title: Effects of exercise on L-carnitine and lipid metabolism in African catfish (Clarias gariepinus) fed different dietary L-carnitine and lipid levels.
abstract: African catfish (Clarias gariepinus) were fed four isonitrogenous diets (34 % crude protein), each containing one of two lipid (100 or 180 g/kg) and two L-carnitine (15 or 1000 mg/kg) levels. After 81 d of feeding, thirty-two fish (body weight 32 g) from each dietary group were randomly selected, sixteen fish were induced to a 3-h swim (speed of 1.5 body length (BL)/s), while the other sixteen fish were kept under resting condition. Fish fed 1000 mg L-carnitine accumulated 3.5 and 5 times more L-carnitine in plasma and muscle, respectively, than fish fed the 15 mg L-carnitine. Muscle L-carnitine content was significantly lower in exercised fish than in rested fish. High dietary lipid level (fish oil) led to an increase in muscle n-3 PUFA content and a decrease in SFA and MUFA content. In liver, the increase in dietary lipid level resulted in an increased levels of both n-6 and n-3 PUFA. L-carnitine supplementation significantly decreased n-3 PUFA content. Exercise decreased n-3 PUFA in both muscle and liver. Plasma lactate and lactate dehydrogenase, normally associated with increased glycolytic processes, were positively correlated with exercise and inversely correlated with dietary L-carnitine level. L-carnitine supplementation reduced significantly the RQ from 0.72 to 0.63, and an interaction between dietary L-carnitine and lipid was observed (P < 0.03). Our results indicate that an increase in fatty acids (FA) intake may promote FA oxidation, and both carnitine and exercise might influence the regulation of FA oxidation selectivity.
authors.affiliation: Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas 289, Porto, Portugal. rodrigo.ozorio@ciimar.up.pt
authors.forename: Rodrigo O A
authors.initials: RO
authors.lastname: Ozorio
authors.forename: Vincent J T
authors.initials: VJ
authors.lastname: Van Ginneken
authors.forename: Rui J B
authors.initials: RJ
authors.lastname: Bessa
authors.forename: Martin W A
authors.initials: MW
authors.lastname: Verstegen
authors.forename: Johan A J
authors.initials: JA
authors.lastname: Verreth
authors.forename: Elbertus A
authors.initials: EA
authors.lastname: Huisman
mesh_terms: D000821:Animal Feed; D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D001835:Body Weight; D002331:Carnitine / Q000378:metabolism*; D002397:Catfishes / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism; D002149:Energy Intake; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D005395:Fish Oils / Q000494:pharmacology; D008055:Lipids / Q000097:blood*; D008099:Liver / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D010805:Physical Conditioning, Animal; D013550:Swimming
chemical_list: D001798:Blood Proteins; D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D008055:Lipids; D002331:Carnitine