title: Effect of feeding fat or intrajugular infusion of glucagon-like peptide-1 and cholecystokinin on dry matter intake, digestibility, and digesta rate of passage in growing wethers.
abstract: A cause and effect relationship between glucagon-like peptide 1 (7, 36) amide (GLP-1) and cholecystokinin (CCK) and DMI regulation has not been established in ruminants. Three randomized complete block experiments were conducted to determine the effect of feeding fat or infusing GLP-1 or CCK intravenously on DMI, nutrient digestibility, and Cr rate of passage (using Cr(2)O(3) as a marker) in wethers. A total of 18 Targhee × Hampshire wethers (36.5 ± 2.5 kg of BW) were used, and each experiment consisted of four 21-d periods (14 d for adaptation and 7 d for infusion and sampling). Wethers allotted to the control treatments served as the controls for all 3 experiments; experiments were performed simultaneously. The basal diet was 60% concentrate and 40% forage. In Exp. 1, treatments were the control (0% added fat) and addition of 4 or 6% Ca salts of palm oil fatty acids (DM basis). Treatments in Exp. 2 and 3 were the control and 3 jugular vein infusion dosages of GLP-1 (0.052, 0.103, or 0.155 µg•kg of BW(-1)•d(-1)) or CCK (0.069, 0.138, or 0.207 µg•kg of BW(-1)•d(-1)), respectively. Increases in plasma GLP-1 and CCK concentrations during hormone infusions were comparable with increases observed when increasing amounts of fat were fed. Feeding fat and infusion of GLP-1 tended (linear, P = 0.12; quadratic, P = 0.13) to decrease DMI. Infusion of CCK did not affect (P > 0.21) DMI. Retention time of Cr in the total gastrointestinal tract decreased (linear, P < 0.01) when fat was fed, but was not affected by GLP-1 or CCK infusion. In conclusion, jugular vein infusion produced similar plasma CCK and GLP-1 concentrations as observed when fat was fed. The effects of feeding fat on DMI may be partially regulated by plasma concentration of GLP-1, but are not likely due solely to changes in a single hormone concentration.
authors.affiliation: Ohio State University Interdisciplinary Nutrition Program (OSUN), USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Relling
authors.forename: C K
authors.initials: CK
authors.lastname: Reynolds
authors.forename: S C
authors.initials: SC
authors.lastname: Loerch
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001786:Blood Glucose; D002766:Cholecystokinin / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary; D004041:Dietary Fats / Q000494:pharmacology*; D004063:Digestion; D004435:Eating; D005769:Gastrointestinal Motility / Q000187:drug effects; D052216:Glucagon-Like Peptide 1 / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood; D008297:Male; D012756:Sheep / Q000254:growth & development*
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin; D052216:Glucagon-Like Peptide 1; D002766:Cholecystokinin