The scales and fins of some freshwater fish species (Sarotherodon galilaeus, Oreochromis niloticus, Tilapia zillii, Barbus callipterus, Hemichromis fasciatus) from Kainji Lake, Nigeria were analyzed for their organic and inorganic matter. The aim of such study is to determine the usefulness of these waste parts of the fish in fish feed preparation. In all instances, the inorganic matter was found to be quite high in the fish exoskeleton, and calcium formed the highest element in the scales and the fins. These waste materials are therefore, considered as possible replacement for mineral sources in fish feed and probably the feed for other livestoc

Akintunde, E.A.

English

Aquatic Commons

POSSIBLE INCLUSION OF FISH WASTE
(SCALES AND'FINS) IN THE DIET OF
FISHES IN AQUACULTURE
by
V.A. AKINTUNDE
Department of ZoologyUniversity of lieIle-Ife, Nigeria
ABSTRACT
The scales and fins of some freshwater fish species were
analysed for their organic and inorganic matter . The aim
of such study is to determine the usefulness of these
waste parts of the fish in fish feed preparation. In allinstances, the inorganic matter was found to be quite highin the fish eNoskeleton, and calcium formed the highest
element in the scales and the fins. These waste materials
are therefore, considered as possible replacement for
mineral sources in fish feed and probably the feed for
other livestock.
INTRODUCTION
The scales, the fins and the viscera_ of fishes aredonsidered as waste parts of fish in Nigeria though in
many other countries, they are used for various purposes.
In fact, some people in this country do not eat the head
of fishes.
Scales are employed to Some degrees in elaesification offishes and they are also important in the estimation of
the age and growth. The biological functions of scalesis for protection, while thb fin serves the purpose of
locomotion.
The chemical analysis of fish scales indicated that the
scales generally contained 41% to 81% organic protein and
up to 16 - 59% mineral residue in dry matter. The former
consisted mainly of echthylepidin and collagen (Van Oosten,
1957). The relative amounts of these two albuminoids
when both present is nearly constant in scales of different
teleost fishes, about 76% ichthylepidin and 24% collagen.
Percentage composition of (ash) mineral residue of scales
had been determined for many fishes. Alosa sp contained
about 98381 Ca3(PO4) 2, 1.79% Mg3(1)04)77-Tlyrinus 0P.
contained 56.74% Ca3(1304)2, 1.66% Mg3(PO4)4, 41.57% CaCo3.Other elements including boron, fluorine, bromine,
lithium, stroneium have been found In scales of marinefishee. The concentration of all these materials varies
with environments.
.241
No importance has been attached to the exoskeleton and
offal of fishes. We have not thought of many useful ways
to which these items can be put.
The author had seen these supposedly useless fish parts
forming large heaps near processing huts or put in baskets
and bowls for disposal. It is therefore, the aim of this
study to determine the proportion the wastes form in the
fish, to analyse them and evalute them in feed preparation
for fishes in aquaculture. The aspect of this study already
carried out is hereby reported.
MATERIALS AND METHODS
Five species of fishes namely Sarotherodon galilaeus,
Oreochromis niloticus, Tilapia zillii, Barbus callipterus
and Hemichromis fasciatus, were caught from Kainji Lake,
Opa Reservoir, Teaching and Research Farm Reservoir both
at the University of Ife and fish collection was done
between 1982 and 1985. Before the scales and the fins
were removed and before the fishes were cut open, the
normal routine like identification, measurement and
weighing were carried out. The moisture content was
determined by drying the scales and fins separately to
constant weight.
The ash content was determined by incineration of weighed
and oven dried scales and fins. The mineral determination
was carried out using Golterman's et al (1978) methods.
RESULTS
Table 1 shows the number of each fish species used for
this investigation.
Table 1 Number of each fish species used
242
Fish Species Number of
Sprans
Examinad.
Range in
Standard
Length
B. callipterus 29 6.0-7.9
O. niloticus 24 7.6-15.0
S. galilaeus 64 6.7-14.0
T. 26 7.9-11.5
H. fasciatus 44 0.9-10.8
Family
Cyprinidae
Cichlidae
Ta
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 (g
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(gm
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Sc
al
es
Proportion of Scales and FinS to the Fish Body
Table 2 shows the proportion of the body formed by scales
and fins (in respect of weights).
The proportion of the scales to the body weight was found
to be highest (6,64%) in H. fasciatus, while the only
Cyprinid, Barbus callipterus gave the lowest value. Similar
ressult was obtained for the fins of the fishes. The weight
eof the scales and fins were found to increase with the fish
body weight.
The Composition of the Scales and Fins
Tables 3 and 4 show the results on moisture and organic
composition of the materials. It is evident from these
tables that organic compound can be as high as 50% and
41% in the scales and the fins respectively.
Xnorganic Fraction Of the Scales and Fins
Tables 3 and 4 show the ratios of water and organic matter
in the ,cles and fins. From the tables, inorganic matter
formed 46.28%, 43.11%, 39.70% 46.71% and 44.22% of the
scales of B. callipterus, O. niloticus, S. galilaeus,
H. fasciatus and T. zillii respectively. Similarly, these
values were 40,20-sE, 54e02%, 55.20%, 52.59% and 47.71% in
the fins of the fishes in the same order.
Table 5 shows the amount of cations in the scales and fins
of the fishes while Table 6 shows the amount of scales and
fins needed to produce each of the cation analysed.
Economic analysis of the feed prepared with the fish waste
as a component was analysed and compared with current
production cost priee (see Tables 7 and 8).
DISCUSSIONS
Provision of cheap and balanced diet that will give
acceileZated growth is the most needed item in fish culture.
A nation that develops easily is the one that does not
believe in waste. That is nothing should be re6.arded as
being useless. Locally produced materials, un-consumable
parts of animals and plants should be used to make feed
for fish at this point in time when it is becoming more
impossible to import things in Nigeria. In many instances
waste parts of fish can be obtained almost free of charge.
Many companies in Nigeria now advertise waste parts of
fish at give away prices. In many fish huts, people will
be glad to give away the waste parts of fish, and the
amount spent will be just that incurred on transportation.
_244
REFERENCES
COLTERMAN, H.L.; R.S. LYNO and M.A.M. OHNSTAD (1978) Methodsfor physical and chemical analysis of freshwaters.
Blackwell Scientific Publicaiton,
HALVER, J.E. (1972) Fish Nutrition. Academic Press.
OGUNFOWORA, A.; B.L. FETUGA; J. KOOPMAN, and A.A. ADEMOSUN(1975) Livestock Feed Report. Federal Livestock De artment,Lagos, Nigeria
Van ()OSTEN, J. (1957) The skin and scales. In thephysiology of fishes. Vol.1. C.M.E. Brown, Ed. New York
Academic Press. 207 - 244
WEBER, H.H and P.F. RIORDAN (1976) Problems of large scale
vertically integrated aquaculture. Paper Presented at FAO
Technical Conference on A uaeulture (FIR: AQ/CONF./76/R.4)
,2+5
The fact that many fishes feed on fish as parts or as a
whole in natural habitats shows that diet containing fish
parts will be very ideal for fishes. Moreover, the cations
so far analysed in fish wastes are very important for good
growth, blood formation ana strong bones not only in fishes
but also in other vertebrates (HaIver, 1972).
The use of fish waste has huge economic implications
especially for the fish feed manufacturing industry.Ogunfowora et al (1975) found out that the rate of expansion
of intensive livestock enterprises in Nigeria had beengreatly reduced due principally to high costs of feeds
arising largely from rising price of raw materials. They
observed that the cost of feed representing about 80% of
the total cost of intensive production was following an
upward trend due to high cost of feed ingredients most
especially specialised components like fish meal. Webber
and Riordan (1976) contended that since the feed cost
reprsents such a high proportion of the operating expenses,
the economics of the aquaculture industry are Particularly
sensitive to variability in cost of the commodities which
enter into feed formulation.
As shown in Tabie 7, the composition of ingredients
used in tho formulaLion of feeds has fish meal as an
important component. The fish meal provides the neededprotein source very rich in essential amino acids, vitamins
and minerals. The material cost for compounding the fishfeed is shown in Table 7. The average market price for
one tonne of fish meal utilizing various fish parts is
14880/tonne or 88k/kg.
More detailed investigations revealed that about 51% of
the cost of this feed is accounted for by the fish parts
used. However, a comparative analysis shows that with the
use of fins and scales (fish wastes), the percentage
contribution of fish parts is greatly reduced with
concomitant reduction in the overall cost of the finalproduct. The cost analysis shows that the final price comes
to 68K/kg and that is allowing for increased profit margin
from 10% (9 Kobo) to about 15% (i.e. 10 Kobo) of final
market price (Table 8).
In sum, the paper reveals the technical as well as
economic implications of adopting the use of fish wastes
such as scales and fins in the production of fish meal.
ACKNOWLEDGEMENTS
I an most grateful to Mr. 0.0. Oludimu of the Department
of Agricultural Economics, who carried out the economic
analysis of the data for this paper. I thank my postgraduate students also for their various contributions.
2.46.
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.6
8
20
.1
6
3.
78
3.
36
90
.9
1
80
.6
5
30
.3
0
26
.8
8
10
.3
2
10
.0
('
T.
 z
ill
ii
60
.2
4
55
.5
6
23
.9
9
22
.2
2
4.
44
3.
70
96
.1
5
89
.2
9
31
.9
5
29
.5
9
10
.9
1
12
.6
6
Fi
sh
 sp
ec
ie
s
N
a+
Ca
2+
M
g2
+
P3
+
Table 7 - Material cost for compounding a tonne of fish
feed using fish waste as source of minerals
Maize 40.50 470.0 300 141.0
Wheat offals 7.50 100.0 100 10.0
Groundnut cake 20.50 405.0 200 81.0
Soybean cake 15.00 450.0 150 67.5
Fish meal 6.00 880.0 880 70.4
Rice bran 4.50 85.0 60 5.1
Fish scales
and fins 5.50 240.0 60 14.4
Vitamin/
mineral mix 0.50 450.0 50 14.4
Total 100.00 1,000 403.3
Table 8 - Cost component of 1 kg of fish meal, 1987
Components
Source: Field survey, Oyo State;
reproduced with kind permission of O. Oludimu
Whole fish Fish wastes
Labour 16 18.2 21 30.9
Depreciation on
Capital Stock 6 6.8 6 8.8
Fish parts 45 51.1 18 26.5
Operating Capital 12 13.7 13 19.1
Profit margin 9 10.2 10 14.7
Ingredients % in the Cost per Quantity Value
Fish feed tonne of need/tonne in.N
feed (N) of Feed(kg)
Amount 96 Amount 96'
(Kobo) (Kobo)
Total 88 100.0 68 100.0


Possible inclusion of fish waste (scales and fins) in the diet of fishes in aquaculture

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