Effects of roof insulation on the thermal conditions of a medium scaled tropical enclosed giant freshwater prawn (Macrobrachium rosenbergii) hatchery

This study was conducted to evaluate the effects of roof thermal insulation on the indoor thermal environment of an existing enclosed giant freshwater prawn hatchery in relation to human thermal comfort and the thermal requirement for optimal larval growth. A typical medium scaled enclosed hatchery in Ipoh, Malaysia was chosen for this study. Thermal performances of five thermal insulation materials installed on the roof of the building were studied using Integrated Environmental Solutions (IES) Virtual Environment software. Results showed no significant differences for indoor air temperatures reduction among the insulation materials. However, the installation of roof insulation gave a cooler indoor thermal environment and provided a suitable water temperature/ improved water thermal condition for the prawn larviculture. The study also suggested the aluminium foil was the best insulation for the partially transparent roof of the building

Feeding & nutritional requirements of young fish

The world annual total fisheries catch continues to decline, a trend observed since 1996. If timely remedial actions are not taken, scientists believe that the ocean seafood stocks and supply will soon be depleted. Aquaculture seems to be the only realistic solution to reduce the pressure on capture fisheries and to supply most of the seafood in the future. Currently, almost half of the world's total fisheries production is contributed by the aquaculture industry,On average, a Malaysian consumes almost 60 kg of seafood per year. Malaysia is tied with Korea for T" place among the top world seafood consumers. Although Malaysia has achieved ≥100% self sufficiency level (SSL) in seafood supply, more than 80% of its seafood comes from capture fisheries. Meanwhile, Malaysia's aquaculture industry has been experiencing an average annual growth rate of23.4% over the last ten years, although most of the growth has been contributed by seaweed production rather than food fish. Thus, in terms of ensuring its food security, Malaysia must increase its cultured food fish production to meet at least 50% of its seafood SSL. The main bottleneck in the expansion and growth of food fish aquaculture in Malaysia is the insufficient seed or fry supply. Despite breakthroughs in the induced breeding of many fish species, use of the right feed remains a major obstacle during the larviculture stage as larval feeding behavior, mouth gape, digestive capacity and nutrient requirements vary with species, growth stage or age. For successful larval and postlarval rearing, each fish species must be given a specific diet comprising the right particle size and nutrients at the correct feeding ration and frequency at each growth stage

Nutritional enhancement of total lipid, n-3 and n-6 fatty acids in Artemia urmiana nauplii by enriching with ICES/30/4

Artemia urmiana nauplii were enriched with three different concentrations (100, 200 and 300 ppm) of commercial emulsion, ICES/30/4 during two periods (12 and 24 h) to evaluate the enhancement of its Highly Unsaturated Fatty Acids (HUFAs). This source was selected because of its high concentration of the longest chain HUFA's in the n-3 and n-6 series. When 24-h-old Artemia nauplii were enriched with 100 ppm concentration of ICES30/4 during 12 h enriching period, the docosahexanoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA) contents of the nauplii increased to 0.77, 1.22 and 0.34 and when enriched with 300 ppm during 24 h increased to 5.99, 4.97 and 0.73 mg g(-1) dry weight, respectively. DHA, EPA and ARA in control nauplii were 0.00, 0.82 and 0.61 mg g(-1) dryweight, respectively. Total lipid increased from 16.79% in control group to 20.87% in the treatment ICES30/4 24-300. The results suggest that high amount of emulsion and prolong the enriching period are effective in enriching Artemia nauplii in both DHA and EPA increasingly (p < 0.05) but in other fatty acids, there are differences only among period treatments (p < 0.05) and concentration are not any increasing effective. There are only differences among concentration treatments in total lipid p < 0.05) and enriching period do not show any differences

Optimum dietary protein requirement of Malaysian mahseer (Tor tambroides) fingerlings.

The optimum dietary protein requirement of the Malaysian mahseer (Tor tambroides) fingerlings was determined in this study. In this completely randomized designed experiment, formulated diets of five levels of dietary protein (30, 35, 40, 45 and 50%) were tested on the T. tambroides fingerlings (initial body weight of 5.85 +/- 0.40 g), reared in aquarium fitted with a biofiltering system. The fingerlings were fed twice daily at 5% of biomass. The fingerling body weight and total length was taken at every two weeks. Mortality was recorded daily. The dietary protein had significant effects on the body weight gain and Specific Growth Rate (SGR) of the fingerlings. The body weight gain and SGR of fingerlings fed with the diet with the dietary protein level of 40% was significantly higher (p<0.05) than that of 30, 35 and 50%. The feed conversion ratio of the 40% dietary protein was the significantly lowest at 2.19 +/- 0.163. The dietary protein level of 40% was the most optimum for T. tambroides fingerlings

Heavy metals (Cd, Cu, Ph and Zn) concentrations in telescopium telescopium from Dumai Coastal Waters, Indonesia

Concentrations of cadmium, copper, lead and zinc in the marine gastropod, Telescopium telescopium, were determined to provide background information on heavy metal levels in the Straits of Malacca in the Indonesian side. Samples ofT. telescopium were collected from intertidal Dumai coastal waters at four stations inJuly 2004. The results of the present study showed that metal concentrations in the soft tissue ofT. telescopium varied at different sampling stations: 0.33 - 0.69 )1g/g; 9.38 - 52.29 )1g/g; 1.73 - 10. 78 )1g/g; 14.69 - 69.87 )1g/g dry weight far cadmium, copper, lead and zinc, respectively. Samples from Sungai Dumai station accumulated mare heavy metals when compared to other stations. Smaller T. telescopium accumulate mare metals than larger ones. Negative carrelations between metal concentrations and size (length and weight) were obseroed (except Cd and Cu in samples from Sungai Mesjid) with some variation in the carrelation coefficients which indicated metal regulation lJy the T. telescopiurn. Sungai Dumai showed the highest Metal Pollution Index (MPl) of 12.57 and Tomlinson Pollution Load Index (PLI) of 34.35 with Lubuk Gaung showing the lowest with 3.26 and 8.89, respectively. In general, the MPI and PU values indicate that metal pollution in Dumai coastal waters is not a serious threat yet and no drastic rectification measures are needed. However, as one of the most developing regions in Sumatera, further studies are necessary to assess temparal variation in metal accumulation and concentration for this species and other possible indicator organisms as well as in sediment from the surrounding areas in order to gain a better understanding of pollution status in Dumai coastal waters

Evaluation of blowfly (Chrysomya megacephala) maggot meal as an effective, sustainable replacement for fishmeal in the diet of farmed juvenile red tilapia (Oreochromis sp.)

Fishmeal is the primary protein source used in farmed fish feed. However, the high price of fishmeal is a major contributor to high production costs in the aquaculture industry. Insect-based diets have been recognized as cheaper alternatives to fishmeal, but the nutritional quality and impact on fish growth remains in question. In this study, the potential of blowfly Chrysomya megacephala maggot meal as an alternative dietary protein source to fishmeal for red tilapia (Oreochromis sp.) was evaluated. The protein and amino acid composition of the meal was assessed and a feeding trial was conducted to determine the effects of varying percentages of fishmeal replacement on growth, feed efficiency, and survival of juvenile tilapia. Blowfly maggot meal contained all the essential amino acids needed by juvenile tilapia for normal growth, and equivalent protein content to fishmeal. Furthermore, diets with increased replacement of fishmeal by blowfly maggot meal improved the growth, feed efficiency and survival of juvenile tilapia with the total replacement diet giving the optimal results. Based on these results we suggest that blowfly maggot meal is an effective and sustainable protein source to replace fishmeal in the diet of farmed tilapia