Molecular performance of Prl and Gh/Igf1 axis in the Mediterranean meager, Argyrosomus regius, acclimated to different rearing salinities

Abstract

Aquaculture industry in the Mediterranean region exhibits a growing interest for the Mediterranean meager Argyrosomus regius. Some preliminary works showed a good growth performance of the species in nearly isosmotic salinities. However, the patterns of alteration of prolactin (Prl) as well as growth hormone (Gh)/insulin growth factor-1 (Igf1) axis at the molecular level are not yet described in this species. Therefore, we cloned and sequenced partial cDNAs for pituitary prolactin (prl) and growth hormone (gh), hepatic insulin-like growth factor (igf1), and β-actin (actb). Expression patterns of these transcripts were tested in juveniles of A. regius acclimated to four different environmental salinities: (1) 5 ‰ (hyposmotic); (2) 12 ‰ (isosmotic); (3) 38 ‰ (hyperosmotic; seawater control); and (4) 55 ‰ (extremely hyperosmotic). All investigated transcripts shared high sequence identities with their counterparts in other perciformes. prl mRNA levels showed inverse pattern with increasing salinities. gh mRNA enhanced significantly in both 12 and 55 ‰ salinity groups in comparison with the control group, while igf1 showed its maximum expression levels under the nearly isosmotic environment. The results indicated clear sensitivity of prl, gh and igf1 to changes in environmental salinity, which can possibly control the euryhalinity capacity of this species.

Effects of salinity level on the survival, growth, feed utilization, carcass composition, haematological and serum biochemical changes of juvenile Meagre (Argyrosomus regius) (Asso, 1801) grown in ground saltwater

“…Consistent with this theory, the energy utilization (EU) measured in the current study increased 11% when the rearing salinity decreased from 32‰ to 24‰, and 34% when salinity increased from 8‰ to 24‰. Oddly that, the results of (Mohammed‐Geba et al, ) showed that growth hormone (Gh) mRNA in A. regius juveniles acclimated to salinities 55% showed its maximum expression levels in comparison with the other salinities (5%, 12%, and 38%). The authors have explained this finding that excessive growth hormone activity may be aimed at aiding acclimation of the estuarine Perciformes, possibly through modifying osmotic adjustments required for fish survival under such extremely hyperosmotic environments.…”

“…This species is characterized by a high tolerance to wide ranges of salinity (5–55‰) (Mohammed‐Geba et al, ) and temperature (13–28°C) (Fountoulaki et al, ). However, to maximize meagre growth in a short period, aquaculturists seek to provide the best nutritional requirements in an ideal and healthy environment (Lisboa et al, ).…”

“…The first study dealt with the effect of salinity on growth and metabolism in fingerlings (Ruiz‐Jarabo et al, ; Tinoco, Rúa, Calvo, & Cárdenas, ) where two levels of salinity (12‰ and 39‰) were tested. The second one dealt with the evaluation of molecular performance of prolactin (prl), growth hormone (gh), insulin‐like growth factor (igf1) and β‐actin (actb) of meagre acclimated to different rearing salinities (Mohammed‐Geba et al, ). Therefore, the present study was performed to carefully examine the effect of four levels of salinity on the survival, growth, feed utilization, body composition and haematological changes in meagre.…”

Environmental Salinity Affects Growth and Metabolism in Fingerling Meagre (Argyrosomus Regius)

“…It has been demonstrated in several species that environmental salinities close to the iso-osmotic point minimized energy demand for osmoregulation, thus enhancing fish growth [16][17][18]. In juvenile A. regius, previous studies suggested that salinities closer to the iso-osmotic point in this species (12 ppt) lowered osmoregulatory work [19] and favor somatic growth by increasing insulin-like growth factor 1 (IGF1) mRNA expression [20]. This may explain why juveniles of some Argyrosomus species inhabit estuaries and brackish coastal waters during the first years of life [12,21].…”

Genomic structure and molecular characterization of growth hormone and its expression response to different feed types in golden pompanoTrachinotus ovatus(Linnaeus, 1758)

“…Growth hormone (GH) belongs to the typical class‐I helical cytokine superfamily and is mainly synthesized, stored and secreted by the pituitary gland (Li, Gao, Ji, & Zhang, ). Through its binding with specific cytokine family receptors located in the membrane of target cells, GH plays a key role in many physiological processes and other functions including immune regulation (Batista, Figueiredo, Almeida, Romano, & Marins, ), somatic growth (Duan et al., ; Feng et al., ; Hobbs & Fletcher, ), host defence (Duan et al., ), reproduction (Chen et al., ; Figueiredo et al., ; Ma et al., ; Zhou, Yu, & Ge, ), food intake and energy metabolism (Bergan, Kittilson, & Sheridan, ; Bergan‐Roller & Sheridan, ; Sugiyama et al., ; Zhong et al., ) and stress resistance (Mohammed‐Geba et al., ) in fish. It is known that the pituitary‐specific transcription factor Pit‐1 is required for normal pituitary development and GH gene expression by binding to AT‐rich cis elements in the GH promoter (Massah et al., ).…”