Effect of the Feed Level on the Seasonality of the Sexual Activity of Timahdite Ewes: Role of the Leptin and IGF System

• Main Authors: B. Archa, M. Chentouf, J.L. Bister
• Format: Article
• Language: English
• Published: CIRAD 2009-01-01
• Series: Revue d’Elevage et de Médecine Vétérinaire des Pays Tropicaux
• Subjects: Ovin; Niveau d’alimentation; Reproduction; Périodicité; Saison; Protéine sanguine; Facteur de croissance IGF; Maroc
• Online Access: http://revues.cirad.fr/index.php/REMVT/article/view/10096

The effects of the feed level on the seasonality of the sexual activity were studied in Timahdite ewes in the Middle Atlas region of Morocco (33°N). Non pregnant and non lactating adult ewes (3-4 years) were allocated to two groups according to two diet levels: HL (n = 10) received double the maintenance requirements and LL (n = 9) the maintenance requirements. Over a one-year period, estrus was recorded twice daily and blood samples were collected weekly to determine progesterone, leptin, IGF-1, IGFBP-2 and IGFBP-3 plasmatic levels. The higher feed level stimulated the reproductive activity in HL ewes, which presented a longer reproductive season and a significantly higher number of normal estrous cycles than LL ewes (7.8 ± 1.4 vs 3.9 ± 1.9, respectively; P < 0.05). Leptin, IGF-1 and IGFBP-2 seemed involved in the stimulation of the reproductive activity. Compared with LL ewes, HL ewes showed significantly higher plasmatic levels in leptin (3.79 ± 0.38 vs 3.30 ± 0.29 ng/mL; P < 0.05) and in IGF-1 (76 ± 28 vs 58 ± 21 ng/mL; P < 0.01), and a significantly lower level in IGFBP-2 (68 ± 21% vs 99 ± 24%; P < 0.01). No significant difference was recorded between the two groups regarding the IGFBP-3 levels (103 ± 52% vs 96 ± 17%; P > 0.05). These results showed that the Timahdite ewe exhibited a seasonal reproductive pattern which was modulated by the feed level.