71 Effect of seminal plasma and hCG on biochemical composition of oviduct and embryo quality on Day 3 after induction of ovulation in alpacas (Vicugna pacos)

The oviduct plays an important role in early embryonic development and there is limited information on the biochemical composition of oviducal fluid in the early phase of embryonic development in camelids. The aim of the study was to evaluate the effect of two different ovulation inducers (seminal plasma (SP) and human chorionic gonadotropin (hCG)) on oviducal fluid composition and embryo quality. Adults female alpacas, 5 to 6 years old were mated with fertile males and randomly distributed and induced to ovulate with the following treatments: T1 (n = 4) = IM application of 1 mL of phosphate-buffered saline (PBS); T2 (n = 4) = IM application 1000 IU of hCG; and T3 (n = 4) = IM application of 1 mL of SP. The females were mated with four fertile males and distributed to the respective treatments. The time to interval between mounting or SP application to ovulation for all treatment, was based on a previous report in 27.4 ± 2.5 h (Huanca et al. 2014 Reprod. Fert. Dev. 27, 173–174). The collection of oviducal fluid and embryos was carried out 72 hours after copulation and ovulation induction. Oviducal fluid and embryo was obtained by flushing of the oviduct ipsilateral to the presence of the corpus luteum with 10 mL of PBS. Five milliliters of the upper fraction was centrifuged at 800 × g for 25 min and 1 mL of the supernatant was placed in vials and kept in liquid nitrogen until analysis. The remaining 5 mL of the lower fraction was placed in plates for the search embryo with a Nikon stereomicroscope. The embryos found were classified based on the classification described by the International Society for Embryo Technologies (IETS). Glucose (GL), total protein (TP), albumin (AL), cholesterol (CO), and triglycerides (TG) levels were determined using specific kits from the FAR Diagnostics laboratory (Italy) and the reading was determined using a semiautomatic biochemical analyzer. Statistical analysis for the biochemical composition of oviducal fluid (FO) with ovulation inducers (SP and hCG) was evaluated with a one-way analysis of variance (ANOVA). Embryo quality with ovulation inducers was checked by the Kruskal–Wallis test. The results for GL were 62.3 ± 12.0, 75.1 ± 5.7, and 77.7 ± 9.2 mg/dL; TP, 0.96 ± 0.19, 1.08 ± 0.28, 1.34 ± 0.33 g/dL; AL, 0.47 ± 0.09, 0.53 ± 0.12, and 0.59 ± 0.1 g/dL; CO, 13.83 ± 5.76, 15.3 ± 9.79, and 17.53 ± 9.42 mg/dL; TG, 13.85 ± 3.56, 16.4 ± 5.61, and 18.6 ± 6.38 mg/dL for PBS, hCG, and SP, respectively. Embryos with 6 and 8 blastomeres were found in T2 and T3 and embryos with 4 and 6 blastomeres in T1. The results suggest that seminal plasma and hCG could contribute to faster embryonic development.