Viability of frozen algae used as food for larval penaeids

Freezing with added chemicals as flocculants and protectants was assessed as a means of preserving stock cultures of 4 algal species used for larval penaeid food Chaetoceros calcitrans, Skeletonema costatum, Tetraselmis chuii and Isochrysis galbana . The maximum storage effectability of the preservation techniques for each species was also determined.

Growth phases of cultured algae used as larval food

A study was undertaken to determine the onset and duration of the growth phases of cultured algae commonly used as larval food (Skeletonema costatum, Chaetoceros calcitrans, Tetraselmis chuii, Chlorella vulgaris, Isochrysis galbana) so as to predict the time of harvest at the desired stage to suit various needs and purposes.

Viability of frozen algae used as food for larval penaeids

Freezing with added chemicals as flocculants and protectants was assessed as a means of preserving stock cultures of 4 algal species used for larval penaeid food Chaetoceros calcitrans, Skeletonema costatum, Tetraselmis chuii and Isochrysis galbana. The maximum storage effectability of the preservation techniques for each species was also determined.

Quality assessment of traditional and solar tunnel dried SIS (Small Indigenous Fish Species) products

Studies were conducted to assessment the quality of traditional and solar tunnel dried SIS products. The moisture content of the solar products ranged from 14.38 to 18.48% with the lowest in batashi and the highest value in tengra. The moisture content of the traditional products was in the range of 23.26 to 26.42%. The range of protein contents on moisture free basis was from 67.57 to 71.90% in solar dried fishes with highest value obtained in dhela and lowest value in batashi. These values were more or less similar to those of traditional dried SIS products which were in the range of 68.02 to 73.54% on dry weight basis. Lipid contents of solar dried SIS varied from 14.10 to 16.26% and on moisture free basis the in the range of 11.73 to 21.98 with highest value found in tengra and lowest in puti. These values were more or less similar to those found for traditional dried products on dry weight basis and ranged from were 12.37 to 22.43%. Maximum reconstitution of solar dried products was obtained at 80°C in all samples and was in the range of 65.26 to 70.51% where the percentage of reconstitution increases with the increase of socking time and reach maximum at the end of up to 60 min. The TVB-N content of solar dried fish is low compared with traditional one ranging from 20.30 to 28.40mg/100g and peroxide value in the range of 12. 54 to 19.20meq./kg oil. The TVB-N of traditionally dried products were in the range of 32.50 to 45.45mg/100g and PO values of the traditionally dried products were in the range of 30.00 to 36.00meq./kg oil. The bacterial load of the solar dried products was in the range of 4.0x10 super(3)/g to 3.6x10 super(5)CFU/g and of the traditionally dried products ranged from 1.45x10 super(5) to 2.52x10 super(6) CFU/g.

Quality assessment of traditional, rotary and solar tunnel dried small indigenous fish species products

Studies on the quality assessments of three traditional, rotary and solar tunnel dried SIS products were conducted. Organoleptic quality of traditional dried SIS products available in the markets was poor compared to those produced in rotary and solar tunnel dryer. Reconstitution of samples were in the range of 54.26% to 75.24%, 69.37% to 83.73% and 55.08% to 80.24% when soaked at 80°C for traditional, rotary and solar tunnel dried products, respectively. The percentage of reconstitution increased with the increase of soaking time and the uptake of water was maximum after 60 min of soaking. The moisture contents of traditional, rotary and solar tunnel dried products were in the range of 26.02% to 27.33%, 16.23% to 22.84% and 13.71% to 19.30%, respectively. The protein contents were in the range of 60.78% to 72.59%, 62.17% to 76.27% and 61.11% to 76.00%, respectively; lipid contents were in the range of 12.26% to 22.60%, 14.00% to 24.71% and 13.92% to 22.39%, respectively and ash contents in the range of 15.11% to 16.59%, 8.32% to 13.51% and 8.71% to 16.45%, respectively on dry matter basis. The TVB-N content of rotary and solar tunnel dried products was low compared to traditional one ranging from 10.64 to 17.52 mg/100g and 14.34 to 15.68 mg/100g, respectively whereas the TVB-N content of traditional samples was in the range of 15.46 to 20.36 mg/100g. The bacterial load of traditional, rotary and solar tunnel dried products were in the range of 1.43x10 super(8) CFU/g to 2.89 x10 super(80 CFU/g, 1.91x10 super(8) CFU/g to 2.84x10 super(8) CFU/g and 1.95x10 super(8) CFU/g to 2.59x10 super(8) CFU/g, respectively. The results of the study indicated that dried fish products from rotary dryer and solar tunnel dryer were found to be of better quality in nutritional and food quality aspects than those of traditional dried products.

Polyculture of carp with small indigenous fish, bata, Labeo bata (Ham.) at different stocking densities

Small indigenous fish species (SIS) play very important role in the diet of the people of Bangladesh. Until recently, the possibilities of culture them in consideration with the Indian major carp yet to be explored. In view of the above, an experiment on the polyculture of carps with SIS, bata (Labeo bata) was carried out to evaluate their production performance in the on-farm condition during 15 March to 15 September 2003. Three different stocking densities of bata with carp species were given. After six months of rearing, the productions obtained were 2,466±98 kg/ha, 2,395 ±88 kg/ha and 2,074±94 kg/ha from treatments-1, 2 and 3, respectively. The highest production was obtained from treatment-1, when compared with treatments-1 and 2. The contribution of bata in terms of production was 10.31% in treatment-1, while it was 13.36% and 14.38% in treatments-2 and 3, respectively.

Production of quality dried small indigenous fish species products using low cost solar tunnel drier

A low cost solar drier was constructed using locally available materials. The size of the drier was 20x3.6x3 having drying capacity of 80 kg of SIS (w/w). Optimization of moisture content was observed for mola, dhela, chapila, chanda and puti at temperature ranges between 40-45°C and 50-55°C in solar tunnel drier. There was little or no change in moisture content at temperature below 40°C during the first 3 hours. Then the moisture content declined gradually with the increase of drying period. On the other hand, at temperature between 50-55°C, moisture content started to decline after 2 hours of drying. The moisture content of the sample reached at about 16% after 26 hours of sun drying at 40-45°C and 20 hours at 50-55°C. The optimum temperature for producing high quality dried products was 45-50°C in solar tunnel drier. The temperature and relative humidity outside and inside the dryers (with fish) at various locations were recorded from 8.00am to 4.00pm. The normal atmospheric ambient temperature was recorded in the range of 25-37°C from at 8:00am to 4:00pm. During the same period the atmospheric relative humidity recorded was in the range of 30-58%. On the other hand, the maximum temperature inside the dryers was recorded in the range of 28-65°C. The lowest temperature recorded was 28°C in the morning and at 13.00pm the highest temperature 65°C was recorded. The maximum relative humidity 58% found in the afternoon and minimum of 28% at noon. There was inverse relationship between temperature intensity of sunshine and humidity which decreased as sunshine increased. In total, it took around 26 hours of drying to reduce the moisture level to about 16%.