Brief Sensory Deprivation Triggers Cell Type-Specific Structural and Functional Plasticity in Olfactory Bulb Neurons.

Can alterations in experience trigger different plastic modifications in neuronal structure and function, and if so, how do they integrate at the cellular level? To address this question, we interrogated circuitry in the mouse olfactory bulb responsible for the earliest steps in odor processing. We induced experience-dependent plasticity in mice of either sex by blocking one nostril for one day, a minimally invasive manipulation that leaves the sensory organ undamaged and is akin to the natural transient blockage suffered during common mild rhinal infections. We found that such brief sensory deprivation produced structural and functional plasticity in one highly specialized bulbar cell type: axon-bearing dopaminergic neurons in the glomerular layer. After 24 h naris occlusion, the axon initial segment (AIS) in bulbar dopaminergic neurons became significantly shorter, a structural modification that was also associated with a decrease in intrinsic excitability. These effects were specific to the AIS-positive dopaminergic subpopulation because no experience-dependent alterations in intrinsic excitability were observed in AIS-negative dopaminergic cells. Moreover, 24 h naris occlusion produced no structural changes at the AIS of bulbar excitatory neurons, mitral/tufted and external tufted cells, nor did it alter their intrinsic excitability. By targeting excitability in one specialized dopaminergic subpopulation, experience-dependent plasticity in early olfactory networks might act to fine-tune sensory processing in the face of continually fluctuating inputs.SIGNIFICANCE STATEMENT Sensory networks need to be plastic so they can adapt to changes in incoming stimuli. To see how cells in mouse olfactory circuits can change in response to sensory challenges, we blocked a nostril for just one day, a naturally relevant manipulation akin to the deprivation that occurs with a mild cold. We found that this brief deprivation induces forms of axonal and intrinsic functional plasticity in one specific olfactory bulb cell subtype: axon-bearing dopaminergic interneurons. In contrast, intrinsic properties of axon-lacking bulbar dopaminergic neurons and neighboring excitatory neurons remained unchanged. Within the same sensory circuits, specific cell types can therefore make distinct plastic changes in response to an ever-changing external landscape

Three Decades of progress in Artificial Insemination in Rabbit Farming: a Review

[EN] The commercial use of artificial insemination (AI) in rabbit farming is relatively recent, especially when compared to other species such as cattle or swine, in which AI has been used for more than 60 years. The large-scale use of AI in rabbit farming dates back to the late 80s. However, despite its short journey, it has not stopped evolving. Although there have been numerous changes, in this review article we aim to highlight two important milestones in optimisation of this technique: the introduction of biostimulation and the addition of Gonadotropin-releasing hormone (GnRH) analogues to the seminal dose to induce ovulation. In the former case, by means of different methods of biostimulation, such as feed and light flushing and/or separation of the litter in the days prior to AI, the use of hormones to synchronise heat with the moment of AI was practically eliminated. Nowadays, the possibility of using pheromones with the same objective is under research, even to increase ovulation rate or improve semen production. Although there are pheromones on the market labelled for use in other species, in the case of rabbit the knowledge of them is limited. Nevertheless, given the verified effects that pheromones produce in other animals, expectations are high. In the latter case, after several attempts by using other methods, the technique commonly used to induce ovulation was the intramuscular administration of GnRH or its synthetic analogues. However, in recent years, it has been proven that administration of GnRH through the vagina is possible, added to the seminal dose, which offers numerous advantages regarding health, animal welfare and the workforce needed. Recently, the European Medicines Agency (EMA) approved this practice, so in the near future it will probably become the most widely used method. Even so, there is still room for improvement, as the dosage of GnRH needed is higher than the one administered intramuscularly. Research on this topic allows us to predict that this problem should be solved in the coming years. Other alternatives such as the ?-Nerve Growth Factor need further research to become a feasible option.The study was supported by the Xunta de Galicia (Plan Gallego de Investigación y Desarrollo Tecnológico, Proyectos Ref. 1999/CG321; Ref. 2000/CG3452) and the Ministerio de Ciencia e Innovación (Plan Estatal de Investigación Científica, Técnica y de Innovación, Proyecto Ref. PID2021-127814OB-I00). The co-authors Yáñez U. and Villamayor P. were funded by Xunta de Galicia (Predoctoral Contract Ref. 2020/122 and ED481A-2020/491430 respectively). We also thank COGAL SL (Pontevedra, Spain) for providing the facilities and animals used in this study, as well as technical support.Quintela Arias, LÁ.; Becerra González, JJ.; Peña Martínez, AI.; Yáñez Ramíl, U.; Rodríguez Villamayor, PR.; Sánchez-Quinteiro, P.; Martínez Portela, P.... (2023). Three Decades of progress in Artificial Insemination in Rabbit Farming: a Review. World Rabbit Science. 31(2):93-107. https://doi.org/10.4995/wrs.2023.186619310731

Assessment of Biostimulation Methods Based on Chemical Communication in Female Doe Reproduction

Biostimulation is an animal management practice that helps improve reproductive parameters by modulating animal sensory systems. Chemical signals, mostly known as pheromones, have a great potential in this regard. This study was conducted to determine the influence of short-term female rabbit exposure to different conditions, mainly pheromone-mediated, on reproductive parameters of inseminated does. Groups of 60 females/each were exposed to (1) female urine, (2) male urine, (3) seminal plasma and (4) female–female (F–F) separated, just before artificial insemination, and compared to a ‘golden method’ female–female interaction. The following reproductive parameters were analyzed for each group: receptivity (vulvar color), fertility (kindling rate), prolificacy and number of born alive and dead kits/litter. Our results showed that the biostimulation methods employed in this experiment did not significantly improve any of the analyzed parameters. However, female doe exposure to urine, especially to male urine, showed no significant higher fertility values (95.4%) when compared to the rest of the experimental conditions (on average 92.4%). Female–female interaction before artificial insemination, which is a common practice in rabbit farms, showed similar results as not establishing social interaction (F–F separated), which suggests that F–F interaction could be replaced by F–F separated, therefore avoiding unnecessary animal management and time cost. On the other hand, fertility ranges were lower for animals with a pale vulvar color whereas no differences were noticed among the other three colors which measure receptivity (pink, red, purple), thus suggesting that these three colors could be grouped together. Future studies should aim at determining potential chemical cues/pheromones released through bodily secretions that influence reproduction in rabbits, therefore contributing to animal welfare and to a natural image of animal production

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population