title: Oxygen consumption constrains food intake in fish fed diets varying in essential amino acid composition.
abstract: Compromisation of food intake when confronted with diets deficient in essential amino acids is a common response of fish and other animals, but the underlying physiological factors are poorly understood. We hypothesize that oxygen consumption of fish is a possible physiological factor constraining food intake. To verify, we assessed the food intake and oxygen consumption of rainbow trout fed to satiation with diets which differed in essential amino acid (methionine and lysine) compositions: a balanced vs. an imbalanced amino acid diet. Both diets were tested at two water oxygen levels: hypoxia vs. normoxia. Trout consumed 29% less food under hypoxia compared to normoxia (p<0.001). Under both hypoxia and normoxia trout significantly reduced food intake by 11% and 16% respectively when fed the imbalanced compared to the balanced amino acid diet. Oxygen consumption of the trout per unit body mass remained identical for both diet groups not only under hypoxia but also under normoxia (p>0.05). This difference in food intake between diets under normoxia together with the identical oxygen consumption supports the hypothesis that food intake in fish can be constrained by a set-point value of oxygen consumption, as seen here on a six-week time scale.
authors.affiliation: Aquaculture and Fisheries Group, Wageningen Institute of Animal Sciences (WIAS), 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: Suluh
authors.initials: S
authors.lastname: Nusantoro
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: D000601:Amino Acids, Essential / Q000008:administration & dosage* / Q000032:analysis; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001823:Body Composition; D002149:Energy Intake; D017686:Oncorhynchus mykiss / Q000502:physiology*; D010101:Oxygen Consumption
chemical_list: D000601:Amino Acids, Essential