Somkiat Piyatiratitivorakul

Effects of a probiotic bacterium on black tiger shrimp Penaeus monodon survival and growth

Bacillus S11 bacterium isolated from black tiger shrimp habitats was added to shrimp feed as a probiotic in three forms: fresh cells, fresh cells in normal saline solution, and a lyophilized form. After a 100-day feeding trial with probiotic supplemented and non-supplemented (control) feeds, Penaeus monodon (from PL30) exhibited no significant difference (p>0.05) in growth, survival nor external appearance between all three probiotic treatments, but significant differences (p<0.05) occurred between probiotic and control groups. After challenging shrimps with a shrimp pathogen, Vibrio harveyi, by immersion for 10 days, all probiotic treatment groups had 100% survival; whereas the control group had only 26% survival. In addition, the control group had an unhealthy external appearance, and deformed texture of the hepatopancreas and intestine, while treatment group shrimp appeared healthy and normal.

Highly unsaturated fatty acid requirements of Penaeus monodon postlarvae: an experimental approach based on Artemia enrichment

Penaeus monodon postlarvae (PL-5 to PL-15) were fed 5 different diets consisting of enriched Artemia nauplii with a specific n-3 HUFA content. Although the postlarvae grew well on an Artemia diet with low HUFA-content, the ability of PL-10 to endure osmotic stress remained low. Feeding Artemia enriched with medium levels of n-3 HUFA (sum n-3 HUFA =12,55mg/g DW) for 5 days considerably enhanced the resistance of PL-10 to osmotic stress and their survival recorded 5 days later. However, very high dietary levels of n-3 HUFA (31,2 mg/g DW) did not have any growth promoting effect, thus suggesting that an excessive supply of n-3 may not be beneficial to the shrimp. Our data demonstrate that subjecting postlarvae to reduced salinities for 2h provides a simple and rapid test for assaying the physiological condition of postlarval shrimp.

Gonadal maturation and reproductive performance of giant tiger prawn (Penaeus monodon Fabricius) from the Andaman Sea and pond-reared sources in Thailand☆

Abstract Broodstock trials were conducted with Penaeus monodon to compare the gonadal maturation and reproductive performance of four combinations of broodstock: wild-caught, pond-reared, and two groups of cross-matings between wild-caught and pond-reared. Wild-caught broodstock were captured from an off-shore area of the Andaman Sea. The average weight of wild-caught females was almost double that of pond-reared females. Wild-caught broodstock produced significantly greater numbers of eggs than pond-reared broodstock, despite comparable egg quality. Cross-matings between broodstock from the two sources did not improve gonadal maturation or reproductive performance.

Optimal dietary levels of lecithin and cholesterol for black tiger prawn Penaeus monodon larvae and postlarvae

Abstract The effect of lecithin and cholesterol on growth and survival of larval and postlarval Penaeus monodon was evaluated using semi-purified diets containing four levels of lecithin (0.0, 0.5, 1.0 and 1.5%) and three levels of cholesterol (0.0, 0.5 and 1.0%). Three early stages (zoeal, mysid and postlarval) of P. monodon were fed the experimental diets. Growth and survival of shrimp fed diets containing 1.0 and 1.5% lecithin were not significantly different ( P >0.05) but these groups had significantly greater growth and survival than those fed 0.0 and 0.5% lecithin diets. Shrimp fed diets containing 1.0% cholesterol had significantly greater ( P P. monodon . During a low salinity stress test, PL-15 shrimp fed diets containing 1.0% cholesterol had significantly greater ( P

An improved, closed seawater recirculation maturation system for giant tiger prawn (Penaeus monodon fabricius)

A large, closed seawater recirculation system for maturation of giant tiger prawns is described. The system consisted of a circular, 7-m diameter, flat-bottom maturation tank (1·4 m water depth), and a separate bio-filter tank. During operation, water recirculation was four times daily. The system was housed in a building with light intensity 5% of ambient. Eight prawn maturation trials were conducted with this system. Each trial normally ran for three months with stocking densities of 3 prawns/m2. Prawn sizes ranged from < 100 to 200 g. Water quality was maintained at optimal condition throughout the trials. Maturation and spawning success appeared dependent on prawn quality and food quality provided.

Effects of different feeding regimes on ovarian maturation and spawning of pond-reared giant tiger prawn in Thailand

Large pond-reared Penaeus monodon were used in three maturation and spawning trials lasting 60 days. One group of prawns was fed a fresh diet only; a second group was supplied a fresh diet combined with a formulated pelleted diet; a third group of prawns received the formulated diet only. Total maturation (N = 66 and 55) and spawning events (N = 63 and 48) were much greater for prawns receiving only the fresh diet, and the combined fresh with formulated diets, respectively. Prawns receiving only the formulated diet matured only 12 times, and spawned 11 times. Prawns fed a fresh diet produced significantly more eggs than those given a formulated diet alone. No significant differences were seen in eggs produced per spawning event, % fertilization, % hatch or % metamorphosis from egg to protozoea. Female prawns exhibited greater mortality than did males, while females on the fresh diet only had greater mortality than did other females, presumably due to greater handling and other stress factors. Female prawns on a combined diet had lower mortality than other females. The formulated diet used is suitable for supplementation, but not as a sole maturation food.

Physico-chemical Activation on Rice Husk Biochar for Enhancing of Cadmium Removal from Aqueous Solution

The biochar was prepared from rice husk by pyrolysis at slow pyrolysis at 300, 400, and 500oC. The obtained biochars were activated by combined physico-chemical methods. An alkaline solution of 1.63 M of KOH was used for chemical pre-activation and made second pyrolysis at the same condition as first pyrolysis. Adsorption efficiency was studied using the batch static method under laboratory conditions. Cd(II) ion removal efficiency of activated biochars was increased from 13–20% to 95–97% over non-activated biochar. The activated biochar at a pyrolysis temperature of 300°C showed the highest Cd(II) ion removal efficiency of 97% at 180 min of contact time. Cd(II) ion adsorption isotherms of activated biochar were fitted well both in Langmuir and Freundlich model. The maximum Cd(II) ion adsorption capacity of activated biochar pyrolysis at 300oC was 45.87 mg g-1, about six times higher than that of the non-activated biochar (7.76 mg g-1). The activated biochar increased the BET surface area from 7.71 to 11.57 m2g-1. It has been suggested that the simplicity of the physico-chemical activation technique, technically feasible, eco-friendly, and cost effective, can stimulate high Cd(II) ion removal efficiency of rice husk biochar.

A tunicate from a Thai coral reef: a potential source of new anticancer compounds

Tunicates have attracted attention as potential sources of anti-cancer compounds (Wright et al. 1990; Scotto 2002). In Thailand, a colonial tunicate has been found on coral reefs by Suwanborirux et al. (2002). Subsequent identification by Teruaki Nishikawa showed this to be Ecteinascidia thurstoni Herdman, 1891 (Fig. 1). A group of alkaloids, the Ecteinascidins (Et), including Et 770 and Et 786, have been isolated with very high yields from E. thurstoni pretreated with potassium cyanide. These extracts exhibited potent cytotoxic activity against cancer cells of breast, lung, colorectal, and nasopharyngeal tissues (Suwanborirux et al. 2002). This tunicate is now only found in one reef area at 1–3 m depth in Phuket Province, southern Thailand, on the Andaman Sea coast. The zooid ranges between 0.8 and 1.2 cm in height. The highest density and abundance of this tunicate is in March, July, and November each year. Analysis of stomach contents of the tunicate revealed the presence of the diatoms Navicula, Nitzschia and Thalassiosira, and dinofla-

Detection of metabolic conversions of ascorbate-2-monophosphate and ascorbate-2-sulfate to ascorbic acid in tiger prawn (Penaeus monodon) using high-performance liquid chromatography and colorimetry☆

Biochemical conversions of ascorbate-2-monophosphate and ascorbate-2-sulfate to ascorbic acid by acid phosphatase and ascorbate-2-sulfate sulfohydrolase, respectively, were found in extracts of a hepatopancreas of Penaeus monodon, bovine liver and tilapia liver. Both enzymes were assayed with high-performance liquid chromatography (HPLC) and colorimetry. Colorimetry was based on the reduction of a color of 2,6-dichlorophenolindophenol (DCIP) when ascorbic acid was released from enzymatic activity. Assay of acid phosphatase either with HPLC or with colorimetry was found to be equally reliable. However, sensitivity of the HPLC assay was slightly higher than that of colorimetry; HPLC was able to detect activity as little as 1 nmol ascorbic acid released per min, whereas colorimetry was limited at 6–7 nmol/min. Assay of ascorbate-2-sulfate sulfohydrolase in crude extracts with the HPLC technique was found to be more specific than that with the colorimetric assay. The excess reduction of DCIP color not related to the sulfohydrolase activity was observed in the colorimetric technique. An accumulation of ascorbic acid in a hepatopancreas of P. monodon fed with feeds supplemented with phosphorylated or sulfated ascorbic acid was higher than that of the prawn fed with feed without ascorbic acid. The accumulated ascorbic acid was possibly from the activity of acid phosphatase or the sulfohydrolase that hydrolyzed phosphorylated or sulfated derivatives in vivo, respectively. Metabolism of the ascorbate derivatives in the prawn is discussed.