Development of low-cost feeds for fattening of native catfish, Clarias macrocephalus

Growth performance, survival, and feed efficiency in native catfish, Clarias microcephalus, fed chicken entrails, earthworm meal, and low-value fish meal were investigated. A simple cost-benefit analysis using this fattening approach was done to evaluate the profitability of using these low-value feed ingredients. Nine 30L aquaria were stocked with native catfish juveniles (about 20 cm in total length and 80 g in weight) at a density of 1 fish per liter. The catfish were fed cooked chicken entrails (Treatment 1), earthworm meal (Treatment 2) and low-value fish meal (Treatment 3) at 3% body weight for 60 days. At the end of the feeding trial, the growth of the fish fed various low-cost feeds was not significantly different. Survival was better in fish fed cooked chicken entrails than with either earthworm meal or low-value fish meal. Feed conversion efficiency (FCE) was relatively similar among the three types of feeds. A simple cost-benefit analysis using these low-cost feeds showed a return of investment (ROI) of 68-79%, indicating the feasibility of using these feeds for fattening of catfish. These preliminary results show that utilizing low value feed ingredients or food wastes as sources of feeds during fattening of native catfish are feasible. In addition, food wastage is reduced by bringing these food sources back to the food chain during aquaculture operations

The effect of diets suplemented with different natural foods on growth and feed utilization of snakehead (Channa striata)

A sixty day feeding study was performed to determine the impact of diets enriched with various natural foods on growth and feed utilization of snakehead. Six hundred fingerlings weighing 4.33 to 4.71 g each fish were randomly stocked into 4 triplicate plastic tanks (1x1x1.5 m), fifty fish each tank. Four isoproteic and isoenergetic diets containing 45% crude protein and 18.5 KJ g-1gross energy were formulated. Control diet was formulated using fishmeal, salted trash fish, tofu by-product meal, rice bran, vitamin and mineral mix. The three diets were prepared with the same ingredients as control diet but were supplemented with 15% fresh earth worm (W), golden snail (S) and frog (F), respectively. The diets were fed to the fish at 6% body weight, twice daily for 60 days. Feeding the fish with diet F and S did not influence fish survival rate, weight gain, specific growth rate, feed intake, feed efficiency ratio, protein efficiency ratio and protein retention. However, feeding the fish with diet W increased weight gain and feed intake. It can be concluded that the supplementation of snakehead diet with fresh worm can improve growth performance and feed intake by the fish

The salmon louse Lepeophtheirus salmonis (Copepoda: Caligidae) life cycle has only two chalimus stages

Each year the salmon louse (Lepeophtheirus salmonis Krøyer, 1838) causes multi-million dollar commercial losses to the salmon farming industry world-wide, and strict lice control regimes have been put in place to reduce the release of salmon louse larvae from aquaculture facilities into the environment. For half a century, the Lepeophtheirus life cycle has been regarded as the only copepod life cycle including 8 post-nauplius instars as confirmed in four different species, including L. salmonis. Here we prove that the accepted life cycle of the salmon louse is wrong. By observations of chalimus larvae molting in incubators and by morphometric cluster analysis, we show that there are only two chalimus instars: chalimus 1 (comprising the former chalimus I and II stages which are not separated by a molt) and chalimus 2 (the former chalimus III and IV stages which are not separated by a molt). Consequently the salmon louse life cycle has only six post-nauplius instars, as in other genera of caligid sea lice and copepods in general. These findings are of fundamental importance in experimental studies as well as for interpretation of salmon louse biology and for control and management of this economically important parasite.publishedVersio

Development of a simple, rapid, cost-effective diagnostic kit for WSSV

Abstract only.Shrimp aquaculture is one of the most important sources of income and livelihood in the Philippines. For the past two decades, the white spot syndrome virus (WSSV) has adversely affected the production of the Philippine shrimp industry resulting to losses in revenue. Shrimps infected by the virus experience up to 100% mortality, 3 to 10 days post-infection. One way of controlling the disease is early detection, which remains to be too complicated and inaccessible to shrimp farmers. Being a DNA virus, the first step to WSSV diagnosis is the isolation of high-quality DNA suitable for polymerase chain reaction (PCR) or loop-mediated isothermal amplification (LAMP). Using readily available and affordable reagents, a DNA extraction protocol has been especially developed for rapid WSSV-detection; DNA has been successfully extracted from the pleopods of shrimps and the results were comparable with that of commercially available kits from Promega and Zymoresearch. LAMP has been optimized for WSSV detection in the temperature range of 55°C to 68°C and was shown to be faster and ten times more sensitive than conventional PCR. This study together with a locally fabricated machine, offers a more convenient, practical and efficient way of detecting WSSV, with the advantage of using non-invasive means of obtaining shrimp tissue therefore not losing any shrimp meat in the process

Rapid Detection of the Philippine Isolate of Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) in Shrimp, Penaeus monodon Using Loop- Mediated Isothermal Amplification (LAMP)

Abstract: The aim of this study was to standardize a Loop-Mediated isothermal Amplification (LAMP) assay for the detection of the Philippine isolate of Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) in postlarvae of shrimp, Penaeus monodon. The assay was optimized at an incubation time of 1 h at 63 o C. The assay was highly specific for IHHNV and did not cross-react with other shrimp viruses including Hepatopancreatic Parvovirus (HPV), Monodon Baculovirus (MBV) and White Spot Syndrome Virus (WSSV). The limit of detection of the IHHNV using the LAMP assay was 10 pg of DNA/mL or 10 fg of the genomic DNA per LAMP reaction and was 10 times more sensitive than conventional PCR in detecting the viral pathogen from infected samples. These results demonstrated that LAMP is a simple and sensitive diagnostic technique that has potential application for routine detection of IHHNV infections in shrimp hatcheries in the Philippines