Semen evaluation and in vivo fertility in a Northern Italian pig farm: Can advanced statistical approaches compensate for low sample size? An observational study

Exploring the full potential of sperm function with nanotechnology tools

Sperm quality is essential to guarantee the success of assisted reproduction. However, selecting high-quality sperm and maintaining it during (cryo)preservation for high efficiency remains challenging in livestock reproduction. A comprehensive understanding of sperm biology allows for better assessment of sperm quality, which could replace conventional sperm analyses used today to predict fertility with low accuracy. Omics approaches have revealed numerous biomarkers associated with various sperm phenotypic traits such as quality, survival during storage, freezability, and fertility. At the same time, nanotechnology is emerging as a new biotechnology with high potential for use in preparing sperm intended to improve reproduction in livestock. The unique physicochemical properties of nanoparticles make them exciting tools for targeting (e.g., sperm damage and sexing) and non-targeting bioapplications. Recent advances in sperm biology have led to the discovery of numerous biomarkers, making it possible to target specific subpopulations of spermatozoa within the ejaculate. In this review, we explore potential biomarkers associated with sperm phenotypes and highlight the benefits of combining these biomarkers with nanoparticles to further improve sperm preparation and technology.

Antimicrobial capabilities of non-spermicidal concentrations of tea tree (Melaleuca alternifolia) and rosemary (Rosmarinus officinalis) essential oils on the liquid phase of refrigerated swine seminal doses

Antimicrobial resistance is increasing within the porcine industry with consequential high impact on human health, leading to a need for new antimicrobials. Lately, the scientific community has turned its interest towards natural compounds, and different essential oils have been tested on spermatozoa for preliminary assessment of toxicity before considering them as good substitutes for standard antibiotics. The aim of the present work was to investigate the potential antimicrobial effect of Melaleuca alternifolia and Rosmarinus officinalis essential oils, already evaluated for toxicity, on swine artificial insemination doses deprived of spermatozoa and stored at 16 °C for 5 days. This was accomplished by setting up an in vitro model with a standardized quantity of E. coli. Essential oils, previously chemo-characterized by means of gas chromatography, were tested at 0.2 and 0.4 mg/ml. Analyses, performed at 24 and 120 h, included optical density evaluation, bacterial DNA quantification by qPCR, and colony count. The results demonstrate that both Melaleuca alternifolia and Rosmarinus officinalis essential oils, at a concentration of 0.4 mg/ml, are capable of delivering similar effects to ampicillin, used as control, on the experimental samples. At the lower concentration, M. alternifolia essential oil seemed more effective when compared to R. officinalis. Overall, these findings strengthen the hypothesis of the potential use of phyto-complexes as antimicrobial agents for reproductive biotechnologies.

In vitro supplementation with unsaturated fatty acids improves boar sperm viability after storage at 6 °C

Liquid preservation of the cold-sensitive boar sperm at a lesser temperature than the standard 17 °C would reduce bacterial growth and minimize the use of antibiotics. There was assessment, therefore, of the capacity of individual fatty acids bound to fatty acid free BSA to improve sperm survival at 6 °C because oxidative stress and lipid degradation are prominent detrimental factors. Different effects of the fatty acids were observed. Supplementation with naturally occurring fatty acids (linolenic, linoleic, oleic, palmitoleic acid), which may become metabolically incorporated into sperm lipids, increased the number of motile and progressively motile sperm after 2 days of storage during a thermo-resistance test (5 h at 38 °C) to that of control samples preserved at 17 °C in pure Beltsville Thawing Solution. With the exception of linolenic acid, all naturally occurring fatty acids enhanced the number of sperm with active mitochondria after 3 days of storage. Palmitoleic acid was the most effective supplement with effects already present when sperm were re-warmed for 30 min after 2 and 7 days of storage. The non-endogenous, non-integrated timnodonic acid (20:5) had no effect on sperm variables. Because the application of individual fatty acids attached to BSA had differing effects in preserving boar sperm at 6 °C, the use of combinations of fatty acids could be more efficacious than with use of natural lipid supplements for low temperature preservation of sperm.

In Vitro Effects of Tea Tree Oil (Melaleuca Alternifolia Essential Oil) and its Principal Component Terpinen-4-ol on Swine Spermatozoa

The growing interest towards essential oils stems from their biological capabilities that include antibacterial and antioxidant effects. Such properties may be extremely useful in the reproductive field; nonetheless essential oils show toxic effects that can lead to cell disruption. The present study aimed to evaluate and compare the effects of tea tree oil (TTO) and its principal component terpinen-4-ol (TER) on the morpho-functional parameters of swine spermatozoa. Experimental samples were prepared by suspending 15 × 10⁷ spermatozoa in 5 mL of medium with different concentrations of the above-mentioned compounds: from 0.2 to 2 mg/mL at an interval of 0.2 for TTO, while TER concentrations were adjusted according to its presence in TTO (41.5%). After 3 h incubation at 16 °C, samples were analyzed for pH, viability, acrosome status, and objective motility. The results highlighted a concentration-dependent effect of TTO with total motility as the most sensitive parameter. TER was better tolerated, and the most sensitive parameters were related to membrane integrity, suggesting a different pattern of interaction. The study confirms the importance of evaluating the effects of natural compounds on spermatozoa before exploiting their beneficial effects. Spermatozoa seem to be good candidates for preliminary toxicological screenings in the light of their peculiar properties.