Enhancing felid conservation: Exploring the impact of in vitro culture media on domestic cat blastocyst production.

This study investigated the optimization of assisted reproductive techniques for wild felid conservation, focusing on in vitro procedures using the domestic cat as a model species. The research evaluated the impact of three different in vitro culture media on blastocyst formation. Oocytes and spermatozoa were collected and processed, followed by in vitro fertilization and culture. Results returned a similar blastocyst rate (ANOVA, p > .05), over 16% across all groups. While demonstrating the potential of these techniques, further investigations are warranted to evaluate embryo quality to refine optimal protocols and their applicability in felid conservation efforts.

Probiotic potential of GABA-producing lactobacilli isolated from Uruguayan artisanal cheese starter cultures.

AIMS: In this study, we sought to identify and characterize a collection of 101 lactobacilli strains isolated from natural whey starters used in Uruguayan artisan cheese production, based on their capacity to produce gamma-aminobutyric acid (GABA) and their probiotic potential. METHODS AND RESULTS: The probiotic potential was assessed using low pH and bile salt resistance assays; bacterial adhesion to intestinal mucus was also evaluated. Selected strains were then identified by 16S sequencing, and their GABA-producing potential was confirmed and quantified using a UHPLC-MS system. Twenty-five strains were identified and characterized as GABA-producing lactobacilli belonging to the phylogenetical groups Lactiplantibacillus (n = 19) and Lacticaseibacillus (n = 6). Fifteen strains of the Lactiplantibacillus group showed a significantly higher GABA production than the rest. They showed the predicted ability to survive the passage through the gastrointestinal tract, according to the in vitro assays. CONCLUSIONS: A set of promising candidate strains was identified as potential probiotics with action on the gut-brain axis. Further studies are needed to assess their possible effects on behaviour using in vivo assay. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows the potential of strains isolated from local natural whey starters as probiotics and for biotechnological use in functional GABA-enriched foods formulation.

Longitudinal study of the bovine cervico-vaginal bacterial microbiota throughout pregnancy using 16S ribosomal RNA gene sequences.

The microbiota composition of the bovine female reproductive tract influences reproductive efficiency, susceptibility to genital pathogens, and the health of newborn calves. However, knowledge about cervico-vaginal microbiota during gestation is scarce. Therefore, the present study aimed to analyze the taxonomic profile of the cervico-vaginal bovine microbiota throughout pregnancy and after calving using high-throughput sequencing of a fragment of the 16S ribosomal RNA gene. Healthy nulliparous Holstein heifers (n = 13) with similar age and body conditional score were selected to collect samples from the cervico-vaginal area with a sterile swab at 5 timepoints. We sequenced the V1-V2 region of the 16S ribosomal RNA gene and analyzed data using the DADA2, phyloseq and vegan R Studio packages. No differences were observed in alpha and beta diversity across sampling points, accounting for the stability of the microbiota throughout pregnancy. The most abundant phyla are Firmicutes, Bacteroidota, Proteobacteria and Actinobacteria, and are present as the main taxa in all five sampling points. Also, several of the least abundant taxa can be observed to change with time. Our comprehensive study of the cervico-vaginal bacterial microbiota during the gestation period contributes to the knowledge of microbiota dynamics on the bovine reproductive tract during and after pregnancy and can serve as a baseline for future research and the development of potential therapeutic interventions.

Successful ultrasound-guided ovum pick-up (OPU) and subsequent in vitro embryo production in a domestic cat.

Ovum Pick Up (OPU) is a minimally invasive technique widely used in cattle and mares for oocyte retrieval, involving ultrasound-guided puncture of ovarian follicles. It has been demonstrated that this technique is safe for its repeated use in the same female without affecting her reproductive health, allowing for the retrieval of oocytes in individuals regardless of their reproductive status. The oocytes obtained through OPU can subsequently be used for in vitro embryo production (IVP) using assisted reproductive techniques (ARTs) or be cryopreserved in biobanks for their future use. Traditionally, the minimally invasive technique of choice performed in vivo in domestic and wild felines was LOPU (laparoscopic-guided ovum pick up). The present study was designed to explore if ultrasound-guided OPU in the domestic cat is safe and effective. In an initial series of ex vivo experiments (n = 92 ovaries, n = 434 oocytes), the effect of different aspiration pressures for oocyte collection was explored. These experiments identified 43 mmHg as the optimal aspiration pressure, resulting in the highest recovery rate and a favorable maturation and blastocyst rate. Subsequently, 16 grade I and II oocytes were retrieved by OPU and 101 oocytes were retrieved following ovariectomy and slicing. Sixteen oocytes obtained with each technique were subjected to in vitro maturation (IVM) and in vitro fertilization (IVF). A total of 14 presumptive zygotes were selected for in vitro culture (IVC) from each group (OPU and slicing), obtaining a cleavage rate of 57.1 % and 64.2 %, a morula rate of 28.5 % in both groups, and a blastocyst rate of 7.14 % and 14.2 % respectively. The hormonal stimulation protocol was well-tolerated, with no adverse effects observed. Moreover, no complications arose during the ovariectomy performed post-OPU. The use of this technique in domestic cats represents a significant step forward in terms of safety, replicability, and invasiveness, serving as a valuable model for its application in wild felids species. Additional research involving a greater number of animals is required to validate these encouraging findings.

Epididymal Spermatozoa Show Higher Cryoresistance to Vitrification Process Than Ejaculated Spermatozoa in Dogs.

The aim of this study was to investigate differences in the sperm response to a vitrification-warming process between ejaculated and epididymal dog spermatozoa, and to evaluate the efficacy of an animal protein-free extender for vitrification of both types of sperm cells. Vitrified-warmed spermatozoa from the epididymis showed greater (p < 0.001) progressive motility and total motility values than ejaculated spermatozoa, regardless of the diluent. The vitrification procedure returned better results for viability and intact acrosome when human tubal fluid (HTF®) was used (25.10 ± 7.90 and 56.50 ± 6.7, respectively) compared with Tris-Citric acid-Glucose (TCG) (15.20 ± 4.70 and 43.70 ± 7.9, respectively) in ejaculated samples. Similarly, higher total motility (34.5 ± 4.5) was observed in HTF postwarmed samples compared with TCG-treated samples (19.52 ± 5.1). The interaction source (epididymis, ejaculated) × extender had a significant effect (p < 0.001) on the values of total motile spermatozoa after warming. HTF-based extender improved (p < 0.001) total motility values in epididymal samples, but not in ejaculated samples. In conclusion, epididymal spermatozoa show higher cryoresistance to the vitrification process than ejaculated spermatozoa in dogs. The use of HTF is adequate for both ejaculated and epididymal canine sperm vitrification.