title: Voluntary feed intake in rainbow trout is regulated by diet-induced differences in oxygen use.
abstract: This study investigated the hypothesis that the voluntary feed intake in fish is regulated by diet-induced differences in oxygen use. Four diets were prepared with a similar digestible protein:digestible energy ratio (18 mg/kJ), but which differed in the composition of nonprotein energy source. This replacement of fat (F) by starch (S) was intended to create a diet-induced difference in oxygen use (per unit of feed): diets F30-S70, F50-S50, F65-S35, and F80-S20 with digestible fat providing 28, 49, 65, and 81% of the nonprotein digestible energy (NPDE), respectively. Each diet was fed to satiation to triplicate groups of 20 rainbow trout for 6 wk. As expected, diet-induced oxygen use decreased linearly (R(2) = 0.89; P < 0.001) with increasing NPDE as fat. The digestible and metabolizable energy intakes of trout slightly increased with increasing NPDE as fat (i.e., decreasing starch content) (R(2) = 0.30, P = 0.08; and R(2) = 0.34, P = 0.05, respectively). Oxygen consumption of trout fed to satiation declined with increasing dietary NPDE as fat (R(2) = 0.48; P = 0.01). The inverse relation between digestible energy intake of trout and the diet-induced oxygen use (R(2) = 0.33; P = 0.05) suggests a possible role of diet-induced oxygen use in feed intake regulation as shown by the replacement of dietary fat by starch.
authors.affiliation: Aquaculture and Fisheries Group, Wageningen Institute of Animal Sciences, Wageningen University, Wageningen, The Netherlands.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Saravanan
authors.forename: Inge
authors.initials: I
authors.lastname: Geurden
authors.forename: A Cláudia
authors.initials: AC
authors.lastname: Figueiredo-Silva
authors.forename: Sadasivam
authors.initials: S
authors.lastname: Kaushik
authors.forename: Johan
authors.initials: J
authors.lastname: Verreth
authors.forename: Johan W
authors.initials: JW
authors.lastname: Schrama
mesh_terms: D000818:Animals; D001823:Body Composition; D004032:Diet / Q000662:veterinary*; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism; D004063:Digestion / Q000502:physiology; D004435:Eating / Q000502:physiology*; D002149:Energy Intake; D004734:Energy Metabolism; D009584:Nitrogen / Q000008:administration & dosage; D017686:Oncorhynchus mykiss / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D013213:Starch / Q000008:administration & dosage / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D013213:Starch; D009584:Nitrogen