Survey of Fungal infestation of some species of fish in Tagwai Dam Minna was carried out from March to June 2002. Fungi were isolated from the scale/skin, gills and fins. Twenty-one fungi species were identified from 18 species of fish microbial growth was measured by direct cell count using Stuart colony counter. Most of the fungi encountered were of the mould group and infestation occurred among all the species sampled. The infestation was predominantly by Aspergillus species and the scale/skin was most widely affected. The study showed the identified fungi in order of frequency to be as follows. Aspergillius niger. Rrhizopus spp. Mmucor spp Aspergilus flavum. Aspergillus parasitous. Aspergillus fumigatus, Microsporum canis. Penicillum virridicalumand Fusarium spp respectively. Aspergillus niger occurred on all the species of fish sampled. Barrilius spa and Chrysichrhy auratus longifilis had significantly higher (P0.05) in the mean fungal load in different parts of the body of other fish species sample

Ayanwale, A.V.

Ojutiku, R.O.

Tsadu, S.M.

English

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SURVEY OF'L INFESTATION OF SOME FISH SPECIES FROM TAGWAI DAM,
MINNA, NIGER STATE
By
S.M. TSADU, R.O. 0JUTIKU2 A.V. ANYAWALE3
I& 2 fisheries department
Federal University of Technology rninna,
2 Government Science College Minna,
ABSTRACT
Survey of Finigai infestation of S01170 species of iriSh 111 TayWai dan. Minna was carried out from
March to June. 2002. Fungi were isolated from the scale / skin, gills and fins. Twenty-one fungi
species were identified from 18 species of fish. Microbral growth was measured by direct cell
count using Stuart colony counter. Most of the fungi encountered were of the mould group and
infestation occurred among all the species sampled. The infestation was predbminantly by
Aspeigillus species and the scale/skin was most tvidoly affected. The study .showe(! The identified
fungi in order of frequency to be as follows: Aspergillus niger Rillizopus spp, Mimeo!. sly),
Aspergilus flavun. Aspergillus parasitious. Aspergillus foiniyalus, Miciospoi un; Gaols. Penicillnin
viridicalum and Fusarium spp respectively. Aspergillos Myer occurre d on all the species of fish
sampled. Barrilius spp and Chrysichrhys auratus had-Significantly highet (P<O. 05) iiieqn
fungal load 011 their fins and gills. There was no sigliificant'difference (P> 0.05) in the ni6:an
fungal load in different parts of the body of other fish species sampled.
INTRODUCTION
Nigeria is blessed with inland water bodies cOvering about 12.5 million hectares and
about 20 million hectares of swamps, lagoons and estuarine, which can be used for fish farming
(Ita, et. al, 1985). Statistical survey has shown that the demand for fish in the country exceeds the
supply and also the domestic production is still very low when -icompared with the increasing
human population (Adeleke, 1999). Consequently, there is a relative susceptibility of different fish
species to infection (Baldwin et al 1967). Disease outbreak is one of the. problems faced in local
fish production in Nigeria.
Disease is defined as the definite morbid process with characteristic trend and
symptoms, which may affect a whole or parts of the body.
Causes of human disease due to fish consumption are comparatively rare despite the potential
ri!-.,.ks. However, chances of disease transmission are now..high due to increased pollUtion and
expansion of aqua cultural activities.
Awacoic (1996) documented preliminary notes in the parasite of fish in the areas of the Kainji
Reserv&r and observed that 30% of Sarothe,rodon niloticus were infected by Acanthocephala
while about 9% of Clarias gariepinus were infected by Cestodes. Ukolo (1969) reported that 40%
of Sarotheiodon niloticus were infected with trematodes, 15% had Acanthocephala in river Niger
area. He also reported cases of heavy Cestode infections from Kainji reservoir. In .eastern
Nigeria, Ugwuzor (1987) carried out a survey of helminth parasites of fish from the Imo River, and
encountered a low (7.7%) infection level. Abubakar and Tsadu (2003) also reported the
occurrence of some fungi on selected commercially important fishes in Minna, Niger state. Niger
state is blessed with large proportion of freshwater bodies as reported by lta et.al (1985). There
are about 772,243. 50 hectares of reservoirs and lakes which includes Kainji, Shiroro, Jebba and
Tagwan Dam. One of the causes of fish shortage is contamination with fungi, which lead to rapid
deterioration.. Therefore, this study was conducted to identify fungi species occurring, among
fishes in Tagwai dam and evaluate the rate of infestation at different parts of the fish body. .
MATERIALS AND METHOD
Fresh fish samples were randomly selected and purchased from fishermen at Tagwai Dam,
9g
Minna, Niger state three tunes in a month for a period of four months (march to June, 2002). They
were transported in sterile _polythene bags covered with paper foil with ice block beside the
polythene bags to the laboratory for analysis. Potato dextrose Agar (PDA) was prepared using
peeled and sliced Irish potato, glucose. Agar- agarschloramphenicol and distilled H20. The media
was prepared according to the method of Alabi (1967). Fungal Smear from fish samples were
taken by the method of Ojala (1968)..The areas Of the_sbodY of the fish samples (scales / skin, gills
or fins) were carefully rubbed with cotton weol swab impregnated with Distilled water in test tubes
according to thee method described by Ojala (1968). The mouth of the test tubes were covered
with cotton wood plugs which allowed air into the medium but prevented the entry of
contaminating microbes. Fungi infections were examined on three parts of the body skill/scale.
gills and fins Swabs from each part of the body were cultured in varied media concentrations in 3
replicates using factorial (3x4x3) experimental design. Fungal growth was observed for 24-72
hour and microbial growth was Observed by direct cell count of the micro-organism using stuart
colony counter. Furigi identification was done- by observing a combination of morphological
features and comparison with ether known taxa using microbial identification by Ogbuile et al
(1998)
The fungal load on the three parts of the body was anaiyzed by one-way analysis of variance.
RESULTS AND DISCUSSION
18 species of fish samples from 6 different families of fish which ncludes: Mormyridae,
Characidae, Bagridae, Cypinidae, Clandae, and cichliclae were analyzed for fungal infestations
from Tagwai Dam.
Table 1 shows the mean %Inge] load. (cfu/rn1)-on skin/scale, gills and fins of fish species form
Tagwai Dam which indicates that all the parts.Of fish analyzed carried fungal load. AuGhenogInnis
biseulatus. Chrysichttlys spp, cinysienthys nigrodigitatus had significant (Ps:
0.05) higher mean fungal load on their skin/scale than on their fins and gills. Flornicluomis
bunaculutus had significantly higher (P < 0.05) mean' fungal load ori. the gills than on their skin
and fins The mean fungal load on all the rest fishe species were not significantly different on all
the three body parts (p < 0.05).
Plate 1- 2 shows 'some fish species infested with fungi. Twenty one (21) fungi species were
identified from the 18 species of fish examined . table 2 shows the fungi spp and their
morphological characteristics for identification.
Aspolgillers ingot plate 3 occurred on all the 18 species sampled. RIlizopus spp (plate 4 )
occurred on 16 species. Plate 5 and 6 shows Asperrifilus fluvus and A.. funnyillius respectively
Both of them occurred in 14 out of 18 species. Aspen:onus species therefore had the highest
cases of occurrence in the fishes of the darn
Table 3 indicates the frequency and site specifity of fungi isolated from fish species samples
which revealed that isolates from the skin/scale of all species had highest number of isolates
(204) followed by the gills (198 isolates) and the least was fins (188). Though the differences
were not statistically significant (P> 0.005) Barillus spp had the highest number of isolates (80)
followed by Moon zilli (74) and Al/estos nurse (66).
The study revealed that different parts of the fish could harbour different types of fungi which
agrees with Eyo and Balogun (1992), who reported that fungí infestation is a major limitation to
good quality fish processing especially in areas where the relative humidity is always high Alkali
(1994) reported that relative humidity is usually high (about 70%) during rainy season in Tagwa
Dz.m-t area where this work was carried out The fungi isolates obtained from this study compared
favourably with those reported by john (1991) from smoke dried fish from River state Nigeria and
Burgos (1967) from his work on fish handling and processing. Both the authors concluded that
mould grovvth was a major problem of processed fish especially where relative humidity is above
70%. IVIost of fungi isolates were members of genus Aspergtilus which as observed by Olufemi
(1984) has the ability to grow under the environmental conditions of the host. Thus they are
environmental conformers The occurrence of Aspemilius species is of significant public health
concern. A niger and A flavus have been known to be common agents of food. seoilaees most
especially in the tropics where their spores are widely distributed easily. Some species of these
organisms are known to secrete toxins known as aflatoxins which cause food poisoning and are
carcinogenetio to man and when ingested by man or animal it affects the liver and no effective
therapeutic treatment has been known yet (Rubin, 1990). Aspergilus spp cause Aspergillosis (a
disease of the lungs) (Abubakar 2001). Many human and animal diseases such as mycotic
abortion, aflatoxin poisoning, alle-rgic reaction, systemic infection are attributed to mould and fungi
ingestion. Mycosis are important cause of morbidity and mortality in humans especially
individuals who are immunosuppressed as a result of othe.r diseases such as AIDS, organ
transplantation, radiation and even age (Zottoia, 1986). Pell!Giliitif77 Spp and Fusarium spp are
also capable of secreting toxins like ichra toxins and penicillic acid that are dangerous to human
health (Rubin 1990; Person and Duston, 1994). Various lung diseases in farmers are associated
with moulds and grain dust. (zottola and smith 1990).
Conclusion
From the study, it was revealed that fungal infestation 'occurs among fish species in Tagwai Dam
which mostly are of mould group. This research finding has shovvn that Aspergillus spp and other
mould fungi can attack fish as does the Saprolegnia.The work also confirms that fungi infestation
occurs among aquatic animals including fish just as they occur in terrestrial animals. Fish
processors and consumers should be aware of the possibility 6f fungi disease and rnycotoxins
from poorly processed fish.
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Survey of fungal infestation of some fish species from Tagwai dam, Minna, Niger State

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