Effect of feeding frequency on growth, survival and feed utilization in fingerlings of Catla catla (Hamilton), Labeo rohita (Hamilton) and Cirrhinus mrigala (Hamilton) in outdoor rearing systems     

Gouranga Biswas  Joy Krushna Jena  Sarat Kumar Singh  & Hare Krushna Muduli 《Aquaculture Research》2006,37(5):510-514

Fingerling rearing of Indian major carps, Catla catla, Labeo rohita and Cirrhinus mrigala, were conducted in concrete tanks under a polyculture system at a density of 0.3 million fry ha^?1 to evaluate the effect of one, two or three feedings per day on growth, survival and feed utilization. Fry were fed with formulated supplementary diet at 10% of biomass per day during the first 15 days, followed by 8% in the next 15 days and 6% thereafter, for 60 days. Feeding of fish three times daily led to higher growth (103.9±8.5 mm/10.3±2.4 g) than those feeding twice (100.2±4.8 mm/9.9±1.5 g) or once (97.2±9.8 mm/9.4±2.1 g) daily, although the values were not significantly different (P>0.05). Survival rate ranging between 72.3% and 75.1% also did not vary significantly (P>0.05) among the treatments. However, higher feeding frequencies resulted in better feed utilization as evident from decreasing feed conversion ratio values. The present study suggested requirement of a higher feeding frequency for rohu compared with catla and mrigal.  相似文献   

Fishing and trade of devil rays (Mobula spp.) in the Bay of Bengal,Bangladesh: Insights from fishers’ knowledge     

Alifa Bintha Haque  Nidhi Gloria D'Costa  Mahi Washim  Amit Robert Baroi  Nazia Hossain  Mashrur Hafiz  Sumaiya Rahman  Karabi Farhana Biswas 《水产资源保护:海洋与淡水生态系统》2021,31(6):1392-1409

1. Devil rays (Mobula spp.) are globally threatened cartilaginous fishes that have attracted global conservation concern owing to their high extinction risk and lack of protection in many countries. Limited resources and data on threatened marine species, including devil rays, impede conservation actions, particularly in developing countries, many of which have high biodiversity.
2. Devil ray catch is a component of artisanal fisheries in Bangladesh, but data on their fisheries and trade are limited. To characterize devil ray fishing practices, fishers’ perception and trade, 230 fishers and traders were interviewed between 4 June 2018 and 22 June 2019, in four areas of south-east Bangladesh. Catch data were also opportunistically collected at landing sites.
3. Six devil ray species were documented, caught in an array of gill nets, set-bag nets and longlines. All interviewed fishers reported life-long devil ray bycatch in some numbers, and also noted a decline in catch over the last decade. Bottom trawling, increased bycatch levels, increased demand for devil ray products and, in some cases, ecosystem changes were identified by fishers as threats to devil ray populations.
4. Unregulated and undocumented trade and retained bycatch, especially by gill nets and set-bag nets, are fuelled by local consumption of devil ray meat and international trade in meat and gill rakers. Compliance with international trade control treaties for all Mobula spp. or the Bangladeshi law protecting Mobula mobular was low, with the majority of fishers (87%, n = 174) unaware of their existence.
5. To manage devil ray fisheries, and prevent possible population declines, we propose a combination of legally enforced gear modifications, and catch and trade control through community-owned implementation strategies. Additionally, we propose the simultaneous implementation of inclusive, community-based awareness and stewardship projects in conjunction with a coast-wide ray monitoring programme. Finally, we emphasize that more research and action rooted in a sustainable fishery model is urgently needed to protect Bangladeshi devil ray populations.

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Optimal Stocking Density with the Provision of Self‐feeders for Striped Knifejaw,Oplegnathus fasciatus (Temminck and Schlegel 1844)          下载免费PDF全文

Amal Biswas  Kenji Takii 《Journal of the World Aquaculture Society》2017,48(3):488-495

To determine the optimal stocking density, three densities of 5 (SD₅), 10 (SD₁₀), and 15 kg/m³ (SD₁₅) were used to culture striped knifejaw, Oplegnathus fasciatus, for 10 wk. A total of 10, 20, or 30 juveniles with mean weights of approximately 96 g were stocked into one of nine 300‐L tanks (with an initial water volume of 200 L) and fed with commercial feed via self‐feeders. The fish were sampled at 4 and 8 wk, and the stocking density was maintained by adjusting the water volume of the tanks. The final body weights in SD₁₀ and SD₁₅ were 183.8 and 178.9 g, respectively, which were significantly higher than 161.7 g in SD₅ (P< 0.05). However, there was no significant difference between the SD₁₀ and SD₁₅ (P > 0.05). A similar trend was observed in the specific growth rate among the treatments. Feed efficiency and the lipid retention efficiency were both significantly higher in SD₁₀ than that in SD₅. The plasma levels of cortisol, glucose, and total protein were similar among the treatments. These results clearly suggest that densities of 10 and 15 kg/m³ can be used to improve the growth performance of striped knifejaw, O. fasciatus, when fed with a self‐feeder.  相似文献   

Dietary medicinal herbs and enzyme treated fish meal improve stress resistances and growth performance at early juvenile stage of red sea bream Pagrus major          下载免费PDF全文

Osamu Takaoka  Seung‐Cheol Ji  Katsuya Ishimaru  Si‐Woo Lee  Gwan‐Sik Jeong  Amal Biswas  Kenji Takii 《Aquaculture Research》2016,47(2):390-397

Red sea bream Pagrus major (RSB) weighing 0.09 g were fed on test diets, composed of 65% fish meal supplemented with 0.49% Crataegi fructus (Cf) and a mixture of Massa medicata, Cf, Artemisia capillaries and Cnidium officinale (HM) or a control diet without herbs, in trial 1. After air exposure and anaesthesia treatment, higher stress tolerances were obtained in herbal groups than control group. Moreover, after challenge test with Vibrio anguillarum, mortalities of the herbal groups were lower than the control group. There was no significant difference in growth performance among the treatments. Feed efficiency (FE) of the test groups was 124–141%. In trial 2, RSB weighing 0.11 g were fed on diets composed of 35% fish meal and 30% enzyme treated fish meal (EFM) with the same herbal treatments as trial 1. The herbal groups revealed higher final body weight and specific growth rate (SGR) and lower daily feed intake than those of the control group. The FE of test groups was 172–203%. These results indicate that the dietary herbs supplementation acts not only as recovery enhancer for some rearing stresses but also as growth enhancer, which is accelerated with dietary EFM in the early juvenile stage of red sea bream.  相似文献   

Dietary supplementation of L-tryptophan: Effect on growth and survival of Pabda,Ompok bimaculatus (Bloch) fry     

Pradyut Biswas  Priya Rawat  Arun Bhai Patel 《Journal Of Applied Aquaculture》2013,25(4):322-336

ABSTRACT

A 30-day experiment was conducted to assess the effect of tryptophan-supplemented diets on growth and survival of Pabda, Ompok bimaculatus fry. Fifty pabda fry (0.114 ± 0.02 g; 2.45 ± 0.13 cm) were stocked into each aerated aquarium following a completely randomized design consisting of four treatments with triplicate each. Four iso-proteinious purified diets were prepared with different levels of tryptophan—0%, 1%, 2%, and 3%—of the dry diet and were designated as Control, TRP1, TRP2, and TRP3 respectively. Fishes were fed with the experimental diet ad libitum four times a day. The results showed that fish fed with tryptophan-supplemented diets exhibited significantly (P < 0.05) lower cannibalism and higher survival than the control diet. Further, the tryptophan-supplemented groups showed a significantly lower coefficient of variation (%) and size heterogeneity (P < 0.05). However, the growth as measured by body weight gain, length increment, and specific growth rate of fry in tryptophan-supplemented groups was significantly lower than the control group (P < 0.05). Moreover, maximum survival (52.67 ± 1.76%) and minimum cannibalism (21.33 ± 5.70%) coupled with higher growth and performance index (0.38 ± 0.01) were recorded in the 2% tryptophan-supplemented group compared to other tryptophan-fed groups. Overall interpretation from the present study concludes that the dietary supplementation of 2% tryptophan is recommended for better survival of pabda fish, although growth was compromised.  相似文献   

Effects of stocking density and presence or absence of soil base on growth,weight variation,survival and body composition of pearlspot,Etroplus suratensis (Bloch) fingerlings     

Gouranga Biswas  Tapas K Ghoshal  Maruthamuthu Natarajan  Arunachalam R Thirunavukkarasu  Jitendra K Sundaray  Muniyandi Kailasam  Debasis De  Krishna Sukumaran  Prem Kumar  Alphis G Ponniah 《Aquaculture Research》2013,44(8):1266-1276

With the objective to develop an indoor tank seed rearing system for pearlspot (Etroplus suratensis), effects of three stocking densities in presence or absence of soil base were evaluated on growth, weight variation, survival and body composition in a 60‐day trial. The experiment had a 3 × 2 factorial design with three levels of stocking density (150, 300 and 450 fish m^?3) and two levels of soil base (with and without) in triplicates. Pearlspot fry (27.5 ± 0.5 mm/0.39 ± 0.02 g) were stocked in experimental tanks (Length×Breadth×Height: 0.65 × 0.50 × 0.48 m) and fed with a formulated diet containing 29.85% crude protein. Increasing the stocking density from 150 to 450 fish m^?3 significantly decreased the growth (average body weight and total length), daily weight gain, specific growth rate and survival (P < 0.001) and increased the feed conversion ratio (P < 0.01). Significantly lower growth and survival were observed in treatment having soil base compared with that of without soil base (P < 0.001). However, coefficients of variation at harvest weight and body composition of fingerlings were independent to stocking density and presence or absence of soil base (P > 0.05). A significant positive interaction effect of stocking density and presence or absence of soil base was observed on average body weight (P < 0.05) and survival (P < 0.001) of pearlspot fingerlings. This study suggests that stocking density of 150 fish m^?3 without soil base in tanks would be appropriate for raising pearlspot fingerlings in brackishwater indoor seed rearing system.  相似文献   

Role of catecholamines and nitric oxide on pigment displacement of the chromatophores of freshwater snakehead teleost fish,Channa punctatus     

Saikat P. Biswas  Arun G. Jadhao  Nikhil V. Palande 《Fish physiology and biochemistry》2014,40(2):457-467

We are reporting for the first time that the catecholamines (adrenaline and noradrenaline) inhibit the effect of nitric oxide (NO) on melanosome dispersion in freshly isolated scales of the freshwater snakehead fish, Channa punctatus. We studied the effect of NO and catecholamines on the pigment displacement by observing the changes in the melanophore index. The scales when treated with solution containing NO donor sodium nitroprusside (SNP) showed dispersion of melanosomes, whereas NO synthase blocker N-omega-Nitro-l-arginine suppresses this action of SNP. Treatment with adrenaline and noradrenaline on the isolated scales caused aggregation of melanosomes. Scales treated with solution containing catecholamines and SNP resulted in aggregation of melanosomes suggesting that catecholamines mask the effect of SNP. These results suggest that the catecholamines are inhibiting the effect of NO and causing the aggregation of the melanosomes may be via surface receptors.  相似文献   

Effect of harvest date,drying, short-term storage and freezing after chilling on the germination of rowan seeds     

Farhana Afroze  Conor O'Reilly 《Scandinavian Journal of Forest Research》2016,31(4):339-346

The effects of seed pretreatment and harvest date on the germination of European rowan (Sorbus aucuparia L) seeds were examined. In one experiment, seeds were subjected to drying, storage, soaking, warm and chilling treatments after harvesting in mid- and late August. In another experiment, fully imbibed (FI) seeds were given warm treatment for six weeks and then various durations of chilling (4?±?1°C) for up to 24 weeks. Thereafter, the seeds were adjusted to target moisture content of 35% and 30% or remained in the FI state and were then subjected to either subsequent chilling or freezing (?3°C) for up to 32 weeks. The treated seeds were allowed to germinate at a constant 15°C with 8 hours of lighting per day. Treatment effects were generally consistent for each harvest date. Seeds did not germinate unless they were chilled and germination rates were low unless the seeds were soaked. Warm treatment applied before chilling appeared to induce dormancy. The effect of storage varied with harvest date and storage treatment, with germination being highest for seeds harvested in late August. Mild freezing of ≥16 weeks duration following 16–24 weeks initial chilling resulted in >80% germination, more than could be achieved using chilling alone.  相似文献   

Horvath-Kawazoe Model Based Evaluation of Pore Volume of Nanoporous Clinoptilolite     

K. Ramesh  K. Sammi Reddy  I. Rashmi  A. K. Biswas  K. R. Islam 《Communications in Soil Science and Plant Analysis》2016,47(13-14):1622-1629

A liquid nitrogen (N₂) adsorption isotherm was employed to understand the differential pore-volume distribution (PVD) patterns of commercial Clinoptilolite (zeolite) fractions (<125 µ (Z8; fine or micro), 125–250 µ (Z9; medium) and >250 µ (Z10; coarse). The differential PVD of the fractions were calculated from the original Horvath-Kawazoe (HK) model. A full spectrum of pore volume distribution has exhibited “curves symmetric around the origin” irrespective of the Clinoptilolite fractions. However, the fractions exhibited a definite pattern of curves for each of the micro, meso and macropore region. Although, ultramicropores couldn’t be seen in any of the fractions, super micropore region exhibited uni-modal distribution curve with mono-disperse pores for all the fractions with varying pore volumes, while multimodal and tri-modal for meso and macro pore region respectively. Irrespective of the pore region, fine fraction (Z8) exhibited higher differential pore volume than other fractions. It was evident from the differential PVD that particle size has a major role in determining the textural properties of Clinoptilolite fractions.  相似文献   

Improving the impact resistance of p-aramid fabrics by sequential impregnation with shear thickening fluid     

Abhijit Majumdar  Bhupendra S. Butola  Ankita Srivastava  Debarati Bhattacharjee  Ipsita Biswas  Animesh Laha  Sanchi Arora  Aranya Ghosh 《Fibers and Polymers》2016,17(2):199-204

A simple and effective method for impregnation of p-aramid (Kevlar^®) fabric with shear thickening fluid (STF) has been developed in this research. Kevlar fabric was impregnated with STF in two stages in a sequential manner. Three levels of pressure (0.5, 1 and 2 bar) were used in each stage of impregnation. It was observed that impact energy absorption by Kevlar fabrics, impregnated with STF in this newly developed method, increased significantly as compared to untreated Kevlar fabrics and Kevlar fabrics treated with STF in conventional way (single step impregnation). Better results were obtained when the first impregnation pressure was higher than that of the second, even with same combination of pressures. Such fabrics also showed a much higher STF add-on (~18 %) as compared to that of fabrics impregnated in single step (3-5 %). Low velocity ballistic tests also confirmed the advantages of the new method as sequentially impregnated fabric showed 124.8 % and 24.4 % increase in impact energy absorption compared to untreated and STF impregnated Kevlar fabrics in single step, respectively.  相似文献