title: Contribution of portal-drained viscera to heat production in Iberian gilts fed a low-protein diet: comparison to Landrace.
abstract: BACKGROUND
  In terms of whole-body metabolism, visceral tissues have a disproportionate influence with respect to their masses, and under certain circumstances their high metabolic rate may compromise nutrient availability to the tissues of productive/economic interest. The low energy efficiency of Iberian compared to modern breeds could be partly explained by the contribution of portal-drained viscera to heat production. The objective of this study was to determine the relative contribution of portal-drained viscera heat production (PDVHP) to total heat production (THP) in Iberian and Landrace gilts fed a diet with low protein content.
  
  
  RESULTS
  Compared to Landrace, Iberian gilts (29 ± 0.9 kg body weight) had lower pre- and postprandial portal vein blood flow (654 vs. 965, and 746 vs. 1133 mL min(-1) , respectively; P < 0.01), postprandial PDVHP (3.09 vs. 3.88 kJ h(-1)  kg(-0.75) ; P < 0.01) and PDVHP/THP ratio (0.08 vs. 0.13; P < 0.05), and greater THP (38.5 vs. 31.8 kJ h(-1)  kg(-0.75) ; P < 0.05), when offered 0.25 of their daily ration in a 6 h sampling period.
  
  
  CONCLUSIONS
  In spite of the low energetic efficiency and growth rate of Iberian compared to modern breeds, the contribution of PDV energy expenditure relative to THP was lower in Iberian compared to Landrace gilts in the present study.
authors: Department of Animal Nutrition, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, CSIC, Camino del Jueves s/n, Granada, Spain.
authors: Lucrecia
authors: L
authors: González-Valero
authors: Department of Animal Nutrition, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, CSIC, Camino del Jueves s/n, Granada, Spain.
authors: José M
authors: JM
authors: Rodríguez-López
authors: Department of Animal Nutrition, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, CSIC, Camino del Jueves s/n, Granada, Spain.
authors: Manuel
authors: M
authors: Lachica
authors: Department of Animal Nutrition, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, CSIC, Camino del Jueves s/n, Granada, Spain.
authors: Ignacio
authors: I
authors: Fernández-Fígares
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001833:Body Temperature Regulation; D018753:Diet, Protein-Restricted / Q000662:veterinary*; D005260:Female; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000502:physiology*; D013030:Spain; D013552:Swine / Q000254:growth & development / Q000502:physiology*; D014781:Viscera / Q000098:blood supply / Q000502:physiology
chemical_list: D009124:Muscle Proteins
keywords: energy; heat production; pig; portal-drained viscera