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CHAPTER NO. 5
HEPATOSOMATIC INDEX AND
GONADOSOMATIC INDEX
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INTRODUCTION
B.carnaticus plays important role in the diet as a source of proteins,
vitamins and minerals such as calcium, iron etc. which is essential for
healthy growth and development of man. In rural areas poor people can‟t
afford to buy vegetables and meat in their daily meal,so it is the fish
B.carnaticus which is easily available to them and fulfill their nutritional
requirement.
As the introduction on different aspects of biology of this species
is very scanty and considering its importance an attempt is made to study
the different aspects of gonadosomatic index (GSI) (ovary and testis ) and
hepatosomatic index ( HSI ) of this species.
Fish body weight and weight of gonad gives the gonadosomatic
index ( G.S.I. )It is the ratio of fish gonad weight to body weight , it is
particularly helpful in identifying days and seasons of spawning , as the
ovaries of gravid females swiftly increase in size just prior to spawning.
The development and growth of gonad simultaneously takes place in the
fish and fish grows and the G.S.I. is high. Present study insured that the
growth of fish, body weight and gonadal development is correlated.
Gonadosomatic index of fish is related to spawning and reproduction of
fish.B.carnaticus is a good source of food for poor people and hence they
must be reproduced in large number so that they are easily available to
poor people and hence the study of G.S.I. is important and essential. At
maturity stage fish has maximum G.S.I. value and after spawning G.S.I.
value declines. The G.S.I. value also related to amount of food available
to them in water and temperature of water also. So generally during the
breeding season of this B.carnaticus shows maximum G.S.I. value and
after spawaning it is reduced. In this study we have carried out G.S.I. of
male and female fish simultaneously. When G.S.I.. of both sexes were
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compared we came to know that maximum values of G.S.I. have occurred
almost at the same time in both sexes and after spawning it is recoreded
that there was a great decrease in G.S.I. values.
On the other hand study of Hepatosomatic index of B.carnaticus is
also carried out simultaneously. H.S.I. is associated with the liver
energetic reserves and metabolic activity. When the food is available in
large amount and conditions are favourable it causes increase in the H.S.I.
value. Increase in the daily weight of the body is related to the increase in
the H.S.I. value and it is also observed that H.S.I. also depends upon
seasonal cycle. As liver is vital organ in the body and it performs various
physiological functions such as it converts excess sugar into glycogen,it
detoxify the toxic substances, it also act as a haemopoietic organ,destroy
the old R.B.C.etc. So its healthy condition is essential for growth of fish.
As weight of body increases weight of liver also increases. The H.S.I.
gives us information about the condition of liver and body and also about
the impact of water pollution on it. H.S.I. also provides an indication on
status of energy reserve in fish. In poor environment fish usually have a
smaller liver with less energy reserved in the liver. H.S.I.has been
reported to decrease in fish exposed to water pollution. H.S.I. values are
indirect indices of energy status on a seasonal basis the H.S.I. values are
variable.
All the statistical analysis was performed by the use of Microsoft
Excell 2007. During study it is observed that there is a correlation in the
increase in the body weight and weight of the gonads i.e. the ovary and
testis in female and male fishes respectively. It results in the increase of
G.S.I. value . The knowledge about G.S.I. is essential for evaluating the
potentials of its stock life histories, practical culture and actual
management of the fishery.
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H.S.I. value also provides us information about the healthy
condition of fish and also about the quality of water, because higher
H.S.I. value means fishes are growing rapidly and have a good aquatic
environment and if H.S.I. value is less it means fish is not growing well
and it is facing unhealthy environmental problems. Thus both G.S.I. and
H.S.I. values gives us indications of development pattern of fishes
B.carnaticus which is a food of poor people and that‟s why they must be
reproduced in large number and must be made available to them
throughout the year. To know the breeding potentials of this fish it is
essential to know about their G.S.I. values.
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MATERIAL AND METHODS
Fish samples of B. carnaticuswere collected from Girna Dam ,
constructed on the Girna river at Nandgaon Dist. Nasik. Maharashtra
state. For the determination of HSI. And GSITen individual fish were
sampled randomly in each month for the experimental year 2011. Fish
samples B. carnaticus were brought to the laboratory and they were
blotted by blotting paper and there body weights were recorded to the
nearest milligram respectively. The HSI.and GSI. Values were calculated
from the ratio of total body weight and gonadal weight.After weighing,
fish were dissected to remove the liver and gonads from them for the
determination of HSI. and GSI. Moisture of the liver and gonads was
removed with the help of blotting paper and then weight of liver and
gonads was recorded in grams. The hepatosomatic index of the fish was
determined by the use of equation cited by Parmeswaran (1974).
H.S.I. =
Similarly the gonadosomatic index of the male fish( i.e. the weight
of testis) and female fish (i.e. the weight of ovaries) were determined by
equation cited by Parmeswaran (1974).
G.S.I. =
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In such a way weight of liver, and gonads (i.e. male and female ) of every
fish per month is recorded and the mean value of the liver and gonads
(testis and ovaries ) of ten fishes per month is given in the table
(no.28).The mean value of liver and gonads of every month of year 2011
gives an idea about the condition of the liver of the fish and maturity of
the fish. The health of fish is directly related to the condition of liver
because it is the organ related with the digestion of food and storage of
reserved food. So the good condition of the liver is the indication of the
good health of fish. Similarly the good and healthy condition of the
gonads is the indication of maturity of fish for the breeding season.
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RESULTS
In present investigation in B.carnaticus of equal weight variation was
found with liver, ovary and testis through out the year. B.carnaticus
follows the normal gonadal development and liver development and
possesses normal reproductive behavior. The mean G.S.I. value for testis
is (18.4317) observed higher in the month of June and low in month of
January 3.2995.The G.S.I. (Ovary) value observed higher in the month of
(June)and lower in month of January Similarly the higher mean H.S.I.
value observed in the month of June And lower mean H.S.I. value is
observed in the month of January (Table No.28). In the graph peak values
were observed in the month of June for mean G.S.I. (Testis)(Graph no.
89) and G.S.I. (Ovary) (Graph no.88) and for mean H.S.I. Peak values in
graph gives us an idea about energy level and metabolic activity of the
fish in that month. (Graph no,90).Similarly we get an information about
gonadal developmental stage and its maturity and reproduction cycle
throughout the year. It is observed that G.S.I. and H.S.I. variation is
common in fish and they are correlated with each other and some workers
have suggested that the reproductive capacity of fish varies according to
availability of space and food.
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Table No 28 Mean H.S.I., G.S.I. and S.T.D.V. of B.carnaticus
for the year 2011.
Month Mean
STDV
H.S.I
Mean
GSI
STDV
GSI
Mean
GSI
STDV
GSI
H.S.I Testis Testis ovary
Jan 0.5144 0.0495 3.2995 0.16436 3.6044 0.3059
Feb 0.7387 0.067 3.9493 0.0951 4.5361 0.0479
March 0.8281 0.0171 4.4275 0.4972 4.016 0.06886
April 0.9134 0.0261 4.9253 0.6341 4.3566 0.3217
May 0.9271 0.0604 9.6677 2.9328 9.5369 0.4384
June 1.4098 0.1209 18.4317 0.8431 18.5728 1.0046
July 1.2543 0.0556 17.4366 0.8272 15.8968 2.3929
Aug 1.2661 0.0425 14.4972 0.8375 13.2979 1.01584
Sep 1.2743 0.0184 12.8008 0.4746 13.1784 0.7537
Oct 0.9048 0.0425 8.4531 0.6451 8.3228 0.8012
nov 0.766 0.0424 7.8993 0.7819 6.1981 0.6195
Dec 0.6872 0.2313 4.1688 0.2182 4.8661 0.2453
* each value is a mean of ten fishesh per month.
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Graph no 88
Natural Changes in GSI values of female B.carnaticus During 2011
0
2
4
6
8
10
12
14
16
18
20
Ch
an
ge
in
GS
I
Months
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Graph No. 89
Natural Changes in GSI values of maleB.carnaticus During 2011
0
2
4
6
8
10
12
14
16
18
20
Ch
an
ge
in
GS
I
Months
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Graph No. 90
Natural Changes in HSI of B.carnaticus During 2011
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Me
an
HS
I
Months
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DISCUSSION
In the present investigation maximum mean G.S.I. (Testis) value
(18.4317) was found in the month of June which indicates the period of
maximum growth in male fish. Similarly maximum mean G.S.I. (Ovary)
value (18.5728)was found in the month of Junewhich indicate the period
of maximum growth in female fish B.carnaticus. A sharp drop in mean
G.S.I. values of male and female fish takes place in the month of January
(3.2995) and (3.6044) respectively this indicates the spawning occurred
before this month. However the breeding season of B.carnaticus starts in
month of early June and it is extended until September.During monsoon
the development and growth of gonad of B.carnaticus simultaneously
took place and hence mean G.S.I. values of both male and female are
higher in breeding season. G.S.I. values increase with increasing mean
body weights and length during gametogenesis in females.
Another factor might be responsible for increase in G.S.I. values in
both male and female of B.carnaticus in the month of May and June is
significant rise in the temperature of water 26.5+-0.50c. Chmilevskiy and
Lavroa (1990) reported that during low temperature (200c) division of the
primary sex cells and gonia was inhibited completely stoping their to
early prophase meiosis.Chmilevsky (1995a) further showed that
differentiation of the female gonads was suppressed in low temperature.
Maximum G.S.I. values corresponds with the spawning season of fish.
Barnabe (1994) reported that high G.S.I. of seabass were found at peak of
its spawning season.
Reviews of oocyte development in teleost fish have been given by
de Vlaming (1983), Guraya (1986, 1994), Selman et al; (1993), Bromage
and Cumaranatumga (1988), Selman and Wallace (1989); West (1990)
and Tyler and Sumpter (1996). The development follows a similar pattern
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in most species. In cyprinid, Meyyen (1927, 1939, cited in Testis weight
and G.S.I clearly changed according to reproductive season reaching their
peak values in the prebreeding season coinciding with the large
accumulation of spermatozoa. Values decreased with spawning in the
breeding season and then rose again in the post breeding season.
Significant differences in testis weight and G.S.I value were found only
in the breeding season. Gonadosomatic index indicates gonadal
development and maturity of fish. It increases with the maturation of fish
declining abruptly thereafter (Parmeswaran et al, 1974).
Testis weight and G.S.I. clearly changed according to reproductive
season in all groups reaching their peak values in the preceding season
coinciding with the large accumulation of spermatozoa G.S.I. (Testis)
values decreased with spawning in the breeding season and then
increased again in the past breeding season. In males the decrease in
G.S.I. corresponds to the loss of gonad weight which is due to the
elimination of the spermatid residual bodies.
The condition of the liver and whole body, as measured with the
heptosomatic index (H.S.I.) can provide information on potential
pollution impacts. Although these parameters are not very sensitive, they
may serve as an initial screening bio meter to indicate exposure and
effects body condition is a practical tool for biologist and managers to
guess the overall health of fish population and a good indicator of fish
habitat quality and pollution levels. While some authors claimed that
H.S.I. might be useful as an indicator of chemical pollution of water,
others showed that it was inconsistent as a biomarker and that it is
dependent on the seasonal cycle. Prior to establishment of H.S.I. as a
pollution indicator standard ranges should be established, and the possible
effects of intestinal biological rhythms and environmental factors on this
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parameters must be accessed.The maximum value for H.S.I. was recorded
in October, while the minimum was in March. Varied between 1.14 and
6.67.In the females the decrease in G.S.I. is the result of ovulation and
characterizes the peak of spawning activity.Temporal changes in G.S.I.
has been used to provide rough estimation of spawning periods for fishes.
In B.carnaticus G.S.I. value peaked in earlyJune and decreased
through late September suggesting spawning period occurred from June
to September, which is similar to the results of Gaikwad M.V.et.al;
(2009), where the ratio between the body weight and the weight of the
gonad showing the status of the ovary in terms of maturity and denotes
the phase of reproduction cycle.The G.S.I. of air breathing fish Channa
gaucha (Ham)found increased with the maturation of the fish and gonad.
Where the G.S.I. was found lowest during post spawning phase and was
highest at the peak of maturity during spawning phase. There is intimate
relationship between the length of ovary and its relative weight.High
G.S.I. high fecundity , low G.S.I. low fecundity . The G.S.I. signifies the
varied number of oocytes observed during study. The peak of the
breeding phase was observed in June where the G.S.I. is higher and rest
of the months deserved for low egg production and low G.S.I. This
information can be helpful for better management of inland fisheries and
prevention of fish capture in breeding season to conserve the fish
diversity.The same result was reported by Lutfun Hussain et al; 2003 in
case of Dhela (Osteobrama cotiocotio). The maximum G.S.I. value was
found in the month of June which indicated the maximum gonadal
growth . A sharp drop in the G.S.I. value had taken place in September
which might have been caused by spawning .The peak value in G.S.I.
coincided with peak spawning period thus showing a close relationship
between the two. In the present study, high values of G.S.I. denoted
attainment of peak maturity of gonads. Hence the high G.S.I. values
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indicate that the peak spawning takes place during June to December.
Shaikh and Prakash Lohar, (2011) also reported that low G.S.I. of Labeo
rohita, Cyprinus mrigala, carp fish during October to January may be due
to dormancy of gonads in post breeding season. The G.S.I. values
correlated with increased amount of protein and lipids in both
prebreeding and postbreeding seasons may be due to augmented
vitellogenesis in ovary and spermatogenesis in testes that require large
amount of lipoproteins.Weight of the gonad followed regular cyclic
changes that were correlated with the reproductive activities of fish. The
lowest G.S.I. values indicated that during this period the weight of the
ovary in fish was minimum possibly due to dormancy of gonads in post
breeding season. Most of the fishes show seasonal variations in
reproductive physiology. Since the gain in weight was recorded in the
gonads of each fish species. During the months of June to September
every year it can be clearly correlated with the breeding season of fish.
On the basis of observed values of G.S.I. in adult fish a reproductive life
cycle of B.carnaticuscan be concluded.It is observed that February –May
is prebreeding season, June – September is breeding season and October
– January is post breeding season of B.carnaticusin each year. The G.S.I.
values also correlated with increased amount of protein and lipids it may
be due to augmented vitellogenesis in ovary and spermatogenesis in testes
that requires large amount of lipoproteins under impact of hormones.
Kingdom T. and Allison M.E., (2011) studied the fecundity and
gonadosomatic index ,hepatosomatic indices in Pellonula leonensis. In
case of B.carnaticus breeding commenced soon after the begining of
monsoon and continued until August with a peak in late June and early
July.Monsoon rain and flood triggers the spawning activity in this species
as amply evidenced during field studies.
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H.S.I. is associated with liver energetic reserves and metabolic
activity. H.S.I. had a maximum value in the month of June. Availability
of sufficient amount of food material in the above said month is
responsible for increase in H.S.I. from (0.5144) (January) to (1.4098)
(June). Yang and Bauman,(2006) stated that H.S.I. depends on seasonal
cycles. Difference in the H.S.I. values that were found in this study
ranging between 0.5144 and 1.4098 were probably also caused by diet in
natural conditions that differed throughout the year.
Mean G.S.I. and H.S.I. values increased with increasing mean body
weights and length‟s during gametogenesis in females.The peak value of
G.S.I. coincides with the peak values of the spawning period indicating
close relationship between G.S.I. and H.S.I. Gross indices are sometimes
indicative of toxicant effects. The condition of the liver and the whole
body as measured with H.S.I. can provide information on potential
pollution impacts. It is used to indicate exposure and effects.
Some authors claimed that H.S.I. might be useful as an indicator of
chemical water pollution, others showed that it was inconsistent as a bio
marker and it is dependent on the seasonal cycle prior to establishment of
H.S.I. As a pollution indicator standard ranges should be established and
the possible effects of internal biological rhythms and environmental
factors on this parameters must be assessed.
Slight increase in the H.S.I. values in the present data was reffered
to the accumulation of pollutants as suggested by many authors.(Kendall,
1977 and Mazhar et. al.,1986) Saleh ( 1982) reported that, liver is the
good indicator of the aquatic environmental pollution where one of the
important function of the liver is to clean any poisons or pollutants from
the blood coming from the intestine.The pollution of the aquatic
environment causes an increase in the heptosomatic index. This probably
227
means that the H.S.I. could be used as a quick indicator for detecting
pollution in the aquatic environments. As a matter of fact , the amount of
pollutants in the fish liver is directly proportional to the degree of
pollution in the aquatic environment by heavy metals and pesticides.
Accordingly the heptosomatic index may be considered as a valid
indicator for this type of pollution.
H.S.I. is most important because it describes stored energy in fish.
Low values of H.S.I. were found from to And in, the mean value was
significantly lower (p<0.05) in relation to other months. In January H.S.I.
increased suddenly and from February on the tendency of the values was
to rise with an exception for the month of April when a significant drop
was recorded. H.S.I. low values were found during receding and dry
period. This result is similar to the one found by Saint-Paul (1984) for
neotropical characoid fish Colossoma macropomum specimens collected
from Lago Manaquiri. The low values found may be due to the usage at
stores accumulated in the liver for supplying energetic requirements
during the time of scarce food items, sexual products elaboration and
spawning activity , which occur throughout the flooding and early rise
respectively . During receding and rising water periods most specimens
present little accumulation of fat in the abdominal cavity.
It is also observed that there is correlation in H.S.I. and G.S.I. i.e.
mean H.S.I. and G.S.I. values increase with increase in mean body
weights and length during gametogenesis in females. Changes in G.S.I.
and H.S.I. followed a similar pattern during gametogenesis. This finding
is similar to that reported for other species e.g. Awaji and Hanyu, 1987,
Delahunty and de vlaming, 1980, Htun-Hun, 1978. Asahina et al, 1990.
Since total fish length and weight are included in the calculation of G.S.I.
and H.S.I., they present an auto correlation.