title: Growth curve and diet density affect eating motivation, behavior, and body composition of broiler breeders during rearing.
abstract: The aim of this work has been to assess the effect of diet density [control (CON) or 15% diluted (DIL)] and growth curve [recommended by the genetic line (RBW) or 15% heavier (HBW)] and their interaction on BW uniformity, feeding motivation, behavior, and body composition of broiler breeder pullets. A total of 3,000 one-day-old female breeders Ross 308, distributed in 20 pens, was randomly assigned to each treatment. Feed allowance was weekly adjusted to reach the desired BW. Feed was provided as pelleted (zero to 3 wk) and crumble (4 to 19 wk). Time eating was measured at 7, 11, and 19 weeks. A feeding rate test was performed after 11 weeks. Behavior was observed at 9 and 15 wk, by visual scan. At 6, 13, and 19 wk of age, one bird/pen was slaughtered for weighing different organs and analyzing the composition of empty whole bodies. Treatments did not affect BW uniformity; relative weights of the ovary, oviduct, or gizzard; or protein content of empty BW. Time eating varied with the growth curve at 19 wk (P < 0.05), HBW pullets spent 19 more min eating than RBW pullets. DIL led to 4 and 8 more min eating at 19 wk for pullets of RBW and HBW (P < 0.05), respectively. Pullets fed DIL consumed 30% (P < 0.05) less during the feeding rate test when kept on a restricted regimen, and they had lower compensatory energy intake after ad libitum feeding than those fed CON, indicating lower feeding motivation. Behavior was affected by the age and by the time of the d measured, but it did not change with the treatments. Birds spent most time pecking objects (50%), feeding (28%), and drinking (17%). Pullets fed DIL had 8% lower breast yield at different ages and higher empty digestive tracts at 6 weeks. Body composition varied with age; fat content increased from 12.7 to 15.9 to 19.8% for 6, 13, and 19 wk, respectively. The lowest body fat was observed for RBW pullets fed DIL (P = 0.003) at 19 weeks. Feeding DIL diets to HBW pullets could be done to increase the time spent eating and reduce their feeling of hunger without negative effects on body composition. However, its influence on behavior and BW uniformity was not proved.
authors.affiliation: Trouw Nutrition R&D, Poultry Research Center, Ctra. CM-4004 km 10.5, El Viso de San Juan, 45950 Spain and Veerstraat 38, 5830 AE Boxmeer, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: de Los Mozos
authors.affiliation: Trouw Nutrition R&D, Poultry Research Center, Ctra. CM-4004 km 10.5, El Viso de San Juan, 45950 Spain and Veerstraat 38, 5830 AE Boxmeer, The Netherlands.
authors.forename: A I
authors.initials: AI
authors.lastname: García-Ruiz
authors.affiliation: Trouw Nutrition R&D, Poultry Research Center, Ctra. CM-4004 km 10.5, El Viso de San Juan, 45950 Spain and Veerstraat 38, 5830 AE Boxmeer, The Netherlands.|Wageningen University, Animal Nutrition Group, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
authors.forename: L A
authors.initials: LA
authors.lastname: den Hartog
authors.affiliation: Departamento de Producción Agraria, E.T.S.I. Agrónomos. Universidad Politécnica de Madrid, 28040 Madrid, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Villamide
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001823:Body Composition; D001835:Body Weight; D002645:Chickens / Q000254:growth & development / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D004435:Eating; D005247:Feeding Behavior; D005260:Female; D009042:Motivation; D011897:Random Allocation; D015430:Weight Gain
keywords: body composition; breeder pullet; diet density; eating motivation; growth curve