Applications of commercial probiotics and astaxanthin during nursing of blue swimming crab (Portunus pelagicus, Linnaeus, 1758) | |
| Author | Anawat Boonyapakdee |
| Call Number | AIT Diss. no.AQ-21-01 |
| Subject(s) | Probiotics Crab fisheries--Thailand |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Aquaculture and Aquatic Resources Management |
| Publisher | Asian Institute of Technology |
| Abstract | Crabs are considered one of the most valuable seafood items whose supply is still limited to catch from wild. Low survival of crab lets during nursing is the main barrier for crab farming. A series of four experiments (Exp) were conducted to test compare nursing methods and the potential applications of astaxanthin and commercial probiotics in blue swimming crab (Portunus pelagicus) with the objective of increasing survival and growth. Exp 1 was conducted for 35 days to compare the effects of nursing system i.e. with Cup and Substrate methods and to investigate the effects of natural astaxanthin supplementation. Exp 2 was to compare three strains of commercial probiotics, and the Exps 3 and 4 were to determine the optimum doses of the selected probiotics and the synthetic astaxanthin respectively. In the Exp 1, survival of crablets was three times higher in cup method; therefore, all the other experiments were conducted by using Cup method. In all the experiments, approx. 1 em (carapace width) size and 10-day old metamorphosed crab from megalopa were stocked and with pellet feed containing 43% crude protein, 4% crude lipid, 4% crude fiber, 3% vitamin mixture and 12% moisture (Kung Best Company). Feeding was done twice daily at 30% of biomass. Effects of treatments on water quality parameters; namely, temperature, pH, NH3, N02 and N03 were also assessed and their relationships with the growth and survival were also determined. Results of the Exp 1 showed that survival of crablets was three times higher (p<0.05) in Cup method (63.0±5.6%) than in substrate method (21.3±4.6%). The dose of 600 mg astaxanthinlkg feed used in Exp 1 showed no effects in the survival of crablets in neither of the nursing methods. Survival of crablets increased with the increase in salinity and dissolved oxygen but decreased with the increase in temperature, pH, nitrite and nitrate. Exp 2 was to select the strains of commercial probiotics with 107 CFU/mL was diluted with water then sprayed on to the shrimp pellets and coated with 5% squid oil. Results showed no significant difference on the survival, which was very high in all the treatments (range 95-100%). However, growth parameters obtained from Bacillus licheniformis showed significantly higher (p<0.05) than other two probiotics in terms of carapace gain (CG), relative weight gain (RWG) and specific growth rate (SGR) suggesting that B. licheniformis was promising probiotic. iv Exp 3 was conducted to determine an optimum dose of B. licheniformis selected from Exp 2. The probiotic dose had significant (p |
| Year | 2021 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Bhujel, Ram C. |
| Examination Committee(s) | Anal, Anil Kumar;Salin, Krishna R. |
| Scholarship Donor(s) | Royal Thai Government;Asian Institute of Technology Fellowship |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2021 |