Effect of adding different levels of caffeine in the extender on some biochemical constituents, enzymatic activities and physical characteristics of chilled and frozen ram semen

Abstract

Two experiments were carried out to determine the efficiency of supplementation of ram semen extender with caffeine on chilled storage and frozen capacity of spermatozoa. In the first experiment, eighty ejaculates were collected by an artificial vagina from five adult Barki rams, aged 2-3 years and weighted 45.0 ± 2.0 kg throughout the experimental period (January to February 2017). The ejaculates were pooled and diluted (1:10) with tris-citric egg yolk extender and were split into five groups. Group 1 served as control, whereas groups 2-5 were supplemented with 0.1, 0.2, 0.3 and 0.4 mM caffeine. All diluted semen specimens were evaluated for physical characteristics immediately after dilution (T ) and throughout preservation period of 48 hr at 4°C. Simultaneously, oxidative stress and indices such as total antioxidant capacity (TAC), malondialdehyde concentrations (MDA) and alkaline transaminase (AKP) concentrations and value of resazurin reduction test (RRT) were determined. In the second experiment, the raw pooled ejaculates were diluted (1:10) with glycerolated tris-citric egg yolk extender, receiving the previously mentioned caffeine levels. The post-thaw assessment of cryopreserved spermatozoa, in all groups, was conducted by a computer-assisted sperm analysis (CASA) system. The results revealed that adding caffeine to ram semen extender at low (0.1 mM) or medium (0.2 mM) levels had positive impact on both physical characteristics of ram sperm and the enzymatic activities compared to the other semen groups. Caffeine supplementation also enhanced post-thaw sperm dynamics, which implies its potential as an exogenous antioxidant supplement.

Effect of Caffeine and Pentoxifylline Added Before or After Cooling on Sperm Characteristics of Stallion Sperm

“…In other species, CF and PT did not stimulate motility in bull sperm, but modified kinematic parameters after 60 minutes incubation [33]. In ram, buffalo, and human sperm, the addition of CF and PT to cooled or frozenethawed sperm had a positive impact on motility during the first 30 minutes [24,32,38,39]. On the other hand, donkey sperm seems to not response to CF and PT inclusion [8].…”

Some Studies to Improve Quality and Fertilizing Ability of Cooled Buffalo Spermatozoa

“…Shukla and Misra (2014) and Spalekova et al (2014) reported that influence of caffeine on motility of spermatozoa may be related to species-specific and/or dose-dependent. Furthermore, Spalekova et al (2014) and Hamid and Ibrahim (2019) in ram, Barakat et al (2015) in bovine and Shukla and Misra (2014) and Chavda et al (2022) in buffalo spermatozoa, recorded a significant improvement in sperm characteristics using caffeine as an additive to semen extender.…”

Liquid Storage of Ram Semen: Associated Damages and Improvement

“…Caffeine (1,3,7-trimethylxanthine) is a natural stimulant belonging to the methylxanthine class and has been utilized as a supplement in sperm capacitation medium to enhance progressive motility in IVF schemes. Inclusion of different levels (0.1 -0.4 mM) of caffeine to Tris-glucose-egg yolk extender during liquid storage of ram semen up to 48 h revealed that low (0.1 mM) and medium (0.2 mM) concentrations of caffeine have a positive impact on physical characteristics and enzymatic activity of ram sperm than higher concentrations [39]. Contrariwise, another study reported no effect of 0.1 mM caffeine supplementation in Tris-citric acid extender on progressive motility after 48 h of liquid storage [38].…”