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In an aquatic habitat, zooplankton organisms are an extremely valuable resource for aquaculture purposes. Potential zooplankton species (Ceriodaphnia cornuta) have been further explored to evaluate their applicability to fed fish larvae in freshwater aquaculture. There is a need to find more options other than Artemia as live food options in freshwater hatcheries. Thus, this study was conducted by enriching Ceriodaphnia cornuta with rice bran (F1), soybean meal (F2), Chlorella vulgaris (F3), Spirulina sp. (F4), and unenriched C. cornuta (control). The result showed that the best growth performance of C. cornuta occurred when enriched with an F1 and F2 compared to F3 and F4. Meanwhile, the best initial age of reproduction occurred when enriched with F1+F3 and F3+F4 (3.67 ± 0.57 days and 3.66 ± 1.15 days). Besides, the gross and net reproduction rate of C. cornuta differed with other enrichments where F1+F3 has the highest rates (67.66 ± 1.52 offspring/female and 56.32 ± 0.90 offspring/female) compared to other treatments. The generation time for C. cornuta was shorter when enriched with F2 (7.11 ± 0.88 days) and longer when enriched with F1+F3 (11.23 ± 0.66 days). Other than that, the best growth performance of P. nasutus larvae occurs when fed with F1+F3. This study indicates that F1+F3 constitutes better sources of enrichment to improve the growth performance and life history of zooplankton. [ABSTRACT FROM AUTHOR]

Sperm activation and short-term storage have important implications in breeding programs. Although silver carp, Hypophthalmicthys molitrix, is an important aquaculture species in South Asia, information on sperm biology and storage is limited. The study aims to test the efficacy of NaCl solutions for activation and short-term storage of silver carp sperm. We found that the motility of silver carp sperm lasted for 45 sec after activation in distilled water. Sperm motility was higher within the first 10 sec of sperm activation, but sperm movement decreased with increasing activation time. When sperm was suspended a graded dilution of NaCl solutions (17 mM to 188 mM), sperm was immobilized at 154mM NaCl (287 mOsmol kg-1). The efficacy of sperm immobilizing solutions was validated during short-term storage at 4°C. A total of 7.1 ± 3.1% sperm was motile in 154 mM NaCl after 5 days of storage. Sperm motility lasted up to 2 days when sperm diluted in 103, 120, 171 and 188 mM NaCl solutions. The osmotic balance between seminal plasma and NaCl solution prepared at 154 mM prevented sperm activation and provided a suitable media for short-term storage. A 154 mM NaCl solution can be used for sperm collection and shortterm storage of silver carp sperm. [ABSTRACT FROM AUTHOR]

The increasing demand for fish produced by aquaculture industries has led to a high demand of live feeds, such as larvae. Further development of culture techniques is important to lower the production costs as well as to maximize the production of natural food for larval rearing. Moina macrocopa is a potential freshwater live feed that can replace Artemia, which originated from a saline environment. This study aimed to quantify the growth, survival, reproduction and overall life table parameters of M. macrocopa when using alternative diets of Chlorella sp., canola oil, or a mixed diet (Chlorella sp. mix with canola oil). M. macrocopa were cultured and enriched with the concentration of 2000 mg L-1 in triplicates for each dietary treatment. It was found that there was no difference in the specific growth rate of M. macrocopa (P= 0.05) between the alternative diets. The survival rate of M. macrocopa fed on the mixed diet (109.97 ± 32.85 %) was significantly higher (P< 0.05) than when fed with Chlorella sp. only or with canola oil only. The reproductive performance (e.g. average initial age of reproduction) did not differ from one dietary treatment to another (4.00 ± 0.00 days). For the generation time (54.42 ± 8.75 days) of M. macrocopa the mixed diet was the most favorable choice. The intrinsic rate (1.32 ± 0.14 ind L-1) was the highest with Chlorella sp. feed. The findings from this study can be used to improve the performance of freshwater fish production in hatcheries by utilizing the highly nutritious M. macrocopa larvae as live food. [ABSTRACT FROM AUTHOR]

Microalgae are considered as a promising resource for high-value substances. In this study, indigenous microalgae were isolated from various habitats and the optimum growth parameters for high lipid production were determined. Species identification was done by using universal 18S rDNA. Water quality was recorded during the sampling to determine the basic physical-chemical parameters for the growth studies. The screening for microalgae growth was done using plate reader with a focus on lipid-rich isolates by Nile Red fluorescent dye at different growth phase for 15 days. Results showed that ten microalgae species have been successfully cultivated from Terengganu water bodies. Analysis from genus Chlorella showed five isolates (TRG1-A01, TRG1-C01, TRG2-E01, TRG5-A01, and TRG3-B01) were clustered together, while two isolates (TRG2-A01, TRG3-A01) from the genus Nannochloropsis were N. oceania. Another two isolates (TRG1-D01, TRG1-E01) were closely clustered with Desmodesmus subspicatus while TRG4-C01 was clustered with Dicloster aquatus. The strain TRG2-A01 showed the highest fluorescent intensity indicating its potential to produce the highest intracellular lipid content. Thus from this study, we can identify which environmental conditions contribute to the most favourable conditions for algal growth to maximize lipid production which later could be used as live feeds in aquaculture industry. [ABSTRACT FROM AUTHOR]

The copepod Cyclopina kasignete is a potential live food in aquaculture and its fatty acid components and digestive enzymes were investigated. Three dry algal products (mixed algae, Melosira sp. and Nannochloropsis oculata) and two fresh microalgae ( Tisochrysis lutea and N. oculata) were fed to the copepod for 30 days. The essential fatty acids ( EFA) in copepods were altered by feeding different types of dry algae. The copepod fed dry Melosira sp. or fresh T. lutea contained higher eicosapentaenoic acid ( EPA), docosahexaenoic acid ( DHA) and arachidonic acid ( ARA), protease and trypsin than fed on other algae. The copepod contained a similar fatty acid profile and digestive enzymes by feeding either dry or fresh N. oculata. Between fresh algal species, the copepod fed T. lutea contained higher EPA, DHA and ARA than that fed fresh N. oculata. The amounts of EPA and DHA in copepods were more concentrated than those in the dietary algae, suggesting that the copepod has the ability to accumulate some EFA. This study indicates that dietary algae can modify the nutritional composition and in digestive enzymes copepods, which in turn may be able to transfer suitable nutrients and digestive enzymes to fish larvae in aquaculture. [ABSTRACT FROM AUTHOR]

In hatchery, an adequate supply of live food for first-feeding fish larvae is essential and nutritional quality of live food organisms can be improved through nutrient enrichment. The use of live food organisms, especially at first feeding, is a requisite for most marine fish larvae. In ocean, marine fish larvae primarily feed on copepods, but the production protocols of copepods as live food is underdeveloped in hatchery. As the food ingestion and the digestive system of copepods are different from other live food organisms (e.g. rotifers), the nutrition enrichment procedures with emulsion oil used in rotifers is not effective on copepods. This review focuses on alteration of nutrient composition of copepods through manipulation of copepod food before they are fed to fish larvae. Specifically, we discuss the relationship between the changes of fatty acid compositions in dietary algae and in copepods. The review links nutrient supply to copepods and the change of nutrition in copepods and suggests ways to improve copepod nutrition in hatcheries. [ABSTRACT FROM AUTHOR]