Aqua drugs and chemicals used in aquaculture of Zakigonj upazilla, Sylhet

In order to investigate present status of aqua chemicals and drugs used in various aquaculture activities in Zakigonj upazilla, Sylhet. A survey was conducted, with carp polyculture, tilapia and catfish farmers, aqua-medicine sellers, representatives of pharmaceuticals companies, from July 2014 to November 2014. Each group consisted of 25 respondents. According to the survey the most common dose of lime used by the farmers during pond preparation (62.67%) and culture period (53%) is 0.5-1 kg/40m 2 . Urea and TSP used by the farmers mostly during culture period with most common dose of 100-150g/40m 2 (37.3%) and 50-100 g/40m 2 (68%) respectively. Various categories of aqua drugs and chemicals were identified that were used by fish farmers for different purposes such as water quality management, disinfectants, improve dissolve oxygen level, disease treatment, antibiotics and growth promoter. Many pharmaceutical companies were found to provide these aqua drugs and chemicals with different trade names to fulfill the farmers demand. For pond and water quality management lime, urea and TSP are mostly used. Bleaching powder, Timsen, EDTA, Polgard, Virex, Aquakleen, Germnill, Pond safe were widely used as disinfectant. Health management and disease treatment were the major activities where farmers were seen to use a lot of chemicals. A range of chemicals including antibiotics were found available in market and being used in the aquaculture sector. Commonly found traditional chemicals in heath management included Potassium permanganate, Lime, Salt, Virex, Timsen, Aquakleen, Germnil, Pond Safe, Deletrix, Spa, Albez, Ablez were used regularly for disease treatment. Mostly used antibiotics are Renamycin, Oxysentin 20% Chlorsteclin Oxy-D Vet, Aquamycin, Orgamycin 15 %, Orgacycline-15% etc. Major active ingredients of these antibiotics were oxytetracycline, chlorotetracycline, amoxicillin, doxycycline etc. There are approximately fifty two pharmaceutical companies have been recorded to market around 300 products. Most of the products have been marketed from different countries like USA, Thailand, Malaysia, Belgium and China etc. The study also indicated some problems associated with the use of such chemicals due to lack of knowledge of farmers about the use of chemicals, appropriate dose, method of application and their indiscriminate use of chemicals. The study also highlighted the names and approximate price of aquaculture chemicals available with the chemicals sellers in Zakigonj, Sylhet.


Introduction
Aquaculture is the fastest growing food production sector in the world which plays a significant role in the economy in term of food, nutrition, income, employment and foreign exchange earnings (Subasinghe et al., 2002).According to the latest available statistics collected globally by FAO, world aquaculture production was 90.4 million tonnes by weight and US$144.4 billion by value in 2012, including 66.6 million tonnes of food fish and 23.8 million tonnes of aquatic algae (FAO, 2014).Use of aqua-medicines in aquaculture systems for various purposes is widely recognized.They are essential components in pond construction, health management, soil and water management, enhancement of natural aquatic productivity, transportation of live organism, feed formulation, manipulation and enhancement of reproduction, growth promotion and processing value enhancement of final product (Alderman et al., 1994, GESAMP, 1997).There are several traditional chemicals and drugs were used in aquaculture for health management.These included sodium chloride, formalin, malachite green, methylene blue, potassium permanganate, glutaraldehyde and trifluralin (Plumb;1992, Philllips;1996;Hasan and Ahmed, 2002;Brown and Brooks 2002;DOF;2002).Other popular traditional aqua-medicines included Zeolite, EDTA, gypsum, lime, alum were used for the purpose of pond soil and water quality management.These are widely used to neutralize acidity, increase total alkalinity, increase hardness in the soil and water of grow out pond, reduce turbidity in ponds, Chalets divalent and trivalent metal cations etc. Potasium permanganate (KMnO 4 ,) was one of the most widely used aqua-medicines in fish health management.It is a strong oxidizing agent approved for the purpose to treat ponds.It is good for treating external protozoa and bacterial infections (Plumb. 1992, Karim andStellwagen. 1998;BFRI, 1999).Zakigonj is an upazilla of Sylhet District in Sylhet Division, Bangladesh.This Upazilla is one of the prominent areas for fish culture in Sylhet Division.Aquaculture in this area is expanding and using more drugs and chemicals in aqua-health management are increasing.Also, pharmaceutical companies and chemical sellers are influencing fish farmers to buy their products.Most of the farmers do not know the appropriate dosages, method of application.Farmers were also not seen too aware about the mode of action of particular chemical.As a consequence, during disease treatment first they try with one chemical and if it does not work, they try for other one.They used doses of particular chemical on either from their own experiences, or from the instruction of the packet, if` there is any and from the suggestion of chemical sellers.Indiscriminate use of drugs and chemicals has harmful effect on ecosystem and human health.Many chemicals may persist for many months in aquatic system, retaining their biocidal properties.Some antibacterial, notably oxytetracycline, oxolinic acid and flumequine, can be found in sediments at least six months (Weston,I996).Antibiotics used in aquaculture involve the development and transfer of drug resistance to pathogenic bacteria from farmed animals to humans.The prevalence of antimicrobial resistance is increasing worldwide and this growing problem is often attributed to the widespread use of antibiotics for clinical purposes in human medicine and by the agriculture industry (lnglis, 1996;Bronzwaer et al., 2002).Transferable antibiotic resistance can also originate in human pathogens.Genetic investigations of drug resistance fish pathogens revealed that known antibiotic resistant genes from human bacterial pathogen is can be responsible for antibiotic resistance in fish bacterial pathogens (Weston,l996).Bangladesh Fisheries Research Institute (BFRI) had initiated a project on drugs and chemicals used in aquaculture.They surveyed on drugs chemicals used in aquaculture with coastal and freshwater environment.They made a list of drugs and chemicals used in aquaculture concentrated some places of the country.However, many places of the country are untouched under this project.Therefore Zakigonj upazilla is one of them.There is a lack of information regarding the present status and consequences of aqua-medicines using in aquaculture activities in Zakigonj upazilla.The study on drugs and chemicals use in aquaculture in Zakigong upazilla needs to be investigated.

Materials and Methods
The present investigation was based on field survey where primary data were collected from farmers, chemical sellers and representative of different pharmaceuticals companies.

Study area
The study area was selected depended on the objectives of the study.Zakigonj upazilla (Figure 1) situated in the north-east region of Bangladesh was selected for the present study.

Preparation of the survey schedule and duration of study
According to the objectives of the study, a survey schedule (for 75 farm owner, 25 shopkeepers and marketing representatives of different pharmaceutical companies) was prepared to collect the expected data.At first a set of questionnaire was prepared and pre-tested to verify the relevance of the questions and the nature of the sample producers.After pre-testing and necessary adjustment, a final set of questionnaire was developed.The questionnaire covered mainly farmer's profile, culture details, type of chemicals used with dose and price.The survey was carried out five months from July 2014 to November 2014.

Target group
Since aquaculture activities in Zakigonj area quite diversified, data were collected from different target group to have an overall picture of the drugs and chemicals used in aquaculture in this area (Table 1).Data were collected from 75 pond owners randomly covering the selected study areas.For each category of farmers, five unions were selected depending on the intensity of fish farming for specific target groups.Then five farmers were selected randomly from each union.

Data collection method
Data were collected through questionnaire interview.The questionnaire was composed of both closed and open form of question.A set of preliminary questionnaire was prepared.Major topic of questionnaire were the name of chemicals, active ingredients purpose of use, method of application and doses duration, source, effects on environment, impact on health and productivity.For the interview, simple random sampling method was followed.

Analysis of data
The collected data were scrutinized and summarized carefully before the actual tabulation.Some of the data were collected into local units and those data were converted into international units.After data entry, the data were analyzed with Microsoft Excel.

Use of fish poison
About 72% farmers did not use any poison in their aquaculture activities.Only rotenone is found to use by the farmer as fish poison in nursery and culture pond for removing predatory, wild and unwanted fish from pond.Most of the farmers did not use any chemical while about 28% farmers use rotenone (Table 2 and Table 3).
A dose of 0.5-1 kg/40m 2 was also used by about 39% of the farmers during culture period.However, the higher dose of >1.6 kg was not used by the farmers during culture period but only 6.67% farmers used this dose in pond preparation.Chinabut and Lilley (1992) stated that quick lime and slaked lime both have a very high p H and in addition to increased alkalinity, can have a sterilizing effect against disease.Chowdhury et al. (2003) reported that lime and salt treatment of 250 kg/ha respectively were found to be the most effective to suppress the ulcer disease through pond treatment.Sultana (2004) also found similar results about lime use in Mymensingh area.Brown and Brooks (2002) also found in a survey that 40% of farmers in Bangladesh use lime for disease treatment.Lilley et al. (1997) reported the success in pond treatment by using agricultural lime at the amount of 150-600 kg/ha in 1.0 m.

Use of urea
A dose 100-150g per 40m 2 was used by most of the farmers.About 37.3% farmers use this dose during pond preparation.Most of the farmers (58.7%) do not prefer to use urea during culture period.The overall average dose of <100g per 40m 2 and 150-200g/40m 2 were used by 8% and 9.3% farmers respectively during culture period.Most of the catfish farmers (72%) did not used urea during culture period, 56% catfish farmer also did   Faruk et al. (2005) observed that commonly used chemicals in aquaculture are lime, salt, urea, TSP etc. Sultana ( 2004) also found similar results about lime use in Mymensingh area.

Triple super phosphate (TSP)
TSP is an important chemical used by the farmers to increase natural food production in pond.Most of the farmers used 50-100 g/40m 2 of TSP.The dose was applied by about 58.7% farmers during pond preparation and 68% farmers during culture period.A dose of <50g per 40m 2 was also used by about 20% farmers during pond preparation and 21.3% farmers during culture period.The highest dose >100g/40m 2 of TSP was used by 10.7% farmers during culture period while during culture period this dose was used by only 2.7% farmers.Faruk et al. (2005) observed that commonly used chemicals in aquaculture are lime, salt, urea, TSP etc. Sultana ( 2004) also found similar results about lime use in Mymensingh area.Brown and Brooks (2002) found that in a survey in Bangladesh about 52% farmers used potassium permanganate, while 40% used lime, 11% used salt as a disease treatment, A few farmers used other treatments such as disinfectants (Savlon and Dettol).Banana leaves, fertilizer, alum and water exchange.

Chemicals used in fish health management 3.3.1. Chemicals used as disinfectant in the study area
Disinfectants are widely used throughout the world in many spheres of aquaculture.The greatest quantities are used in intensive culture, particularly in fish and shrimp hatcheries and grow-out facilities, they are used in site and equipment preparation, to maintain hygiene throughout the production cycle and in some cases, to treat disease.(2000) observed that traditional disinfectants were Lime, Teaseed Cake, Fonnalin, Benzalkonium Chloride, Malachite Green and Hypochlorite.According to the information of leaflets provided by the Eon Animal Health Products Ltd, Timsen was also used as preventive measures for some bacterial, fungal and viral infections.According sales representative of Eon Animal Health Products Ltd, Efinol uses as stress resistant and Formalin to control protozoan diseases.Ali (2008) observed that Timsen was effective to prevent some bacterial and fungal infections Herwig (1979) mentioned that Formalin was active against a wide range of organisms, such as fungi, bacteria and ectoparasite.Lime was also used as disinfectant in both the study areas.Apud (1984) observed that farmers used Formalin as disinfectant and to control protozoan diseases and Lime as disinfectant.

Chemicals used to improve dissolved oxygen level in the study area
Several chemicals with very similar names were seen readily available in the chemical shops of the study are used for increase dissolved oxygen in fish pond.Oxidizing agent, hydrogen peroxide is the major active ingredients of such chemical.Farmers of the investigated areas used several chemicals with very similar names to increase dissolve oxygen in fish ponds like Oxyflow, Oxymax, Oxy Plus, Bio Care, Bio-Ox, Oxy-Gold and Oxy•A.Rahman (2011) observed that aqua drugs like Oxy-Gold, Oxy Life, Bio Care, Oxy Plus, Pure Oxy, Oxymax and Oxyflow were used to increase dissolve oxygen.Oxydizing agent, Hydrogen Peroxide was the major active ingredients of such chemicals According to local agents of Novartis Pharmaceuticals Ltd. and Eon Animal Health Products Ltd., Oxyflow and Oxymax are used to remove hardness and poisonous gases.Ali (2008) mentioned that Oxyflow and Oxymax were used to remove hardness and poisonous gases.

Chemicals used for disease treatment in study area
Farmers used several chemicals for treating a variety of fish diseases with different dosage.Mostly traditional chemicals were available in the shops for treatment of fish disease.Potash, Lime, Salt, Virex, Timsen, Aquakleen, Germnil, Pond Safe, Deletrix, Spa, Albez, Ablez were used regularly for disease treatment (Table 5).

255/250g
Fish disease treatments form the major areas where farmers use ample amount of traditional chemicals.
According to the farmers of Zakigonj upazilla, chemicals such as Potassium Permanganate, Lime, Formalin, Salt, Bleaching Powder and Timsen were commonly used in aquaculture.Some previous studies also revealed that chemicals used in fish disease treatment included Potassium Permanganate, Lime, Formalin, Salt, Methylene Blue, Malachite Green, Melathion, Bleaching Powder and Timsen in aquaculture of Bangladesh (Phillips, l996, Brown and Brooks, 2002;DoF, 2002;Faruk et. al., 2005).Ali (2008) and Rahman (20ll) found several aqua drugs like Lime, Salt, Potassium Permanganate, Sumithion, Melathion, Formalin and Bleaching Powder were used as disease treatment.According to the farmers of the study area, treatment of diseases in aquaculture had a great value when chemicals used properly but could cause great threads for aquatic organisms if not properly applied Moreover for the success of aquaculture, chemicals must be judiciously and responsibly used.Smith (2002) also contributed that it is important to apply drugs appropriately against disease and proper application methods should apply for aqua-health management.

Antibiotics used for disease treatment in study area
In the present investigation about 8 branded antibiotics with different trade name were seen in the market as well as used by the fish farmers in the study area which are shown in Table 6.The active ingredients of such antibiotics are mainly oxytetracyclin, chlorotetracycline amoxicillin etc.According to the information leaflet of above antibiotics, all of those antibiotics are effective against bacterial disease.Some of above antibiotics like oxysentin 20%, orgamycin 15% and orgacycline 15% is also effective against EUS.Chlorsteclin and fish cure plays vital role in growth promotion as well as effective against some of disease like dropsy, tail and fin rot, gill rot of fish, etc.

Chemicals used for growth promoter in study area
Several chemicals were found in the chemical shops used as growth promoter as well as for increasing production.Aqua boost contains ß-glucan, immunostimulant, which enhance non-specific immunity in fish.A list of growth promoters is shown in Table 7.
All of the growth promoters play a vital role for rapid growth of fish.Some of these chemicals like aqua boost, fish vita plus, Aqua savor, Eon fish grower, Aqua gel, Panvit aqua, Charger gel, Vitamin F aqua, Aci mix super fish, etc. also improve disease preventing ability of fish.Megavit aqua also increase hatching rate and Aquamin helpful in developing bone of fishes.Aqua savor and Grow fast help in recovering in from malnutrition as well as improve physical condition of fishes.Aqua drugs of different companies found in the chemical shops of both the study areas as growth promotors were Megavit Aqua, Aqua Bost, Aqua Savor, Fibosol, Aqua Grow•P, Vitamix F Aqua, AQ Grow•G, Aquamin, ACmix Super-Fish and Aquamin Powder.The active ingredients of the mentioned products are Vitamin, Mineral, Amino Acid, Organic Acid, B-Glucan, Binder, Aloe Vera and Multivitamin.Ali (2008) observed Aqua drugs like Megavit Aqua, Aqua Bost, Orgavit Aqua, Vitamin Premix, Aqua Savor, Grow Fast, Diginex Aqua, Fibosol, Aqua Grow-P, Vitamix F Aqua, Cevit Vet, Diamond Fish, AQ Grow-G, Nature Aqua GP, ACmix Super-Fish and Aquamin Powder with the active ingredients included Vitamin, Mineral, Amino Acid, Organic Acid, B-Glucan, Binder, Aloe Vera and Multivitamin were used as growth promotor.From the research finding of Rahman (2011), it was observed that aqua drugs used as growth promotor were Charger Gel, Aqua Boost, Bio-Grow and Grow Fast.All the growth promotors played a vital role for rapid growth of fishes.According to chemical sellers of both the study areas, Aqua Boost and AC Mix Super-Fish also used to prevent diseases in fish.Moreover Aqua Savor and Aqua Grow-P were used against malnutrition as well as to improve health of fish.Faruk et al. (2008) observed that Aqua Boost and AC Mix Super-Fish also had disease preventing ability in fishes.The authors farther mentioned that growth promotors like Vitamins, Minerals and Phospholipids enhanced in growth and survival of cultured fishes.

Chemicals used as immunity increaser and stress reducer in study area
Several aqua-medicines were found in the aqua-medicine shops that were reported to be used as immunity increaser.The available immunity increaser were Ossi-C, Vitex-C, Charger gel, Biomin Pondlife, Profs, Aqua photo, Novio plus, Uni sense, Osmosaline, Aquaclear-S etc.The active ingredients of such medicines were mainly vitamin-C, Ca, P, Amino nitrogen, betain, glucan, polyssceharides, beta-glucans, oxolinic acid bitaglucan, Vit-D3, herbs, polyssccharix, oligossccliarix.The price was found to be quite affordable by the commercial aqua farmers.

List of aqua medicine marketing companies in Bangladesh
Commercial aquaculture has been significantly going through a silent revolution in Bangladesh for last few years.Fish farmers are getting habituated to modern aquaculture technology and systems day by day.As the culture system is developing to a high density aquaculture from extensive culture system so that the associated risks during culture have been increasing simultaneously in the culture ponds.At present there are approximately around 52 national, multinational and local companies involved in production, import and marketing of aqua medicines throughout Bangladesh.The list of these aqua medicines marketing companies in Bangladesh are as follows (Table 10).

No. of Products of Different Pharmaceuticals companies
In the present study, about 52 companies were found either producing or marketing products targeting aquaculture.ACI Animal Health Ltd., Organic Pharmaceuticals Ltd., Renata Ltd., Square Pharmaceuticals Ltd., Acme Laboratories, Novartis Animal Health Ltd etc. were seen to produce different products for aquaculture.While Eon Animal Health Products Ltd., CP Company, Rals Agro Ltd., Ellwellas Marketing Ltd. have been marketing various products from different countries including India, USA, Thailand, Taiwan, Indonesia, Malaysia and Spain.They provide detail information about the purposes, dosages, duration and method of application of chemicals in the leaflet.However, farmers had different opinion about the use and efficacy of many of the products.Some companies were seen to provide technical assistance to the farmers.Thus, the farmers fetch considerable pressure from the commercial companies to use a variety of products in their farms.Several products have been sold without any explanation of their action.The present survey revealed that among the 52 companies more than 50 % of the products were produced by twelve companies like Fish Tech BD,(6%), Organic Pharmaceuticals Ltd. (4%), Rals Agro Ltd. (4%), Novartis Animal Health Ltd. (5.66%), Eon animal Health Product Ltd. (7%), ACI Animal Health Ltd. (7.34%), CP Aquaculture (5.66%), Square Pharmaceuticals Ltd. (4.33%), Advanced Animal Health(5.67%).C.P. India (2%), First Care Agro.Ltd. (4%), Novartis (2.33%) and the rest (46.67%) were supplied by the 26 companies.At present approximately 300 products of about 52 animal health companies were seen to market and field level.The pharmaceutical companies also employ number of promotion officers to sell their chemicals.Some companies were seen to provide technical assistance to the farmers.Thus, farmers come under considerable pressure from commercial companies to use a variety of aqua drugs and chemicals in their farms.There are new aqua drugs being made available continually and often there is very little information available about their efficacy.Some aqua-medicines were found only trade names.Either farmers or sellers did not have clear idea about the active ingredient and method of applications of the particular aqua-medicines though they were using those without hesitation.Only few companies provide details product profile to the farmers.lt was seen that same products of different companies variable dosage.So farmer feels hesitation before using those aquamedicines.Most of the farmers does not know efficacy of that products.The pharmaceutical companies should take care about those products.

Problems in use of drugs and chemicals
The present study identified some problems associated with the use of drugs and chemicals which included: i) Lack of knowledge about use of chemicals ii) Lack of knowledge of application of drugs and chemicals iii) Indiscriminate use of chemicals iv) Pressure on farmers from pharmaceutical companies and pesticide sellers v) Lack of awareness about the safety issues in using hazardous chemicals vi) Lack of information on the label of chemical about possible hazard vii) Lack of knowledge about residual effect and expiry date.

Conclusions
The present study demonstrated current status of drugs and chemicals using in aquaculture in Zakigonj upazilla and pointed out some problems of the use of chemicals by the farmers which include lack of knowledge of the chemicals, doses and methods of application of these chemicals.There are few alternatives to minimize the adverse effects of aquaculture chemical are simply use less of them.Other alternatives could be used as bioremediation and use of probiotics, immunostimulants, vaccination and alternative therapeutic.However, policy makers, researchers and scientists should work together in addressing the issues of chemical use in aquaculture with the view to reduce the negative impacts.

Figure 2 .
Figure 2. Doses of lime used (%) during pond preparation and culture period.
during the pond preparation.Only a few farmers (4%) were found to use higher dose 200-250 g of urea during pond preparation.This dose was found to use by only (1.3%) during culture period.

Figure 3 .
Figure 3. Use of urea (%) during pond preparation and culture period.

Figure 4 .
Figure 4. Use of TSP (%) during pond preparation and culture period.

Table 4 . List of available disinfectant in market and used by the farmers in study area.
Rahman (2011) are widely used in many sphere of aquaculture.They are used mainly to disinfect hatchery and other equipment and in some cases as disease treatment.The chemicals widely used as disinfectants in aquaculture in Zakigonj area include Formalin, Lime, Bleaching Powder, Timsen, Malachite Green, EDTA, Virex, Etinol and Polgard Plus.Rahman (2011)also found disinfectants in his study such as Polgard Plus, Bactisal, Virex, Biogaurd, Lenocide, Timsen, Emsen, Aqua Cleaner Plus, Formalin and Bleaching Powder.Sheriff et al.