Curbing Antimicrobial Resistance in Farmed Fish in Kenya
By Mary Hearty
George Muga, Director of Muga Fish Farm, located in Karachuonyo, Homabay County; uses salt bath as a way of treating fish infections that occur in his farm as it is affordably cheaper unlike use of antimicrobials.
Whenever he detects fish with problems like bleeding scales in the ponds, he dips them in a container with a gallon of salty water for about two minutes before transferring them to an aquarium with fresh water in segregated place.
During this process, the population of the disease-causing microorganisms that may have gotten into the infected part decline because of water or fluids loss into the surrounding saline environment.
Immediately after the salt bath, the fish is quarantined in the aquarium for about two to three weeks before taking it back to its original pond, Muga says.
In Kenya, 250mg of Tetracycline tablets (costs USD6) is twenty times more expensive than a kilogram of table salt.
George Ogembo, a fisheries officer within Homabay County says this is one of the cheapest and effective treatments they are sensitizing fish farmers to adopt as an effort to prevent unnecessary use of antimicrobials in their farms.
He adds that the fish farmers are not allowed to use antimicrobials without the help of a fisheries officer. “We usually advise them to consult with us first because some infections do not even need treatment with antimicrobials because, salt bath, iodine solution, copper sulphate solution can be alternatively effective,” he says.
At the moment, Ogembo says fish infections are rarely reported in the county, especially due to the protective mucus covering which can prevent infections.
However, he adds, poor aquatic environment through bad quality of water, rough handling, are some of the factors that can cause damage to the protective mucus leading to occurrence of infections.
Some of the health infections that have been reported in the county include: fin and tail rot caused by bacteria which occurs in poor environmental conditions including high temperatures; and scabies rash which causes little bumps on the body of fish, just to mention a few.
Others like Hemorrhagic septicemia caused by bacteria known as Pseudomonas spp, which spreads very fast from one fish to another, have been reported in the country as well.
Aquaculture now plays an increasingly important role in national fish supply as fresh water fish accounts for close to 98% of the reported aquaculture production, according to the Kenya Marine and Fisheries Research Institute (KMFRI).
Statistics from the Kenya National Bureau of Statistics (KNBS) shows that the number of fish farmers as well as ponds countrywide has increased tenfold over the past ten years. KMFRI reports that Kenya is now ranked fourth largest producer of farmed fish in Africa.
With the cumulative fish farming, chances are high that issues like infections and those related to infections particularly antimicrobial resistance (AMR), will occur in cultured fish, hence create a catastrophic event if the farmers are not sensitized on fish health management.
Moreover, with the issue of climate change, it is predicted that the rising temperatures as a result of global warming, could accelerate the growth of infectious microorganism, especially in Homabay County which experiences hot conditions.
Therefore, the fisheries officers are training fish farmer on infection prevention practices as efforts to curb occurrence of infections that could need treatment with antimicrobials, especially antibiotics.
These include: ensuring quality and sufficient water supply in ponds, quarantine, and disinfection, screening water systems, using quality feeds, and controlling stocking density, among others.
As a commercial fingerling producer, Muga says that having knowledge and skills on fish health management is crucial in order to ensure healthy stocks.
When he started doing fish farming almost 10 years ago, he recalls, the performance of his stock was very poor because many died. Reasoning that, he had no prior knowledge or skill in aquaculture. However, his harvest improved when he started consulting the fisheries department.
With only four ponds in the beginning, the fish farmer is now capable of producing up to 100,000 quality fingerlings on a weekly basis through the support he gets from the trainings.
Having 57 fish ponds separated into three units: the hatchery, nursery and brood stock unit, Muga explains that they ensure that water quality in the units are monitored and regulated.
For instance, this is determined through the color of the water, or death of some fish. He explains that dark green water show that the ammonia content is too high so water is regulated.
This is by draining water in the pond up to a certain level through the outlet, then clean fresh water is pumped in through the inlet.
When some deaths are recorded, it could be as a result of reduced level of oxygen in the pond.
In the hatchery unit, Muga ensures that not everybody is allowed to get into the unit. “We have a standard operating procedure for managing the hatchery in order to prevent the occurrence of infections,” he said, noting that the unit in one of the key areas that farmers are keen on.
As the farmers come in the hatchery unit, they have to disinfect their hands and the sole of their shoes first before proceeding into the hatchery. Sanitization is done on a wet rug with disinfectant at the door before getting into the hatchery.
Also, the water in the hatchery has to pass through a filter made of small stones and sand before getting into the hatching jars. This prevents residues carrying infectious agents from getting into the jars.
From the hatching system, there is another system where the water is allowed to settle before being recycled for use in the hatching jars.
In addition, after every hatching session, the farmer explains that water in the whole system is normally drained and cleaned thoroughly. Thereafter, disinfection is done using chlorine or iodine before introducing the next batch of eggs.
This ensures that there is no relationship between the previous batch and the next one. And this maintains bio-security in the hatchery.
He has also fenced his farm with barbed wires and covered the ponds with harper nets to prevent birds and other animals like dogs, cattle, sheep and goats from getting into the farm as they can be agents of transmitting infectious pathogens.
The farmer also ensures that no foreign fish is introduced into the farm unless the source is known.
“And when we bring in a new fish breed into the farm, we usually quarantine the fish in a quarantine pond for some time to observe if they have any infection before they are released into the farm,” he states.
During quarantine, the fisheries officers advise farmers to check for symptoms of infections such as changes in skin color, loss of equilibrium, changes in respiratory rate, fin and skin erosions, among others.
They are also advised to check on their fish constantly to help them detect any abnormal issue earlier, noting that if checkup is not done regularly, other healthy fish will also be infected.
Although, he says that he has never encountered this kind of scenario because they are dealing with a semi-intensive aquaculture system (a maximum of 1000 fish in each pond), the infection is normally worse in an environment where intensive fish farming system takes place.
Since the farmer has over ten years of experience in fish management, he notes that he also supports other farmers on better fish management practices.
For farmers that are getting their water directly from the streams where wild fish are found like Muga, they are advised to screen their water system in order to prevent fish from the wild from coming into their farm as they can also be a source of infection.
Muga has also benefitted from other trainings which were very intensive on fish diseases, disease management, production, hatchery management, as well marketing organized by the Food and Agriculture Organization of the United Nations (FAO) and Farm Africa.
The extension officers also teach farmers on local alternative ingredients that can naturally help boost the growth and development of fish over a short period of time instead of adding antimicrobial agents to their feeds.
Due to the higher prices of the commercial feeds, Muga fish farm is coming up with an innovative way of getting supplementary feeding to the fish through the production of black soldier fly, which he says is very rich in proteins.
“We started this because most of the feeds we have contain very low protein content yet they are very costly. So, we want to supplement them with black soldier fly especially the brooders in order to reduce the cost of feeds,” he adds, stating that they got the idea from a workshop.
Muga says that the high cost of fish feeds is one of the biggest challenges that farmers complain about as feeds like the Growers mash costs about USD 30 per 25 kilogram, yet the post fingerlings stage is where fish are fed the most.
The farmer is currently supplementing his feeds with fresh water shrimps locally known as Ochong’a, which are very affordable and rich in protein. The farmer explains that fish are fed ochong’a at around two to three months before harvesting as it gives fish its natural taste as well.
Although, the commercial feeds are better they contain all the necessary ingredients including the immunity booster which can enable the fish to grow stronger and fight any infection, unlike the on-farm made feeds.
Muga further explains that the disadvantage of using on-farm feeds is that when a farmer fails to control its moisture content, it can deteriorate very fast, and if given to fish, it can cause an infection.
Mashel Mboga, Founder of the Zulu Works is also a fish farmer from the county and a beneficiary of the training programs conducted by the fisheries officers.
He also supplements the commercial feeds with ochong’a, arrow roots, soya and sunflower. On infection prevention, Mboga says he normally ensure water in the fish pond is routinely regulated.
“The fish ponds like the one for catfish contain an underground inlet for letting in fresh water from the nearby spring. So by the time the water reaches the pond, it naturally gets filtered through the underground cracks,” Mboga says.
The water quality is also regularly tested with a pH meter; 7-9 pH is considered clean water. This helps to determine the ammonia content and the oxygen level also influences the health of fish.
“The pH of water is tested every two to four weeks to determine chemicals such as ammonia which are harmful to fish,” Mashel notes.
The KMFRI state that the water pH and temperature also helps to determine selected viral infections. Other important water quality variables are oxygen, carbon dioxide, alkalinity and suspended solids.
Hope and Kindness Orphanage, located at the outskirts of Kosele Centre in Rachuonyo South Sub County within Homabay County, is also benefitting from the trainings offered by the fisheries extension officers in the county as they have not encountered any severe infections on their fish.
The orphanage does fish farming as a sustainable source of livelihood for children living there. It has raised ponds built inside five huge greenhouses which help them prevent other animals from getting into the farm.
Patrick Onyango, one of the farm assistant managers at the orphanage explains: “dirty water from the fish ponds are let out to the grow beds which contain play pebbles that act as filters.
At the center of the grow bed, there is a syphon which helps in breaking water when it reaches three-quarter level of the grow bed tank.
In addition, plants like the eggplant are grown on the grow bed, as they also biologically filter water by absorbing fish wastes as nutrients. The already filtered water is let out of the grow beds into an underground tank which pumps water back to the ponds.
The orphanage rears crickets as supplements to fish feeds, which he says are highly rich in protein hence they help fish to grow rapidly unlike use of antimicrobial agents.
The crickets are fed chicken growers mash and vegetative leaves like sweet potato vines, Irish potato peels, blackjack leaves, among others; and moisten soil substrates They also use soil substrate which are kept moisten by sprinkling water, arguing that the crickets do not consume water directly.
“Apart from the chicken growers mash, it is important to have feeds that are locally available so that it does not cause stress on the crickets,” Onyango clarifies.
The crickets are harvested after every four months by dipping them in warm water to die; then they are sundried and crushed into powder form. Afterwards, they are mixed with commercial feeds for fish.
Attack by predators like the lizards and spiders remains the worst challenge they are facing as they feed on the eggs and the younger crickets.
“We have tried using the nets but some still manage to get in. So we have to check in the boxes daily,” Onyango intimates.
The fisheries officers encourage farmers to supplement the commercial feeds with local ingredients such as the ones used by Mboga, Onyango and Muga to help reduce the cost of fish feeds.
According to Ogembo, one of the biggest challenges they are facing as the fisheries department in Homabay is lack of enough personnel particularly at the grass root level as every sub county has only one officer, who attends to all the fish farmers in the area.
Meanwhile, through the Economic Stimulus Program which was introduced in 2009, the fisheries officers in Homabay County have trained 600 fish farmers in every Sub County on fish health management, among others
At the moment, through the Aquaculture Business Development Program (ABDP), the fisheries officers are training about 1600 fish farmers in the County.
In Rachuonyo South Sub County, Ogembo says there are about 400 active fish farmers who they engage, and the ABDP is currently supporting 136 fish farmers as they are planning to add 64 more farmers in the program.
The trainings are conducted in groups as workshops or through free individual consultation. The fisheries officer affirms that diseases are rarely encountered by farmers who consult with them.
The counties which are currently benefitting from these training initiatives are Kakamega, Busia, Homa Bay, Siaya, Migori, Kisumu, Kisii,Kakamega, Kirinyaga, Nyeri, Meru, TharakaNithi, Kisii, Kisumu, Siaya, Busia, Embu, Kiambu, Machakos, and Kajiado as well, where inland fish farming takes place.
With the increasing fish farming in the country, The KMFRI recommends that there is need to invest in training and education of fish health specialists to deal with both disease diagnostics, treatments and the correct drugs for use in the industry.
The organization also urges the government to invest in vaccination in aquaculture as it is the most effective disease preventive strategies, evidenced by the fact that vaccinated fish are less likely to contract infections.
In addition, KMFRI also suggests that issues of drug application in aquaculture need to be regulated to prevent problems of residues in the environment and consequent drug resistance.