Antibiotic sensitivity
Bacterial resistance is an issue that needs to be considered when choosing an appropriate antibiotic. While it may be necessary to start a course of treatment based on personal experience, it is also prudent to have bacterial identification and antibiotic sensitivity tests carried out at the same time. At worse this simply confirms the treatment choice, while possible saving valuable time and money if the initial course of action is ineffective.
A sterile swab is used to take a bacterial sample from either the posterior kidney or other organ of a newly dead fish, or alternatively from a body ulcer. When taking a swab of a body ulcer it should be sampled from the infected rim of the ulcer only.
The swab is then sent to a specialist laboratory for analysis and testing. Your local veterinarian can arrange this. The results from a body ulcer can be difficult to interpret because of the problem of secondary pathogens. It is quite common for samples from body lesions to show a mixed growth of several bacterial species and takes some experience to determine the relevance of the results.
Saturday, July 5, 2008
Bacterial Diseases- A general overview
Antibiotics and bacterial diseases
bacteria – what are they?
Bacteria are minute organisms invisible to the naked eye. There are many different types of bacteria and they are probably the most diverse group of organisms on the planet – each like a little chemical factory. Very few species are pathogenic (disease-causing). Those that are harmful can be divided into two basic types; Gram-negative and Gram-positive. This simple grouping is based on a staining technique in which Gram-negative bacteria stain red, while the Gram-positives stain blue because of differences in the cell-wall structure.
Most bacterial fish pathogens, such as Aeromonas, Pseudomonas, Vibrio, Flavobacterium and Cytophaga are Gram-negative bacteria. These are the bacteria that are usually involved with bacterial disease such as ulcers, fin rot, acute septicaemia and bacterial gill disease. Less common pathogens are Mycobacterium and Norcardia sp. which cause chronic granulomas (or abscesses).
How do bacteria cause disease?
Although they are incredible small most pathogenic bacteria have tremendous reproductive potential. They simple divide in two and once each half has re-grown sufficiently they divide again. Under ideal conditions the reproductive cycle can be as little as 20 - 30 minutes, which means that just one bacterium can multiple to several million within 24-hours or so!
As I have said, bacteria are like little chemical factories. Some bacteria produce toxins that are excreted into the blood and tissues of the host. Other bacteria, particularly the Gram-negatives do not secrete a soluble toxin but make an endotoxin that is liberated when the cell dies and disintegrates. These endotoxins are usually lipopolysaccharide structural components of the bacterial cell-wall (specifically the lipid A portion). In addition to toxins the virulence of many bacteria is partly due to the production of extracellular enzymes, which attack healthy fish cells.
So although tiny, the net effect of millions of bacteria can quickly overwhelm the defences of the fish host – which is why early treatment is so vital if the fish is to survive.
How do antibiotics work?
Antibiotics are chemical substances produced by microorganisms that either destroy (bactericidal) or inhibit the growth of other microorganisms (bacteriostatic). Antibiotics can be either broad spectrum, which means that they are active against a wide range of microorganisms – both good and bad. Narrow spectrum drugs target a specific group of microorganisms and are able to interfere with a metabolic process specific to those organisms. In general antibiotics work by;
Preventing the synthesis of bacterial cell-wall components – typically penicillin
Damaging the bacterial cytoplasmic membrane
Interfering with protein or nucleic acid synthesis – typically tetracyclines
However, the microorganisms under attack don’t take all this sitting down. Many are able to produce enzymes that neutralise antimicrobial compounds. Others can acquire resistance to weak, short-term or repeated exposure to antibiotics. For example there are now high levels of resistance to oxolinic acid and oxytetracycline because of overuse and misuse.
What antibiotics are available?
Every country has its own regulations on the control of antibiotics and therefore availability will vary. The range of drugs available or licensed for use with fish is generally small. In the UK all antibiotics are classed as POMs (Prescription only Medicines) and are only available under veterinary supervision. Among the antibiotics in common use are;
Broad-spectrum penicillins that include amoxycillin and ampicillin. These are bactericidal in action and are effective against Gram-positive and Gram-negative bacteria, but not very effective against Pseudomonas.
Chloramphenicol is a broad spectrum antibiotic, but again it is not usually effective against Pseudomonas. Because it is used in human medicine it is illegal for use in food animals in most countries. Some people are sensitive to the drug so rubber gloves should be worn when it is handled.
There are several potentiated sulphonamide drugs in which a sulphurdrug is combined with trimethoprim. They are broad spectrum and mainly bacteriostatic. They are well absorbed from the gut when used with medicated food but poorly absorbed from water. They can sometimes form crystals in urine and should not be used where there is already kidney damage. They should not be used at the same time as organophosphates. Co-trimazine is a combination of trimethoprim and sulphadiazine and Borgal is a combination of trimethoprim and sulfadoxine. They are effective against Aeromonas and other Gram-negatives, but not particularly effective against Pseudomonas.
Gentamicin is a broad spectrum antibiotic with a bactericidal effect. It is useful against all Gram-negatives including Pseudomonas but can be toxic to kidneys. There is concern that bacteria may acquire rapid resistance, so it would not be the drug of first choice but does have a use when other drugs do not work.
Nitrofurans are a group of synthetic antimicrobials. Both nifurpirinol and nitrofurazone are effective against many fish pathogens. They are well absorbed through the skin, making them ideal for bath treatments. However, they are carcinogenic and mutagenic and their use with food fish is illegal in most countries.
Oxytetracycline is bacteriostatic drug with a broad spectrum of activity. However, there is widespread resistance and it has little effect on Pseudomonas. The long-acting injectable formulation has caused sterile cysts at the injection site. When used for bath treatments it readily chelates calcium and magnesium ions found in hard water, significantly reducing its effectiveness. It is also light-sensitive when used as a bath treatment, turning brown as it decomposes. The degraded form can be toxic to both fish and humans. Some studies show that oxytetracycline is immunosuppressive in some fish species.
The quinolones are narrow spectrum range of drugs acting mainly against Gram-negatives such as Pseudomonas and Aeromonas. The first generation quinolones include oxolinic acid to which there is now widespread resistance. Newer quinolones include enrofloxacin and sarafloxacin. These are effective against Pseudomonas and Aeromonas and as yet there is little resistance. All quinolones are chelated in hard water, so they are not practical for bath treatments. They are well absorbed through the gut, making them useful for medicated food.
bacteria – what are they?
Bacteria are minute organisms invisible to the naked eye. There are many different types of bacteria and they are probably the most diverse group of organisms on the planet – each like a little chemical factory. Very few species are pathogenic (disease-causing). Those that are harmful can be divided into two basic types; Gram-negative and Gram-positive. This simple grouping is based on a staining technique in which Gram-negative bacteria stain red, while the Gram-positives stain blue because of differences in the cell-wall structure.
Most bacterial fish pathogens, such as Aeromonas, Pseudomonas, Vibrio, Flavobacterium and Cytophaga are Gram-negative bacteria. These are the bacteria that are usually involved with bacterial disease such as ulcers, fin rot, acute septicaemia and bacterial gill disease. Less common pathogens are Mycobacterium and Norcardia sp. which cause chronic granulomas (or abscesses).
How do bacteria cause disease?
Although they are incredible small most pathogenic bacteria have tremendous reproductive potential. They simple divide in two and once each half has re-grown sufficiently they divide again. Under ideal conditions the reproductive cycle can be as little as 20 - 30 minutes, which means that just one bacterium can multiple to several million within 24-hours or so!
As I have said, bacteria are like little chemical factories. Some bacteria produce toxins that are excreted into the blood and tissues of the host. Other bacteria, particularly the Gram-negatives do not secrete a soluble toxin but make an endotoxin that is liberated when the cell dies and disintegrates. These endotoxins are usually lipopolysaccharide structural components of the bacterial cell-wall (specifically the lipid A portion). In addition to toxins the virulence of many bacteria is partly due to the production of extracellular enzymes, which attack healthy fish cells.
So although tiny, the net effect of millions of bacteria can quickly overwhelm the defences of the fish host – which is why early treatment is so vital if the fish is to survive.
How do antibiotics work?
Antibiotics are chemical substances produced by microorganisms that either destroy (bactericidal) or inhibit the growth of other microorganisms (bacteriostatic). Antibiotics can be either broad spectrum, which means that they are active against a wide range of microorganisms – both good and bad. Narrow spectrum drugs target a specific group of microorganisms and are able to interfere with a metabolic process specific to those organisms. In general antibiotics work by;
Preventing the synthesis of bacterial cell-wall components – typically penicillin
Damaging the bacterial cytoplasmic membrane
Interfering with protein or nucleic acid synthesis – typically tetracyclines
However, the microorganisms under attack don’t take all this sitting down. Many are able to produce enzymes that neutralise antimicrobial compounds. Others can acquire resistance to weak, short-term or repeated exposure to antibiotics. For example there are now high levels of resistance to oxolinic acid and oxytetracycline because of overuse and misuse.
What antibiotics are available?
Every country has its own regulations on the control of antibiotics and therefore availability will vary. The range of drugs available or licensed for use with fish is generally small. In the UK all antibiotics are classed as POMs (Prescription only Medicines) and are only available under veterinary supervision. Among the antibiotics in common use are;
Broad-spectrum penicillins that include amoxycillin and ampicillin. These are bactericidal in action and are effective against Gram-positive and Gram-negative bacteria, but not very effective against Pseudomonas.
Chloramphenicol is a broad spectrum antibiotic, but again it is not usually effective against Pseudomonas. Because it is used in human medicine it is illegal for use in food animals in most countries. Some people are sensitive to the drug so rubber gloves should be worn when it is handled.
There are several potentiated sulphonamide drugs in which a sulphurdrug is combined with trimethoprim. They are broad spectrum and mainly bacteriostatic. They are well absorbed from the gut when used with medicated food but poorly absorbed from water. They can sometimes form crystals in urine and should not be used where there is already kidney damage. They should not be used at the same time as organophosphates. Co-trimazine is a combination of trimethoprim and sulphadiazine and Borgal is a combination of trimethoprim and sulfadoxine. They are effective against Aeromonas and other Gram-negatives, but not particularly effective against Pseudomonas.
Gentamicin is a broad spectrum antibiotic with a bactericidal effect. It is useful against all Gram-negatives including Pseudomonas but can be toxic to kidneys. There is concern that bacteria may acquire rapid resistance, so it would not be the drug of first choice but does have a use when other drugs do not work.
Nitrofurans are a group of synthetic antimicrobials. Both nifurpirinol and nitrofurazone are effective against many fish pathogens. They are well absorbed through the skin, making them ideal for bath treatments. However, they are carcinogenic and mutagenic and their use with food fish is illegal in most countries.
Oxytetracycline is bacteriostatic drug with a broad spectrum of activity. However, there is widespread resistance and it has little effect on Pseudomonas. The long-acting injectable formulation has caused sterile cysts at the injection site. When used for bath treatments it readily chelates calcium and magnesium ions found in hard water, significantly reducing its effectiveness. It is also light-sensitive when used as a bath treatment, turning brown as it decomposes. The degraded form can be toxic to both fish and humans. Some studies show that oxytetracycline is immunosuppressive in some fish species.
The quinolones are narrow spectrum range of drugs acting mainly against Gram-negatives such as Pseudomonas and Aeromonas. The first generation quinolones include oxolinic acid to which there is now widespread resistance. Newer quinolones include enrofloxacin and sarafloxacin. These are effective against Pseudomonas and Aeromonas and as yet there is little resistance. All quinolones are chelated in hard water, so they are not practical for bath treatments. They are well absorbed through the gut, making them useful for medicated food.
Thursday, June 12, 2008
CATFISH FARMERS ONLINE FORUM CONFERENCE REPORT
Highlights
Basic Management procedures in Fish Farming – Presented and Coordinated by Ganiyu Tiamiyu
Need to understand the system of fish production adopted. Is it recirculatory, flow-through or earthen pond or a combination of any.
Water quality parameters such as Ph, Dissolved Oxygen levels, nitrites, ammonia, iron and metals must be checked before buying land and must be monitored daily or weekly even when farm operations is ongoing.
Need to stock the right quality and quantity of fingerling or juveniles but special attention should be giving to raising to 40 – 50g before transferring to the main grow –out system. Sorting or grading into various sizes should also be done as need arises.
Following the proper feeding regimes as to what type, size and quantity of feed to give at each point in time. There are literature guides to this, but most importantly is to feed according to the reaction of the fishes to the feed while feeding.
Ability to identify stress factors and conditions and how to manage them.
Importance of record keeping is very key.
Feed dynamics, production cost and formulation – presented and coordinated by Dr. Aderolu Zaid.
This topic was approached from the point of view of common errors in feeding were discussed here in details. These include, feeding wrong size of feed, using wrong feed type, feeding at wrong times of the day, wrong feed or feed formulation especially for those who formulate their pellet feed.
Having the right staff assigned the role of feeding is very important. Feeding operations is key to the overall success of the farm, as a farmer cannot afford to overfeed or underfeed. The two extremes have negative consequences and as such the staff(s) assigned this role must be intelligent enough.
The owner of the farm must ensure to feed at times himself or herself to observe the response of the feed and general conditions first hand. The farmer must also put measures to monitor and supervise staffs in the process of feed production, storage and accountability for all feed ingredients.
The problem of lack of standards in the quality of feed ingredients and adulterations available was also highlighted. The conference urged the government to put measures to have some standardization and control. Farmers are also urged to buy feed ingredients from reputable sources.
Of greatest importance is that a farmer who wants to formulate feed must have a way of testing or verifying the quality of feed ingredients and have a good understanding of feed constituents and how to combine them to meet the nutrient needs of different stages of growth of the fish.
In deciding which feed is better between floating extruded feed or pelleted feed, is very dependent on a combination of factors especially on its cost, how it’s being used and some of the issues raised above. However, after a breeding circle and checking the FCR (Feed Conversion Ratio), one can then be able to determine which is better.
Use of sinking pellet feed will require more attention to be paid to the quality of water and water flow/change to prevent the settling of residues.
On exhibition at the conference was a feed milling equipment which is able to pellet feed out with about 15 – 20 % moisture content and with no dust. Other equipments for use on the farm were also on display by Capsfeed limited.
Marketing models and Links - Presented and coordinated by Michael Ukabam
Marketing was defined as the performance of all business activities involved in the flow of product from farm to plate. This involves Advertising, Processing, Transportation, Retail, Policy, etc.
We need to Market in other to Increase profit and Expand market.
We need to make Profit in other for the Businesses to survive and grow.Growth is necessary to improve economies of scale.
Economies of scale were highlighted as
o More bargaining power for purchasing and selling
o More efficient use of staff - Reduced staff cost
o Ability to take on larger challenges
Improving profitability means either reducing cost or increasing revenue
o Reducing Cost
o Improving efficiency
o Improving economies of scale
o New technology
o Sharing cost
o Increasing Revenue
o Reduce mortality and increase output per pond
o Capturing more market margin.
Market Margin was defined as the total available cash between farm and Plate. This Market margin exists because value is added by different actives in the marketing chain. This market margin is what we all as farmers need to tap into.
To develop and execute a good marketing plan one needs to understand the value that goes into every step of the marketing chain and substitute these.
Sales options
o Whole Sale distributor
o Direct Sales
To shops
To Restaurants
Fish farmers market
End consumer
Policy trust and Guidelines to form a concrete pressure group
It was agreed that there is the need to form such a visible group as there are many benefits that could accrue to us as a group and individuals if we do this. Such as having government or World Bank funding.
There is need to have a pressure group that can begin to work on setting some standards in the industry especially in the farm inputs such as feeds, feed ingredients and fish seed.
We agreed too that there is need to form a business company out of the group to pursue the basic economic interest of farmers in terms of alternative marketing of there products. These would be optional to those who can subscribe to it financially.
To this end, every participant has been urged to send in their proposals as to how to form both the pressure group and the business company to the conference secretariat at cafigtrainingconference@yahoo.com.
List of Participants
NAME E-MAIL PHONE NO.
Iyiola Mukail Omotayo omotayoiyiola@yahoo.co.uk
035209982
Alhaji Iyiola M.O Same as above 08038290410
Seun Keyede farm_dominion@yahoo.co.uk
08022222229
Tiamiyu Toba pashoman@yahoo.com
08023224264
Ganiyu Tiamiyu tiaga77@yahoo.com
08025420201
Ojeomogha Leticia Oizy2000@yahoo.com
08033212646
Barister Nike Rep Ronald Hommes 08037148803
Olayide Majekodunmi ocmajek@yahoo.com
08027339241
Dr Aderolu A.Z dezaid@yahoo.com
08033225139
Epemolu Ayobami dolerando@yahoo.co.uk
08033668178
A.A Fakunle capsfeed@yahoo.com
08033244318
Adedeji A Abiodun Adfab1171@yahoo.com
08033135761
Micheal Ukabam ukabamm@yahoo.com
08039580006
Anselm U. Ojezua anselmojezua@yahoo.com
08033460363
Basic Management procedures in Fish Farming – Presented and Coordinated by Ganiyu Tiamiyu
Need to understand the system of fish production adopted. Is it recirculatory, flow-through or earthen pond or a combination of any.
Water quality parameters such as Ph, Dissolved Oxygen levels, nitrites, ammonia, iron and metals must be checked before buying land and must be monitored daily or weekly even when farm operations is ongoing.
Need to stock the right quality and quantity of fingerling or juveniles but special attention should be giving to raising to 40 – 50g before transferring to the main grow –out system. Sorting or grading into various sizes should also be done as need arises.
Following the proper feeding regimes as to what type, size and quantity of feed to give at each point in time. There are literature guides to this, but most importantly is to feed according to the reaction of the fishes to the feed while feeding.
Ability to identify stress factors and conditions and how to manage them.
Importance of record keeping is very key.
Feed dynamics, production cost and formulation – presented and coordinated by Dr. Aderolu Zaid.
This topic was approached from the point of view of common errors in feeding were discussed here in details. These include, feeding wrong size of feed, using wrong feed type, feeding at wrong times of the day, wrong feed or feed formulation especially for those who formulate their pellet feed.
Having the right staff assigned the role of feeding is very important. Feeding operations is key to the overall success of the farm, as a farmer cannot afford to overfeed or underfeed. The two extremes have negative consequences and as such the staff(s) assigned this role must be intelligent enough.
The owner of the farm must ensure to feed at times himself or herself to observe the response of the feed and general conditions first hand. The farmer must also put measures to monitor and supervise staffs in the process of feed production, storage and accountability for all feed ingredients.
The problem of lack of standards in the quality of feed ingredients and adulterations available was also highlighted. The conference urged the government to put measures to have some standardization and control. Farmers are also urged to buy feed ingredients from reputable sources.
Of greatest importance is that a farmer who wants to formulate feed must have a way of testing or verifying the quality of feed ingredients and have a good understanding of feed constituents and how to combine them to meet the nutrient needs of different stages of growth of the fish.
In deciding which feed is better between floating extruded feed or pelleted feed, is very dependent on a combination of factors especially on its cost, how it’s being used and some of the issues raised above. However, after a breeding circle and checking the FCR (Feed Conversion Ratio), one can then be able to determine which is better.
Use of sinking pellet feed will require more attention to be paid to the quality of water and water flow/change to prevent the settling of residues.
On exhibition at the conference was a feed milling equipment which is able to pellet feed out with about 15 – 20 % moisture content and with no dust. Other equipments for use on the farm were also on display by Capsfeed limited.
Marketing models and Links - Presented and coordinated by Michael Ukabam
Marketing was defined as the performance of all business activities involved in the flow of product from farm to plate. This involves Advertising, Processing, Transportation, Retail, Policy, etc.
We need to Market in other to Increase profit and Expand market.
We need to make Profit in other for the Businesses to survive and grow.Growth is necessary to improve economies of scale.
Economies of scale were highlighted as
o More bargaining power for purchasing and selling
o More efficient use of staff - Reduced staff cost
o Ability to take on larger challenges
Improving profitability means either reducing cost or increasing revenue
o Reducing Cost
o Improving efficiency
o Improving economies of scale
o New technology
o Sharing cost
o Increasing Revenue
o Reduce mortality and increase output per pond
o Capturing more market margin.
Market Margin was defined as the total available cash between farm and Plate. This Market margin exists because value is added by different actives in the marketing chain. This market margin is what we all as farmers need to tap into.
To develop and execute a good marketing plan one needs to understand the value that goes into every step of the marketing chain and substitute these.
Sales options
o Whole Sale distributor
o Direct Sales
To shops
To Restaurants
Fish farmers market
End consumer
Policy trust and Guidelines to form a concrete pressure group
It was agreed that there is the need to form such a visible group as there are many benefits that could accrue to us as a group and individuals if we do this. Such as having government or World Bank funding.
There is need to have a pressure group that can begin to work on setting some standards in the industry especially in the farm inputs such as feeds, feed ingredients and fish seed.
We agreed too that there is need to form a business company out of the group to pursue the basic economic interest of farmers in terms of alternative marketing of there products. These would be optional to those who can subscribe to it financially.
To this end, every participant has been urged to send in their proposals as to how to form both the pressure group and the business company to the conference secretariat at cafigtrainingconference@yahoo.com.
List of Participants
NAME E-MAIL PHONE NO.
Iyiola Mukail Omotayo omotayoiyiola@yahoo.co.uk
035209982
Alhaji Iyiola M.O Same as above 08038290410
Seun Keyede farm_dominion@yahoo.co.uk
08022222229
Tiamiyu Toba pashoman@yahoo.com
08023224264
Ganiyu Tiamiyu tiaga77@yahoo.com
08025420201
Ojeomogha Leticia Oizy2000@yahoo.com
08033212646
Barister Nike Rep Ronald Hommes 08037148803
Olayide Majekodunmi ocmajek@yahoo.com
08027339241
Dr Aderolu A.Z dezaid@yahoo.com
08033225139
Epemolu Ayobami dolerando@yahoo.co.uk
08033668178
A.A Fakunle capsfeed@yahoo.com
08033244318
Adedeji A Abiodun Adfab1171@yahoo.com
08033135761
Micheal Ukabam ukabamm@yahoo.com
08039580006
Anselm U. Ojezua anselmojezua@yahoo.com
08033460363
Subscribe to:
Posts (Atom)