The Influence of Gamete Co‐incubation Length on the In Vitro Fertility and Sex Ratio of Bovine Bulls with Different Penetration Speed

Abstract

The objectives of this work were to evaluate whether the sperm penetration speed is correlated to the in vitro fertility and whether adapting the gamete co-incubation length to the kinetics of the bull improves in vitro fertility and affects the sex ratio. In vitro matured oocytes were co-incubated with spermatozoa from four different bulls (A-D). At various post-insemination (p.i.) times (4, 8, 12, 16 and 20 h), samples of oocytes were fixed and stained with DAPI for nuclei examination, while the remaining ones were transferred into culture to evaluate embryo development. The blastocysts produced were sexed by PCR. Two bulls (A and B) had faster kinetics than the others (C and D), as shown by the higher penetration rates recorded at 4 h p.i. (43%, 30%, 11% and 6%, respectively for bulls A, B, C and D; p<0.01). The differences in the kinetics among bulls did not reflect their in vitro fertility. The incidence of polyspermy was higher for faster penetrating bulls (36%, 24%, 16% and 4%, respectively for bulls A, B, C and D; p<0.01) and at longer co-incubation times (0%, 16%, 19%, 30% and 34%, respectively at 4, 8, 12, 16 and 20 h p.i.; p<0.01). The fertilizing ability of individual bulls may be improved by adapting the co-incubation length to their penetration speed. A sperm-oocyte co-incubation length of 8 h ensured the greatest blastocyst yields for the two faster penetrating bulls. On the contrary, 16 h co-incubation was required to increase (p<0.01) cleavage rate of the two slower bulls. Bulls with a faster kinetics did not alter the embryo sex ratio towards males. The female/male (F/M) ratios recorded were 2.1, 1.4, 1.2, 1.3 and 1.6, respectively at 4, 8, 12, 16 and 20 h p.i.

Influence of γ-glutamyltransferase and alkaline phosphatase activity on in vitro fertilisation of bovine frozen/thawed semen

“…Furthermore, IVF was carried out on abattoirderived cumulus-oocyte-complexes that were in vitro matured, fertilised and cultured according to our standard procedure (Sattar et al 2011). In particular, frozen-thawed sperm from each ejaculate were separated by Percoll gradients and used at the concentration of 1 Â 10 6 sperm/mL to inseminate on average 225 oocytes, over 4 replicates.…”

On the estimation of heat-intensity and heat-duration effects in time series models of temperature-related mortality in Stockholm, Sweden

“…Two studies estimated the overall temperature-mortality relationship using non-linear distributed lags and two-dimensional spline functions, and then tested the sensitivity of this parameterization [10,20]. Other studies used less complex linear and/or non-linear exposure response relationships, with a small number of lag days of between 1 and 3 [6,8,9,13,21].…”

Transformation of ram sperm nuclei in oocytes cytoplasm during in vitro fertilization

“…Polyspermia significantly increased with the prolongation of fertilization time (P<0.05). Sattar et al, (2011) and Long et al, (1994) confirmed that too long fertilization time leads to the increase in polyspermia. The length of time IVF is associated with the occurrence of aneuploidy (Gould and Griffin, 2018).…”

“…It is possible for each species to have different needs in incubation time, caused by species specific. However, the prolongation of incubation time increases the incident of polyspermia (Sattar et al, 2011). The understanding of tranformation process of sheep sperm is necessary to increase the fertilization rate and decrease polyspermia that which cause the increasing of embryo development rate.…”