Supplementation of cauda epididymal plasma improves sperm characteristics following liquid preservation of ram semen at 3–5°C

Abstract

Mammalian spermatozoa remain immotile and metabolically inactive in the cauda epididymidis, thus maintaining fertility for several weeks. The aim of this study was to functionally characterise and evaluate the effect of cauda epididymal plasma (CEP) on liquid preservation of ram spermatozoa. Four experiments were conducted to investigate the effects of: (1) CEP and its fractions on sperm motility; (2) CEP (10%, 15%, 20% v/v) on liquid preservation of ram spermatozoa; (3) seminal plasma (SP; 20%, 30%, 50% v/v) on liquid-preserved spermatozoa; and (4) both CEP and post-storage SP treatment on sperm characteristics. Biochemical characterisation of ram CEP revealed high protein (30.9 mg mL−1), catalase (68.9 IU mL−1), alkaline phosphatase (17.5 IU mL−1) activities and total antioxidant capacity (1112 µM Trolox equivalent). Progressive motility of prewashed cauda spermatozoa was reduced (P < 0.05) by CEP or its protein-rich fraction compared with protein-free plasma or phosphate-buffered saline. After 48 h storage, total motility, rapid motility (average path velocity >75 µm s−1; 53.9%, 73.5% and 71.8% with 0, 15% and 20% CEP respectively) and straight line velocity (86.3, 102.1 and 102.4 µm s−1 with 0, 15% and 20% CEP respectively) were significantly (P < 0.05) higher in the CEP-treated groups than the control. Viability and acrosomal integrity were similar between groups; however, functional membrane integrity was higher (P < 0.05) in the 15% CEP-treated group. Treatment of liquid-preserved spermatozoa with either 20%, 30% or 50% SP improved (P < 0.05) rapid motility and kinematics at each time point of storage compared with control. In conclusion, liquid preservation of ram spermatozoa in the presence of 15% or 20% CEP and post-storage treatment with SP significantly improve sperm characteristics.

Grape Seed Procyanidin Extract (GSPE) Improves Goat Sperm Quality When Preserved at 4 °C

“…Considerable progress in semen preservation has been made over the past few decades; however, the decline that occurs in sperm quality during this process has not been resolved [5,11,20]. During in vitro preservation, there is a risk of oxidative damage to sperm owing to ROS accumulation [8,12].…”

“…Excessive ROS damages cellular proteins, and the lipid structure of the cell membrane, furthermore excessive ROS causes gene mutations and accelerates cell death [10]. Previous studies have shown that the addition of antioxidants can significantly improve sperm quality in the rat [22], bull [11], dog [12], boar [8], and ram [5] by reducing ROS accumulation during the preservation process. GSPE has been reported to have a strong antioxidant capacity [13,15,16,23].…”

“…The sequence of events involves lipid peroxidation, loss of membrane integrity with increased permeability, reduced sperm motility, structural DNA damage, and apoptosis [7,11]. Many previous studies have confirmed that this increase in ROS levels reduces sperm quality owing to imbalances in the antioxidant defense system [5,8,11,12]. SOD and CAT are important components of the antioxidant system in seminal plasma, which can antagonize and block free radicals [30,31].…”

“…One of two sperm preservation protocols, liquid or frozen, may be employed for AI [4]. Liquid preservation results in better conception rates than frozen [5,6]; however, as preservation time increases, the conception rate decreases. This decline is due to the gradual deterioration of sperm quality, including sperm motility, mitochondrial activity, acrosome and plasma membrane integrity [4].…”

“…Mammalian sperm contain large amounts of unsaturated fatty acids, which are susceptible to ROS attack [7,8,9]. ROS causes lipid peroxidation, DNA damage, increased membrane permeability, and even reduces reproductive capacity [5,10]. There are many reports regarding the antioxidant properties used for semen preservation, such as the use of Lycium barbarum , Laminaria japonica polysaccharides [1], and glycine [6].…”