title: Effect of insulin-like growth factor-I on some quality traits and fertility of cryopreserved ovine semen.
abstract: The objective was to evaluate the effects of insulin-like growth factor-I (IGF-I) on the quality and fertility of frozen/thawed ovine semen. Five rams (five ejaculates/ram) were used for evaluation of semen parameters. Before cryopreservation, ejaculates were divided into four aliquots and extended with Tris alone or supplemented with human IGF-I (50, 100, or 250 ng/mL). Semen was evaluated immediately after thawing (T0), after 1 h (T1) and 2 h (T2) post-incubation at 37 °C. The percentage of live cells (fluorescence analysis-calcein and ethidium), acrosome integrity (NAR) and motility were analyzed, and hypo-osmotic swelling tests (HOST) were used to evaluate membrane resistance. In addition, AI was performed using 121 ewes to compare the optimal concentration of IGF-I vs. Tris alone on pregnancy rates after laparoscopic insemination. Pregnancy diagnosis was performed by transrectal ultrasonography. After 1 and 2 h post-incubation, in every group, percentage motile sperm, NAR and HOST decreased compared to semen at T0. Motility was higher (P < 0.05) in the IGF-I 100 and IGF-I 250 groups when compared to the IGF-I 50 and Tris groups (76.2 and 74.4% vs. 66.2 and 64.4 percent, respectively) at T0, after 1 h (67 and 63.6% vs. 56.2 and 54.7%) and 2 h post-incubation (58.2 and 55.8% vs. 48 and 47.2%). Furthermore, viability was higher (P < 0.05) in the insulin-like growth factor-I (IGF-I) 100 and IGF-I 250 groups than in the IGF-I 50 and Tris groups (88.7 and 88.3% vs. 76.6 and 77.6%, respectively) at T0. There was no difference (P > 0.05) in NAR or hypo-osmotic swelling tests (HOST) among groups. There were no differences (P > 0.05) in fertility between the IGF-I 100 and Tris groups. In conclusion, IGF-I improved subjective sperm motility and structural integrity of the plasma membrane without a significant effect on 45-day pregnancy rates after laparoscopic insemination of ewes with frozen-thawed semen.
authors.affiliation: Rede Nordeste de Biotecnologia, Universidade Federal Rural de Pernambuco, Dom Manoel de Medeiros Street, Dois Irmãos, Recife 52171-900, PE, Brazil. rodrigopadilhavet@yahoo.com.br
authors.forename: R T
authors.initials: RT
authors.lastname: Padilha
authors.forename: D M
authors.initials: DM
authors.lastname: Magalhães-Padilha
authors.forename: M M
authors.initials: MM
authors.lastname: Cavalcante
authors.forename: A P
authors.initials: AP
authors.lastname: Almeida
authors.forename: K T
authors.initials: KT
authors.lastname: Haag
authors.forename: M O
authors.initials: MO
authors.lastname: Gastal
authors.forename: J F
authors.initials: JF
authors.lastname: Nunes
authors.forename: A P R
authors.initials: AP
authors.lastname: Rodrigues
authors.forename: J R
authors.initials: JR
authors.lastname: Figueiredo
authors.forename: M A L
authors.initials: MA
authors.lastname: Oliveira
mesh_terms: D000177:Acrosome / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000662:veterinary; D004353:Drug Evaluation, Preclinical; D005260:Female; D005298:Fertility / Q000187:drug effects* / Q000502:physiology; D007315:Insemination, Artificial / Q000662:veterinary; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D009997:Osmotic Pressure / Q000187:drug effects / Q000502:physiology; D011247:Pregnancy; D018873:Pregnancy Rate; D012661:Semen / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D055101:Semen Analysis / Q000662:veterinary; D012662:Semen Preservation / Q000009:adverse effects / Q000379:methods / Q000662:veterinary; D012756:Sheep / Q000502:physiology
chemical_list: D007334:Insulin-Like Growth Factor I