Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Embryonic and Larval Development of Thai Pangas (pangasius Sutchi Fowler, 1937)

Asiful Islam
Khulna University, Khulna

Abstract/ Executive Summary:

The embryonic and larval development of Thai pangas was investigated during peak (May–July 1995) and late spawning (August–October 1995) periods. The fertilized eggs are adhesive and spherical with a yellowish or greenish-brown egg capsule. The yolk sac is yellowish-brown in color and 1.20–1.80 mm in diameter. Nine hours post-fertilization, the first cleavage stage, embryonic shield, head, tail region, neural grooves and somites were evident. The incubation period ranges from 24–36 h at a temperature of 20–30^oC. The newly hatched larvae are quite transparent and light yellowish in color with a body length of 2.98–3.10 mm. Eye pigments appear and the heart starts to work within 12–14 h of hatching. In 1-day-old pro-larvae, the mouth becomes well developed; barbules are elongated, prominent and look like tiny threads. The yolk sac is fairly well absorbed and the palatine teeth are fully developed during the 3 day pro-larval stage. At the end of 12 days of larval development, the stomach becomes functional and aerial respiration starts. After 2 weeks, the young fry is well developed, and is of an adult appearance, that is, measuring up to 13.56 mm in length.

Keywords: Larval development, Pangasius sutchi , Siluriformes, Thai pangas

Location: Khulna University

Start Date: 00-00-1995

End Date: 00-00-1995

Program Area: Animal Health and Management

Commodity: Pangus

Objectives:

To describe the early life cycle from oocyte activation to the beginning of the adult fingerling periods (2 weeks) of P. sutchi under laboratory conditions.

Methodology:

Adult specimens used in this study were collected from a native fish seed multiplication farm in Dhaka, Bangladesh (20 ^o34' and 26^o36' north latitude and 88^o1' and 92^o41' east longitude) for insemination. They were kept in large circular conditioning cisterns (3X3X1 m³), kept at 22–28^oC with a 12:12 h photoperiod, and were well-aerated and provided external filtration. The adaptation of adult individuals to cistern conditions took 2–4 weeks. Fish were normally fed with commercial pellet food (Saudi-Bangla, Bangladesh, India). The male and female fishes were kept in separate tanks with continuous showering and generated diffused O₂supply for about 6 h before they were treated with pituitary gonadotropin (PG) and human chorionic gonadotropin (HCG) hormones for artificial propagation. Eggs and larvae described in this study were obtained from 15 pairs of fish from peak (May–July) and late spawning (August–October) periods. Live or recently fixed in 5% formalin specimens were observed and measured microscopically. The main morphological and functional features of each developmental stage were described and the hours or days of development were determined considering the moment of insemination as 0 h. The incubation period ranged from 24–36 h at a temperature of 20–30^oC. Young fry fed on freshly hatched nauplii Artemia salina during days 1–4 and Tubifex worms and powdered dry food during days 5–14. A micrometer (Kafer .001, Precision Graphic Instruments, Spokane, WA, USA) was used to measure the diameter, height and length of the developmental stages of the specimens. By using a Ken-A Vision Micro Projector (model X-1000–1, objective power 16 mm, eyepiece power 10x, Capital Microscope Services, Marietta, GA, USA), the diagrams of the different stages were sketched out.

Source of Information: Develop. Growth Differ. (2005) 47, 1–6

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

The embryonic and larval developmental stages of Thai pangas show significant and rhythmic development. Cannibalism is a common criterion of catfish, which also exhibits in Thai pangas larvae in when food is insufficient. Temperature is inversely related to the incubation and hatching periods of P. sutchi . The notochord is gradually extended up to the caudal region of the hatchlings by the seventh day of successive developmental periods. After 2 weeks, the larvae become vigorous, active and moved spontaneously in the cistern water, and appeared to be adult. Comparative developmental studies of Thai pangas and different catfishes could provide a better understanding of their early embryonic stages and also their reproductive behavior.

Knowledge Management: Journal