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Fungal Infections in Some Economically Important Freshwater Fishes

  • University of the Punjab, Lahore,Pakistan

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Aim of this study was to investigate fungal infections in four species of carps including goldfish, Carassius (C.) auratus L.; silver carp, Hypophthalmichthys (H.) molitrix Richardsons; rahu, Labeo (L.) rohita Hamilton and Ctenopharyngodon (C.) idella Valenciennes. Nine specimens of each species were studied for the presence of fungal infections. Infected fishes showed clinical signs such as fungal growth on skin, fins, eyes, eroded fins and scales, hemorrhages on body surface and abdominal distension. The specimens from infected organs of fish were inoculated on each, malt extract, Sabouraud dextrose and potato dextrose agars. The fungal colonies of white, black, green, grey and brown colors were observed in the agar plates. Slides were prepared and stained with 0.05% Trypan blue in lactophenol. C. auratus showed the highest infection rate (44.4%) followed by H. molitrix and L. rohita (11.1% each). Five fungal species viz. Aspergillus (33.3%), Penicillium (22.2%), Alternaria (27.7%), Blastomyces spp (11.1%) and Rhizopus (5.5%) were isolated. Posterior part of the fish had significantly (P=0.05) higher (62.5%) infection as compared to anterior part (37.5%). The caudal fin with 31.25% infection was the single most affected area. This study showed that most of the fungi isolated from fishes are considered as normal mycoflora, yet many fungi can cause natural infections in ponds and aquarium.
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Pakistan Veterinary Journal
ISSN: 0253-8318 (PRINT), 2074-7764 (ONLINE)
Accessible at:
Fungal Infections in Some Economically Important Freshwater Fishes
Zafar Iqbal*, Uzma Sheikh and Rabia Mughal
Department of Zoology, University of the Punjab, Lahore, 54590, Pakistan
*Corresponding author:
September 12, 2011
January 22, 2012
February 18, 2012
Key words:
Carassius auratus
Ctenopharyngodon idella
Fungal infections
Labeo rohita
Aim of this study was to investigate fungal infections in four species of carps
including goldfish, Carassius (C.) auratus L.; silver carp, Hypophthalmichthys (H.)
molitrix Richardsons; rahu, Labeo (L.) rohita Hamilton and Ctenopharyngodon (C.)
idella Valenciennes. Nine specimens of each species were studied for the presence
of fungal infections. Infected fishes showed clinical signs such as fungal growth on
skin, fins, eyes, eroded fins and scales, hemorrhages on body surface and abdominal
distension. The specimens from infected organs of fish were inoculated on each,
malt extract, Sabouraud dextrose and potato dextrose agars. The fungal colonies of
white, black, green, grey and brown colors were observed in the agar plates. Slides
were prepared and stained with 0.05% Trypan blue in lactophenol. C. auratus
showed the highest infection rate (44.4%) followed by H. molitrix and L. rohita
(11.1% each). Five fungal species viz. Aspergillus (33.3%), Penicillium (22.2%),
Alternaria (27.7%), Blastomyces spp (11.1%) and Rhizopus (5.5%) were isolated.
Posterior part of the fish had significantly (P=0.05) higher (62.5%) infection as
compared to anterior part (37.5%). The caudal fin with 31.25% infection was the
single most affected area. This study showed that most of the fungi isolated from
fishes are considered as normal mycoflora, yet many fungi can cause natural
infections in ponds and aquarium.
©2012 PVJ. All rights reserved
To Cite This Article: Iqbal Z, U Sheikh and R Mughal, 2012. Fungal infections in some economically important
freshwater fishes. Pak Vet J, 32(3): 422-426.
Freshwater fishes are an important protein source for
people of many countries (Hussain et al., 2011; Rubbani
et al., 2011). However, globally fish from freshwater and
marine sources are in severe decline, driven in large part
by economic and human population growth (Limburg et
al., 2011). Fish farming in various parts of the world has
increased many folds in the last decade. As a result, fish
culture has now become commercially an important
industry worldwide. In the Punjab province of Pakistan,
five species of carps including H. molitrix, C. idella, L.
rohita, Catla catla Hamilton and Cirrhinus mrigala
Hamilton are cultured. The establishment of 7829 fish
farms (area 45650 acres) in private sector is an indicator
of rapid growth of fisheries sector (Khan et al., 2011).The
growth of fish culture has also raised issues of fish health.
Bacterial hemorrhagic septicemia, lernaeasis, saprolegnia-
sis and anoxia are the most commonly occurring fish
diseases in pond fishes in Punjab (Iqbal et al., 2001).
Ornamental fish keeping has become an increasingly
popular hobby worldwide. The trade of ornamental fish is
a multi-million dollar industry now. Twenty species of
ornamental fishes are imported from Southeast Asian
countries into Pakistan (Ahmad, 1996). These fishes are
transported alive and sold to the hobbyists by the pet
shops. Fungi are known to attack fish eggs, fry,
fingerlings and adult fish. Water molds infections cause
losses of freshwater fishes and their eggs in both natural
and commercial fish farms (Bangyeekhun and Sylvie,
2001). The fungal diseases occur in brood stock and all
life stages of fish and eggs. Fungal infection cause low
productivity of fry and low production in fish culture
(Kwanprasert et al., 2007). The mortality rate due to
fungal infection may reach some time up to 80-100% in
incubated eggs (Chukanhom and Hatai, 2004). According
to Akande and Tobor (1992) post-harvest handling of
fishes may also result in infection with microorganisms
such as bacteria and fungi. The ubiquitous fungi are
part of the normal mycoflora of fresh and estuarine
ecosystems and have a worldwide distribution. However,
there are certain fungi which cause fish diseases.
Shahbazian et al. (2010) isolated Penicillium expansum,
Penicillium citrinium; Aspergillus terruse, Aspergillus cli-
Pak Vet J, 2012, 32(3): 422-426.
vatus; Alternaria spp; Saprolegnia parasitic, Saprolegnia
lapponica, Saprolegnia ferax and Saprolegnia hypogyna
and 7 other species of fungi from infected eggs of rainbow
trout, Oncorhynchus mykiss in Iran. However, Fadaeifard
et al. (2011) isolated 8 species of fungi from eggs and
brood stock of rainbow trout O. mykiss. These isolates
were Penicillium spp, Acreomonium spp, Alternaria spp,
Fusarium solani, Aspergillus spp, Mucor spp,
Saprolegnia spp. and Cladosporium spp. Primary
infections in fishes and fish eggs by oomycetes are also
reported (Walser and Phelps, 1993). Although, infection
as a result of microbial contamination does not usually
result in disease but environmental stress may upset the
balance between the potential pathogens and their hosts.
Under such conditions the chances of infection increases.
This study was aimed to investigate the mycoflora
associated with apparently healthy as well as diseased
ornamental and culturable fishes.
Nine goldfish, C. auratus were collected from a pet
fish shop in Lahore and nine specimens each of culturable
carps, grass carp (C. idella), silver carp (H. molitrix) and
rahu (L. rohita) were obtained from Fish Research Farms,
University of the Punjab, Lahore, Pakistan. The fishes
were transported immediately to laboratory in sterile
polyethylene bags in aerated aquarium/pond water. The
fishes were kept separate in glass aquariums with
continuous air supply at ambient temperature. Total length
(TL) and weight (Wt) of each specimen was measured and
health status of every individual fish was also observed.
The fish body was divided into two parts; Anterior part
(head, eyes and gills) and posterior part (all fins and rest
of the body) to note the infection site and data thus
obtained was analyzed by Chi-square test.
For culturing of fungal specimens, three different
types of media including malt extract agar (MEA),
Sabouraud dextrose agar (SDA) and potato dextrose agar
(PDA) were prepared and streptomycin sulphate was
supplemented to each preparation of media to avoid
bacterial contamination. The body surfaces of all the
fishes under study were disinfected by dipping each fish
in 1% formaldehyde for 1 to 5 minutes followed by 70%
alcohol and finally in sterile water in which it was
thoroughly rinsed. The fungal isolates were collected from
infected organs of fish with sterile needle and inoculated
on malt extract (Oxoid, UK), Sabouraud dextrose (Oxoid,
UK) and potato dextrose (M096-India) agars. The agar
plates were incubated at 28-30°C and fungal growth was
observed after 4-7 days. The fungal colonies of various
colors were observed in the agar plates. For microscopic
examination, slides were prepared from each colony and
stained with 0.05% Trypan blue in lactophenol. The slides
were observed under Digipro-labomed microscope and
photographed. The fungi were identified with the help of
available fungal identification keys and literature
(Willoughby, 1994).
A total of 36 fishes of four species were examined
(Table1). Fungal infection was observed in C. auratus, H.
molitrix and L. rohita. However, no fungal infection was
observed in C. idella (Table 1). The clinical picture of
infected C. auratus showed fungal growth on head, gills,
eyes and fins. Additionally, infected fishes had eroded
scales and hemorrhages over body surface and moderate
body distension. Tips of caudal fin were eroded in H.
molitrix. Early infection was seen on caudal fin of L.
rohita. Posterior part of the fish had 62.5% had
significantly (χ2=3.38; P=0.05) more infection than
anterior part (37.5%) infection and Hence, the attack on
both anterior and posterior part of the fish was not equal.
The attack on the posterior part was always recorded
higher because of having 85-90% more surface area. The
single most affected site was caudal fin (31.25%). The
infection on head, gills and eyes of fish may lead to
serious pathological conditions as extensive growth of
fungal hyphae in eyes may cause complete blindness and
from eyes may penetrate into brain and in such condition
the treatment is impossible and eventually the fishes die
(Srivastava, 2009). Fin infection is considered less
pathogenic as such fishes survive but this infection may
lead to complete damage of the fins.
Table1: Infection level and site of infection in fishes.
Mean Wt
Site of infection in
C. auratus (44.4%) 10.75±3.32 19.46±8.10 Head, eyes, gills,
fins, abdomen
H.molitrix (11.1%) 19.78±5.33 146.33±99.80 Head, Abdomen,
Caudal fin
L.rohita (11.1%) 23.56±3.61 183.89±105.71Caudal fin
C. idella (0%) 21.50±3.41 127.44±56.76 No infection
Table 2: Fungal species isolated from different organs of fishes.
Organ Fungal
Fungi isolated
Head a (1) Penicillium spp. C. auratus
CdF a (2) Aspergillus spp.
PcF a & b (2) Penicillium spp.
PvF and AnF a & b (2) Alternaria spp.;
Blastomyces spp.
Eye a & b Aspergillus spp.;
Alternaria spp.
Gills a (1) Alternaria spp.
C. auratus
Head a (3) Aspergillus spp.;
Penicillium spp.
CdF a (1) Rhizopus spp. C.auratus
Ab a (1) Penicillium spp.
CdF a (1) Aspergillus spp. C.auratus
Gills a (2) Blastomyces spp.
CdF a (1) Alternaria sp.
Head a (2) Alternaria spp.
Ab a (1) Aspergillus spp.
L.rohita CdF A Aspergillus spp.
Note: fungal colony a (3) means, 3 colonies of which one ‘a’ was
processed for identification; colony a&b (2) means, 2 colonies and both
were processed. Abbreviations of organ studied: PcF = pectoral fin;
PvF= pelvic fin; Anf = anal fin; CdF = caudal fin; Ab = abdomen.
Five fungal genera viz. Aspergillus spp. (33.3%);
Penicillium spp. (22.2%); Rhizopus spp. (5.5%) (Fig. 1, 2,
3), Blastomyces spp. (11.1%) and Alternaria spp. (27.7%)
were isolated from C. auratus. Two genera Aspergillus
spp. and Alternaria spp. were isolated from H. molitrix.
From L. rohita only Aspergillus spp. was isolated (Table
2). Mixed fungal infection was also observed in C.
auratus, in three combinations as Alternaria spp.,
Blastomyces spp., Aspergillus spp., Alternaria spp. and
Aspergillus spp. Penicillium spp. The most prevalent
genus was Aspergillus spp. It was isolated from C.
Pak Vet J, 2012, 32(3): 422-426.
Fig 1: A, Colonies of Rhizopus on MEA,(fish 4,C.auratus).B, C, Rhizopus
(from plate–A) showing long branched sporangophore with sporangium
bearing spores.
auratus; H. molitrix and L. rohita. Alternaria spp. was
isolated from C. auratus; H. molitrix and Penicillium spp.,
Blastomyces spp., and Rhizopus spp. were isolated from
C. auratus only (Table 2).
Aspergillomycosis has been principally described in
African fish, especially the tilapia Oreochromis sp.
(Olufemi, 1983). A number of Aspergillus species such as
A. flavus, A. japonicus, and A. terreus are involved in this
infection. These species presumably cause infection via
entry into the fish through contaminated feed. Jalilpoor et
al. (2006) reported infection of Aspencer percicus eggs
with Penicillium spp., Fusarium spp., Mucor spp. and
Saprolegnia spp. which caused 7 and 22% mortality of
these eggs.
Fig 2: A, colonies of Aspergillus on PDA, (fish 5, C.auratus). B. Aspergillus
spp. (isolated from plate A) with round head and black conidia.
Fayioye et al. (2008) isolated five different species of
fungi including Fusarium, Aspergillus, Rhizopus, Mucor,
and Penicillum from 8 edible smoke-dried freshwater
fishes. Junaid et al. (2010) isolated 7 fungal species from
stockfish in Nigeria and these included A. flavus, A.
fumigatus, A. niger, Trihophyton verrucosum, Rhizopus
Mucor and Penicillum spp. and among these Mucor spp.
showed the highest occurrence. In another study, fungi of
eight different genera; Saprolegnia, Aspergillus,
Fusarium, Mucor, Pencillium, Rhizopus, Scopulariopsis
and Curvularia were isolated from two fish species,
Oreochromis spp. and Claris gariepinas (Refai et al.,
2010). Shahbazian et al. (2010) isolated Penicillium
expansum, Penicillium citrinium; Aspergillus terruse,
Aspergillus clivatus; Alternaria spp. and 11 other fungal
species from infected eggs of rainbow trout. Moreover,
Fadaeifard et al. (2011) reported the occurrence of
different fungal species of genera including, Penicillium,
Acreomonium, Alternaria, Fusarium, Aspergillus, Mucor,
Saprolegnia and Cladosporium from the eggs and brood
stock of rainbow trout.
Shabana (2002) reported Alternaria eichhorniae in
Nile tilapia, Oreochromis spp. A fatal behavioral disorder
of carp was attributed to cerebral infection with Alternaria
spp. probably following exposure to adverse
environmental conditions (Sharaburin and Bazderkina,
Pak Vet J, 2012, 32(3): 422-426.
1990). Blastomycosis is caused by Blastomyces
dermatitidis. This infection occurs by inhaling fungal
spores and it is increasingly recognized in immuno-
compromised hosts (Pappas et al., 1993).
Fig 3: A. Colonies of Penicillium on SDA, (fish 1, C. auratus). B, C,
Penicillium sp. showing brush like arrangement of fruiting head.
Findings of the present study are comparable to the
findings of Refai et al. (2010), Shahbazian et al. (2010)
and Fadaeifard et al. (2011). However, Refai et al. (2010)
has characterized Aspergillus spp., Penicillium spp. and
Rhizopus spp. as normal mycoflora and these spp. may be
regarded as opportunistic pathogens (Refai et al., 2004) as
many of them possess virulence factors which enable
them to cause disease (Refai et al., 2010), especially
under favorable predisposing conditions. Ecological
differences play an important role in species diversity of
fungi that develop on both fish and eggs (Hussein et al.,
2001). Interaction of physiochemical factors generally has
influence on the diversity of water molds (Paliwal and
Sati, 2009).
Lack of good aquarium keeping in pet shops and fish
farms increases the chances of fungal infection in fishes.
The basic health management practices may be easily
over looked due to dearth of trained personal or resources.
This study indicates that although most fungi isolated
from fishes are considered as normal mycoflora, yet they
can cause infections. This is confirmed by the presence of
fungal hyphae in the lesions on the body of the fish. These
findings point our attention to the possible role of fungi in
affecting both ornamental and culturable fishes.
Acknowledgement: We are thankful to Dr. Abdul Nasir,
Associate Professor, Department of Botany, University of
the Punjab, Lahore for authentication of fungal species
identified in the present study.
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... In a study on three freshwater ornamental fish species, Carassius auratus, Poecilia reticulate, and Xiphophorus maculatus, C. auratus exhibited eroded scales, lesions, and hemorrhages on the abdomen and fins, while X. maculatus had a higher infection rate in the eyes and mouth (Haroon et al. 2014). In our study, the posterior parts of the fish body showed the highest infection rate compared to the anterior parts, which is contrary to some other studies (Iqbal et al. , 2012. These differences may be attributed to the fact that anterior parts come into contact with fungal spores first during feeding and swimming activities in water . ...
... These differences may be attributed to the fact that anterior parts come into contact with fungal spores first during feeding and swimming activities in water . Severe infections of the eyes and gills have been reported to cause respiratory distress and impairment in fish, and may even be fatal due to fungal hyphae (Srivastava 2009;Iqbal et al. 2012). This study provides valuable insights into the clinical signs and symptoms of fungal infections in common carp, contributing to a deeper understanding of the pathological aspects and overall health status of the affected fish. ...
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... Environmental stress may increase the chances of infection and fish may display signs of illness. A lack of good aquarium keeping in fish farms increases the chances of fungal infection in fish (34). ...
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Cascadura, (Hoplosternum littorale) is a delicacy in some countries; however, literature on this species is limited. This study aimed to identify gastrointestinal and hematological parasites and their potentially associated pathological effects in wild and farmed Cascadura in Trinidad. Samples of forty (40) wild and farmed Cascadura fishes were collected for this study. Morphometric measurements of whole fish and gastrointestinal tracts (GIT) were recorded. Blood smears were processed and stained with Wright's Giemsa and GIT sections stained with Hematoxylin and Eosin (H&E) and Periodic Acid Schiff (PAS). The gross anatomy and histological features of the GIT of the Cascadura were consistent with the fish belonging to the Callichthyidae family. Hematological parasites were found in 13 out of the 40 (32.5%) fishes (nine wild; four farmed): 6 of 13 belonged to Alternaria spp. (15%), 6 of 13 were protozoa (15%) and 1 of 13 (5%) was a blood fluke belonging to the family Aporocotylidae. Three gastrointestinal nematodes were found in three wild fish, one identified as an anisakid. Gastric and intestinal structures appeared normal; however, inflammatory cells were found in one wild fish with damaged villi and degenerated epithelium of the intestine.
... Microbial contamination can lead to infection and disease; environmental pressures can destabilise prospective pathogens and their hosts (Iqbal et al., 2012). When these bacteria are consumed, they have a wide range of effects on the human health system, from minor illnesses to severe illnesses and even death. ...
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Smoked fish and fish products are widely consumed in Ghana because they are comparatively affordable. However, studies in other parts of Africa have reported microbial contamination of processed fish and fish products. It is for this reason that this study was undertaken to assess the microbial quality of smoked fish vended in the Nyankpala and Tamale markets. Fish samples were collected from vendors from Nyankpala and Tamale Markets and analysed using standard procedures and methods. Out of the 66 samples, 22.76% had Shigella spp. whilst 77.36% were free of Shigella spp. The highest count of 4.31 × 10 5 cfu/ml Shigella spp. isolates was from Tamale Central Market samples and lowest count of 1.00 × 10 3 cfu/ml was from the Tamale Vodafone Office Area Market. Out of the 66 samples, only 13.63% of the samples had Salmonella spp. and 86.37% were free of it. Salmonella spp. showed the highest count of 1.00 × 10 5 cfu/ml and lowest count of 1.00 × 10³ cfu/ml of samples from Tamale Central Market. Out of the 66 samples, 18.20% had E. coli whilst 81.80% were free from it. The highest count of 2.74 × 10 5 cfu/ml E. coli isolates were recorded from samples from the Tamale Central Market and lowest count of 1.00 × 10³ cfu/ ml from Lamashegu Market. Shigella spp., Salmonella spp. and E. coli were the microbes obtained from the smoked catfish. Shigella spp., Salmonella spp. and Escherichia coli could be attributable to vendors' unhygienic practices and unsanitary ambient circumstances. It is therefore recommended that the processors and vendors should employ best practices in processing and handling fish and fish products to minimise the level of contamination.
... The histopathological organ changes observed in this study were comparable to reports of Iqbal et al, [10], who reported Aspergillus infection in the gills resulted in damage of secondary lamellae and this may be a source of respiratory problems. ...
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Aims: This study aimed to investigating the pathogenicity of Aspergillus fumigatus in the experimental infection of Clarias gariepinus fingerlings and juvenile catfish. Methodology: One hundred and forty healthy eight-week old Clarias gariepinus fingerlings (average weight of 4g) and 140 healthy sixteen-week old juvenile (average weight of 10g) were purchased from a commercial fish farms in Ibadan. The fingerlings and juveniles were randomly divided into seven groups, each with 20 fish in five litters of water. The fungal suspension containing 3.2 X 10 6 spores/ml of Aspergillus fumigatus was used for the pathogenicity test. Six groups were infected by immersion in water containing fungal spores at the rates of 2ml/L and 5ml/L for fingerlings and juveniles respectively. The clinical signs, skin lesions and mortality were observed daily for 14 days. Results: Aspergillus fumigatus isolated in this study has green spiked conidia; and the size of the conidia is 2.5µm. The conidia have a smooth surface and small spikes covering their surface. Moreover, the mortality rate was significantly (p = 0.40) higher in infected fingerlings (80%) than juveniles (62%) at fourteen days post-infection. The gross lesions observed during experimental infection of fingerlings and juveniles included exophthalmia, atrophied barbel, congested trunk kidney, hyperemia of gill filaments, and skin depigmentation. The histopathological organ changes caused by Aspergillus fumigatus were obvious in the liver and gills. Vacuolar degeneration of hepatocytes and necrosis of some melanomacrophage cells, in addition, severe erosion of the primary and secondary lamellae, were observed in infected juveniles. Conclusion: Aspergillus fumigatus causes high mortality in fingerlings and juvenile of African Catfish (Clarias gariepinus).
... Another reason why Tilapia spp. aquaculture is becoming more popular is the availability of these fish in brackish and seawater resources (Iqbal et al., 2012;Yaqub et al., 2019). Moreover, these fish are a good alternative protein source for humans, especially in tropical and subtropical areas (El-Sayed,2019). ...
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The soybean meal replacement with corn meal and chestnut meal was evaluated on growth performance, feed utilization efficiencies, nutrient digestibility, organosomatic and body composition of Oreochromis niloticus fingerlings. Seven experimental diets were categorized into various groups containing 0 (control), 5, 15, and 25% of corn and chestnut meals respectively. The experimental diets were given to triplicate groups of Nile tilapia (7.31 ± 0.12g) at a rate of 3% of body weight for 12 weeks. Similar growth performance and feed conversion ratio was observed in control group and groups fed corn gluten meal and chestnut meal based diets. There was no significant difference ( P ˃0.05) in feed efficiency ratio and protein efficiency ratio in control group and treatment groups. The hepatosomatic index values were not significantly different ( P ˃0.05) in control group and other treatment groups. The viscerosomatic index values differed significantly ( P ˂0.05) among experimental groups. The highest value was obtained in group fed diet containing 5% corn meal and lowest for group fed diet containing 15% chestnut meal. The substitution of soybean meal had no significant impact ( P ˂0.05) on moisture, protein and fat contents in fish whole body composition. The apparent digestibility of protein, fat, fiber, carbohydrates and ash were significantly different ( P ˂0.05) for groups fed control, corn meal and chestnut meal based diets. The ADC value for protein was highest in group fed 5% chestnut containing diet and lowest value was exhibited by group fed 15% chestnut meal diet. The ADC values of crude fiber and crude fat were highest for diets containing 15% chestnut and 15% corn respectively and lowest in control group. The apparent digestibility of crude ash was highest for group fed diet containing 15% corn and lowest for diet containing 5% chestnut meal. It can be concluded that up to 25% of corn and chestnut meal can be used to substitute soybean meal in diet for Nile tilapia fingerlings on basis of weight gain without any negative effect on growth and feed utilization efficiency.
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Research into freshwater fungi has generated a wealth of information over the past decades with various published articles, i.e., reviews, books, and monographs. With the advancement of methodologies used in freshwater fungal research, and numerous mycologists working on this ecological group, our knowledge progress and understanding of freshwater fungi, including novel discoveries and new insights in the ecology of freshwater fungi, has advanced. With this enormous progress, it is timely that an updated account of freshwater fungi be compiled in one volume. Thus, this account is published to give a comprehensive overview of the different facets of freshwater fungal biology. It includes an updated classification scheme based on the latest taxonomic and phylogenetic analysis of freshwater fungal taxa, including their evolutionary history. The biology, diversity, and geographical distribution of higher and basal freshwater fungi are also discussed in the entries. A section on dispersal and adaptation of filamentous freshwater fungi is included in the present work. The ecological importance and role of fungi in the breakdown of wood in freshwater habitats, including their physiology, are discussed in detail. The biotechnological potential of freshwater fungi as producers of bioactive metabolites are reviewed, with methodologies in antimicrobial drug discovery. The present volume also provides an overview of different high throughput sequencing (HTS) platforms for freshwater fungal research highlighting their advantages and challenges, including recent studies of HTS in identification and quantification of fungal communities in freshwater habitats. The present volume also identifies the knowledge gaps and direction of future research in freshwater fungi.
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Scientifically substantiated and experimentally proven the feasibility of conducting proper risk-based control of the safety and quality of freshwater fish in the Kyiv region's agro-food markets following the regulatory document's requirements, developed by express, improved methods for determining freshness and microstructural examination of muscle tissue. At organoleptic assessmentUkrainian scaly carp, crucian carp, and pike perch were fresh, and rotan was of dubious freshness. Regarding pH value, Nesler number, and qualitative reaction to the content of ammonia and ammonia salts with ’Nesler’s reagent, the meat of Ukrainian scaly carp, crucian carp, and pike perch corresponded to fish of a fresh degree. For rotan meat, its dubious freshness was established. In the photometric determination of the studied fish's freshness, the optical density of the supernatant correlated with the quality indicators for the content of ammonia and ammonia salts. An improved benzidine test with a filtrate from the gills of the mouth confirms the doubtfulness of the freshness of the fish. The studied fish samples corresponded to the standard indicators according to microscopic indicators and the number of mesophilic aerobic and facultative anaerobic microorganisms. By determining the chemical parameters of the studied fish, it was found that the mass fraction of water in meat was the highest in rotan (78.30 ±0.13%) and was accompanied by the smallest mass fraction of dry matter (21.70 ±0.09), the proportion of proteins (16.96 ±0.06), indicators of fat in meat (3.01 ±0.06%) and formed the lowest indicator of its relative biological value – 92.5%. In benign fish with organoleptic indicators, a microstructural study of muscle tissue revealed significant changes in its structure with atrophy of individual muscle fibers and growth in these areas of connective, mainly fatty tissue.
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Over the past 80 years, tilapia have been translocated globally for aquaculture; active production is recorded in >124 countries. Of 7 million tonnes of tilapia produced in aquaculture, 79% is from 79 countries outside the natural range of tilapia. Capture fisheries account for a further 723,627 tonnes of tilapia, and >47% of this is landed from established invasive populations outside Africa. Tilapias host a rich fauna of parasites, many of which have been translocated with their hosts. This review summarises >2500 host–parasite records from 73+ countries and >820 recorded tilapia translocations (provided in the supplementary materials). This work focuses on the notable pathogens that threaten the health of cultured populations of tilapia, providing a description of their pathology and includes species that also have substantial impacts on wild tilapia populations, where relevant. For each major parasite taxonomic group, we highlight which parasites have been translocated or have been acquired from the new environments into which tilapia have been introduced, together with remarks on standard treatment approaches and research on them and their management and control. Regarding the theme ‘Tilapia health: quo vadis?’, Africa has enormous potential for aquaculture growth, but substantial knowledge gaps about tilapia parasites in many African states remain, which creates associated production and biosecurity risks. For each parasitic group, therefore, the risks of parasite translocation to new regions as tilapia aquaculture industries expand are highlighted.
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Fungal diseases of fresh water eggs and fishes are known to be a problematic disease. The aim of this study was to investigate the aquatic fungal flora specially oomycete fungi in rainbow trout hatcheries from west part of Iran during fall and winter 2008, an attempt to isolate fungi from the eggs and broodstocks showing fungal infection at the three rainbow trout farms. A total of 150 randomly selected eggs and 15 broodstocks were obtained. A sterile swab was taken from outer surface of body (skin, gills, fins), as well as eggs. sabouraud dextrose agar, glucose yeast agar and Hemp seed in sterile tap water was used for fungi isolation. Identification of the fungi was based on their vegetative organs, including hyphae shape and size, asexual reproduction organs, shape of sporangium and spores, and generative organs, structure of oogonium, oosporangium and antheridium. In this study eight genus and species were identified and the most common were Penecillium sp., Acreomonium sp., Alternaria sp., Fusarium solani, Aspergillus sp., Mucor sp., Saprolegnia sp. and Cladosporium sp. Among the above species Penecillium sp. with 23% and Saprolegnia sp. with 3% have more and less occurrence, respectively. Identification of Saprolegnia sp. which is an important pathogen in aquaculture needs further study in the future.
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The present research was conducted on different life stages (90, 120, 150 and 180-day age) of Indian major carps to check the growth responses under sub-lethal chronic toxicity of iron. Fish of each age group were stressed with iron for 30 days and growth parameters viz, average weight, fork and total length before and after exposure of iron were measured. Feed intake and feed conversion ratio of each fish species were also determined to evaluate the condition and health of fish during the stress period. Statistical analysis of data showed that age of 150 days for Catla catla, Labeo rohita and Cirrhina mrigala were the most sensitive in terms of fish growth. All the fish species of 150 days age showed significantly (p<0.05) negative growth in terms of weight, fork length and total length. Condition factor of control fish reveals that weight gain was maximum in relation to length of fish as compared to fish kept under chronic exposure of iron. The results also showed that feed intake increased during stress of iron but this feed does not take part in growth as shown by lower values of feed conversion ratio (FCR) of all fish species in iron stressed medium. This study concluded that among four age groups sublethal chronic exposure of iron disturbed the feed intake, FCR, growth, condition and fish health in 150-day fish.
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Fungal infection in the eggs of freshwater fish is well known as a problematic disease. The aim of the present study was to isolate and identify parasitic and saprophytic fungi from affected eggs of rainbow trout at two fish hatchery in Kermanshah province. The sample were inoculated in culture media (SDA,CMA,GPA and stilled water with cotton seed culture) at room temperature (18-24°C).17 species of fungi isolated from the fungal eggs. Five fungi species that isolated in this study were belonged to the saprolegniaceae family including
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This study was aimed at isolating and identifying the fungi associated with stockfish contamination in Jos Metropolis. A total of 100 stockfish samples were randomly purchased from four markets namely, Terminus, Kwararafa, Katako and Gada biu in Jos town, Plateau State, Nigeria. The stockfish samples were assayed for fungal contamination and moisture content using standard procedures. All the stockfish samples were contaminated with fungi. Seven different fungi were found to be associated with the stockfish samples sold in the four different markets. The associated fungi were Mucor Spp, Asergillus flavus, Trichophyton verrucosum, Aspergillus niger, Aspergillus fumigatus, Penicillin Spp and Rhizopus Spp. It was observed that Mucor Spp had the highest rate of occurrence among the isolated fungi. The moisture content was between 6 -27%. Results from the study are useful in developing and establishing public health standards as consumption of these fungi exposes the consumers to the probable toxic metabolites produced by the fungi.
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This study was carried out on 360 freshwater fishes (240 Oreochromis species and 120 Clarias gariepinus). They were collected from different governorates and during different seasons. Naturally infected fishes showed clinical abnormalities such as skin darkening, exophthalmia, corneal opacity, abdominal distention, ulceration of the skin and cotton wool like growths on various parts of the body. Fishes were then subjected to post mortem examination which revealed many abnormalities. Mycological examination revealed the isolation of 2081 fungal isolates from 150 diseased and 210 apparently healthy fish samples (1658 mould and 423 yeast isolates), of which 1334 were isolated from Oreochromis species and 747 isolates from Clarias gariepinus. Isolated moulds belonged to the following genera: Saprolegnia (4.2%), Aspergillus (43.0%), Fusarium (14.1%), Mucor (14), Penicillium (17.2), Rhizopus (4.8%), Scopulariopsis (1.2%), Paeciliomyces (1%) and Curvularia (0.4%). Yeasts isolated also from both fish species had the following incidence: Candida albicans (35.9 %), other Candida species (19.1%), Rhodotorula species (31.4%) and Torulopsis species (13.5%). Experimental infection with the most predominant fungi (Aspergillus flavus, Fusarium species and Candida albicans) was conducted to evaluate the pathogenicity of these isolates. Clinical pictures of experimentally infected fish were similar to those of natural infection. Inoculated fungi were re-isolated from different organs. Results were confirmed with histopathological examination, which revealed the presence of fungal hyphae and spores in different organs.
The apparent digestibility coefficients of dietary protein levels of reference diet and soybean meal based diets were estimated for Labeo rohita. Three test diets and three reference diets having 28, 30 and 32% crude protein levels were prepared. Chromic oxide was used as an inert marker for the evaluation of digestibility. Ten acclimatized fingerlings were stocked in 70L water tank system and fed twice daily at the rate of 2% wet body weight. Water level was maintained at 40 cm throughout the experimental period of eight weeks. The apparent digestibility of dry matter, crude fat and gross energy of reference and test diets were significantly different (p<0.05) except crude protein. It was concluded that the apparent digestibility of dry matter, crude protein, crude fat and gross energy was higher at 32% dietary protein level.
The genus of moulds known as Aspergillus has always been a factor in man’s environment. Even before the development of the microscope, Aspergillus colonies were well known as the white, yellow, green, red or black moulds seen on foods and rotting vegetation, although of course attempts at proper interpretation of the cause of such growths were not feasible.
An across the board (random) survey of various fish farms revealved 148 cases of disease and infection. The majority of cases (70%) has abdominal dropsy, Lernaeasis and anoxia. All culturable fish species, Labeo rohita, Cirrhinus mrigala, Catla catla, Hypophthalmichthys mlitrix and Ctenopharyngodon idella were found to be infected with various diseases. Labeo rohita being the most affected and Catla catla least affected species. The addition of organic manure and decayed food in fish ponds contributes to the occurrence of fish diseases. The causative agents are discussed with particular emphasis on diseases prevention through improved management techniques.