Yew-Hu Chien

The resistance to physical stresses by Penaeus monodon juveniles fed diets supplemented with astaxanthin

Abstract This study was aimed to determine if the increase of body astaxanthin content through dietary supplementation in tiger prawn Penaeus monodon juvenile could enhance its antioxidant defense capability and resistance to thermal and osmotic stress. Hemolymph total antioxidant status (TAS) and superoxide dismutase (SOD) were chosen as indices of shrimp antioxidant capacity. Resistance to thermal and osmotic stress was expressed as shrimp recovery, and hemolymph aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Tiger prawn 5-day postlarvae were fed diets supplemented with 0 or 80 mg astaxanthin/kg diet for 8 weeks so that the resulting juveniles contained two levels of astaxanthin. Subsequently, shrimp were subjected to a rapid change in water temperature (27 to 5 °C) and/or salinity (32‰ to 0‰) for 5 min. The treated shrimp contained markedly higher body astaxanthin than the control shrimp. Significantly higher average recovery in treated shrimp (56%) than control shrimp (48%) suggested that astaxanthin supplement had improved the resistance against thermal and osmotic stress. Thermal stress had a more profound effect than osmotic stress on the recovery of shrimp, as indicated by the difference in recovery, 73% versus 24%. TAS was improved and SOD was reduced by the presence of dietary astaxanthin. The enhancement of antioxidation capacity by dietary astaxanthin and consequently, the improvement of recovery against thermal and osmotic stress have demonstrated that astaxanthin is a ‘semi-essential’ nutrient for tiger prawn. The presence of astaxanthin can become critical when the animal is under physiological stress caused by abiotic changes. However, complicated interactions were observed among thermal and osmotic stresses and improvement of resistance conferred by dietary astaxanthin. Shrimp hepatopancreatic function may have been improved by dietary astaxanthin since hemolymph AST of the control shrimp was significantly higher than that of the treated shrimp. However, hemolymph AST and ALT content of shrimp did not reflect improvement in health following thermal and osmotic stresses, respectively.

Pigmentation of kuruma prawn, Penaeus japonicus Bate, by various pigment sources and levels and feeding regimes

Color is one of the major factors which determines the price of live kuruma prawns, Penaeus japonicus Bate, in the Japanese market. This study was designed to determine the effects of various pigment sources, and levels and feeding regimes on the pigmentation of kuruma prawns. A 7 × 3 factorial design was used which included seven pigmented diets fed for three time durations with two replications. The seven pigmented diets contained astaxanthin at concentrations of 50, 100 and 200 mg/100 g diet, β-carotene at concentrations of 50, 100 and 200 mg/100 g diet, and algal (Dunaliella salina) meal at a concentration of 100 mg pigment/100 g diet. Prawns were fed each pigmented diet for 1, 2 or 3 months. During the other months, the prawns were fed a non-pigmented diet. The control group was fed a non-pigmented diet exclusively. Astaxanthin was found to be the most effective pigment. No difference in pigment concentration was found between prawns fed the β-carotene and algal meal. Pigmentation by astaxanthin at 50 mg/ 100 g diet was poorer than at 100 and 200 mg/100 g diet. No significant difference in pigmentation was found among prawns fed the three levels of β-carotene. There was no difference in pigmentation among prawns fed the pigmented diets for the three time periods. The best feeding strategy for pigmentation was to feed the prawns a diet containing astaxanthin at 100 mg/100 g for 1 month before harvest. Prawns fed the astaxanthin diet had a higher rate of survival than those fed the β-carotene or algal meal diets. A positive correlation between survival rates and pigment concentration in prawn tissue indicated that pigment may play a role in improving the survival of prawns.

Effects of stocking density and aged sediment on tiger prawn, Penaeus monodon, nursery system

Abstract Our study aimed to assess the effects of stocking density and aged sediment on a tiger prawn, Penaeus monodon , nursery system. Twenty-four aquaria were assigned to 12 treatments in a 3 × 4 factorial arrangement, namely, three stocking densities of prawn fry PL35: 72, 108, and 144/m 2 ; by sediment with four ooze contents: 0, 33, 66, and 100%, four degrees of sediment deterioration. Two replications were used for each treatment. The fry were reared for 54 days. Stocking density was the main factor affecting the growth of prawn fry; ooze content had a relatively slight effect. The growth rate was best at 72/m 2 . The growth rate at 108/m 2 was not significantly different from that at 144/m 2 . Survival rates were affected by stocking densities only. Survival rate at 144/m 2 was the lowest. There was no significant difference in survival rates between 72/m 2 and 108/ m 2 . Since the sediment on day 54 did not show any marked deterioration, it appeared that the nursery period could be extended beyond 54 days. Since organic loading and toxic metabolites were proportional to stocking density, which directly affected water quality and growth of fry, stocking density should be one of the main factors to consider in nursery culture. Since the reduction-oxidation potential was closely related to most constituents in the sediment and the growth and survival rates of fry, it can be used as an indicator of the sediment aging process and as a semi-quantitative indicator of the sediments effects on cultured organisms.

Effects of light sources on growth and carotenoid content of photosynthetic bacteria Rhodopseudomonas palustris

This study investigated the effects of eight light sources on photosynthetic bacteria (Rhodopseudomonas palustris) growth and carotenoid content (CD), cultured for 144 h. Light sources were incandescent lamp (IL), halogen lamp (HL), fluorescence lamp (FL), and light-emitting diodes (LEDs) of white (LW), yellow (LY), red (LR), blue (LB), and green (LG). Dark condition served as the control. Under around 2000 lux, light sources ranked greatest to least bacterial growth effect were (LB=IL) > FL > LW ≥ HL ≥ LR ≥ (LG=LY=DK). Ranking effect on CD content was LB > IL ≥ LY ≥ (HL=LR=LG) ≥ LW ≥ DK ≥ FL. Energy efficiency for bacterial growth was LB > LW > LY > IL > LG > HL > FL > LR. CD productivity ranking was LB > LY > LW > LG > IL > HL > LR > FL. Results revealed that LB saved 75% energy and increased CD productivity by 348% compared with IL.

Transformation of chloramphenicol and oxytetracycline in aquaculture pond sediments

Abstract Transformation processes of two antibiotics, chloramphenicol (CM) and oxytetracycline (OTC), in aquaculture pond sediments collected from a freshwater eel pond and a marine shrimp pond were investigated. The sorption rates of CM in the freshwater and marine sediment slurries (10%, wt/vol) were 4% and 2%, respectively. In contrast, the sorption rates of OTC in the freshwater and marine sediment slurries (10%, wt/vol) were 99.8% and 90.3%, respectively. CM amended at 60–70 mg/L was transformed within 4 days in the freshwater and marine pond sediment slurries when incubated under anaerobic conditions, and within 12 days under aerobic conditions. OTC amended at 60–70 mg/L was not transformed after incubation for 70 days in the freshwater and marine pond sediment slurries under anaerobic conditions. However, OTC was transformed to undetectable levels within 47 days when incubation proceeded under aerobic conditions. OTC was in fact also removed in the sterile sediment slurries under aerobic conditions...

The Pacific White Shrimp, Litopenaeus vannamei, in Asia: The World’s Most Widely Cultured Alien Crustacean

The Pacific white shrimp, Litopenaeus vannamei, is native to the western Pacific coast of Latin America, from Peru to Mexico where water temperatures are normally over 20oC throughout the year. It was introduced into Asia experimentally from 1978 to 1979, but commercially only since 1996 into Taiwan and China and subsequently to several countries in southeast and south Asia. In 2008, 67% of the world production of cultured penaeid shrimp (3,399,105 mt) consisted of L. vannamei (2,259,183 mt). Such dominance was attributed to an 18-fold increase of production in Asia, from 93,648 mt in 2001 to 1,823,531 mt in 2008, which accounts for 82% of the total world production of L. vannamei. The commercial success of introducing L. vannamei into Asia can be attributed to its superior aquaculture traits compared with Penaeus monodon, the most popular cultured Asian penaeid. These include higher availability of genetically selected viral-pathogen-free domesticated broodstock, high larval survival, faster growth rate, better tolerance to high stocking density, lower dietary protein requirement, more efficient utilization of plant proteins in formulated diets, stronger adaptability to low salinity, better tolerance to ammonia and nitrite toxicity, and lower susceptibility to serious viral pathogens infecting P. monodon. China leads the world cultured L. vannamei production from 33% in 2001 to 47% in 2008 (1,062,765 mt), among which 51% (542,632 mt) were produced in inland freshwater ponds. The culture of L. vannamei in freshwater is expected to continue increasing in China, Thailand, and other countries in Asia due to higher profits compared to other freshwater aquaculture species, and higher land availability in inland than in coastal areas. Although Taura Syndrome Virus, the most economically significant viral pathogen of L. vannamei is not reported to be detrimental to aquaculture production in Asia nor have affected indigenous cultured or wild shrimp populations, precautionary measures have been advocated or enforced by government authorities and executed by some private sectors. Potential problems that can affect future Asian production of L. vannamei include: decreasing genetic diversity through domestication and selection; increasing trans-boundary movements between continents and within the Far East; and emergence of new and Asian-specific viral and other microbial diseases. These potential problems will require Asian governments to take preventive measures through legislative control as well as scientific and technical measures.

Alterations of Antioxidant Capacity and Hepatopancreatic Enzymes in Penaeus monodon (Fabricius) Juveniles Fed Diets Supplemented with Astaxanthin and Exposed to Vibrio damsela Challenge

This study aimed at determining whether increased body astaxanthin content in Penaeus monodon juvenile resulting from dietary astaxanthin supplementation followed by Vibrio damsela challenge could alter the shrimps antioxidant defense capability and hepatopancreatic enzymes. Haemolymph total antioxidant status (TAS) and superoxide dismutase (SOD) were chosen as indices of shrimp antioxidant capacity. Hepatopancreatic enzymes measured were aspartate aminotransferase (AST) and alanine aminotransferase (ALT). P. monodon, 5-day old postlarvae, were fed diets supplemented with 0 or 71.5 mg astaxanthin/kg diet for 8 weeks and the resulting juvenile contained 10.5 and 45.6 μg/g body astaxanthin. Shrimp were then subjected to bath challenge of V. damsela. Up to 48 h after challenge, the survival of control shrimp, 36.5±3.2% was significantly lower than that of the astaxanthin-fed (AX) shrimp, 45.2±2.8%. After the bath challenge, AX shrimp had higher TAS and lower SOD and ALT than controls. AST was not influenced by either body astaxanthin or bath challenge. In conclusion, dietary astaxanthin increased body astaxanthin and concomitantly enhanced antioxidant defense capability in P. monodon juveniles, consequently provided protection to some extent against V. damsela challenge in the early stage, which reflected in slightly higher survival and lower ALT.

Modeling the effects of sodium chloride on degradation of chloramphenicol in aquaculture pond sediment

Sodium chloride was added to aquaculture pond sediment to determine effects of different salinities on degradation of chloramphenicol (CM). In this experiment, freshwater (0 ppt salinity) eel pond sediment slurries (10% w/v) were amended with sodium chloride to obtain salinities of 12, 24 and 36 ppt. There were no significant differences in sorption rate either between aerobic and anaerobic conditions or among various salinities. Degradation of CM fitted well to the decaying exponential curve. The degradation rates under anaerobic conditions were significantly greater than those under aerobic conditions. As salinity increased, the degradation rates decreased under both aerobic and anaerobic conditions. The differences in degradation rates either between aerobic and anaerobic conditions or among various salinities were attributed to the effects of microbial activities under different environments.

The potential of Yucca schidigera extract to reduce the ammonia pollution from shrimp farming

This study investigated the feasibility of using Yucca schidigera extract (YUPE) to reduce ammonia pollution resulting from shrimp farming. YUPE was added at ratios of 18, 36, and 72 mg L(-1) to effluent from an experimental shrimp culture system containing total ammonia nitrogen (TAN) of 0.592, 0.672, and 0.718 mg L(-1). TAN reduction increased with an increase in YUPE, and at 18 mg L(-1) reduced TAN by 71-72% and 86-87% at 6 and 24h, respectively. Shrimp feed containing YUPE at 300, 600, and 1200 mg kg(-1) was submerged, allowing the ammonia to leach out. The addition of YUPE in feed reduced TAN leaching by 50-83% compared with the control. The application of YUPE in water or feed could considerably reduce the accumulation of ammonia in waste water discharge during shrimp production, thereby providing a feasible solution to ammonia pollution in coastal environments.

Chromatosomes in Three Phenotypes of Neocaridina Denticulata Kemp, 1918: Morphological and Chromatic Differences Measured Non-Invasively

Abstract External colour differences in crustaceans were examined using a non-invasive study of morphology and colour in epidermal chromatosomes. Three different phenotypes of the shrimp, Neocaridina denticulata (< 2 cm total length), differ in the quantity and dispersal of chromatosomes in the epidermis, with resulting differences in body colour. Also, pigmentation pattern is most pronounced in the anterior body parts. The exopod of uropod was the most suitable body area to monitor colour changes in this shrimp. This non-invasive method allows for the study of external pigmentation in crustaceans at different stages and may help to understand how these animals manipulate their chromatosomes under physiological and environmental variability in order to acquire the final external colour.