Diplodus sargus interrenal-pituitary response: chemical communication in stressed fish.
In the present study the response of white sea-bream (Diplodus sargus), used as experimental model, to different stocking densities was tested to assess whether the induced stress conditions were able to activate a chemical communication. Once a good recovery was evident, six days after capture and transportation, experiments started to evaluate eventual changes in cortisol plasma levels as well as in both plasma and pituitary alpha-melanocyte stimulating hormone (alpha-MSH) levels. These studies demonstrated that a low stocking density (2.5kg/1000L) is not deleterious for this species while a higher one (10kg/1000L) induces the activation of the hypothalamus-pituitary-interrenal axis (HPI). Thus, in these fish were evident both a significant increase of cortisol plasma levels and a significant decrease of alpha-MSH pituitary levels, while no significant changes were detected in alpha-MSH plasma concentrations. The most relevant result reported in this study, for the first time in marine species, is the presence of a chemical communication among stressed fish. It also should be noted that the data obtained from cortisol and alpha-MSH detections strongly indicate a gender specificity of this chemical signal.
Olivotto
Ike
I
Istituto di Scienze del Mare, Università di Ancona, Via Brecce Bianche 60131, Italy.
Mosconi
Gilberto
G
Maradonna
Francesca
F
Cardinali
Marco
M
Carnevali
Oliana
O
D000819:Animal Communication; D000818:Animals; D001685:Biological Factors; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D007401:Interrenal Gland / Q000502:physiology*; D008297:Male; D010902:Pituitary Gland / Q000737:chemistry / Q000502:physiology*; D011156:Population Density; D021541:Sea Bream / Q000502:physiology*; D012727:Sex Characteristics; D013045:Species Specificity; D013312:Stress, Physiological; D000521:alpha-MSH / Q000032:analysis / Q000097:blood
D001685:Biological Factors; D000521:alpha-MSH; D006854:Hydrocortisone