Efecto de la suplementación con nanocomplejos de colesterol-metil-B-ciclodextrina en la calidad seminal ovina

Abstract

Cryopreservation of sheep semen constitutes an essential livestock biotechnology for the conservation and dissemination of genetic resources of high zootechnical value within sustainable production systems. However, the critical phases of thermal descent, freezing, and thawing induce severe oxidative stress (EO) and the accumulation of reactive oxygen species (ROS), triggering irreversible alterations in the lipid architecture of the sperm plasma membrane due to its high proportion of polyunsaturated fatty acids (PUFAs) and low endogenous cholesterol concentration. To mitigate this cryogenic damage, the addition of methyl-β-cyclodextrin-cholesterol nanocomplexes (CLC) in commercial diluents represents a superior biotechnological alternative to stabilize the membrane and preserve cell viability. The purpose of this research was to determine the optimal concentration of (CLC) as a substitute for egg yolk within the Triladyl diluent, evaluating its impact on post-thaw sperm quality. Five ejaculates from a Katahdin ram were collected using an artificial vagina, adjusted to a concentration of 50 × 10⁶ sperm per dose. The samples were divided into four groups: one control and three treatments supplemented with 1 mg, 2 mg, and 3 mg of (CLC). After cryopreservation in liquid nitrogen, the semen was evaluated using the computerized CASA system, Eosin-Nigrosin staining, the HOST test, and the fluorescent probe MitoTracker Green. The results showed that supplementation with 1 mg of (CLC) provided superior protection to the sperm membrane against osmotic and thermal variations, significantly improving its functional integrity and flagellar beat frequency, while the parameters of overall viability and mitochondrial activity remained stable compared to the control. It is concluded that the use of (CLC) nanocomplexes optimizes ovine semen cryopreservation, offering a biosecure alternative to the use of avian-origin yolks.

Keywords: methyl-B-cyclodextrin-cholesterol (CLC), cryopreservation, ovine semen, oxidative stress, sperm quality.