Water Stability and Nutrient Leaching of Different Levels of Maltose Formulated Fish Pellets

The effects of different levels of maltose on feed pellet water stability and nutrient leaching were studied. Five treatments, including control with three replicates with setup (0.0, 20, 25, 30 and 35%). Pellet leaching rates were used to indicate pellet water stability. The results show that the presence of maltose in the diets significantly improved pellet water stability (p<0.05), but the leaching rates of the feed (35% maltose) observed higher than other feeds. Increased maltose resulted in the corresponding decrease in pellet stability. The protein leaching rate of control feed and feed (20% maltose) was significantly (p < 0.05) lower than the rates of other diets The lipid leaching rate of control feed was lower than the rates of other diets, while the feed (35% maltose) was more leaching rate. It improved feeds water stability is one important reason why maltose enhances fish growth

Movement patterns of blue swimming crab, Portunus pelagicus in the Sarawak coastal water, South China Sea

A study was carried out to determine the movement patterns of P. pelagicus within the near-shore marine embayment of the Sarawak coastal water, South China Sea. These mark-recapture tagging studies were conducted for about five months from 26th March till 30th August 2005 comprising 48 sampling trips. Out of 976 crabs tagged and released, 212 (21.72%) were recaptured. The mean distances moved by male and female crabs were 7.36 km ± 1.78 and 9.15 km ± 1.87 respectively. The study shows that the female crabs moved significantly (p=0.01; p<0.05) further than males. The percentage of tagged crabs recaptured within the original release site were 50.0% for male and 45.83% for female crabs. The result shows that the male crabs only significantly (p=0.01; p<0.05) moved towards the deeper off-shore areas as compared to the near-shore areas. On the other hand, the female crabs moved significantly more towards both deeper off-shore and shallow near -shore areas. Most of the tagged crabs were recaptured within the sampling site of 2 km radius after a minimum of 30 days at liberty. The movement activities from the study were not necessarily limited because only 21.72% of the tagged-and-released crabs were recaptured. Thus, the main movement activities were attributed to the migration movements associated with reproduction and this can be seen from the tagged crabs which were recaptured at the off-shore deeper water

Live foods for juveniles production of blue swimming crab, Portunus pelagicus (Linnaeus, 1766)

The study were aim to demonstrate the affects of live food type’s i.e., mixed diatom, Artemia nauplii and rotifer on survival rate and molt time of larvae stage till 1st day juvenile crabs (C1) of P. pelagicus. Three types of feeding regimes given to the crab larvae through out the study trials are with and without mixed diatom, with and without Artemia nauplii and with and without rotifer. The study shows that zoea fed with rotifer alone was not enough to sustain survival in the next zoea stages and to promote metamorphosis up to megalopa stage. Survival of zoea fed with Artemia nauplii alone shows that this type of food is not suitable for the very early zoea stages. The study also shows that the adding of mixed diatom to larvae rearing system where rotifer and Artemia nauplii is main food items did not produced high survival rate as compared to larvae rearing fed on rotifer and Artemia nauplii alone. The results of the study demonstrated that the food types not only effect survival rate but also the growth of crab larvae. The study generally ended that the combination diet of rotifer and Artemia nauplii alone is enough to produced C

Supplementation of Indigenous Lactobacillus Bacteria in Live Prey and as Water Additive to Larviculture of Portunus pelagicus (Linnaeus, 1758)

Abstract: Experimental trials were conducted to demarcate the effects of indigenous Lactobacillus probiotics as bioencapsulated in live prey (rotifers Brachionus plicatilis and Artemia franciscana) and water additives together on the survival of blue swimming crab, Portunus pelagicus larvae. Three LAB probiotics L. plantarum, L. salivarius and L. rhamnosus at final concentration 1x10 7 cfu/mL were bioencapsulated in live prey added daily and same allowance was added to culture water on day 1, 3, 5, 7, 9, 11, 13 as a single isolates to treatments A, B, C and multi isolates to D with no probiotic added to control tanks. Bacteria were successfully accumulated in both rotifers and Artemia within two hours of incubation. Total viable count of bacteria in Artemia observed lower at sampling days in inoculated tanks compared to those at time of incubation, contrary it increased in controls and no Vibrio was determined in Artemia in LAB mixture isolate inoculated samples on the day 13. Highest LAB bacteria 4.10×10 3 was determined in Artemia on day 11 in those inoculated with mixture of LAB isolates. At the end of the trials, larvae treated with a mixture of LAB probiotics did produce significantly highest survival 13.83±0.76% over other LAB treatments. As a single isolate L. plantarum did produce survival 13.50±1.32% compared with those treated with L. salivarius and L. rhamnosus and those without probiotics (control). There was no statistical significance (p&gt;0.05) in the survival of larvae in any treatment. Results indicate that LAB probiotics could be used to enhance survival of P. pelagicus larvae