TOWARDS DEVELOPMENT OF MICROBOUND DIET AND ITS APPLICATION ON LARVAL AND POST LARVAL OF FRESHWATER PRAWN, Macrobrachium rosenbergii

Effects and application of microbound diets (MBD) in larvae and post larvae (PL) of Macrobrachium rosernbergii were investigated in series of experiments. Microbound diets were formulated with different binders (agar, zein, alginate, carrageenan and carboxymethyl cellulose) and the MBD stability was analyzed by monitoring the dry matter retained and turbidity of water over progressive time up to 360 minutes. MBD with zein showed higher dry matter retained, followed by MBD with agar. After 20 minutes of immersion, the dry matter retained of MBD with zein (97.16%) was significant highest than that of MBD with CMC (88.76%) (P<0.05) and after 40 and 90 minutes of immersion time, water stability of MBD with zein was significantly higher than MBD with carrageenan and CMC (P<0.05). At the end of 180 minutes, the water stability of all diets was found to be almost the same. Absorbance value of MBD water sample was increased with the increasing disintegration of the MBD in the water over time. Throughout the experiment, MBD with zein consistently showed the lowest value of absorbance.

Survival, development and growth performance of larvae and PL of M. rosenbergii fed with MBD similar to the above were also evaluated for 14 days. At the end of the feeding trial, survival rate of larvae fed with live feed and MBD formulated with agar, zein, alginate, carrageenan and CMC were 77, 53, 48, 42, 47 and 43%, respectively. For developmental stages, larval fed rotifer had variety of stages (stage VII, VIII, IX, X and XI) compared to the all larval which fed with MBD (stage X and XI). Stage X is a dominant stage for all treatments receiving MBD meanwhile larval fed on rotifer had dominant stage IX (p<0.05). For PL of M. rosernbergii, PL fed with MBD with agar consistently showed higher survival rates, similar to those achieved by larvae fed with rotifer. For growth performances, there were no significant difference (P>0.05) was observed for all MBD treatments including when the larvae were fed on rotifer.

In third experiment, MBD formulated with agar were fed to PL of M. roserbergii at various frequencies and timing (0800, 2000, 0800-2000, 0800-1400-2000 and 0800-1200-1600-2000) for two weeks. The effects of this feeding regime on PL of M. rosernbergii was investigated using survival, growth performances and fatty acids composition as parameters. Results showed that PL fed three times a day, 0800-1400-2000 had significantly higher survival rates (45%) compare to other treatments. No significant different was obtained from growth performances however, 0800-2000 feeding had the best growth performance in weight gain, specific growth rate and daily growth rate compared to other treatments. For body composition and fatty acid composition, no significant different was observed among all treatments (P>0.05). Results from these experiments have high practical value and readily applied. Appropriate binder type and optimal feeding regime will boost hatchery culture of M. rosernbergii by optimizing their survival, growth, reduce management cost and manage good water quality.