Feed deprivation in Senegalese sole (Solea senegalensis Kaup, 1858) juveniles: effects on blood plasma metabolites and free amino acid levels.
The effects of prolonged feed deprivation were assessed on blood plasma metabolites and free amino acid levels in Solea senegalensis. Juvenile specimens were maintained at two experimental conditions (24 h fasted and 21 days feed-deprived). In feed-deprived fish, relative growth rate and hepatosomatic index as well as plasma triglycerides and proteins levels were significantly lower. However, plasma cortisol levels were higher in feed-deprived fish, while plasma glucose and lactate values were not significantly different between treatments. Furthermore, feed-deprived fish showed higher levels of total plasma free amino acids than 24 h fasted fish. In 21 days feed-deprived sole, an increase in plasma cortisol levels may suggest a functional role in mobilizing energy due to the catabolic action of this hormone in teleosts. Higher levels of glutamine, arginine and ornithine in 21 days feed-deprived fish may be indicative of a dual role for these amino acids: ammonia detoxification and carbon source for gluconeogenesis. The increased plasma glucogenic and branched-chain amino acid levels, together with the maintenance of plasma glucose in 21 days feed-deprived sole, suggest active liver gluconeogenic processes supported by tissue proteolysis.
CIMAR/CCMAR-Centro de Ciências do Mar do Algarve, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal. bcostas@ualg.pt
Benjamín
B
Costas
Cláudia
C
Aragão
Ignacio
I
Ruiz-Jarabo
Luis
L
Vargas-Chacoff
Francisco Jesús
FJ
Arjona
Maria Teresa
MT
Dinis
Juan Miguel
JM
Mancera
Luís E C
LE
Conceição
D000596:Amino Acids / Q000097:blood*; D000818:Animals; D001786:Blood Glucose; D005412:Flatfishes / Q000097:blood* / Q000378:metabolism; D005508:Food Deprivation / Q000502:physiology*; D006854:Hydrocortisone / Q000097:blood; D007773:Lactates / Q000097:blood; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D000596:Amino Acids; D001786:Blood Glucose; D007773:Lactates; D014280:Triglycerides; D006854:Hydrocortisone