Effect of enriched rotifer (Brachionus plicatilis) with thyroxin and n-3 HUFA on larval growth and survival of grouper (Epinephelus fuscoguttatus) reared at different salinities | |
| Author | Abidin Nur II |
| Call Number | AIT Thesis no. AS-98-06 |
| Subject(s) | Groupers Fish-culture |
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The main problem with grouper culture is heavy mortality during early larval stages, especially prior to metamorphosis. Experiments were carried out under laboratory conditions to eva_luate : 1) the effect of thyroxin, n-3 HUFA and their interaction; and 2) the effect of salinity on larval growth and survival of grouper, E. fuscoguttatus. Larvae were fed screened rotifers (mean lorica length 106 ~tm) staiiing on day two and provided with green water of Chiarella sp. at the density of 3xl05 cells/ml. In experiment-I, thyroxin was administered at four levels (0.1; 0.5; 1.0; and control) directly in lai·vae culture media, and indirectly through enrichment via rotifer culture media. All treatments were replicated with or without n-3 HUF A. Mean value of specific growth rate (SGR) varied from 8.17 to 8.80 % per day and showed no significant (P>0.05) difference between treatments. Regression analysis showed a linear (P<0.01) relationship between survival and thyroxin concentration within the treatment range. The relationship between thyroxin (X) and laival survival (Y) was Y = 6.46X + 5.11; r 2 = 0.89; O:s;X:s;l. There was no significant relationship between SGR and thyroxin concentration.. Larvae treated with n-3 HUF A showed significantly (P<0.05) higher survival than untreated laivae at all levels of thyroxin. No interaction (P>0.05) between thyroxin and n-3 HUF A on larval growth and sUtvival rate was found. However, those treated with thyroxin (1 ppm) combined with n-3 HUF A emulsion (1 ml/L) showed the highest larval SUlvival rate of 8.62 %. In experiment-2, laivae were fed enriched-rotifer with thyroxin (1 ppm) and n-3 HUFA (1 ml/L) and reared at salinity of25; 28; 31; and 34 ppt. Maximum survival rate (6.13 %) was found with larvae reared at salinity of 31 ppt . This salinity level was similar to that in which broodstock were conditioned (31-33 ppt). Salinity had no significant (P>0.05) effect on hatching and yolk-sac absorption rate, but did have a significant effect on initial yolk-sac area. It is concluded that survival of E. fuscoguttatus laivae can be enhanced in early larvae stages tlu·ough combined treatment with thyroxin at 1 ppm and n-3 HUF A, but many other factors continue to constrain the overall survival rate such as egg quality and low feeding incidence. |
| Year | 1998 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Aquatic Systems (AS) |
| Chairperson(s) | Hambrey, John B.; |
| Examination Committee(s) | Yakupitiyage, Amararatne ;Lin, C. Kwei; |
| Scholarship Donor(s) | United Kingdom ; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1998 |