Investigation of mortality in Macrobrachium rosenbergii larvae associated with hatchery management at Universiti Putra Malaysia Marine Science Research Centre, Port Dickson, Malaysia

Since the middle of year 2011, high mortalities in Macrobrachium rosenbergii larvae at Universiti Putra Malaysia Marine Science Research Centre, Port Dickson, Malaysia were regularly observed, which had caused severe economic losses. This research was carried out to investigate the biological and non-biological factors in the hatchery that contributed to disease development in order to postulate the relationship of the factors involved in larvae mortality and to examine the appropriate culture management approach to reduce mortality. Six experimental trials were carried out, namely physical examination of water quality parameters in the hatchery, microbiological studies of culture water, larvae, feed (including Artemia nauplii, egg custard, and blood cockles), and parasitological and mycological studies of culture water and larvae in hatcheries. The samples were taken twice a week. Physical quality of water was checked twice a day, in morning and evening using portable hand-held water quality kit. For bacteriology study, the isolation of bacteria were done using TSA and TCBS agar and identification using commercial test kits, BD BBL Crystal™ and API 20E™. Methylene blue stain was used for routine parasitology and mycology studies. The water quality in all tanks were within the recommended range, where the temperature was between 28-31°C for larvae and 27-32°C for brood stock. The pH for brood stock culture was between 7–7.2 while for the larvae it was between 7.2–7.4. The salinity ranged between 12–16 ppt for larvae and 3–5 ppt for brood stock. Two main bacteria were isolated during this study, which were Aeromonas hydrophila type II and Bukholderia cepaciae. A. hydrophila type II, B. cepaciae and Enterobacter spp. were normal flora of water and also opportunistic bacteria but could cause septicaemic diseases. No parasite or fungus was detected. In conclusion, early mortality in M. rosenbergii prawn larvae was closely related to hatchery management i.e. the use of green water system, feed preparation and sanitary procedures

The application of electro-coagulation in biodiesel wastewater treatment

A large quantity of oily wastewater is generated by biodiesel refineries which results in terrible environmental pollution and resource utilization problems. This wastewater must be treated before being released into the environment due to it normally rich in biological oxygen demand (BOD) and chemical oxygen demand (COD) which usually have damaging and harmful effects on plants, sea, river as well as surface and groundwater sources. Conventional biodiesel wastewater treatment methods such as gravity separation and skimming, air flotation, coagulation, de-emulsification and flocculation, posses several disadvantages including high operation cost, low efficiency, corrosion and recontamination problems. Indeed, most of these conventional methods unable to remove the micron or submicron sized oil droplets efficiently. Currently, new processes for efficient and adequate treatment of various industrial wastewaters with relatively low operating costs have been developed to meet the strict environmental regulations. At this point, the electrocoagulation process has attracted a great deal of attention in treating industrial wastewaters because of its versatility and environmental compatibility. Therefore, in this chapter, the advatages and application of electro-coagulation techniques were reviewed and discussed

Preliminary assessment of Ram's horn snail (Gyraulus sp.) as live feed for common carp (Cyprinus carpio)

Gyraulus sp. or Ram’s horn snail (Figure 1) is a freshwater, air breathing snail of the family Planorbidae. It has a characteristic flat spiral shape shell in the shape of a Ram’s horn. Snails from this family are hermaphrodites. They can be found abundantly in freshwater bodies such as lakes and ponds in Malaysia. Their diet consists of mainly of algae and dead plant matter. Many larger organisms such as water birds, turtles and freshwater fishes consume these snails as part of their normal diet. Currently, no studies have been conducted on the viability of this snail species as fish feed. Thus this study was conducted firstly to determine the protein content of the Ram’s horn snail and its effects on the growth rate of common carp, an omnivorous freshwater fish and as an alternative source of fresh live-feed for freshwater fish aquaculture industry. Concurrently, the study also screen for the presence of parasites, fungus and pathogenic bacteria that may be carried by the snail. Three groups of ten carps, Cyprinus carpio fish were allocated into individual tanks supplied with individual filteration and aeration systems. Two groups of carps were fed Ram’s horn snail at 5% body weight while the control group was fed commercial fish pellets at 5% body weight thrice daily. The growth rate of the fish was scored by measuring the weekly increment in length and body weights. A sample of whole snail was also sent for crude protein proximate analysis. Concurrently, the microbial burden of the snail was screened using the standard aerobic plate count (SPC) method from the snail’s intestines. The bacteria colonies attained were sub-cultured and the species identified by biochemical tests. Samples of the snail were screened for parasites and fungus using squash smears preparations. This study showed that fish fed with Ram’s horn snail had a daily growth rate of 0.8 to 1% body weight per day, while fish fed with commercial fish food had a daily growth rate of 1.6% body weight (Figure 2). The normal daily growth rate of common carp according to the FAO is 1.6% body weight. Proximate analysis done on the whole snail revealed a crude protein content of 11.3%. Bacteriology results revealed a bacterial content of 2.2 CFU × 106/g of intestinal tissues. Aeromonas hydrophila type II and Pseudomonas oryzihabitans were predominantly isolated from the snail’s intestines. A.hydrophila is an opportunistic pathogen in fish that can cause ‘motile aeromonas septicaemia’ disease. However A. hydrophila and P. oryzihabitans are two of the most common bacteria in freshwater habitats throughout the world. Moreover, the experimental infective dose of A. hydrophila, type II was 1 × 106 CFU/mL. No parasite or fungus was detected in the snail’s body squash smears. No mortality associated with the feeding was recorded. In conclusion, the Ram’s horn snail is cheap to culture, easily available, well-accepted by fish, had reasonably good protein content and could be incorporated into the diet of common carp (cyprinids) and other species of cultured food and ornamental fishes without detrimental effect

Stress level in red tilapia hybrid (OreochromisSp.) treated with chemical and nonchemical anesthesia

Red Tilapia hybrid, Oreochromis sp., is one of the most reared food fish due to its good growth and high tolerence to adverse condition. Aquatic animals can be easily stressed by physical disturbances such as handling and anesthesia. Stress is the response in the form of a suite of neuroendocrine events that is activated by a perceived threat and whose purpose is to protect any physiological imbalance or to reestablish homeostasis. In aquaculture, anesthetic protocol can be commonly divided into two, i.e. chemical and non-chemical anesthesia, which are the MS-222 and hypothermia, respectively. In this study, Red Tilapia hybrid (n=45) were exposed to chemical and non-chemical anesthesia using MS-222 and hypothermic method, respectively. Their stress level was determined by measuring the plasma glucose level and hematology. Non-chemical method which is the hypothermia showed the highest glucose level followed by MS-222 and control groups. This showed that the non-chemical anesthesia was more stressful than the chemical anesthesia. However, there were no significant observation in haematology

One health in animal production: biosafety and biosecurity issues

World human population is expected to increase tremendously in forthcoming years. More human meaning more food needed. In addition, concurrent natural disasters such as floods, earthquake, war and crop failure due to environmental changes have put intense extra strains on demand for food. Animals and plants (land and aquatic origin) are the main supplier of energy and protein rich food. At present most of the animal food source are coming from domesticated animal, capture fisheries and aquaculture. Increased demand for animal meat and its products has led to the use of chemicals to hasten animal and plant growth, uncontrolled used of antimicrobials leading to rise of antibiotics resistant bacteria, intensifying of culture, especially monospecies culture which lead to disease to be readily spread and animal to be in close contact with man. While overzealous in capturing wild animals as exotic food and exhibits, and overfishing, led to transfer of exotic diseases from wild animals to man and extinction of many species. Inevitably also, to cater for the increase demand for seeds for culture and with easy and safe transportation, animal culturists has purposely transferred many species of animals across the continents in matter of hours. This increase in live animal traffic led yet again to biosecurity threat to receiving countries. Laws and regulations are prepared. But are they enough to maintain biosafety and biosecurity? Are we able to interpret the statistics and plan appropriate and better strategies? One health-One medicine-One World concept was introduced to integrate human, animal and ecosystem disciplines in a synchronize and collaborative approaches to resolve issues concerning human, animal and ecosystem health. Multifacet effects of one’s health either in human, animal and ecosystem will certainly effect one another in terms of food biosafety and biosecurity of production. Thus multi directional and interdisciplinary methodologies are needed in lieu to single spear method

Histological assessment of blood cockles (Anadara granosa) using different stains and fixatives.

Blood cockles (Anadara granosa) or locally known as ‘kerang’ are mollusc belonging to Bivalvia class. It is an important fisheries commodity and a delicacy in Malaysia. In RMK-9, one of the objectives of Malaysia’s aquaculture industries is to maximize the production of bivalves up to 130,000 MT per year, which includes cockles, green mussels, clams and oysters. Cockles become one of the important bivalves cultured in Malaysia as it had very good market value in Malaysia, Thailand and Singapore. According to Phillips and Muttarasin (1985), 80% of the cockles marketed in Thailand were imported from Malaysia. In spite of the diversity and its economic importance, the knowledge of bivalves specifically cockle medicine should be developed in order to meet the requirement of diagnostic work which is necessary in determining the cause of diseases infecting the animals. Up to date, there is no comprehensive information of the histology of cockles. Thus, this study was undertaken to provide basic histological descriptions of normal and anomalies microstructures in Anadara granosa by using different fixatures and stains. Forty live cockles were divided into two groups; one group was fixed with Davidson solution and the other fixed with 10% buffered formalin. The tissues were then processed for 18 hours, and later embedded with paraffin wax and sectioned at 5 µm thickness. There were stained with four stains namely, Haematoxylin and Eosin, Masson’s Trichome, Periodic Acid Schiff’s and Van Gieson’s stains. The sections were evaluated under a computer attached-compound light microscope at low and high magnification. The organs were assessed for microscopic structures staining affinity (Cox et al., 2006). Haematoxylin and Eosin stain was considered the better stain to be used for mantle, foot complex and haemocytes tissues. Combination of Haematoxylin and Eosin and Periodic Acid Schiff’s stains can be used to stain digestive system and palp. Gills could be stained with Masson’s Trichome and Van Gieson’s, while for gonads Masson’s Trichome would be the preferred choice. Van Gieson’s on the other hand, was the choice for foreign body detection. Gills of cockles could be divided into three parts: frontal, intermediate and abfrontal zone similar to Mytella falcate (David et al., 2008). The intermediate zone have a homogenous densely stained structure embedded in the filament which highly indicative that it provided supportive frame to the frontal zone

Tissue culture isolation, electron microscopic characterization and PCR-detection of a betanodavirus isolated from diseased Asian sea bass.

A viral agent was successfully isolated from Asian sea bass juveniles (Letes calcarifer) exhibiting clinical signs of viral nervous necrosis (VNN) in southern Malaysia on February 2008. Eyes and brains of diseased fish were pooled, extracted and filtered. The filtrates were inoculated on SSN-1 cells and incubated at 25°C. Cytopathic effect (CPE) recognized as rounded cells continued to aggregate and the vacuolation. Electron micrographs of the infected SSN-1 cells revealed icosahedral nucleocapsid virions with 22-28 nm in diameter. Viral harvest was resistant to chloroform and iodine treatments, which indicated that it was naked and contained RNA genome. Identification using reverse transcription polymerase chain reaction (RT-PCR) and sequence analysis of PCR product was conducted and gave a single PCR product at 460 bp in agarose gel, followed by nested PCR with specific primers for PCR products at 220 bp. Partial nucleotide sequence of the nervous necrosis virus coat protein gene showed 94.0-96.1% homology to the nucleotide sequences of coat protein gene from nervous necrosis virus isolated from other countries in the Southeast Asia

Histopathological changes of skin and gills of catfish (Clarias gariepinus) exposed to organophosphate toxicant

The usage of pesticide in the industry will help increase crop yield and meet consumer demand for Malaysia, a country that is undergoing economic revolution through the agricultural. However, the excessive and inappropriateness use of pesticides can affect the environment, water quality and public health. In this experiment, 40 adult African catfish (Clarias gariepinus) were divided and exposed into sublethal concentrations of Malathion (0.8, 1.6 and 3.0 ppm) and a control group for 48 hours. At the end of the study, all fish were sacrificed before skin and gill samples were collected to determine the effect of malathion on the gills and skin. The histopathological lesions in the gills and skin were scored and statistically analysed to compare between group. Histological examination of the gill showed epithelial lifting at secondary lamella, hyperplasia of primary epithelium, fusion of secondary lamella and infiltration of inflammatory cells with peeling and rupture of epithelial cells of secondary lamellae. In the skin, the changes observed were hyperplasia of mucus cell and shrinkage of the club cells after the exposure to malathion. There were significant differences between treatment and control groups. Thus, malathion causes concentration-independent and nonspecific lesions in the gills and skin of African catfish