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Background: Nerve Growth Factor (NGF) plays an important role in the reproductive system through its receptor's interaction (p75NTR). This paper aims to analyze the impact of NGF p75NTR in epididymal and ejaculated rabbit semen during in vitro sperm storage. Methods: Semen samples from 10 adult rabbit bucks were collected four times (n = 40) and analyzed. NGF was quantified in seminal plasma, and the basal expression of p75NTR in sperm was established (time 0). Moreover, we evaluated p75NTR, the apoptotic rates, and the main sperm parameters, at times 2–4 and 6 h with or without the administration of exogenous NGF. Results: Based on the level of p75NTR, we defined the threshold value (25.6%), and sperm were divided into High (H) and Normal (N). During sperm storage, p75NTR of H samples significantly modulated some relevant sperm parameters. Specifically, comparing H samples with N ones, we observed a reduction in motility and non-capacitated cell number, together with an increased percentage of dead and apoptotic cells. Notably, the N group showed a reduction in dead and apoptotic cells after NGF treatment. Conversely, the NGF administration on H sperm did not change either the percentage of dead cells or the apoptotic rate. Conclusion: The concentration of p75NTR on ejaculated sperm modulates many semen outcomes (motility, apoptosis, viability) through NGF interaction affecting the senescence of sperm. [ABSTRACT FROM AUTHOR]

Simple Summary: Each animal hosts a large community of bacteria, protozoa, fungi, and algae that colonize every surface of the body. The microbiota is defined as the complex microbial community that inhabits a specific anatomic region of animals and interacts with it, developing symbiotic relationships. In this regard, the intestinal microbiota has a vital impact on metabolism, digestive activity, immune development, resistance to infections, health, and welfare of the host. Therefore, knowing its characteristics is important for understanding its action in these specific functions. This study provides a comprehensive map of the most common bacterial communities that colonize different parts of the rabbit gastrointestinal tract (stomach, duodenum, jejunum, ileus, caecum, and colon) while using a modern methodological approach and comparing it with the studies that have been conducted to date on other animal species and human beings. It could be the starting point for further research on gut microbiota modulation with the ultimate goal to promote the health and welfare, in order to prevent or treat gastrointestinal diseases, decrease antibiotic use, and increase the productive performance of rabbit. The microbiota is extremely important for the animal's health, but, to date, knowledge on the intestinal microbiota of the rabbit is very limited. This study aimed to describe bacterial populations that inhabit the different gastrointestinal compartments of the rabbit: stomach, duodenum, jejunum, ileum, caecum, and colon. Samples of the luminal content from all compartments of 14 healthy New White Zealand rabbits were collected at slaughter and analyzed using next generation 16S rRNA Gene Sequencing. The findings uncovered considerable differences in the taxonomic levels among the regions of the digestive tract. Firmicutes were the most abundant phylum in all of the sections (45.9%), followed by Bacteroidetes in the large intestine (38.9%) and Euryarchaeota in the foregut (25.9%). Four clusters of bacterial populations were observed along the digestive system: (i) stomach, (ii) duodenum and jejunum, (iii) ileum, and (iv) large intestine. Caecum and colon showed the highest richness and diversity in bacterial species, while the highest variability was found in the upper digestive tract. Knowledge of the physiological microbiota of healthy rabbits could be important for preserving the health and welfare of the host as well as for finding strategies to manipulate the gut microbiota in order to also promote productive performance. [ABSTRACT FROM AUTHOR]

In the last two decades, the human sperm count linearly decreased in Western countries. Health problems, lifestyle, pollutants, and dietary behaviours are considered as the main risk factors, and the unbalance of dietary n -6/ n -3 fatty acids is one of the most relevant. The aim of the present research is to study the effect of different dietary sources of n -3 polyunsaturated fatty acids (PUFA) on reproductive traits using rabbit buck as the animal model. Fifteen rabbit bucks were assigned to three experimental groups: the control group, the FLAX group fed 10% extruded flaxseed, and the FISH group fed 3.5% fish oil for 110 days (50-day adaptation and 60-day experimental periods). Semen samples were collected weekly, whereas blood was collected every two weeks for the analytical determination of semen traits, oxidative status, fatty acid profiles, isoprostanes, neuroprostanes, and the immunocytochemistry of docosahexaenoic acid (DHA) and eicosapentaenoic (EPA) acid. At the end of the trial, the rabbits were killed and the testes were removed and stored for the analysis of fatty acid profile and immunocytochemistry. Results showed that dietary administration of n -3 PUFA improved the track speed of the sperm and increased the n -3 long-chain PUFA mainly confined in the sperm tail. Seminal plasma increased the thiobarbituric reactive substances (TBARs) by three times in the groups fed supplemental n -3, whereas the F 2 -isoprotanes (F 2 -IsoPs) and F 4 -neuroprostanes (F 4 -NeuroPs) were lower and higher, respectively, in both supplemented groups than in the control. The testes and sperm showed a higher DHA and EPA distribution in rabbits from the n -3 supplemented groups compared with the control. In conclusion, supplemental dietary n -3 PUFA improved sperm motion traits and resulted in an enrichment of membrane fatty acid in the sperm and testes of the rabbits. However, such an increased amount of PUFA negatively affected the sperm oxidative status, which was mainly correlated with the generation of F 4 -NeuroPs with respect to F 2 -IsoPs. Accordingly, the latter cannot be considered a good marker of oxidation when diets rich in n -3 PUFA are provided., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2019 Cesare Castellini et al.)