Antioxidant Effects of Seminal Plasma on Cellular Morphological Viability of Swine Semen Post-Cryopreservation

Hernandez Dak Barrientos

doi:10.4172/2157-7579.1000225

Abstract

The aims of this study were to measure the antioxidant enzyme activity of superoxide dismutase (SOD) and glutathione peroxidase (GPX1) in seminal plasma (SP), the influence of temperature overtime on such enzymes and, to assess post-thaw viability of semen supplemented with autologous or homologous SP by nigrosine-eosin (NE) and hypoosmotic tests (HOST). A total of 48 sperm-rich fractions from 8 boars were collected and equally divided for SP antioxidant activity determination or cryopreservation experiments. Marked differences in SP antioxidant activity were found amongst individuals. SOD values ranged from 7.88 ± 0.04 U/g to 12.01 ± 0.07 U/g. Restricted maximum likelihood variance components estimates (REML) indicated that 98% of the variation resided between individuals (p<0.05). In addition, GPX1 activity ranged from 0.03 ± 0.001 U/g to 0.05 ± 0.005 U/g with a REML between and within individual of 58% and 42%, respectively (p<0.05). Further, temperature largely influenced SOD and GPX1 activity (Spearman’s ρ ≥ 0.77; main effect p<0.01). Regardless, sperm viability improved significantly in groups supplemented with 20% (v/v) SP compared with control as per NE 27 ± 0.59 % vs. 26 ± 0.23 % or HOST 28 ± 0.27 % vs. 18 ± 0.27 % (p<0.05). Although there was an additive effect of SP on sperm viability, the antioxidant levels were not strongly correlated to sperm morphology. Therefore other factors in seminal plasma are contributing to sperm viability and overall fitness towards a successful fertilization.

Highlights

Successful swine fertility programs can be achieved using extended cooled semen when compared to those using natural service
Restricted maximum likelihood variance components estimates indicated that 98% of the variation resided between individuals (p
GPX1 analysis showed that boar E expressed the highest value of antioxidant enzyme activity (0.05 ± 0.005 units per gram (U/g)) and it was significantly different compared to boars A, B and C (0.03 ± 0.002 U/g, 0.03 ± 0.003 U/g and 0.03 ± 0.001 U/g; p

Summary

Introduction

Successful swine fertility programs can be achieved using extended cooled semen when compared to those using natural service. During freezing about 50% of sperm cells lose viability due to several factors such as heat shock, intracellular ice crystal formation, oxidative stress and cryocapacitation [3,4] that negatively affects fertility rates [5,6]; effects include motility impairment, chromatin damage and membrane alterations like decreased mitochondrial membrane potential [6,7]. These cellular changes may potentially shorten the life span of spermatozoa by modifying regulatory pathways such as those of the acrosome reaction and leaving a significant portion of the sperm population unable of interacting with the oviduct or of fertilizing the eggs [8]

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Conclusion