Imen R.,Tunis el Manar University |
Khaoula T.,Institute National Of Science Et Technologies Of La Mer Instm |
Nabila G.,Tunis el Manar University |
Imene C.,Tunis el Manar University |
And 3 more authors.
Marine and Freshwater Behaviour and Physiology
Changes in plasma osmolality haematology, lipid content and fatty acid composition of the gills, intestine and kidney of the Thicklip Grey Mullet (Chelon labrosus) were investigated along a salinity gradient from seawater (SW, 38 p.p.t.) to low salinity water (LSW, 5 p.p.t.). Plasma osmolality has changed as evidenced by the dynamics of the osmoregulatory parameters. These dynamics have revealed two stages during hyperosmotic and hypo-osmotic acclimations: (i) an adaptive period during the first days of acclimation (3-7 days), with important changes in these parameters and (ii) a chronic regulatory period (after 3 days of transfer) where osmotic parameters reached hom0eostasis. From a metabolic point of view, we found that salinity decrease induced mobilization of lipids in the gills, kidney and intestine of C. labrosus. We also observed changes in fatty acid profiles but with differences between tissues. In gills and intestine, SFAs and MUFAs decreased and PUFAs increased in the first day of the transfer. However, in the kidney, PUFAs increased and SFAs and MUFAs decreased at the end of the transfer. We conclude that the changes made during salinity acclimation are followed by a qualitative variation in the lipids and that the decrease in salinity leads to an improvement in the synthesis of PUFAs fatty acid. This suggests that lipids are important in meeting the energetic demands resulting from exposure to salinity. © 2013 Copyright Taylor and Francis Group, LLC. Source
Comparative development and growth of the larvae of thick lipped mullet Chelon labrosus (Mugilidae) reared in intensive conditions: Green water and clear water [Développement et croissance comparés des larves du mulet lippu Chelon labrosus (Mugilidae) élevées en conditions intensives: Eau verte et eau claire]
Besbes R.,Institute National Of Science Et Technologies Of La Mer Instm |
Besbes Benseddik A.,Institute National Of Science Et Technologies Of La Mer Instm |
Ben Khemis I.,Institute National Of Science Et Technologies Of La Mer Instm |
Zouiten D.,Institute National Of Science Et Technologies Of La Mer Instm |
And 4 more authors.
In the framework of the national research program entitled Rearing Technologies for New Marine Species with Aquaculture Potential (TENMIA), experimental larval rearing of thicklip grey mullet Chelon labrosus (Risso, 1827) has been realised simultaneously under intensive conditions with techniques "green water" and "clear water" from a same egg batch. This study presents the development of larvae, linear and weight growths and survival of the larvae and juveniles from day 1 (J1) to day 57 (J57) and their comparison according to rearing conditions. Rearing is performed in 500 1 cylindroconical tanks, in similar thermal conditions and initial densities of 100 larvae/1. At 15°C the opening of the mouth take place at the seventh day (J7) and swim bladder primary inflation at J10. Metamorphosis begins at J20 and finishes at J40. Chelon labrosus larvae are also characterized by slow initial growth, that accelerates appreciably only towards the 3rd week of rearing. Also the two techniques: "green water" and "clear water" are appropriated for larval rearing of this species. They give comparable final survival rates at J57, respectively 22 ± 2% and 18 ± 2%. But weight growth and linear growth are appreciably better when using the "green water" technique. The relative difference in the end of rearing between growths is 30% for linear growth and 38% for weight growth in favour of "green water" rearing. Source