Presentation created by Heydee A. Santos

1. TILAPIA NILOTICA AS A
BIOLOGICAL INDICATOR
By Heydee A. Santos

2. Parts of Tilapia Nilotica which
can be use to assess the water
lake pollution

3. In vitro piscine chromosome gene
methodology ( modified from
Moodhead)
 In vitro piscine chromosome gene
methodology ( modified from Moodhead)
 Remove ovaries or other appropriate tissues
from female and dissociates the cells using
standard procedures Separate the cells from
the digesting solution by low speed
centrifugation , and resuspend the cell pellet in
5ml of media prepared as follows:

4. Continuation






100ml of McCoy 5c media
20ml fetal calf serum
1ml sodium bi carbonate solution
200 iµ/ ml penicillin
200 mg/ ml streptomycin
30 mg/ ml amphotericia B.

5. Continuation:
 3. Place the cell suspension in a 25 ml plastic
culture flask and incubate at 26oC
 4. If the cell density is low and growth
appears to be quite slow , add additional cells
to the inoculation using the above procedure.
A confluent monolayer of cells should be
obtained within three weeks ,
 5. Once the monolayer is obtained, establish
replicate cultures, these can be stored in
liquid nitrogen.

6. 7. Irradiated cell cultures ( control cultures are
show irradiated) and incubate culture for an
appropriate period of time in accordance with the
aims of the experiment and the cell cycles time of
the culture.
8. Approximately 5th prior to harvest, add
colcemid ( 0.1 ml of a 10 mg /ml solution ) to the
culture media.
9. Harvest cells by gently trypsinisation and
centrifuged to form a pellets
10. Treat the pellet with hypotonic solution
composed of 1ml of media and ¼ ml of distilled
water for 35 min at room temperature.

7. Continuation:
 11. Centrifuged the cells, disregard the
hypotonic solution , and add 3: 1 ethanol –
acetic acid for a minimum of 45 min to fix the
cells.
 12. After two further changes of fixative ,
disperse a few drops of cell suspension onto a
clean wet slide and air – dry on a slide warmer
at 40-50 oC
 13. Place thoroughly dried preparations in
methanol for 15 min, rinse in distilled water ,
and stin overnight in lacto- acetic orcein.

8. Some points in favour of the use of
Cytogenetic analysis and its limitation
Advantages:
 Applicable to a variety of hosts
 Direct observation of chromosomal
abnormalities
 Both somatic and germ cells may be analysed
 Comparatively low in cost
 Moderate time consuming
 Can be adopted to standard toxicology
procedure

9. Some points in favour of the use of
Cytogenetic analysis and its
limitation
 Disadvantages:
 Needs highly trained investigator
 Quantitative correlation to point mutation
not known
 No distinction between viable and nonviable
cells
 Chromatid aberration mainly selected

10. Tilapia nilotica use to determined
the metal content of a certain lake
 Cadmium and lead were determined in different
tissues (muscle, gill, stomach, intestine. liver,
vertebral column and scales) of Tilapia nilotica
to assess the lake water pollution with those
toxic metals. Fish samples were chosen from
different ages and weights to be analyzed along
with samples of the aquatic place, sediment and
lake water. The results showed that cadmium
and lead concentrations were higher in fish
scales and vertebral column than in the other
parts of the fish. Cadmium and lead levels in
High Dam lake water and fish (Tilapia nilotica)

11. Continuation:
 Were a result of the pollution which uptakes
from aquatic plants, sediments and gasoline
containing lead that leaks from fishery boats.
Tilapia nilotica fish was used as a good bioassay indicator for the lake pollution with
cadmium and lead. The fish muscles in this
study were in the safety baseline levels for
man consumption.

12. THANK YOU!