Report: "rotifer food for aquatic animals" potx

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Body size variation among
strains of the Rotifer
Brachionus plicatilis
The United states – israel Binational Agriculture
Reseach and Development Fund (BARD)
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I. INTRODUCTION

Rotifer usefulness in aquaculture

Problem cosidered: size
This subject: Body size
variation among strains of the Rotifer

Brachionus plicatilis


The object of this work: 3
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II. Methods and materials

The 13 strains of Rotifer aren’t
genetic non-relationship.

Laboratary conditions

Time: 1 year
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1. Standard pre-experimetnal

procedure

After 3 days of
exponential growth, 200
females were removed
to repeat the procedure

After another 3 days of
exponential growth,
preserved for
measuring or initiate
other experiment
200
females
200
ml of
IOM
+ SF




S
E
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2. Determinate body size
Measuring body
size on 50 adult
females
Body size: lorica

length and
width
Tool: an ocular
micrometer
an ocular micrometer
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3. Comparation of reproductive
rates among strains

Consist 3
steps:

Pre-
experemental
conditions

Isolated singly

Count and
calculate
•
Population
growth rate
(r):
t
NoNt
r
lnln −
=
8

4. Size of a female over her
lifespan (McK8_3 days)
Collecting neonates
Cultivation neonates
Samples preservation procedure
Measuring lorica size
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5. The dietary effects on
lorica size
Other 6 diets were used
Special culture conditions
Transfer to new culture condition
Samples were culture in SE
Preserve
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6. The effects of temperature,
salinity and rotifer strain
A factorial experemental design was
used
Transfer to standard pre-experemental
conditions (after 7 days)
After 6 days of growth, preserve and
measure
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III. Result
1. The range of lorica sizes
The range of lorica sizes among strains
is large
High correlation level between lorica
length and width (r = 0.974)

The reproduction rate depends on
rotifer strain
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2. Size of a female over the
lifetime
The sizes grow
rapidly from
neonate to
adulthood
The growth
curve isn’t
smooth
The breeding
causes the
growth rate to
slow
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3. Effect level of enviromental
conditions on lorica size
Diets effect on lorica size is small
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4. The effect of temperature and
salinity
Salinity general effects on other
rotifer strains
Temperature special effects on other
rotifer strains
Rotifers tended to be smaller at higher
salinities and temperature for all
strains

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5. Main effects and interactions
of salinity, temperature and
rotifer strain on lorica length
Lorica size is a characteristic that is
largely genetically determined
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III. DISCUSSION
1. Range of lorica size

The other examinations suggest that
the lorica size is a wide range:

Samples collected from serveral
different locations by Ahlstrom

The range for laboratory-cultivated
is smaller than samples collected from
nature
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2. Dietary effects
Type of diet has only small influence
on adult female body size (Fukusho
& Iwamoto and Yufera)
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3. The effects of temperature

The effects of temperature on the
body size are entirely dependent on

strain type:

The respones of all strains for
temperature change
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
The role of temperature in
cyclomorphosis was initiated by
Fukusho and Iwamoto
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Rotifer body size is
primarily geneticaliy determined,
not great influenced by
enviromental conditions
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IV. Conclusion
Inappropriately sized larval prey
redures larval growth rate and
increases mortality
Selection of suitable rotifer
size is entirely feasible
The variety of rotifer size
and “enrichment” should improve the
reliability and usefulness of rotifer
in aquaculture
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