Blood cell histology of horseshoe crab, Tachypleus gigas.

Amoebocytes are the main carrier of innate immune system in horseshoe crabs. Cytoplasm of these cells are packed with granules which consist of all coagulation factors and anti-bacterial compounds. Light microscopy (using May-Grunwald and Giemsa staining technique) of 46 blood specimen for both sexes of Tachypleus gigas and observation under Transmission Electron Microscopy (TEM) were performed. Light microscopy revealed that these are ovoid cells containing blue nucleus surrounded by a cytoplasm packed with pink granules. Large and small axes measured 18.8±0.5 and 12.8±0.4 μm, respectively. Total blood cell count (33000 cell mm-3) does not show any significant difference between sexes. TEM of normal and degranulated blood cells revealed that T. gigas hemocytes consist of two type of granules (large and small). Blood cells have all the necessary organelles of normal cells. During the granule formation, fusion of different intermediate granules were observed. Degranulated hemocytes under light microscope and TEM showed cells containing large nucleus and cytoplasmic granules were replaced with a large cytoplasmic vacuole. In light and electron microscopy only one type of hemocyte was observed, the granular cells. These granular cells consist of large and small granules

A review on mycotoxins in food and feed: Malaysia case study

Fungi are distributed worldwide and can be found in various foods and feedstuffs from almost every part of the world. Mycotoxins are secondary metabolites produced by some fungal species and may impose food safety risks to human health. Among all mycotoxins, aflatoxins (AFs), ochratoxin A (OTA), trichothecenes, deoxynivalenol (DON and T-2 toxin), zearalenone (ZEN), and fumonisins (FMN) have received much attention due to high frequency and severe health effects in humans and animals. Malaysia has heavy rainfall throughout the year, high temperatures (28 to 31 °C), and high relative humidity (70% to 80% during wet seasons). Stored crops under such conditions can easily be contaminated by mycotoxin-producing fungi. The most important mycotoxins in Malaysian foods are AFs, OTA, DON, ZEN, and FMN that can be found in peanuts, cereal grains, cocoa beans, and spices. AFs have been reported to occur in several cereal grains, feeds, nuts, and nut products consumed in Malaysia. Spices, oilseeds, milk, eggs, and herbal medicines have been reported to be contaminated with AFs (lower than the Malaysian acceptable level of 35 ng/g for total AFs). OTA, a possible human carcinogen, was reported in cereal grains, nuts, and spices in Malaysian market. ZEN was detected in Malaysian rice, oat, barley, maize meal, and wheat at different levels. DON contamination, although at low levels, was reported in rice, maize, barley, oat, wheat, and wheat-based products in Malaysia. FMN was reported in feed and some cereal grains consumed in Malaysia. Since some food commodities are more susceptible than others to fungal growth and mycotoxin contamination, more stringent prevention and control methods are required

Comparisons in prosomal width and body weight among early instar stages of Malaysian horseshoe crabs, Carcinoscorpius rotundicauda and Tachypleus gigas in the laboratory

The three Southeast Asian horseshoe crab species are diminishing not only locally but also regionally and protection of them is now an urgent matter. Two species of horseshoe crab, Tachypleus gigas and Carcinoscorpius rotundicauda, were artificially inseminated, and the eggs were incubated at 28±1°C and in the salinity of 33±2 ppt. The fertilized eggs hatched after 42 days and 41 days with hatching rates of 98.1 and 98.9% for T. gigas and C. rotundicauda, respectively. This study reveals that in the identical laboratory condition, C. rotudicauda underwent more frequent molting than T. gigas. After 328 days of rearing, 63.8 and 22.9% of C. rotundicauda larvae had molted to the 6th and 7th instars, respectively, while 56.6 and 20.1% of T. gigas at the end of 355 days of rearing had molted to the 5th and 6th instars, respectively, but only 0.6% had molted to the 7th instar. There is a wide variation in the molting rate among larvae obtained from synchronized inseminated eggs and reared under uniform laboratory conditions

Assessment of possible human risk of probiotic application in shrimp farming

Aquaculture is one of the fastest growing industries. This impressive industry is incorporated with prophylactic use of antibiotic for disease prevention. Probiotics seems to be appropriate substitute for the antibiotic, but because those are live bacteria and residual of the probiotics in the aquaculture product may cause health problem for the consumers and labors in the aquaculture processing plant and aquaculture farms. In this study we used LD50 in a mammalian model animal to assess the safety of probiotics used in shrimp culture for human consumption. After assessment for an approximate range of lethality in a preliminary experiment, treatment groups were fed via a gavage with certain dosage range of candidate probiotic, Shewanella algae. The LD50 value was approximately 1036 cfu/animal with 95% fiducial limitation of 34.95 (lower band) and 37.07 (upper band), which is fairly high and most likely safe to use as probiotic. Furthermore, this study may aid to onset of thinking about an evaluation technique for safe using of probiotic in aquaculture

Heavy metal concentration in horseshoe crab (Carcinoscorpius rotundicauda and Tachypleus gigas) eggs from Malaysian coastline

The level of trace elements (Cu, Zn, Fe, Ni, Pb, and Cd) was measured in eggs of horseshoe crabs, Carcinoscorpius rotundicauda, and Tachypleus gigas, from Malaysia. The concentrations (μg/g wet weight) of these elements in C. rotundicauda eggs ranged from 18.84 to 65.44 for Cu, 34.65 to 104.08 for Zn, 4.497 to 75.95 for Fe, 1.88 to 11.17 for Ni, 0.52 to 3.64 for Cd, and non-detectable for Pb. The level of these elements in T. gigas eggs was from 30.54 to 120.32 for Cu, 46.34 to 88.96 for Zn, 21.88 to 88.96 for Fe, 4.71 to 7.82 for Ni, 0.02 to 4.11 for Cd, and 10.00 to 25.84 for Pb. C. rotundicauda eggs showed significantly higher amounts of trace elements except for Ni and Cd. The heavy metals analyzed were higher than the range of permissible limit for human consumption

Bacteria flora associated with different body parts of hatchery reared juvenile Penaeus monodon, tanks water and sediment

Bacteria flora of intestine and hepatopancreas, body surface and muscles of juvenile Penaeus monodon along with its rearing water and sediment was analyzed. Juvenile shrimp were reared in four tanks in the Hatchery complex, Department of Aquaculture, Faculty of Agriculture, University Putra Malaysia. Water quality parameters were measured every day. Samples were collected aseptically and homogenized before being inoculated in Tryptone Soy agar, Thiosulphate Citrate Bile Salt agar, MacConkey agar and Pseudomonas-isolating agar. There was no significant difference between water quality parameters and shrimp body weight of replicate tanks. Total plate count for water and total Vibrio count for rearing water and digestive system were within previous reported ranges. Eight different genera were isolated in which 7 genera were identified. Gram negative bacteria were dominant (72%) Vibrio was the most dominant genera followed by Shewanella and Burkholderia. Clavibacter followed by Staphylococcus were the most dominant gram positive bacteria. No coliform bacteria was detected in the shrimp body parts and rearing environment. Incidence of Shewanella in the digestive system was significantly higher than sediment, rearing water and muscles. This may be implied its ability to colonize in the digestive tract of juvenile P. monodon

Effect of supercritical fluid extraction on the reduction of toxic elements in fish oil compared with other extraction methods

High-quality fish oil for human consumption requires low levels of toxic elements. The aim of this study was to compare different oil extraction methods to identify the most efficient method for extracting fish oil of high quality with the least contamination. The methods used in this study were Soxhlet extraction, enzymatic extraction, wet reduction, and supercritical fluid extraction. The results showed that toxic elements in fish oil could be reduced using supercritical CO2 at a modest temperature (60°C) and pressure (35 MPa) with little reduction in the oil yield. There were significant reductions in mercury (85 to 100%), cadmium (97 to 100%), and lead (100%) content of the fish oil extracted using the supercritical fluid extraction method. The fish oil extracted using conventional methods contained toxic elements at levels much higher than the accepted limits of 0.1 μg/g

Effect of Bacillus subtilis on the growth and survival rate of shrimp (Litopenaeus vannamei)

The effect of Bacillus subtilis, isolated from digestive tract of Macrobrachium rosenbergii was investigated on growth and survival rate of Litopenaeus vannameiduring 60 days of culture. Sixteen aquaria with four replicates were used for treatments and controls. Treatment groups were consisted of і) shrimp fed diet withB. subtilis (T1), and ii) shrimp fed diet mixed with B. subtilis and commercial probiotic (T2). Control groups were consisted of і) shrimp fed diet with commercial probiotic as positive control, and ii) shrimp fed unaltered diet as negative control. Results showed that B. subtilis was proliferated in digestive tract of treated shrimps, and the number of Vibrio spp. was reduced in digestive tract during the cultural period. Survival rate, 75.5± 4.62 %, and yields of shrimps, 190.00 ± 13.13 g, treated with B. subtilis were significantly greater (P<0.05) than the other treated and control groups. Also population density of total viable bacteria and B. subtiliscounted in digestive tract of shrimps treated with B. subtilis were significantly higher (P<0.05) than the other treated groups. Results of this study indicate that the addition of B. subtilis can improve shrimp (L. vannamei) survival rate and yield