165 EFFECT OF INJECTION OF SEMINAL PLASMA ON OVULATION RATE, CORPUS LUTEUM DEVELOPMENT, AND SENSITIVITY TO PROSTAGLANDIN IN ALPACAS (VICUGNA PACOS)

Abstract

The seminal plasma (SP) of camelids contains a protein identified as β Nerve Growth Factor with capacity of induced ovulation and develop a corpus luteum. A study was designed to evaluate the effect of application of SP on the interval of time from injection of stimulus to the ovulation and corpus luteum (CL) size (Experiment 1, n = 24) and on the sensitivity of CL to the injection of prostaglandin (196 µg of tiaprost) (PG) at different periods from ovulation (Experiment 2, n = 86). Exp. 1: Adult female alpacas with presence of a follicle ≥7 mm were assigned to the application of 1 mL of SP via IM (T: n = 12) or application of 50 µg of acetate of busereline IM (T2: n = 12). Exp. 2: Alpacas with presence of a follicle ≥7 mm were induced to ovulation with 50 µg of acetate of busereline or 1 mL IM of SP. Animals were evaluated by ultrasound to confirm the ovulation and were assigned to the following treatment: T1 (n = 8): SP + PG Day 4; T2 (n = 8): buserelin acetate + PG Day 4; T3 (n = 8): SP + PG Day 5; T4 (n = 8): buserelin acetate + PG Day 5; T5 (n = 8): SP + PG Day 6; T6 (n = 8): buserelin acetate + PG Day 6; T7 (n = 8): SP + PG Day 7; T8 (n = 8): buserelin acetate + PG Day 7; T9 (n = 8): SP + PG Day 8; T10 (n = 8): buserelin acetate + PG Day 8 and T11 (n = 6) (Control): Application of 1 mL of saline solution. The animals were evaluated by ultrasound with an Aloka SSD500 (Aloka, Tokyo, Japan) and 7.5-MHz linear transducer each 2 h (Exp. 1) and each 12 h (Exp. 2) after of application of PG. In Exp. 1, the ovulation rate was 95.7% to T1 and T2 and an interval of time between injection of stimulus and ovulation was 27.4 ± 2.5 h and 26.8 ± 1.8 to T1 and T2, respectively. In Exp. 2, luteolysis was 0.0%, 0.0%, 25.0%, 0.0%, 100.0%, 100.0%, 100.0%, 100.0%, 100.0%, 100.0%, and 0.0% for the treatments T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, and T11 respectively. The results suggest that no differences exist between in the ovulation rate and interval to the ovulation between the application of buserelin acetate or SP and that the CL was sensible at Day 5 to the prostaglandin respect SP and with similar response to the sensibility of CL from Day 6 to Day 8.