Evaluación de la eficiencia de la administración oral de progesterona en la sincronización del celo en cobayas

Abstract

The present study evaluated the efficiency of oral progesterone administration (altrenogest) at different doses on estrus synchronization in guinea pigs, with the purpose of recovering physiologically produced structures between days two and four post-assembly in these animals. Thirty-five adult multiparous guinea pigs between 4- 5 months of age of mixed breed and 5 guinea pigs older than 5 months of age with proven offspring were used. The guinea pigs were randomly placed in 5 experimental groups and received different doses of altrenogest from day zero to day 15 of the protocol: T1=0.33mg/kg (n=7); T2=0.28mg/kg (n=7); T3=0.22mg/kg (n=7); T4=0.17mg/kg (n=7); T5=0.11mg/kg (n=7). From day 16 onwards, the opening of the vaginal membrane was evaluated, obtaining as results that 94.3% of guinea pigs responded to the administration of oral progesterone. When analyzing the cytology results, it was established that T1 guinea pigs presented 50% of anucleated surface cells on day 1, T2 animals reached this percentage on day 2 and T3, T4 and T5 animals on day 3 post progesterone withdrawal. Results for determining effective mating indicate that treatments 1 (1.86 ± 0.26 days) and 2 (2.17 ± 0.17 days) required similar days for effective mating (P>0.05). For the day of ovulation, it was determined that T1 presented neutrophils in high percentages from day 3 onwards, differentiating from treatments 2, 3, 4 and 5 from that day onwards. However, the neutrophil values in treatments 2, 3, 4 and 5 on the fifth day showed values indicative of ovulation. In two of the 10 guinea pigs sacrificed on day 4.5 postassembly, a structure with two quality 2 morula stage embryos was recovered. In conclusion, high doses of oral progesterone are more effective in synchronizing estrus in guinea pigs, obtaining effective mating, ovulation at 48 hours and recovery of structures at 4.5 days post-estrus.