AQUACULTURE(SAPROLEGNIASIS)

Saprolegniasis, also known as winter fungus, is a disease caused by fungi usually in the genus Saprolegnia. Found in freshwater fish and fish eggs, saprolegniasis is a secondary infection typically seen when water temperatures dip below 59°F and then begin to increase in the early spring. A fish suffering from saprolegniasis will exhibit cotton-like growths on the skin and gills, depigmented skin, and sunken eyes. In more severe cases, the cotton-like growths can extend into the muscle tissue. Infected fish will begin to die slowly over time.



During months where rapid change in water temperature is common, extra measures should be taken to prevent or detect saprolegniasis, so now would be the time to take precautions! Saprolegniasis can be prevented by avoiding rough handling, crowded stocking conditions, and poor water quality. To prevent further spread and reduce overall mortality, fish should be harvested as soon as saprolegniasis is observed.

I. Causative Agent and Disease
The disease saprolegniasis is caused
by water molds (oomycetes) mostly in
the genus Saprolegnia. Genetic sequencing places oomycetes in the class Oomycota, phylum Heterokontophyta, related
to photosynthetic brown algae, diatoms
and api complexan protozoa. They are
filamentous protists based on production
of oospores, diploid chromosomes, cell
walls of beta glucans and cellulose, two
types of zoospore flagella and tubular
cristae in the mitochondria. Saprolegniasis describes any cotton-like growth
adherent to skin or gills that include several genera of molds. Water molds occur
in fresh and brackish water less than
2.8 ppt salinity. Most are saprophytes
occurring naturally in the environment
and are opportunistic pathogens, usually requiring prior injury of external
tissues from mechanical abrasion or
other primary pathogens. Some species
of Saprolegnia (parasitica) are primary
pathogens producing a systemic disease.
II. Host Species
All freshwater fish species, incubating eggs and other lower aquatic
vertebrates/invertebrates worldwide are
susceptible to saprolegniasis.
III. Clinical Signs
The mold produces white/brown
cotton-like foci on the surface of the
skin and/or gills. Early foci are pale with
peripheral areas of erythema and central
zones of lifted scales that frequently
ulcerate, exposing underlying musculature. Systemic infections produce
mycelial masses in the gut and viscera
causing peritonitis, extensive hemorrhage, necrosis and adhesions. In smaller
juvenile fish, external signs of bloating
caused by gut obstruction may progress
to perforation of the abdominal wall.
IV. Transmission
External mold infections are
transmitted through ambient water by
infectious biflagellated zoospores released from hyphal sporangia. Systemic
infections in cultured fish occur by
ingestion of uneaten food that has been
colonized by mold hyphae.

1. FISH AND SHELL FISH MANAGEMENT ASSIGNMENT ASSIGNMENT TOWARDS PARTIAL FULFILMENT OF 2 nd Internal Examination ASSIGNMENT REPORT FOR SEMESTER –III M.Sc. ZOOLOGY(2 ND year) NAME-AKANKSHA ROUT REG. NO.-190705180139 SECTION – A CAMPUS –BBSR GUIDED BY-DR. Yashaswi Nayak

2. Alternative therapy towards the MANAGEMENT OF THE S aprolegniasis DISEASE OF FISH Akanksha Rout Centurion University Of Technology and Management , BBSR Core Course-Fis h and shell fish management M.Sc Zoology (3rd semester) 2019-2021 Sec B

3. What is SAprolegniasis??? Pathogen :Fungal disease of fish and fish eggs. Causative agent : Spores of Saprolegnia species which is in the group of "water moulds." These moulds ( fungi) Habitat generally affected : Commonly seen in the fresh or slightly salty water ( brackish water ). Fungal spores are found in all fish ponds and create problems in stressed fish. Generally attacks open wounds on fish and spreads to healthy tissue. Saprolegnia is sometimes called “ COTTON WOOL’ DISEASE” or “ WHITE HAIR DISEASE ” Causes of saprolegniasis : Poor water quality . Low temperatures (at or below 20°C), hence high mortalities in winter. Presence of chemical irritants (e.g. disinfectants, soaps , or detergents) in the water. Chemicals remove protective mucous layer on fish’s skin leaving it vulnerable to infection by Saprolegnia . Overcrowding (which leads to risk of skin damage). Malnutrition. Saprolegniasis affected koi fis h Branched hyphae of Saprolegnia species

4. SYMPTOMS OF S aprolegniasis : C otton-like outgrowth- coloured white, grey or brown on the skin , fins, gills, or eyes of fish — or on fish eggs. Respiratory distress evident if the gills are affected and death can follow rapidly. Infection makes lethargic ( weak) and less responsive to external stimuli . Sunken eyes with depigmented skin. Condition makes it easy to betargeted by predators.  Microscopic view depicts, Saprolegnia as branching trees called hyphae.  Protozoan parasites are frequently found on gills of fish suffering from winter Saprolegniasis .

5. TREATMENT ,prevention and control:- Bath treatment with Sodium hydroxide at 10-25g/ litre (10-20min); Potassium permanganate at 1g/100liters (30-90min); or Copper sulphate at 5- 10g/per100liters (10-30min ), Malachite green (C 23 H 25 ClN 2 ). Other common treatments recommended include formalin and povidone iodine solutions. Over treatment can further damage fish tissue, resulting in recurring infections . Saprolegniasis is best prevented by good management practices such as: Maintenance of good water quality (high dissolved oxygen, low ammonia concentration etc ) ▪ Avoid overstocking of fish to reduce injury and cannibalism ▪ Provision of good and healthy nutrition. ▪ Removal of any injurious element from the ponds. ▪ Avoid overfeeding of fish ▪ Handle fish with care to reduce (mechanical) stress due to handling ▪ Removal of any fish with open injury ▪ Disinfect ponds with quick lime ▪ Promptly removal of dead eggs from the hatchery; potentially in all freshwater fishes, incubated eggs are readily infected (Eli et al ., 2001 ). ▪ Promptly removal of dead fish from the pond. ▪ Avoid the use of unprocessed organic matter to fertilize the pond.

6. Phytotherapy as an Alternative TREATMENT against s aprolegniaisis : in fish: Azadirachta indica or neem leaves known to have antifungal properties are quercetin and ß- sitosterol , polyphenolic flavonoids and seeds hold valuable constituents including gedunin and azadirachtin . Vernonia amygdalina has antifungal properties as studied from the bioactive compounds isolated from it are Vernodalin , Vernomygdin , Vernoniosides A1, A2, A3, B1 , Vernoniosides A4, B2, B3 , Vernoniosides D and E, Vernodalol and Epivernodalol . Cassia fistula stem-bark alcoholic extracts were effectively able to inhibit hyphal growth and kill both of the zoospores and hyphae of the three pathogenic water mold . Its bark also contain flavonoids fistulic acid, rhein , fistucacidine , kaempferol , procyanidine , tannin, oxyanthraquinone , emodin , steroids like luperol , β- sitosterol proteins, carbs, sennoside A and B, rhein , its glucoside barbaloin , aloin , pectin ,, fistulic acid, oxyanthraquinone , emodine and chrysophanol Piper betle has chavibetol , chavibetol acetate, allypyrocatechol diacetate, campene , chavibetol methyl ester, eugenol, α- pinene , β- pinene , a-limonene, chavicol , pcymene,caryophyllene , chavibetol , cineole and estragol as the major components whose roots has antifungal activity against fish water mold