A comparative study of the effects of intramuscular administration of gonadorelin, mating and intrauterine infusion of either raw seminal plasma or seminal plasma purified β-NGF on luteal development in llamas.
The aim of this study was to compare the effect of the intramuscular administration of 50 μg of gonadorelin acetate versus natural mating, intrauterine infusion (i.u.) of a physiological relevant dose of either raw llama seminal plasma (SP) or purified beta-nerve growth factor from seminal origin (spβ-NGF) on ovulation rate and corpus luteum (CL) development and function in llamas. Females with a follicle (≥8 mm) were assigned to groups: (i) i.m. administration of 50 μg of gonadorelin acetate (GnRH; positive control; n = 4); (ii) single mating (mating; n = 6); (iii) i.u. infusion of 4 ml of llama SP (SP; n = 4); or (iv) i.u. infusion of 10 mg of spβ-NGF contained in 4 ml of PBS (phosphate-buffered saline) (spβ-NGF; n = 6). Ovaries were examined by power Doppler ultrasonography at 0, 1, 3, 6, 12 and 24 hr after treatment to determine preovulatory follicle vascularization area (VA), and additionally every 12 hr until Day 2 (Day of treatment = Day 0) to determine ovulation. Afterwards, ovaries were examined every other day until Day 8 to evaluate CL diameter and VA. Blood samples were collected on Days 0, 2, 4, 6 and 8 to determine plasma progesterone (P4) concentration. Ovulation rate did not differ (p = .7) among groups, but treatment affected (p < .0001) preovulatory follicle VA. Neither treatment administration nor treatment by time interaction affected (p ≥ .4) CL diameter, VA and plasma P4 concentration. Mating tended (p = .08) to increase CL VA when compared to the seminal plasma group by Day 8. Intrauterine administration of seminal plasma or spβ-NGF does not increase CL size and function when compared to i.m. GnRH treatment, suggesting that the administration route of spβ-NGF influences its luteotrophic effect in llamas.
Universidad Católica de Temuco, Temuco, Chile.
M
M
Silva
Universidad Austral de Chile, Valdivia, Chile.
F
F
Urra
Universidad de las fuerzas Armadas ESPE, IASA I, Sangolquí, Ecuador.
C
C
Ulloa-Leal
Universidad Austral de Chile, Valdivia, Chile.
M H
http://orcid.org/0000-0002-6072-7469
MH
Ratto
D000818:Animals; D002161:Camelids, New World / Q000502:physiology*; D003307:Copulation / Q000502:physiology*; D003338:Corpus Luteum / Q000187:drug effects*; D004333:Drug Administration Routes / Q000662:veterinary; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D020932:Nerve Growth Factor / Q000008:administration & dosage*; D010053:Ovary / Q000187:drug effects; D010060:Ovulation / Q000187:drug effects; D011374:Progesterone / Q000097:blood; D012661:Semen; D014463:Ultrasonography
D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D007986:Luteinizing Hormone; D020932:Nerve Growth Factor
corpus luteum; llamas; ovulation; seminal plasma; β-NGF