Role of ghrelin in the link between nutrition and reproduction in ewe

FURNUS C; CARRANZA A; RELLING A; COLLEMAN D

Columbus

Simposio; 14th Annual Russel Klein Nutrition Research; 2017

Russel Klein Nutrition Research

Background:Ghrelin is a hormone associated with a negative energy balance (NEB) which might suppress reproductive activities in sheep.Objective/Hypothesis: To evaluatethe possible role of ghrelin as a modulator between nutrition and reproduction by infusing a ghrelin antagonist in sheep in NEB.Methods:Eighteen synchronized adult ewes were allotted in nine pens during breeding season for 30 days (EXP I) or 13 days (EXP II). Each pen was randomly assigned to one of the following treatments:?Control: maintenance diet?Negative energy balance(NEB):fed 70 % of the nutrient required for maintenance?Ghrelin antagonist (GA):Fed as NEB plus daily SC injections of 7.5 µg/Kg of D-Lys3-GHRP-6, a ghrelin antagonist.Ewes were weighed and bled at the start and every three days until the end of experiment. On day 13 of EXP II ewes were slaughter for ovary and hypothalamus collection. Plasma glucose, non-esterified fatty acids (NEFA) and progesterone concentration and ovary macroscopic data were collected. Data were analyzed as a complete randomized design with repeated measures (SAS 9.4).Results:Body weight and plasma NEFA concentration showed asignificant time by treatmentinteraction (P0.1). There were not differences in ovary weight and gonadosomatic index (P>0.1), but there was a tendency for smaller ovaries on the GA group.Conclusions: A 30% restriction in energy intake during a short period of time (30 d) does not affect the cyclicity of adult ewes. Under these conditions the infusion of ghrelinantagonist does not improve reproductive activities.