Comparisons of commercial Triladyl and locally manufactured extenders for the chilling of semen and their effects on pregnancy rates after transcervical AI in Bangladeshi Indigenous (Ovis aries) sheep

Abstract

Two different extenders were compared for their effects on preservation of semen from Indigenous rams and on pregnancy rate (PR) in Indigenous ewes. Semen was collected from nine Indigenous rams (Ovis aries) once a week using an artificial vagina. Each ejaculate was divided into 2 aliquots, diluted with either commercial (Triladyl ® ) or locally manufactured (tris, fructose, citric acid, egg yolk: TFE, prepared in own laboratory) extenders and kept at 4°C for 48 h. Motility, viability, functional integrity and morphological changes were evaluated at 0, 24 and 48 h. Synchronized oestrus ewes inseminated transcervically with 24 and 48 h of preserved chilled semen diluted with Triladyl and TFE extenders separately. Semen preserved in Triladyl had better motility, viability, and functional integrity at 24 and 48 h (P < 0.001) than did in TFE. The morphologically normal spermatozoa up to 48 h of preservation did not differ between extenders. However, in abnormalities studied, Triladyl had detrimental effect on sperm acrosome and TFE on sperm tail (P < 0.001) at 24 and 48 h of preservation. But, midpiece was not affected by any extender (P > 0.05) over the entire period of preservation. The quality of semen decreased (P < 0.001) with increasing preservation time for both extenders. The extenders did not differ (P > 0.05) the overall PR after transcervical AI (TCAI) in ewes. Increased preservation time (48 h) negatively affected the PR in TFE extended semen compared with than that of Triladyl. The results suggest that the quality of chilled semen (motility, viability, and functional integrity) is more improved when preserved in Triladyl than if extended with a TFE. PR may higher when TCAI is performed with chilled semen preserved in Triladyl for a longer time than TFE. However, TFE extender may be used to dilute the semen for chilling and used in TCAI to get similar PR of Triladyl up to 24 h of preservation.

Effect of Extenders Containing Glycerol and Egg Yolk on Motility and Viability of Chilled Ram Semen collected during Non-Breeding Season

“…A positive effect of Triladyl on ram semen preservation has been observed by different authors (Morrier et al, 2002;Rekha et al, 2016;Badi et al, 2018). Morrier et al, (2002) detected no significant effect on the motility parameters or viability of the sperm during storage at 5°C for 24 h in presence or absence of 7% glycerol in the egg-yolk extender.…”

“…Tris-based extenders protects spermatozoa from cold shock during preservation in low temperatures (0-5 0 C) (Morrier et al, 2002;Gill et al, 2003;Stefanov et al, 20015;Rekha et al, 2016). Glycerol is penetrating protector which interacts with bound proteins and glycoproteins, increases the bioenergetic requirements of the sperm cells and is added to extender at concentrations of 3%-7% (Hammerstedt et al, 1990;Gill et al, 2011;Pelufo et al, 2015).…”

A Comparison of Freezing Methods and Diluents Types on Post-Thaw Sperm Quality of Ram Sperm

“…Usually, during freezing-thawing process of semen, the sperm undergoes several vital biological and functional changes due to cold shocks and cryo-injuries, especially affects membranes that distresses their functional abilities (Nur et al, 2010;Chelucci et al, 2015). To establish a simple and sustainable cryopreservation protocol for ram semen in Bangladesh, efforts are focused on different types of diluents, dilution and freezing methods (Mahmuda et al, 2015;Rekha et al, 2016;Rekha et al, 2018;Jha et al, 2019). Evidence from previous studies, a hand-made tris-fructose-citrate (20% egg yolk and 5-7% glycerol) and commercial diluents Triladyl ® , two-steps dilution (fractional procedure) and three-steps manual freezing (in LN2 vapourusing styrofoam) are seemed to be recommended protocol for freezing ram semen in Bangladesh, already extended for field fertility testing (Rekha et al 2016;Rekha et al 2018;Jha et al, 2019).…”

“…To establish a simple and sustainable cryopreservation protocol for ram semen in Bangladesh, efforts are focused on different types of diluents, dilution and freezing methods (Mahmuda et al, 2015;Rekha et al, 2016;Rekha et al, 2018;Jha et al, 2019). Evidence from previous studies, a hand-made tris-fructose-citrate (20% egg yolk and 5-7% glycerol) and commercial diluents Triladyl ® , two-steps dilution (fractional procedure) and three-steps manual freezing (in LN2 vapourusing styrofoam) are seemed to be recommended protocol for freezing ram semen in Bangladesh, already extended for field fertility testing (Rekha et al 2016;Rekha et al 2018;Jha et al, 2019). However, more effort needs to standardize and select a sustainable frozen ram semen production technology, both in terms of dilutes and freezing methods.…”

Effects of cervical ripening treatments on pregnancy rates following transcervial artificial insemination in ewes

“…To establish an AI program in Bangladeshi ewes, studies on estrus synchronization, AI techniques using chilled and frozen Introduction semen have been accomplished (Roy et al, 2014;Jha et al, 2020). However, the pregnancy rates reported 60 -70% with fresh semen and 11 -26% with frozenthawed semen following transcervical insemination (TC-AI; Azizunnesa, 2016;Rekha et al, 2016Rekha et al, , 2018Jha et al, 2020), which is not acceptable for field AI purpose. This lower pregnancy rates in ewes are due to complex cervical anatomy (long, convoluted funnelshaped cervix) that prevents the passage of AI pipette into the body of uterus, as a result, there is the reduction in a high proportion of the spermatozoa when they arrive the place of fertilization (Wulster-Radcliffe et al, 2004;Kershaw et al, 2005;Leethongdee, 2010).…”