Induction of the acrosome reaction test to in vitro estimate embryo production in Nelore cattle

Abstract

The effectiveness of induction of the acrosome reaction (AR) test as a parameter to in vitro estimate embryo production (IVP) in Nelore breed and the AR pattern by the Trypan Blue/Giemsa (TB) stain were evaluated. Frozen semen samples from ten Nelore bulls were submitted to AR induction and were also evaluated for cleavage and blastocyst rates. The treatments utilized for AR induction were: control (TALP medium), TH (TALP medium + 10μg heparin), TL (TALP medium + 100μg lysophosphatidylcholine) and THL (TALP medium + 10μg heparin + 100μg lysophosphatidylcholine). Sperm acrosomal status and viability were evaluated by TB staining at 0 and after 4h incubation at 38°C. The results obtained for AR presented a significant difference (P<0.05) in the percentage of acrosome reacted live sperm after 4h of incubation in the treatments that received heparin. The cleavage and blastocyst rates were 60% and 38% respectively and a significant difference was observed among bulls (P<0.05). It was founded a satisfactory model to estimate the cleavage and blastocyst rates by AR induction test. Therefore, it can be concluded that the induction of the AR test is a valuable tool to predict the IVP in Nelore breed.Keywords: cattle, fertility, semen, acrosome reaction, fertilization Palavras-chave: bovino, fertilidade, sêmen, reação acrossomal, fertilização RESUMO Avaliou-se a eficiência da técnica de indução da reação acrossomal (RA) como parâmetro para estimar a produção in vitro (PIV) de embriões Nelore e analisou-se o padrão de RA pela técnica de coloração Azul de Tripan/Giemsa (TB). Amostras de sêmen congelado de dez touros foram submetidas à indução da RA e avaliadas quanto a taxa de clivagem e blastocisto. Os tratamentos utilizados para indução da RA foram: controle (meio TALP), TH (meio TALP + 10μg heparina), TL (meio TALP + 100μg lisofosfatidilcolina) e THL (meio TALP + 10μg heparina + 100μg lisofosfatidilcolina

In vitro induction of the acrosome reaction in spermatozoa from endangered Spanish bulls: Effect of breed, culture media and incubation time

“…In general, the incidence of AR obtained in vitro in the current study is in consonance with those obtained by previous authors (Birck et al, 2010;Costa et al, 2010;Januskauskas et al, 2000;Parrish et al, 1988;Somfai et al, 2002), indicating that doses of semen stored at Andalusian Genetic Bank responded satisfactorily to in vitro AR test. We also observed that the incidence of spontaneous AR at 0 h was on average 6%.…”

“…This can partly be explained by breed differences in plasma membrane composition of bull spermatozoa (Casali et al, 1985). Due to this, the calculation of cattle fertility index from the outcome of AR test as suggested by previous authors (Costa et al, 2010;Molnarova et al, 2006;Mukhopadhyay et al, 2008) could not be recommended due to the effect exerted by breed, incubation protocol, and their interactions on the AR status of bull spermatozoa. Nevertheless, low AR rates could be a cause of unexplained infertility (Lessard et al, 2011).…”

“…Although it has been previously demonstrated the influence of several paternal factors, such as male (Katska and Smorag, 1996;Ward et al, 2001), age (Ward et al, 2002), breed , species (Pontes et al, 2010), and semen collection method (García-Á lvarez et al, 2009) on IVF outcomes, this is the first attempt to assess the effect of cattle breed on induced AR results. Early reports suggest that the ability of spermatozoa to undergo AR in vitro may be a useful method for predicting the result of IVF in cattle (Costa et al, 2010;Giritharan et al, 2005;Mukhopadhyay et al, 2008). In fact, AR status has been previously used as predictor of both freezability (Molnarova et al, 2006) and in vivo fertility (Birck et al, 2010;Collin et al, 2000;Giritharan et al, 2005) in cattle.…”

“…It may suggest that the classical semen parameters might not be enough to assess the fertilizing capacity of a semen sample. Previous studies have suggested the use of in vitro acrosome reaction (AR) test as a valuable tool to predict both field fertility (Birck et al, 2010;Waberski et al, 1999) and in vitro fertilizing capacity of semen in cattle (Costa et al, 2010;Molnarova et al, 2006).…”

Effects of chelating calcium in cryopreservation extender on frozen-thawed dog semen

“…We used EDTA to chelate free calcium in maintenance and freezing extender, making it unavailable to sperm. Under physiological conditions, after binding to zona pellucida, the sperm undergoes AR releasing the enzymes necessary for sperm penetration (Breitbart, 2002;Costa et al, 2010;Witte and Schäfer-Somi, 2007). This process depends on the mobilization of extra and intracellular calcium reservoirs (Hewitt and England, 1998;Alhaider and Watson, 2009;Száz et al, 2000).…”