246 Luteal function, biometrics, and echotextural attributes in Santa Ines ewes superovulated with three different doses of porcine follicle stimulating hormone
J. Bevilaqua A , G. Vergani A , J. Fonseca B , M. Oliveira A and P. Bartlewski CA Department of Pathology, Reproduction and One Health, School of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, SP, Brazil
B Embrapa Goats and Sheep, Coronel Pacheco, MG, Brazil
C Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
Reproduction, Fertility and Development 35(2) 252-253 https://doi.org/10.1071/RDv35n2Ab246
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Premature luteal regression may adversely affect the outcome of hormonal ovarian superstimulation (SOV) in small ruminants. It is not known whether the prevalance of short-lived corpora lurea (CL) in ewes is related to the total amount of porcine follicle stimulating hormone (pFSH) used in SOV protocols. Hence, the main objective of this study was to evaluate the effects of different pFSH doses on biometry, blood perfusion, and echotextural luteal characteristics in superovulated ewes. 27 Santa Ines ewes (mean bodyweight of 45.2 ± 5.8 kg and aged 3.0 ± 1.0 years) received an intravaginal P4-releasing device (CIDR) from Days 0 to 8. An i.m. injection of d-cloprostenol (37.5 μg) was given on Days 0 and 8; on Day 6, all ewes received 300 IU of equine chorionic gonadotrophin (eCG) i.m. and were divided into three groups (each n = 9): G100 (100 mg); G133 (133 mg) and G200 (200 mg of pFSH), administered i.m. every 12 h in eight injections. After CIDR removal, the ewes were placed in paddocks with fertile rams (1:5 ratio). Transrectal ovarian ultrasonography and jugular blood sampling for serum P4 assays were performed on Days 11–15. Images of each CL at the largest cross-sectional (B-mode) or colour Doppler area were selected for analysis of the luteal and Doppler indices by Adobe FireWorks®. Numerical pixel values and heterogeneity were computed with Image ProPlus® (Media Cybernetics, Inc.). On Day 15 (embryo recovery), all ewes underwent videolaparoscopy and were classified as nCL (normal CL only), rCL (regressing CL only), and both nCL and rCL. Statistical analyses were done using the Statistical Analysis System software (SAS). There were no significant differences (P ≥ 0.08) in mean CL number (total, nCL or rCL) among groups. However, the proportion of nCL ewes was greater for G100 compared with G200 (67% vs 14%, respectively). Circulating P4 concentrations were greater (P < 0.05) in G100 than in G133 on Day 15. Total luteal area was greater (P < 0.001) in G100 and G200 compared with G133 on Days 14 and 15. There were no differences (P > 0.05) in luteal numerical pixel values or pixel heterogeneity between the three groups of ewes. Total Doppler luteal area was greater (P < 0.001) in G200 compared with G133 on Days 14 and 15. There were weak to moderate correlations (r = 0.18 to 0.41) among several biometric, echotextural, and haemodynamic attributes of ultrasonographically detected CL and P4 concentrations throughout the entire observation period. In conclusion, our results indicate that the superovulatory treatment of ewes with the lowest pFSH dose (100 mg) is followed by a similar CL development as that obtained with the highest SOV dose (200 mg). Luteal biometrics and Doppler indices are correlated with the ewes’ P4 secretory ability.
We thank the Sao Paulo Research Foundation (FAPESP), Brazil (17/04193-9), for providing the grant for J.R. Bevilaqua.
