Use of aqueous extract of noni in extender for sheep semen freezing

A.L.C Nascimento,G.O Pinheiro,H.C Azevedo,A.D.F Santos,L.C Gomes,J.M.D.S Velarde,C.A Lima,M.A Pereira

doi:10.1590/1678-4162-9944

Abstract

ABSTRACT The study aimed to evaluate the action of aqueous extract of noni in an extender for sheep semen freezing. Treatments differed in inclusion of aqueous extract of noni in the extender: T1 ˗ no addition; T2 ˗ 24µg/mL; T3 ˗ 72µg/mL; and T4 ˗ 120µg/mL. Ejaculates were collected, diluted in the four treatments, and frozen. After thawing, the semen was subjected to a thermoresistance test and evaluated for subjective motility, vigor, membrane integrity assessment by hypo-osmotic swelling test, live-dead assay, computer-assisted sperm analysis and the status of sperm capacitation and acrosome reaction. Data were subjected to ANOVA, and then to Student Newman Keuls’s test at 5% significance level. In the thermoresistance test after two hours of incubation, motility in T4 (120µg/mL) was lower than in the other treatments, with no differences in the HoS test in either diluted semen or in the semen evaluated immediately post-thawing, while for the other times, treatments showed similar responses. Regarding the motility parameters, a difference was observed for progressive motility, curvilinear velocity, average path velocity, and amplitude of lateral head displacement. As to the sperm capacitation status, a difference was observed between treatments for the sperm capacitated with intact acrosome.

Highlights

The semen freezing process impairs the sperm membranes in many ways, which may be due to the increased lipid peroxidation
This study aimed to evaluate the inclusion of different concentrations of aqueous extract of noni in an extender for sheep semen freezing, focusing on sperm motility and membrane integrity
We can infer that the ideal concentration of aqueous extract of noni to be added to the extender for reducing lipid peroxidation is between 24 and 124μg/mL

Summary

Introduction

The semen freezing process impairs the sperm membranes in many ways, which may be due to the increased lipid peroxidation. The sperm cell undergoes oxidative damage caused by the imbalance between antioxidant substances and physiological concentrations of oxidants resulting from the reduced total antioxidant capacity of the semen and increased production of reactive oxygen species (Guerra et al, 2004). Studies conducted in the last few years have shown that these imbalances between oxidant and antioxidant substances negatively affect the cell energy metabolism and the motility, viability, and integrity of the sperm cell DNA (Maia et al, 2009; Câmara and Guerra, 2011). Spermatozoa and the semen plasma have an antioxidant defense system that plays a key role in sperm viability. When the semen is diluted for freezing, the efficiency this antioxidant defense system is reduced (Câmara and Guerra, 2011). For better sperm viability post-thawing, substances with antioxidant activity must be included in extenders aiming to provide balance to the activity of oxidants produced during preservation procedures

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Conclusion