Effect of fat supplementation on leptin, insulin, growth hormone and IGF-1 in cattle

BECU-VILLALOBOS, D .; GARCIA-TORNADU,I; SHROEDER,G.; SALADO,E.E.; GAGLIOSTRO,G.; DELAVAUD C; CHILLIARD, Y; LACAU-MENGIDO, I. M

CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE.

Canadian Veterinary Medical Association

Año: 2007 vol. 71 p. 218 - 225

0830-9000

We investigated the effect of fat supplementation on hormones related to metabolism, with special attention to leptin, in early lactating cows and in feedlot steers. In experiment 1, lactating cows received no fat or two doses of partially hydrogenated oil in addition to their basal diet, from day -20 to 70 postpartum (pp). In experiment 2, corn from the concentrate was substituted by partially hydrogenated oil, in order to have isocaloric diets. Half of the cows received the control diet and the other half the fat substituted one, from day -20 to 75 pp. In experiment 3, feedlot steers were supplemented with calcium salts of fatty acids, added to their basal diet, during 80 days.  Basal levels of leptin were higher in cows than in steers and were not affected by dietary fat in early lactating cows. However, in feedlot steers serum leptin concentration was lowered by fat supplementation despite increased energy intake and body fatness.  IGF-I and insulin levels were decreased by fat diets in lactating cows but were unaffected in steers suggesting that responses to fat ingestion depends on physiological state of  the animal, including age an sex. Finally, no effects of fat on serum GH concentration could be demonstrated in any of the models used.