Effects of iso-nitrogenous fertilizers as nutrient sources on carp polyculture in Bangladesh

A 120-day long experiment was conducted to find out the effects of urea plus triple super phosphate (UT), cow manure (CM) and poultry manure (PM) having iso-nil:rogen content on pond productivity and fish yield. Three fertilizer treatments, with three replicates each, were randomly assigned into nine earthen ponds of 100 m2 each. The stocking fish were rohu (Labeo ruhita), catla ( Catla catla) and mrigal ( Cirrhinus mrigala) in each treatment pond at the rate of 10000/ha with the ratio of 1:1:1. All ponds were fertilized fortnightly at the rate of 125 kg/ha urea plus 100 kg TSP/ha, 7000 kg/ha cow manure and 3500 kg/ha poultry manure for the treatment of UT, CM and PM, respectively, having an iso-nitrogen content of 56 kg in each. Though the physicochemical water quality parameters were more or less similar in all treatment ponds, the chlorophyll-a content and abundance of total plankton were significantly higher (P < 0.05) in the ponds receiving the treatment PM. Final growth as well as per unit production of fish was significantly higher (pcarp polyculture system under prevailing conditions.

Growth and yield of GIFT (Oreochromis niloticus) and Thai silver barb (Barbodes gonionotus Bleeker) in rice fields and their effects on the yield of rice

(GIFT) (Oreochromis niloticus) and Silver barb (Barbodes gonionotus) in rice fields and their effects on the yield of rice was carried out in nine experimental rice plots. Three treatments viz., treatment-1 with 0. niloticus (T1), treatment-2 with B. gonionotus (T2) and treatment- 3 was kept as control (T3, without fish) were used in this study. Fertilizers such as, Urea (178 kg ha-1), T.S.P (125 kg ha-1) and M.P. (67 kg ha-1) were applied in each treatment. The fishes were stocked @ 6250 ha·1 and the experiment was continued for a period of 107 days. The values of water quality parameters such as, water temperature, dissolved oxygen, pH and chlorophyll-a were found within suitable level. Between the two species, higher specific growth rate was recorded in 0. niloticus than that of B. gonionotus. But B. gonionotus showed much higher survival (72%) than that of 0. niloticus (35%). Similar to survival, higher production (244 kg ha-1) and income (Tk. 6399 ha-1) were recorded in B. gonionotus than those of 0. niloticus (142.8 kg ha'1 and Tk. 2137 ha-1). Significant differences (p

Bacterial load in pond water and different organs of a Indian major carp Cirrhinus mrigala Ham.

During the study period (August, 1993 to July,l994) the mean bacterial load in surface water was found to vary from 1.39 xl05 (July'94) to 3.llxl07CFU/ml (September'93), while that of botrom water ranged from l.Olxl06 (May'94) to 5.90xl07CFU/ml (October '93). The mean total number of bacterial load in body slime, liver and kidney was found to vary from 0.58xl03 (July'94) to 2.37xl07CFU/g (March'94),from 0.22xl03(July'94)to 9.64xl06 CFU/g (March'94) from O.l5xl03 (July'94) to 9.36xl06 CFU/g (March'94), respectively. Bacterial load in slime was significantly correlated with bacterial load in liver, bacterial load in slime was significantly correlated with bacterial load in kidney and bacterial load in liver was significantly correlated with bacterial load in kidney.

Sperm cryopreservation of Indian major carp, Labeo rohita: cryodiluents, sperm: cryodiluent dilution ratio and cryoprotectan t concentration

Cryogenic preservation trials of spermatozoa of Labeo rohita were carried out. Twenty four cryodiluents (extender + cryoprotectant), with the combination of six extenders such as egg-yolk citrate, urea-egg-yolk, 0.9% NaCl, Kurokura-2, Ma and Mb and four cryoprotectants viz. DMSO, glycerol, methanol and ethanol, were used to screen out the suitable cryodiluents. Sperm was preserved in 0.25ml plastic straw in programmable freezer. Two step freezing method was followed. Sperm preserved with egg-yolk citrate and urea-egg-yolk containing 10% DMSO showed best post-thaw motility (80%) followed by 0.9% NaCl (60%) and Kurokura-2(30%) solutions. Sperm with the extenders M" and Mb clotted at the time of equilibration and also after few days of preservation. Egg-yolk citrate mixed with ethanol and methanol also showed good percentage of motility (80%) but egg-yolk citrate with glycerol showed less sperm motility (>60%). To determine suitable dilution ratio of milt and cryodiluent two best extender eggyolk citrate and urea-egg-yolk with four cryoprotectants such as DMSO, glycerol, methanol and ethanol at different ratio viz 1:2,1:4,1:7,1:10,1:15 and 1:20 were used. Highest post-thaw motility (>80%) was observed when milt was preserved with egg-yolk citrate containing 10% DMSO at 1:2, 1:4, 1:7 and 1:10 dilutions. Meanwhile using glycerol as cryoprotectants provided less post thaw motility at lower dilution ratio but with the increase of its dilution showed good sperm motility compared with other cryoprotectants. Finally, evaluation on the effect of cryoprotectant concentration on post-thaw sperm motility was conducted. Egg-yolk citrate and four cryoprotectant i.e. DMSO, glycerol, methanol and ethanol with six different concentrations namely 5%,7%, 10%, 15%, 20% and 30%.were evaluated. Among the cryoprotectants DMSO, methanol and ethanol showed highest post-thaw motility (about 80%) at 7% and 10% concentrations. Although glycerol was not suitable at low concentration but its 20% and 30% concentration levels provided best post-thaw motility. No post-thaw motility was obtained with DMSO at 30% concentration. The overall analysis on cryoprotectant concentration indicated that below 5% and above 20% cryoprotectant concentrations could not be suitable for effective cryopreservation of spermatozoa.

Size related feeding patterns and electivity indices of silver barb (Barbodes gonionotus Bleeker) from a pond, Bangladesh

The feeding patterns with respect to quality and quantity of food of silver barb, Barbodes gonionotus varied with their size and development. The results indicated that the fish in the size group I (7-25 mm TL) were fairly omnivore with particular liking for rotifera, green and blue-green algae while the size group II (25.1-44 mm TL) and III (44.1-55 mm TL) were omnivore with higher tendency of feeding on debris, aquatic plants, green algae, blue-green algae and rotifera. However, the fish of the size group IV (55.1-80 mm TL) were found to be herbivore with feeding preference for aquatic plants, green and blue-green algae. In all the size groups, debris was the most dominant food item. Feeding preference of the fish showed clear ontogenetic shift. The electivity indices revealed that the fish were selective feeder.

Performance of Amblypharyngodon mola with Barbodes gonionotus, Cyprinus carpio and Macrobrachium rosenbergii in rice-fish culture system

An experiment was conducted to assess the performance of mola (Amblyphmyngodon mola) in rice fish culture system with freshwater prawn Macrobrachium rosenbergii), Thai silver barb (Bm·bades ganianotus) and common carp (Cyprinus cmpia) for a period of 4 months at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, Bangladesh. Four treatments viz., treatment-I (T1) with A. mala and M. rosenbergii; treatmen t-II (T2) with A. mala, M. rosenbergii and B. gonianatus ; treatmentIII (T3) with A. mala, 1Vf. rosenbergii and C. cmpia, and treatment- IV (T4) as control (without fish) were used in triplicate. All treatments were equally fertilized with urea (200 kg/ha), TSP (150 kg/ha) and MP (75 kg/ha). The mean values of water quality parameters viz., temperature, dissolved oxygen, pH, nitrate-nitrogen showed a very small variations among different treatments, but phosphate-phosphorus and chlorophyll-a were relatively higher in T4 without fish (i.e., control). The fish production of 480.5 kg/ha in T3 was significantly higher than that of 355.6 kg/ha T2 and 223.8 kg/ha in T 1• The values of soil organic matter, total-nitrogen, phosphorus and potassium at harvest were significantly (P<0.05) higher in the treatments with fish than without fish, but pH did not show any significant differences. The yield of rice grain and straw was also obtained significantly (P<0.05) higher in the treatments with fish. The increase in grain was higher over the control by 11.81%, 9.41% and 14.76% and that in straw was by 9.83%, 4.77% and 13.29% in Tl> T2, and T3 respectively.

Effect of carp PG doses on induced breeding of Shing, Heteropneustes fossilis (Bloch)

Five hormone doses viz. 25, 50, 75, 100, and 125 mg of carp PG/kg of body weight of the recipient fish were tested and they were designated as T1 T2, T3, T4, and T5 respectively. Significantly higher fertilization (98%) and hatching rates (38%) were obtained from T3 (75 mg of carp PG extract/kg body weight). While T4 (100 mg of carp PG extract/kg body weight) and T5 (125 mg of carp PG extract/kg body weight) gave the highest (90%) ovulation rate. In June and July the highest fertilization rate of 96 and 96.4% respectively and hatching rate 42.5 and 48.7% respectively were obtained. In over all consideration carp PG extract at a dose of 75 mg/kg body weight appears to be the suitable dose for induced breeding of H. fossilis and June and July are the suitable time for its induced breeding.

Effect of feeding frequency on the growth of common carp (Cyprinus carpio L.) fry

A laboratory-feeding trail was conducted for 45 days with fry of common carp Cyprinus carpio L. (0.45±0.03g) in aquaria in a static indoor fish rearing system. The fry were fed on a pelleted diet containing 33% crude protein having fishmeal as major protein source. The fish fry in five treatments A, B, C, D, and E, each with two replicates were fed on 5% daily ration divided into different feeding frequencies of 2, 3, 4, 5 and 6 times a day respectively in order to observe the growth performance. Each replicate contained 15 fry having total initial weight of 6.87±0.31g. At the end of the feeding trial, significantly different and higher (p<0.05) growth response was observed in treatment C having a feeding frequencies of 4 times a day. Significantly the highest and the lowest percent growth of 334.30 and 218.91% were observed in fish fed on the diet (Treatment C) with 4 times and (Treatment A) 2 times feeding frequencies per day, respectively. Food conversion ratio (FCR) of 1.78 was significantly higher (pcarpio was the best at 4 times feeding in a day using 33% dietary protein containing fish meal as major protein source.

Culture feasibility of silver barb (Barbodes gonionotus Bleeker) and GIFT with shrimp (Penaeus monodon Feb.) in brackishwater pond

An experiment was conducted to understand the culture feasibility of sliver barb (Barbodes gonionotus) and GIFT (Genetically Improved Farmed Tilapia) with shrimp (Penaeus monodon). There were three different treatment (T) combinations: (T1) shrimp (10,000/ha) and silver barb (10,000/ha), (T2) shrimp (10,000/ha) and GIFT (10,000/ha), and (T3) shrimp (10,000/ha). Shrimp, after 120 days of culture, attained an average weight of 23.77g in T1, followed by T3 (23.70g). The highest average weight was recorded in T2 (24.93g). The specific growth rate (SGR) of shrimp was 6.9%, 6.94% and 6.9% for T1 T2 and T3, respectively. The SGR for the B. gonionotus and GIFT was 2.56% and 4.26%, respectively. The final weight of silver barb was 69.75g and that of GIFT was 161.83g. Survival of shrimp was higher (65.50%) in T2, followed by T3 (59.97%) and T1 (57.03%). Survival rate of silver barb (58.10%) was lower compared to that of GIFT (78.43%). Sporadic and scanty mortality of silver barb with a symptom of blind-red-protruded eye, swollen belly and body lesion was observed. Production of shrimp was higher of 284.05 kg/ha in monoculture, followed 162.47 kg/ha in concurrent culture with silver barb and 136.77 kg/ha culture with GIFT. In spite of similar stocking density of B. gonionotus and GIFT in T1 and T2, respectively, the production of GIFT was higher (1272.95 kg/ha) than that of silver barb ( 402.72kg/ha). Survival, final weight and production rates of shrimp among the treatments were found insignificant while total production of shrimp/fish was found to vary significantly (P

Performance of genetically improved farmed tilapia (GIFT) under mono and mixed cui ture with silver barb (Barbodes gonionotus) in south-west Bangladesh

A participatory on-farm trial was carried out to evaluate the production performance of GIFT (genetically improved farmed tilapia) strain of Oreochmis sp., either alone or with silver barb (Barbodes gonionotus), in six rain-fed freshwater ponds of coastal area. There vvere two treatments; (i) GIFT alone at a stocking density of 24,700/ha (T1) and (ii) 1:1 combination of GIFT and silver barb (T1). Each of the treatments had three replications. A significantly (psilver barb. In the 1:1 combination treatment, the production of GIFT (2036.06 kg/ha) was also higher than that of silver barb (1444.32 kg/ha). The results reveal that GIFT monoculture can performe better in rain-fed seasonal freshwater ponds of southwest coastal areas.

Development of canned products from Indian major carp, catla (Catla catla)

Pieces of catla fish (Catla catla, a major carp of lndian subcontinent) of length 10 to 11 cm and thickness 1.0 to 1.5cm were precooked by two methods; steam precooking and frying. The precooked pieces were packed_in No.1 tall can (30lx411) with various hot filling media like oil, brine, tomato sauce and curry. Cans were seamed by a hand seamer and retorted at 117.2° C (12 psi) for 90 minutes. All the canned products had satisfactory cut-out, biochemical and organoleptic characteristics. Steam precooked canned products had moisture content of 65.6 to 74%, protein content of 20.8 to 22%, fat content of 1.1 to 6.6% and ash content of 2.1 to 2.5%; whereas fried canned products had moisture content of 65.4 to 68.2%, protein content of 21.3 to 22%, fat content of 7 to 10.2% and ash content of 2.1 to 2.7% on wet wt. basis. Salt content in steam precooked and fried canned products varied from 1.2 to 1.9% and 2.0 to 2.5% respectively. All the canned products were organoleptically good. However, degree of preference varied for different products. Canned fried catla in curry was the best product among all types of packs. Among the precooking methods, frying was more efficient than steam precooking in controlling the amount of exudate to a desirable limit in canned products. However, crispness, the characteristic quality for a fried fish, was lost during retorting. There was no change in quality characteristics during a storage period of 3 months at ambient temperature (32±2°C).

Effects of iso-nitrogenous and iso-phosphorus fertilizers as nutrient sources on carp polyculture in Bangladesh

A 120 day long experiment was conducted to find out the effects of cow manure with urea and triple super phosphate (CUT), poultry manure with urea and triple super phosphate (PUT) and cow manure with poultry manure (CP) having similar quantities of nitrogen and phosphorus on pond productivity and fish yield. The stocking fish were rohu (Labeo rohita), catla ( Catla catla) and mrigal ( Cirrhinus mrigala) in each treatment pond at the rate of 10000/ha. All ponds were fertilized fortnightly at the rate of 4000 kg/ha cow manure with 62 kg/ha urea and 65 kg/ha TSP, 2700 kg/ha poultry manure with 62 kg/ha urea and 16 kg/ha TSP, and 4000kg/ha cow manure with 2700 kg/ha poultry manure for the treatment CUT, PUT and CP respectively. Each treatment contained an iso-nitrogen and iso-phosphorus of 56 kg and 46 kg respectively. Though the physico-chemical parameters were more or less similar in all ponds, the chlorophyll-a content and abundance of total plankton were significantly higher (P< 0.05) in the ponds receiving the fertilizer treatment of PUT than those of other treatments. Final growth as well as per unit production of fish of treatment PUT (1773 kg/ha) was significantly higher (P< 0.05) than that of treatment CP (1528 kg/ha) followed by that of treatment CUT (1336 kg/ha). The over all results showed that poultry manure with urea and triple super phosphate proved to be superior to cow manure with urea and triple super phosphate, and poultry manure with cow manure, even when nitrogen and phosphorus content was similar, in carp polyculture system under prevailing conditions.

Effect of stocking density on the production of common carp (Cyprinus carpio Lin.) in cages at Kaptai lake, Bangladesh

Growth, survival and food conversion ratio (FCR) of Cyprinus carpio in cages at different stocking density were studied in Kaptai lake. Fingerlings of common carp (12.47 ± 4.29 g) were stocked at 25/m2 , 50/m2 and 75/m2 each with replication in six floating net cages each of Sm x Sm x 4m and reared for 240 days. The growth rate was inversely related to the stocking density with the mean weights of 325.5 ± 11.74 g, 268.99± 8.44 g and 167.0 ± 11.66 g at low, medium and high densities, respectively. At harvest, standing crop biomass averaged 7 .82, 12.83 and 11.58 kg with the survival of 98.9%, 97.6% and 94.4% and food conversion ratios of 4.51, 3.82 and 4.21 for the above three densities, respectively. Weight gain and production at density 25 fish/m 2 were significantly different (p< 0.01) from other two densities. Water quality was not affected in the cages having different stocking densities.

An observation of performances in carp-prawn polyculture in respect of fingerlings size and water area

Performances of fingerling size and water area was studied. Seven species of fish included 25% of Hypophthalmichthys molitrix, 15% of Gada catla, 20% of Labeo rohita, 10% of Cirrhinus mrigala, 10% of Ctenophyringodon idella and 20% of Macrobrachium rosenbergii were stocked at the rate of 8,000 individual/ha along Barbodes gonionoms at 6.0g weight size with a stocking density of 2,000 indl./ ha. Survival of all species was in the range of 39.9 to 96.3% except M. rosenbergii The highest survival was obtained from L. rohita (96.3%) followed by C mrigala (96.0 %)., B. gonionotus (92.3%), C idella (90.6%), H. molitrix (84.0%), C cada (81.7%) respectively. While the survival of M. rosenbergiiwas 13.1%. The highest production of 4912 kg/ha/yr was obtained from the bigger ponds (0.4 ha) stocked with 20-32g size of fingerlings, while lowest production (3123 kg/ha/yr) from small pond (0.1 ha) stocked with 3-10 g fingerlings. Economic analysis shows the highest net profit in bigger ponds stocked with bigger fish seed.

Influence of formulated diets with varying protein levels on growth and ammonia excretion in the fry of Indian major carp, Cirrhina mrigala

The influence of formulated isocaloric diets of different protein levels (30, 35, 40, 45 and 50%) on the growth and ammonia excretion of the Indian major carp Cirrhina mrigala fry was studied for a rearing period of four weeks in the laboratory. Fishmeal, groundnut oilcake and silkworm pupae formed the source of protein in all the diets. As the dietary protein level increased from 30 to 40%, the growth and conversion efficiency increased significantly. Further increase in the protein level resulted in decrease in growth and conversion efficiency. Growth rate, weight gain (%), and gross and net feed conversion efficiencies were maximum at 40% dietary protein level. Ammonia excretion was directly proportional to the level of protein in the diet.