Milk, caseinate and lactoferrin addition to equine semen cooling extenders

Abstract

Cooled semen has been used routinely to prolong sperm viability until artificial insemination time. However, spermatozoa are subjected to oxidative stress. The aim of the present work was to investigate the protective and antioxidant effect of the milk proteins lactoferrin (Lf) and caseinate added to equine semen cooling extenders. Semen from six stallions was cooled at 5 °C after resuspension with C1) milk- and glucose-based, C2) 0.6% caseinate, C3) C2 + Lf 200 μg ml , C4) C2 + Lf 500 μg ml and C5) C2 + Lf 1000 μg ml extenders, and kept at 5 °C for 24 h. Sperm motility characteristics and intact membrane rates were not different among the treatments (P > 0.05). As a result of the cooling process, the nitrite concentration increased significantly in the cooled semen (69.6 ± 78.9 μm per ×10 spermatozoa) compared with the fresh semen (8.6 ± 1.9 μm per ×10 spermatozoa). In contrast, the H O concentrations were lower in the 0.6% caseinate extender (265.9 ± 221.3 μm per ×10 spermatozoa) than in the milk extender (430.9 ± 199.8 μm per ×10 spermatozoa, P < 0.05), showing an antioxidative effect of the caseinate compared with the milk. However, in all groups, hydrogen peroxide concentrations were similar to the undiluted fresh semen (332.8 ± 151.3 μm per ×10 spermatozoa). Caseinate showed to be as efficient as milk to protect equine-cooled spermatozoon.

Lactoferrin increases sperm membrane functionality of frozen equine semen

“…The lack of positive effect on equine sperm motility when antioxidants were added to skim milk (Aurich, Schönherr, Hoppe, & Aurich, ), and caseinate‐based extenders have been previously reported with cooled stallion semen (Martins et al., ). This effect was observed in the present work, even after seminal plasma removal with the usually performed centrifugation during the equine freezing semen procedure.…”

“…This “cryocapacitation” results in changes in the sperm membranes similar to those, which occur during the in vitro capacitation (Ball, ). The sperm motility decreases, and membrane defects increase due to an increase in ROS (Martins et al., ), which increases the peroxidation of unsaturated fatty acids (PUFA) of sperm membranes.…”

Alternatives in Donkey semen cryopreservation: Mare vs. Jenny Colostrum

“…Also, colostrum has anti‐inflammatory properties (Massouras, Triantaphyllopoulos, & Theodossiou, ; Playford et al ; Yadav, Angolkar, Kaur, & Buttar, ). Both the protective and antioxidant effects of the colostrum components added to extenders have been studied separately (Lagares et al., ; Martins et al., ).…”

Sodium bicarbonate and HEPES as buffer components for cooling the semen of pony stallions

“…One of the extenders used for cooling equine semen is skim milk, glucose and antibiotic (KENNEY et al, 1975;MANJUNATH, 2006;FLOREZ-RODRIGUEZ et al, 2014). Extenders are known for their practicality and for the protection afforded to the sperm during cooling (AURICH, 2008), but the longevity of spermatozoa seems to vary according to the extender composition (PAPA et al, 2014;MARTINS et al, 2016). Most diluents are based on skim milk or egg yolk.…”

“…Substances used in semen extenders must, at the very least, meet the following requirements: a similar or slightly higher osmolarity than the semen (300-350 mOsm/L), and slightly acidic (6.8) to neutral (7.0) pH. Essential components include substances that stabilize the pH and control microorganism growth, a readily available source of energy, and ingredients that stabilize membranes and maintain the metabolic function of sperm, as well as neutralizing metabolic substances (MARTINS et al, 2016). Ideally, extender components should not interfere with the results of semen evaluation (AURICH, 2011); however, some components in extenders can interfere in computer-assisted semen analysis (FLOREZ-RODRIGUEZ et al, 2014), even reducing the efficiency of sperm sexing by flow cytometry (MORRIS, 2005).…”