Replacing antibiotics by natural polyphenol-rich extracts from grape marc in pig semen extenders for refrigerated storage: Physicochemical properties

Artificial insemination (AI) is critical for breeding in the modern pig industry. Nearly 14Ml/year of semen extenders with antibiotics are used in the EU, contributing to the generation of antimicrobial resistance.

The objective was to substitute antibiotics by natural polyphenol-rich extracts from grape marc (LIDSA- USC/i-Grape, Spain), testing the physicochemical properties of the formulations.

We tested Beltsville Thawing solution (self-made, BTS) and Vitasem (commercial, Magapor). Vehicles and extracts (1:1 water:vehicle, ethanol E, ethyl lactate EL, propyleneglycol PG) were tested at 2% and 0.625% in a pig semen storage protocol at 17°C (sampling at days 0, 3, 7 for conductivity, pH, osmolality, and redox potential, ORP).

Conductivity (mS/cm) did not vary (BTS: 6.65±0.02; Vitasem: 10.47±0.01) between treatments, but pH (BTS: 7.74±0.01; Vitasem: 8.05±0.00) decreased in EL (BTS and Vitasem, 0.625%: 6.17±0.01, 6.55±0.01;

2%: 4.40±0.06, 5.18±0.08). Osmolality (mOsm/kg) increased with vehicle 2% (BTS: 319±2, E: 515±1, EL:

492±1, PG: 483±2; Vitasem: 299±2, E: 489±3, EL: 469±1, PG: 453±1). Only EL vehicle in BTS increased

ORP (182.1±3.6, 0.625%: 216.8±2.1, 2%: 307.9±0.9). Extracts decreased ORP in all cases, showing the powerful antioxidant effect of polyphenols from grape marc.

In summary, vehicles modified pH and osmolality, but E and PG effects at 0.625% were not concerning. Polyphenol formulations showed potent antioxidant capacity inducing ORP-changes. Further experiments are in need to determine the effects on sperm conservation at 0.625%.

Acknowledgment The authors thank G. Rivas and Magapor SL (Spain).

Funding This study was supported by NeoGiANT H2020 project (UE 101036768).

Publikationsverlauf

Artikel online veröffentlicht:
16. November 2023