title: Plasma concentrations of acyl-ghrelin are associated with average daily gain and feeding behavior in grow-finish pigs.
abstract: The objectives of this study were to determine the effect of sex, sire line, and litter size on concentrations of acyl-ghrelin and total ghrelin in plasma of grow-finish pigs and to understand the relationship of plasma concentrations of ghrelin with feeding behavior, average daily gain (ADG), and back fat in grow-finish swine. Yorkshire-Landrace crossbred dams were inseminated with semen from Yorkshire, Landrace, or Duroc sires. Within 24 h of birth, pigs were cross-fostered into litter sizes of normal (N; >12 pigs/litter) or small (S; ≤ 9 pigs/litter). At 8 wk of age, pigs (n = 240) were blocked by sire breed, sex, and litter size and assigned to pens (n = 6) containing commercial feeders modified with a system to monitor feeding behavior. Total time eating, number of daily meals, and duration of meals were recorded for each individual pig. Body weight was recorded every 4 wk. Back fat and loin eye area were recorded at the conclusion of the 12-wk feeding study. A blood sample was collected at week 7 of the study to quantify concentrations of acyl- and total ghrelin in plasma. Pigs from small litters weighed more (P < 0.05) and tended (P = 0.07) to be fatter than pigs from normal litters. Postnatal litter size did not affect ADG, feeding behavior, or concentrations of ghrelin in plasma during the grow-finish phase. Barrows spent more time eating (P < 0.001) than gilts, but the number of meals and concentrations of ghrelin did not differ with sex of the pig. Pigs from Duroc and Yorkshire sires had lesser (P < 0.0001) concentrations of acyl-ghrelin than pigs from Landrace sires, but plasma concentrations of total ghrelin were not affected by sire breed. Concentrations of acyl-ghrelin were positively correlated with the number of meals and negatively correlated with meal length and ADG (P < 0.05). A larger number of short-duration meals may indicate that pigs with greater concentrations of acyl-ghrelin consumed less total feed, which likely explains why they were leaner and grew more slowly. Acyl-ghrelin is involved in regulating feeding behavior in pigs, and measuring acyl-ghrelin is important when trying to understand the role of this hormone in swine physiology.
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA. Electronic address: clay.lents@ars.usda.gov.
authors.forename: C A
authors.initials: CA
authors.lastname: Lents
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Brown-Brandl
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Rohrer
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA.
authors.forename: W T
authors.initials: WT
authors.lastname: Oliver
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Freking
mesh_terms: D000818:Animals; D001823:Body Composition; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D054439:Ghrelin / Q000097:blood*; D008297:Male; D013552:Swine / Q000097:blood* / Q000502:physiology; D015430:Weight Gain / Q000502:physiology*
chemical_list: D054439:Ghrelin
keywords: Breed; Feeding behavior; Ghrelin; Growth; Programming; Swine