A Synopsis onFatty Acid Profiles and Growth of Stinging Catfish (Heteropneustes fossilis) Larvae Fed on Freshwater Rotifer (Brachionus calyciflorus) and Artemia as Live Starter foods

(Brachionus calyciflorus) (Heteropneustes fossilis) -

IntroductionStinging catfish (Heteropneustes fossilis) is one of the commercially farmed fish in Bangladesh and it has gained rapid popularity because of its fast growth and high yields. The species is important for its nutritional and medicinal value. However, the absence of a readily available starter feed in commercial hatcheries remains a major problem in its production. Fish larvae rely on the yolk sac for its nutritional requirements during early stages of growth. Then larvae require live foods such as Artemia nauplii, yeast, unicellular algae, rotifers, copepods, cladocerans as the most appropriate starter foods because the larvae have difficulty in assimilating dry prepared diets due to their incomplete development of the digestive system (Arimoro, 2006; Olurin et al. 2012). These live foods offer an appropriate size ingestible by a wide range of larval fish species and are rich carriers of digestive enzymes (Kolkvoski, 2001). Live foods also affect the fatty acid profile of larvae (Kainz, 2004; Das, 2006; Tocher, 2010). However, information on appropriate live foods for the larviculture of stinging catfish are scarcely available.

ObjectivesThe present research will be conducted with the following objectives- To investigate the growth performance of stinging catfish fed on freshwater rotifer (B. calyciflorus) and Artemia as live foods. To find out fatty acid profile of stinging catfish fed on freshwater rotifer (B. calyciflorus) and Artemia as live foods.

MethodologyStudy Area The Live Food Culture Laboratory of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) will be used for the culture of freshwater rotifer (B. calyciflorus). The wet laboratory of Department of Aquaculture of BSMRAU will be used for larval rearing of stinging catfish.

Culture of algae (Chlorella sp.)Chlorella sp. will be cultured to act as a source of food for B. calyciflorus. Twenty five liters size rectangular glass tanks will be required for this culture with continuous supply of aeration.

Acquisition of B. calyciflorusSeed of freshwter rotifers (B. calyciflorus) will be collected by selective netting with 200, 100 and 50 zooplankton nets from ponds of BSMRAU. B. calyciflorus will be kept on Chlorella as food.

Decapsulation of Artemia cysts Artemia cysts will be collected from a commercial source. Decapsulation of cysts will be done using standard method. Decapsulation consists of chemically removing, in a hypochlorite solution, the shell or chorion of the Artemia cysts and leaving only the embryo.

Experimental DesignThe experiment will be carried out under CRD with eight treatments each having three replications. Details are shown in the following table.Table: Experimental design of stinging catfish cultureTypes of Live FeedDoseTreatmentsReplicationDuration(Days)

Rotifer food200 rotifer/larvae/dayT1314

300 rotifer/larvae/dayT2

400 rotifer/larvae/dayT3

Artemia food*100 Artemia /larvae/dayT4

150 Artemia /larvae/dayT5

200 Artemia /larvae/dayT6

Rotifer+Artemia food(100 rotifer + 50 Artemia)/larvae/dayT7

(200 rotifer + 100 Artemia)/larvae/dayT8

*Decapsulated Artemia cysts.Rearing of stinging catfishLarvae of stinging catfish will be collected from a commercial hatchery. Larvae will be reared in 20 liters glass aquaria and feeding will be done according to treatments as shown in the table above. Each aquarium will be stocked with 400 larvae of uniform initial size. The rearing experiment will be conducted for 14 days.

SamplingAt the end of 14 days rearing period length, weight and survival of larvae will be recorded. Then larvae samples will be collected and preserved for proximate and fatty acid analysis.

Proximate composition and fatty acid profile of stinging catfishFor fatty acid profiles, at the end of 14 days, a sub sample of 30 larvae will be randomly collected from each of the experimental tanks of each treatment, dried with filter paper and wrapped in aluminum foil and preserved for fatty acid analysis. Fish larvae samples will be dried in a hot air oven at a constant temperature of 600 C. The dried samples will be used for estimation of fatty acids. Fatty acid profiles and proximate composition will be estimated following standard methods (AOAC, 1995).

ActivitiesMonths of the Year

Sep16Oct16Nov16Dec16Jan17Feb17Mar17Apr17May17Jun17Jul17Aug17

Overall planning

Culture of algae (Chlorella sp.)

Acquisition of B. calyciflorus

Rearing of stinging catfish

Sampling

Data analysis

Reporting

Time Frame: 1 Year (September 2016-August 2017)

Data analysisThe data obtained will be analyzed using one-way analysis of variance (ANOVA) and DMRT.

Socio-Economic Importance Stinging catfish in Bangladesh is a popular food fish item for its taste and medicinal values and has a high market value. In its larval stage, mortality due to lack of proper nutrition is a major problem. To avoid this problem, intensive care and live foods are required. This culture can make people socio economically beneficial because the sector will provide many job opportunities.

References

AOAC (Association of Official Analytical Chemists). 1995. Official Methods of Analysis, 16th ed. AOAC, Washington, DC.Arimoro F. 2006. Culture of the freshwater rotifer, Brachionuscalyciflorus, and its application in fish larviculture technology.African Journal of Biotechnology; 5(7):536-541.Das UN. 2006. Essential fatty acids - a review.CurrentPharmaceutical Biotechnology; 7:467-482.Kainz MJ, Arts MT, Mazumder A. 2004. Essential fatty acids in the planktonic food web and their ecological role forhigher trophic levels. Limnology and Oceanography; 49:1784-1793.Kolkvoski S. 2001. Digestive enzymes in fish larvae and juveniles: implications and application to formulated diets. Aquaculture; 200:181-201.Olurin KB, Lwuchukwu PO, Oladapo O. 2012. Laval rearing of African catfish, Clariasgariepinus fed decapsulatedArtemia, wild copepods or commercial starter diet. African Journal of Food Science and Technology; 3(8):182-185.Tocher DR. 2010. Fatty acid requirements in ontogeny of marine and freshwater fish, Aquaculture Research; 41:717-732.

Imran HossainResearcherMS StudentDepartment of AquacultureBangabandhu Sheikh MujiburRahman Agricultural University, Gazipurimran.nagar@outlook.com

Major Professor

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