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

Impact of Sex Ratio on the Spawning Success of Zebrafish in the Laboratory Settings

UO Rahman
Department of Fisheries Biology and Genetics; Fisheries Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.

A Jaman
Department of Fisheries Management; Fisheries Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.

M Shahjahan
Department of Marine; Fisheries Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.

MS Islam
Department of Marine Fisheries Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.

Abstract/ Executive Summary:

Zebrafish, Danio rerio belonging to the family Cyprinidae is one of the most important native ornamental model species used in fisheries researches globally. The present study was conducted to evaluate the effects of sex ratio on the spawning of zebrafish and to observe the ovarian maturity in the laboratory condition. This experiment was conducted for 12 weeks in the glass aquaria (25×16×26 cm³ in size) and the zebrafish were reared in five different sex ratio treatments like -T₁ (1m:1f), T₂ (1m:2f), T₃ (1m:3f), T₄ (2m:1f) and T₅ (3m:1f) and the fertilized eggs were collected daily from the aquaria. The results showed that the mean number of eggs was found to be highest at T₃ (821±67.11) and the average egg-lay day interval was 1.9 days which significantly (p<0.05) differ from other treatments. These research findings will provide a guideline to small-scale fish farmers, entrepreneurs, and hatchery owners to develop the spawning of zebrafish in laboratory settings with little investment. It will also provide opportunities to construct zebrafish hatchery and produce commercially zebrafish fry to a large extent.

Keywords: Zebrafish, Spawning, Sex-ratio, Spawning interval

Location: Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh.

Start Date:

End Date:

Program Area: Resource Development and Management

Commodity: Fish

Objectives:

The present study addresses the effects of different sex-ratio on egg production. Following that the spawning frequency and ovarian maturity of the zebrafish were also assessed.

Methodology:

Wild-type adult zebrafish (D. rerio) were collected from the field complex pond of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh. Good and healthy broods were selected for spawning treatments. Identification of male and female brood fish was done on the basis of some secondary sexual characters. The female zebrafish could be easily recognized by their swollen abdomen. On the other hand, the mature males were identified by their flat abdomens and slender body. Males were darker in color than females and had more yellow coloration in the anal fin. A total of ten glass aquaria were used for this experiment each having (25X16X26 cm³) in size. The water holding capacity of each aquarium was 15 liters. All aquaria were arranged in two rows (5 aquaria per row). The aerator was set in each aquarium. Cleaned with detergent, sponged thoroughly with tap water, and siphoned out. Filled with fresh water for experimental purposes. Then fish were released into the aquaria for this experiment. Ten glass aquaria with 15 liters’ water holding capacity were used for this experiment. A total of 32 male and female fish were kept in different sex ratio in ten aquaria. Two layers of marble in a petridish were placed as a substrate and small artificial trees were also provided in each aquarium for breeding purposes. Aerators with airstones were also provided for aeration in the aquaria. Water exchange and aquarium cleaning were done as required. Zebrafish likes clean water. For this reason, any uneaten food, dead eggs and fry, and detritus were removed from the bottom of the aquarium. This work was done daily to prevent the dirt from being accumulated on the bottom of the aquarium. Zebrafish laid eggs every day. They eat most of their own eggs as a way of recycling the protein that is lost from producing the eggs. That is why they need high protein-rich food. Fish were fed twice a day with a commercial floating feed (Mega Fish Feed Ltd.) and often with zooplankton (enriched with Cyclops, Daphnia, Cladocerans, etc.) Egg collection is very important for any breeding biology-related study. In the present study, eggs were collected at 8 AM daily from the aquarium. Eggs were deposited in between the gaps of marble in the Petri dish. To collect the eggs Petri dish was taken out of the aquarium, the eggs were separated from the marble and transferred into a hatching tray to count the eggs. Then the eggs were checked with the help of a microscope equipped with a camera (OPTICA B350, Italy) to check whether they are fertilized or not. The effect of temperature on the spawning of zebrafish was also measured during the collection and counting of eggs from each aquarium. Aquarium water temperature was also recorded using a Celsius thermometer.

Source of Information: Progressive Agriculture 32 (1): 78-83, 2021

Article Link (Online Journal):

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Zebrafish is one of the native freshwater ornamental fish of Bangladesh and spawning is an important part of zebrafish husbandry which understanding is crucial for optimizing scientific research in which D. rerio is used as a model organism. From the study, the spawning success was found higher at T₃ (1m:3f) and at which the spawning interval was also the lowest. So, it has been proved T₃ (1m:3f) would be the best sex ratio in all aspects of zebrafish spawning in laboratory conditions. With respect to the breeding of zebrafish, this study provides clear evidence that sex ratio had a significant effect on their spawning in laboratory settings. For better production sex ratio should be carefully maintained. These research findings will provide a guideline to develop the spawning protocol of zebrafish in laboratory settings.

Knowledge Management: Journal