The metabolic response in fish to mildly elevated water temperature relates to species-dependent muscular concentrations of imidazole compounds and free amino acids.
Fish species show distinct differences in their muscular concentrations of imidazoles and free amino acids (FAA). This study was conducted to investigate whether metabolic response to mildly elevated water temperature (MEWT) relates to species-dependent muscular concentrations of imidazoles and FAA. Thirteen carp and 17 Nile tilapia, housed one per aquarium, were randomly assigned to either acclimation (25°C) or MEWT (30°C) for 14 days. Main muscular concentrations were histidine (HIS; P<0.001) in carp versus N-α-acetylhistidine (NAH; P<0.001) and taurine (TAU; P=0.001) in tilapia. Although the sum of imidazole (HIS+NAH) and TAU in muscle remained constant over species and temperatures (P>0.05), (NAH+HIS)/TAU ratio was markedly higher in carp versus tilapia, and decreased with MEWT only in carp (P<0.05). Many of the muscular FAA concentrations were higher in carp than in tilapia (P<0.05). Plasma acylcarnitine profile suggested a higher use of AA and fatty acids in carp metabolism (P<0.05). On the contrary, the concentration of 3-hydroxyisovalerylcarnitine, a sink of leucine catabolism, (P=0.009) pointed to avoidance of leucine use in tilapia metabolism. Despite a further increase of plasma longer-chain acylcarnitines in tilapia at MEWT (P=0.009), their corresponding beta-oxidation products (3-hydroxy-longer-chain acylcarnitines) remained constant. Together with higher plasma non-esterified fatty acids (NEFA) in carp (P=0.001), the latter shows that carp, being a fatter fish, more readily mobilises fat than tilapia at MEWT, which coincides with more intensive muscular mobilization of imidazoles. This study demonstrates that fish species differ in their metabolic response to MEWT, which is associated with species-dependent changes in muscle imidazole to taurine ratio.
Laboratory of Animal Nutrition, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820 Merelbeke, Belgium; Department of Animal Sciences, College of Agriculture and Veterinary Medicine, Jimma University, P.O. Box 307, Jimma, Ethiopia. Electronic address: fikremgeda@gmail.com.
Fikremariam
F
Geda
Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
Annelies M
AM
Declercq
National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029, 5817 Bergen, Norway.
Sofie C
SC
Remø
National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029, 5817 Bergen, Norway.
Rune
R
Waagbø
Laboratory of Animal Nutrition, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820 Merelbeke, Belgium.
Marta
M
Lourenço
Laboratory of Animal Nutrition, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820 Merelbeke, Belgium.
Geert P J
GP
Janssens
D000064:Acclimatization; D000596:Amino Acids / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D002347:Carps / Q000378:metabolism*; D006639:Histidine / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism; D006358:Hot Temperature; D007093:Imidazoles / Q000032:analysis / Q000378:metabolism*; D009132:Muscles / Q000737:chemistry / Q000378:metabolism; D013045:Species Specificity; D013654:Taurine / Q000032:analysis / Q000378:metabolism; D013696:Temperature; D017210:Tilapia / Q000378:metabolism*
D000596:Amino Acids; D007093:Imidazoles; D013654:Taurine; D006639:Histidine; C023495:N-acetylhistidine
Carp; Histidine; Mildly elevated water temperature; N-α-acetylhistidine; Taurine; Tilapia