FINALS AQUACULTURE

• Fish pharmacology- is essential for undertaking treatment of fishes using any therapeutic chemicals or drugs.
• According to WHO in 1966- “Drugs is any substance or product which is used or intended to be used to modify or explore physiological systems or pathological states for the benefit of the recipient
• Methods by which drugs are given to fish?

  • ENTERAL
  • TOPICAL
  • PARENTERAL (Injected)
• ENTERAL METHOD? (FWG)

  • feed medication
  • water medication
  • gavage
• Oral administration- is a route of administration where drugs are administered through the mouth.
• Oral administration-Less wasteful method of administration than water medication.
• In-feed medication- is standard practice for a large number of diseases but it is actually prophylactic not therapeutic.
• Medicated feed in pellet form either of floating or sinking variety are thrown upon the surface of the water a process termed broadcasting feeding.
• Antibacterial & Anti parasitic drugs used in feed for feed medication method.
• In other classes of vertebrates there specie differences especially for proteinaceous drugs such as: gonadotropins and gonadotrophin-releasing hormones, and some vaccines.
• Pelleted medicated feed- the ideal way to medicate feed is to add the medicinal product to the feed mix prior to pelleting.
• Surface-coating pelleted feed- This process is suitable to the medication of small batches of feed and can be used for drugs which are heat-liable It is therefore the normal means of medicating feed on fish farms
• Spray-medication of pelleted feed- Sex hormones are important examples of a class of drugs which are, for practical purposes, insoluble in water and which are used in very small doses.
• Leaching of drug into the water occurs with all forms of in-feed medication but is a particular problem associated with surface- coated feed.
• • Extent of leaching varies according to the water solubility of the active ingredient and time for which the feed remains in the water.
  • The smaller the pellets the faster will be the leaching
• Micro-encapsulation of drugs:

  • A micro-capsule structure that has been well researched so far is a calcium alginate core and a chitosan-alginate shell into which the drug is mixed.
  • Whether a micro-capsule is retained in the stomach or not is largely a question of its size.
• Artemia Enrichment:

  • Artemia enrichment has the disadvantage of other forms of in-feed medication that only healthy fishes can be treated, also a costly and extremely wasteful method
  • To enrich artemia cysts they are decapsulated and placed in seawater which has been pre-sterilized by UV light and is well oxygenated.
• Gavage- is a form of oral administration extensively used in experimental work
• Gavage- It is rarely used in routine fish management as it is labour intensive and stressful to the fish.
• Few fish such as brood fish or valuable ornamentals have to be dosed orally.
• Immersion or Dipping:

  • The preparation of a small volume of medicated water in a separate container.
  • The fish, usually held in a net, are immersed for a short period of time and then returned to their normal environment
• Immersion or Dipping:

  • It is also advisable that the water to be medicated should be taken from the pond or tank containing the fish so that chemical and temperature stresses are minimized.
• The freshwater dip- is probably the most common dip for saltwater species and will rid the fish’s body of many potential harmful parasites.
• Parasites such as:

  • Paravortex
  • Cryptocaryon
  • Velvet or coral fish disease
• • Paravortex- the black spot disease a.k.a. (black ick)
• • Cryptocaryon- a.k.a. marine or saltwater “ick”
• • Velvet or coral fish disease (similar life cycle as “Ick”)
• Saltwater Dip (for freshwater fish only)

  • Fish stress is relieved and the organism can fight off diseases easier which aides in the recovery.
• The concentration should be 4 teaspoons per Gallon and the duration of the bath about 30 minutes.
• Saltwater Dip (for freshwater fish only)

  • This bath will also stimulate the protective slime coat, which will further enhance the fish’s’ ability to cope with the disease.
• Protozoa (one celled parasites) on skin, gills, and fins can effectively be removed by a salt bath.
• However, some fish do not respond well to a salt bath (i.e. some barbs, tetras, catfish and koi).
• A heavy concentration can make them loose their equilibrium and they simply “roll over”. At this point the fish has to be moved to clear water very quickly.
• Bath Treatment

  • The difference between a bath and a dip is the time frame.
  • Dips have a limited treatment duration which not to exceed, while a bath requires a prolonged treatment time.
• Bath Treatment

  • Tarpaulins are placed around the cage, separating the contained from the surrounding water and the drug is added, preferably at several points in the bath to ensure rapid mixing.
• Formalin (formaldehyde gas dissolved in water)- is used as a bath to rid external parasites.
• Formalin- works by altering cell proteins
• Malachite Green- This compound rids the fish of all fungal infections. Malachite green is a respiratory poison and damages the cell metabolism.
• Formalin and Malachite Green

  • Both compounds are often used in combination because both increase the benefits of each other. They are also less toxic as if used separately.
• Methylene Blue

  • is effective against skin and gill flukes, ick, velvet, fungus and many external parasites and bacterial infections.