The present study deals with the histological analysis of testicular development in Ompok pabda. For the study, male gonads were collected month wise from January to September at Freshwater Station, BFRI, Mymensingh. From the analysis, 4 stages of sperm formation, namely, spermatogonia, spermatocytes, spermatids and spermatozoa, were distinguished. The percent distribution of spermatozoa was highest in July (about 92%). Maximum GSI value was 1.129±0.271 found in July. By analyzing the histology of spermatogenesis it was established that this species breeds once in a year

Ahmed, A.T.A.

Hussain, M.G.

Islam, M.S.

Siddiqua, K.A.

Aquatic Commons

Bangladesh]. Fish. Res., 4(2), 2000: 185-189 
A histological study of the spermatogenesis in Ompok 
pabda (Hamilton-Buchanan 1822) 
K.A. Siddiqua*, M.S. Islam\ M.G. Hussain1 and A.T.A. Ahmed 
Department of Zoology, University of Dhaka, Dhaka 1 000) Bangladesh 
1 Freshwater Station) BFRI) Mymensingh 2201 
* Corresponding author 
Abstract 
The present study deals with the histological analysis of testicular development in Ompok 
pabda. For the study, male gonads were collected monthwise from January to September 
at Freshwater Station, BFRI, Mymensingh. From the analysis, 4 stages of sperm 
formation, namely, spermatogonia, spermatocytes, spermatids and spermatozoa, were 
distinguished. The percent distribution of spermatozoa was highest in July ( about 92%). 
Maximum GSI value was 1.129 ± 0.271 found in July. By analysing the histology of 
spermatogenesis it was established that this species breeds once in a year. 
Key words: Histology, Spermatogenesis, Ompok pabda 
Introduction 
Ompok pabda belonging to the family Siluridae of the order Siluriformes is a 
freshwater catfish, locally known as " madhu pabda" , found in beels, haors, baors, 
flooded waterbodies, ponds, streams and rivers of Bangladesh. Although many 
researchers of our country as well as of other countries have worked on other 
commercially important catfish and other teleost fishes, very little attention has so far 
been paid to 0. pabda in Bangladesh. Chaudhury (1962) worked on induced breeding and 
development of 0. bimaculatus, Hossain et al (1991) studied the food and feeding habits of 
0. pabda, Hossain et al (1992) worked on the reproduction and fecundity of 0. pabda, 
Khanum (1994) studied the Helminth endoparasites in both 0. pabda and 0. bimaculatus, 
Palmer et al (1995) studied the histology of seasonal ovarian development in freshwater 
drum, and Janseen et al. (1995) examined the annual ovarian cycle of a flounder, etc., but 
no work has been reported on histology of spermatogenesis in 0. pabda. 
Considering the economic as well as biological importance of 0. pabda, an attempt 
was made to define the successive maturational stages of male gonads histologically for 
detecting the spawning season, to classify the gonads by measuring the percent 
distribution of different developmental stages of spermatogenesis at successive months. 
Materials and methods 
To complete the experiment, studies were conducted from January to September, 
1996, at the Freshwater Station, Bangladesh Fisheries Research Institute (BFRI), 
K.A. Siddiqua et al. 
Mymensingh. To study the testicular development histologically, the experimental fish 
(0. pabda) which were more or less of same year-class were collected from the same 
rearing pond. 
Before dissecting the fish sample in every month, total body length and body weight 
were measured. After dissection, the gonads were carefully removed and were cleaned of 
all surrounding tissues. Before fixing the gonads in Bouin's fluid the gonad weight and 
the physical features of testes were also observed and noted. 
GSI ( Ganado Somatic Index ) was determined by using the following formula: 
Gonad weight of fish 
GSI = ---------------------------------------------- X 100 
Total weight offish 
For the histological investigation, permanent microscopic slides of the successively 
collected gonads were prepared in the laboratory by microtechnique method. The 
prepared slides were examined and studied by a compound microscope in laboratory and 
all the successive stages of spermatogenesis were observed. The percentage of different 
stages of sperm formation was determined and photomicrography was done. 
Results and discussion 
General morphology of testes: The male gonad consisting of a pair of testes was situated 
dorsa-laterally to the gut, and these were attached to the dorsal body wall by the 
mesorchium. In immature stage the testes were thin, whitish thread-like structures, very 
small and translucent, but they became thick, creamy white, highly coiled and opaque at 
the mature stage. Maximum mean gonad weight was about 0.22g found in June. 
GSI: Monthly variation of GSI in male is presented in Fig. I. The GSI values increased 
slowly from January to April and from May to July increased highly with a peak in July 
(1.129 ± 0.271). GSI values began to fall steeply from August. 
1.2 
"' 
" 
0.6. ~ 
~ 
Vi 0.6 Cl 
c 
"' 
" 0.4 ::; 
0.2 
Months 
Fig. I. Month wise changes in mean GSI values of male 0. pabda. 
186 
Spermatogenesis in Ompok pabda 
Histology of gonads 
A. Spermatogonia: This is the primary stage of spermatogenesis which is the largest 
germ-cell in the testis. It was spherical in shape and the cell membrane was clearly 
seen (Fig. 2A). An oval, slightly basophilic nucleus was present in the centre of the cell. 
About 65% of this stage was observed in January and only 1-2% in July. 
B. Spermatocytes: Spermatogonia transformed into spermatocytes by meiotic 
division which were also spherical in shape containing a nucleus in the centre. These 
were smaller in size than the spermatogonia (Fig. 2B). The percent distribution of this 
stage was 20% in January, but only 1-4% in July. 
C. Spermatids: These were spherical shaped in which nucleus was not clearly seen 
for its dark appearance under the microscope (Fig. 2C). About 15% of this stage was 
observed in January, but only 3-8% in July. 
D. Spermatozoa: These were the functional male gametes which were the smallest 
cells of all germ cells in testes. They appeared as small black-coloured spots under the 
microscope. Spermatids transformed into spermatozoa by the process of spermiogenesis 
(Fig. 2D). This stage was found from February and percent distribution in testes was 
only 5%, but 75-92% in July. 
Fig. 2. Different development stages of spermatogensis: A. Spermatogonia (SPG), 
B. Spermatocytes (SPC), C. Spermatids (SPT), D. Spermatozoa (SPZ). 
187 
K.A. Siddiqua et al. 
Average frequency distribution (%) of different cj.evelopmental stages of sperm 
formation in testes is presented in the Fig. 3. 
100% 
90% 
80% 
70% 
60% 
50% 
40% 
30%· 
20% 
10% 
0% 
13 SPG [] SPC lJ SPT (! SPZI 
January February March April May June July 
Months 
Fig. 3. Average frequency distribution(%) of different development 
stages of sperm formation in testes of 0. pabda at successive months. 
Testicular development 
A. Immature testes: It was very small, whitish, slightly coiled and translucent in 
which histologically large number of spermatogonia, a few spermatocytes and a very 
small number of spermatids were present. The mean gonad weight was 0.012g. 
B. Maturing testes: It was observed from February to April and histologically it 
contained 5-45% spermatozoa, 20-40% spermatids, 10-50% spermatocytes approximately. 
Spermatogonia decreased gradually from 35-5%. It became opaque gradually and creamy 
white in colour. The mean gonad weight ranged from 0.051g to 0.07g. 
C. Mature testes: It was seen from May to July with highest mean gonad weight in 
June (0.22g). Histologically, it contained 60-92% spermatozoa, and other developmental 
stages were also seen, but very small in numbers. 
Acknowledgements 
The authors are thankful to Dr. M.A. Mazid, Director Central, Bangladesh Fisheries Research 
Institute, Mymensingh for providing necessary laboratory facilities during this study. 
References 
Chaudhuri, H., 1962. Induced breeding and development of a common catfish, Ompok bimaculatus 
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188 
Spermatogenesis in Ompok pabda 
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(Manuscript received 2 May 1999) 
189 


A histological study of the spermatogenesis in Ompok pabda (Hamilton-Buchanan 1822)

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A histological study of the spermatogenesis in Ompok pabda (Hamilton-Buchanan 1822)

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