toward the bottom of the sediment. In areas with shallow gas iron reduction, sulfate reduction and methane production processes coexist, showing that the traditional redox cascade is highly simplified and suggesting that iron may be involved in a cryptic sulfur cycle and in the oxidation of methane.

Uncoupling of apoptosis and Jun/AP-1 activity in human promonocytic cells treated with DNA-damaging and stress-inducing agents.

Earlier studies have indicated that Jun/AP-1 activity is associated with, and probably required for apoptosis induction by DNA-damaging and stress-inducing agents in human myeloid cells. To investigate this possibility, we examined the capacity of continuous treatments with etoposide (10 microM) and camptothecin (0.4 microM), and pulse treatments with X-rays (20 Gy), heat (2 h at 42.5 C) and cadmium chloride (2 h at 200 microM) followed by recovery, to provoke apoptosis and to simulate c-jun and c-fos expression and AP-1 binding in U-937 human promonocytic cells. All these treatments generated apoptosis with similar efficacy (50-60% apoptotic cells at 6 h of treatment or recovery). However, the capacity to increase c-jun and c-fos mRNA levels and to stimulate AP-1 binding was very different, ranging from more than a twelve-fold increase in the case of cadmium, to almost no increase in the case of heat-shock and etoposide. When the cells were pre-conditioned with a soft heat shock (1 h at 42 degrees C) the cadmium-provoked apoptosis was greatly inhibited, but the stimulation of AP-1 binding was not affected. The administration of cAMP-increasing agents also reduced the etoposide- and cadmium-provoked apoptosis. However, cAMP greatly stimulated c-jun and c-fos expression and AP-1 binding when applied together with etoposide (which itself was ineffective), and potentiated the cadmium-induced AP-1 binding. Conversely, retinoic acid abrogated the cadmium-provoked stimulation of AP-1 binding and transactivation capacity, and greatly inhibited the stimulation of binding caused by camptothecin and X-rays. However, retinoic acid did not inhibit the induction of apoptosis by these agents. These results indicate that Jun/AP-1 activity is not necessarily coupled with apoptosis, nor required for apoptosis induction by DNA-damaging and stress-inducing agents in human promonocytic cells.

The role of intracellular oxidation in death induction (apoptosis and necrosis) in human promonocytic cells treated with stress inducers (cadmium, heat, X-rays).

Treatment of U-937 human promonocytic cells with the stress inducers cadmium chloride (2 h at 200 microM), heat (2 h at 42.5 C) or X-rays (20 Gy), followed by recovery, caused death by apoptosis and stimulated caspase-3 activity. In addition, all stress agents caused intracellular oxidation, as measured by peroxide and/or anion superoxide accumulation. However, while pre-incubation with antioxidants (N-acetyl-L-cysteine or butylated hydroxyanisole) inhibited the induction of apoptosis by cadmium and X-rays, it did not affect the induction by heat-shock. Pre-incubation for 24 h with the GSH-depleting agent L-buthionine-[S,R]-sulfoximine (BSO) switched the mode of death from apoptosis to necrosis in cadmium-treated cells. By contrast, BSO only caused minor modifacions in the rate of apoptosis without affecting the mode of death in heat- and X-rays-treated cells. BSO potentiated peroxide accumulation in cells treated with both cadmium and X-rays. However, while the accumulation of peroxides was stable in the case of cadmium, it was transient in the case of X-rays. Moreover, the administration of antioxidants during the recovery period sufficed to prevent necrosis and restore apoptosis in BSO plus cadmium-treated cells. Cadmium and X-rays caused a decrease in intracellular ATP levels, but the decrease was similar in both apoptotic and necrotic cells. Taken together, these results demonstrate that (i) stress inducers cause intracellular oxidation, but oxidation is not a general requirement for apoptosis; and (ii) the duration of the oxidant state seems to be critical in determining the mode of death.

Modulation of HSP70 and HSP27 gene expression by the differentiation inducer sodium butyrate in U-937 human promonocytic leukemia cells.

The treatment of U-937 human promonocytic cells with the differentiation inducer sodium butyrate (0.75 mM) transiently increased heat-shock protein 70 (HSP70) mRNA levels between 3 and 6 h, and heat-shock protein 27 (HSP27) mRNA levels between 12 and 24 h, as indicated by northern blot assays. Gel retardation assays indicated that butyrate also stimulated heat-shock factor (HSF) binding activity between 3 and 6 h, suggesting that the activation of HSP70 gene expression was mediated by the heat-shock factor DNA response element (HSE). In addition, the treatment provoked a biphasic alteration of the c-fos mRNA level, consisting of a slight increase between 0.5 and 3 h followed by a greater increase between 12 and 48 h, while it caused a single increase between 12 and 48 h in c-jun mRNA level. The possible involvement of the heat-shock protein genes in the butyrate-induced differentiation of U-937 cells is discussed.

Percepciones de los estudiantes sobre sus vivencias en las prácticas clínicas / Students' perceptions about their experiences in their clinical practices / Percepciones dos estudantes sobre suas vivências nas práticas clínicas

Resumen Introducción Los estudiantes de enfermería deben adquirir conocimientos, habilidades, actitudes y valores, para proporcionar cuidados de calidad. Las prácticas clínicas son el contexto ideal para lograr algunas de las competencias requeridas. Objetivo Explorar las percepciones de los estudiantes sobre sus vivencias durante sus prácticas clínicas. Método Abordaje metodológico descriptivo de tipo cualitativo y con un encuadre sociocrítico. Se analizaron los 45 portafolios de estudiantes de 4º curso de la Escuela Universitaria de Enfermería (EUE) Cruz Roja, donde explican sus vivencias en prácticas. Se optó por un portafolio semiestructurado en función de la competencia a demostrar definiendo previamente las tareas o evidencias Se realizó un análisis de contenido que comprendía las siguientes fases: reducción de los datos; categorización-codificación, presentación de datos y conclusiones/verificación de los datos. Se alcanzó saturación en la información sobre las categorías presentadas. Resultados Del análisis de los datos emergen distintas unidades de significado que se engloban en tres categorías: aprendizaje en prácticas, dificultades del entorno, crecimiento personal y profesional. Conclusiones El estudio evidencia la importancia de las prácticas clínicas para los estudiantes dentro del plan de estudios, ya que es donde aplican lo que han aprendido en el aula y son conscientes de la realidad a la que se enfrentan. El entorno clínico y la relación que se establezca entre este y el estudiante determina en muchas ocasiones el aprendizaje. Queda patente que los estudiantes durante sus prácticas clínicas toman conciencia de aquellos conocimientos del saber, saber hacer y saber estar.

Abstract Introduction Nursing students need specific knowledge, skills, attitudes and values in order to provide quality of care; and the clinical practices represent an ideal context to develop some of these required competences. Objective To explore the perceptions of nursing students about their own experiences in their clinical practices. Method This a qualitative descriptive study with social and critical focus. 45 practice-files from nursing students in the 4th course of a Mexico Red Cross School of Nursing were analyzed considering the following stages: data reduction, categorization-coding, data presentation, and data verification and conclusions. Data saturation was reached from the identified categories. Results From the data analysis, diverse units of meaning emerged within three main categories: learning in practices, difficulties in the environment, and personal and professional growth. Conclusions The study highlights the importance of clinical practices since it is there where students apply in real life what they learn in the classroom. The relationship between the student and the clinical environment greatly determines the quality of learning. So, it is suggested that students keep in mind reflecting on their to know, to know how, and to know how to be.

Resumo Introdução Os estudantes de enfermagem devem adquirir conhecimentos, habilidades, atitudes e valores, para proporcionar cuidados de qualidade. As práticas clínicas são o contexto ideal para atingir algumas das competências requeridas. Objetivo Explorar as percepções dos estudantes sobre suas vivências durante suas práticas clínicas. Método Abordagem metodológica descritiva de tipo qualitativo e com um enfoque sociocrítico. Analisaram-se os 45 portfolios de estudantes de 4º curso da Escuela Universitaria de Enfermería (EUE) Cruz Roja, onde explicam suas vivências em práticas. Optou-se por um portfólio semiestruturado em função da competência a demostrar definindo previamente as tarefas ou evidências. Realizou-se uma análise de conteúdo que compreendia as seguintes fases: redução dos dados; categorização-codificação, apresentação de dados e conclusões/verificação dos dados. Atingiu-se saturação na informação sobre as categorias apresentadas. Resultados Da análise dos dados emergem distintas unidades de significado que abrangem três categorias: aprendizagem em práticas, dificuldades do entorno, crescimento pessoal e profissional. Conclusões O estudo evidencia a importância das práticas clínicas para os estudantes dentro do plano de estudos, já que é onde aplicam o que aprenderam na aula e são conscientes da realidade à que se enfrentam. O entorno clínico e a relação que se estabeleça entre este e o estudante determina em muitas ocasiões a aprendizagem. É evidente que os estudantes durante suas práticas clínicas tomam consciência daqueles conhecimentos do saber, saber fazer e saber estar.

Environmental sensitivity differs between rabbit lines selected for reproductive intensity and longevity.

To better understand the mechanisms that allow some animals to sustain their productive effort in harsh environmental conditions, rabbit does from two selection lines (LP and V) were housed in normal (NC), nutritional (NF) or heat (HC) challenging environmental conditions from first to third partum. The LP line (n=85) was founded on reproductive longevity criteria by selecting does from commercial farms that had a minimum of 25 partum with more than 7.5 kits born alive per parity. Line V (n=79) was constituted from four specialised maternal lines into a composite synthetic line and then selected by litter size at weaning for 36 generations. Female rabbits in NC and NF environments were housed at normal room temperature (18°C to 24°C) and fed with control [11.6 MJ digestible energy (DE)/kg dry matter (DM)] or low-energy diets (9.1 MJ DE/kg DM). HC does were housed at high room temperatures (25°C to 35°C) and fed the control diet. Female rabbits in the HC and NF environments ingested 11.5% and 6% less DE than NC does, respectively (P<0.05). These differences between environments occurred in both lines, with the differences being higher for LP than for V does (+6%; P<0.05). Milk yield responses followed those of energy intake also being higher for LP does (+21.3 g/day; P<0.05). The environmental conditions did not affect the perirenal fat thickness (PFT), but a genotype by environment interaction was observed. In NC and HC, the PFT was higher for line V (+0.23 and +0.35 mm, respectively; P<0.05) than for LP does, but this was not the case at NF (-0.01 mm). Moreover, the PFT evolution was different between them. In the NC environment, LP does used the accreted PFT in late lactation (-0.29 mm), whereas V does did not (-0.08 mm). Conversely, in the HC environment, LP does showed a flat PFT evolution in late lactation, whereas V does accumulated PFT. In the NF environment, LP and V does had a similar PFT evolution. There was also a litter size reduction for V does of -2.59 kits total born in HC and -1.78 kits total born in NF environments, whereas this was not observed for LP does. The results for LP does indicate a direct use of DE ingested for reproduction with little PFT change, whereas V does actively use the PFT reserves for reproduction.

Comparison of immune response to lipopolysaccharide of rabbit does selected for litter size at weaning or founded for reproductive longevity.

To evaluate differences in maternal lines to the immune response of reproductive rabbit does, a total of 64 animals of two different lines: (1) founded for hyper-longevity and litter size criteria (LP) and (2) selected for litter size at weaning (V) were used. Females were subjected to three different reproductive efforts: post-partum (PP) mating at first lactation and 9 kits during the second; post-weaning (PW) mating at first lactation and 9 kits during the second; and PW mating at first lactation and 5 kits during the second. At second weaning (30 days PP), an acute response was induced by intravenous infusion of lipopolysaccharide (LPS). LP females seemed to be lower affected during the hyper-acute phase than V females, showing lower plasma glucose content at 1.5 h post infusion (pi) and rectal temperature at 6 h pi; and showed higher ulterior immune response, with higher levels of C-reactive protein at 48 h pi and haptoglobin in plasma from 24 h pi. Survival test conferred a higher risk of culling for V than for LP females during the first hours after challenge. These results may suggest that, regarding immune response to LPS challenge, foundation by hyper-longevity productive criteria lead to obtain a more robust population of rabbit does, characterized by improved response ability.

Effects of feeding programme on the performance and energy balance of nulliparous rabbit does.

A total of 190 rabbit females were used to evaluate five feeding programmes from 9 weeks of age to the first parturition: CAL, fed ad libitum with a control diet (C: 11.0 MJ digestible energy (DE) and 114 g digestible protein (DP)/kg dry matter (DM)) until first parturition; CR, fed ad libitum with C diet until 12 weeks of age and then C diet restricted (140 g/day) until first parturition; F, fed ad libitum with a low-energy, high-fibre diet (F: 8.7 MJ DE and 88 g DP/kg DM) until first parturition; FC, fed with F diet ad libitum until 16 weeks of age, and C diet ad libitum until first parturition; FCF, fed with F diet ad libitum until 16 weeks of age, then C diet ad libitum until 20 weeks and then F diet ad libitum until first parturition. The rabbits were artificially inseminated at 18 weeks of age. CAL group had a higher mortality rate compared with the other groups between 9 and 12 weeks of age (34% v. 3%; P < 0.05) and during the last 3 weeks of first pregnancy (14% v. 3%; P < 0.05). The CAL and FC females presented higher BW and perirenal fat thickness (PFT) than CR females at 11 days of pregnancy (+0.41 kg and +0.6 mm; P < 0.05), with F females showing medium values. The type of feeding procedure did not affect the fertility rate of young females at first artificial insemination. Differences in BW disappeared at parturition, when only CAL females presented a greater PFT than CR and FC females (+0.3 mm; P < 0.05). In comparison with FCF, CAL females had smaller and thinner live born litters (-2.5 kits and -139 g, respectively; P < 0.05), with CR, F and FC females showing medium values. The low number of kits born alive for CAL females was because of their lesser total number of kits born (-1.7 kits; P < 0.05) and the greater mortality of their litters at birth (+13.9%; P < 0.05) compared with FCF females. Non-esterified fatty acid was higher in the blood of females fed C diet (CAL and CR) than in others at partum day (on average +0.15 mmol/l; P < 0.05). In conclusion, the ad libitum use of diets for lactating rabbit does throughout the rearing period could lead young rabbit females to present a higher risk of early death and smaller litter size at first parturition. Feed restriction or earlier use of suitably fibrous diets led females to achieve the critical BW and fat mass at first mating to ensure reproduction.

Differences in productive robustness in rabbits selected for reproductive longevity or litter size.

The aim of this work was to evaluate the ability of a line selected for reproductive longevity (LP) to confront productive challenges compared to a line selected during 31 generations for litter size at weaning (V). A total of 133 reproductive rabbit does were used (72 and 61 from LP and V lines, respectively). Within each line, three groups with different levels of productive effort were planned: PP9, inseminated at day 4 after the first partum and with nine kits during the second partum, and inseminated after first weaning (30 days) and with nine (PW9) or five kits (PW5) during the second partum. The reproductive performance, body condition (perirrenal fat thickness (PFT)) and lipolytic response were controlled. LP does showed greater mean live weight (LW; +128 g; P < 0.05), PFT (+0.47 mm; P < 0.05) and estimated body energy (EBE; +0.29 MJ/kg; P < 0.01) than V does at second partum. However, LP does that mated at first post partum did not significantly differ in EBE relative to V does at second partum. During the first week of lactation, dry matter (DM) intake was similar for both lines (94 and 95 g DM/kg LW0.75 day for V and LP does, respectively). There was a significant difference in milk yield between both lines during the first week when litter size was nine (60 v. 54 g of milk/kg LW0.75 day for LP and V does, respectively; P < 0.01), but no difference when litter size was five. Consequently, when litter size was nine, LP does showed a lower recovery of PFT (0.6 mm less; P < 0.05) than V does during the first 10 days of lactation. However, when litter size was five, LP does showed a higher LW (+210 g; P < 0.05) than V does at 10 days of lactation and a similar recovery of PFT. During the last 3 weeks of the lactation, LP does showed a higher feed intake (+6 g DM/kg LW0.75 day; P < 0.05) and milk yield (+27 g/day; P < 0.001) than V does when litter size was nine, resulting in no significant differences in LW at 30 days of lactation. However, when litter size was five, both lines showed similar feed intake and milk yield, maintaining their differences in LW at 30 days of lactation (+206 g for LP does; P < 0.05). These results show that the rabbit line selected for reproductive longevity is more robust with respect to coping with productive challenges, than a line selected for reproductive intensity.