NSF REU Fisheries Bio Medical Presentation Summer 2011

8/3/2019 NSF REU Fisheries Bio Medical Presentation Summer 2011

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Approach for Assessing

Histological Sections of thePyloric Stomach in Matureand Kelt Steelhead Trout

Veatasha H.Dorsey


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Outline

Steelhead Background

1. Morphology

2. Life Cycle

3. Life History Theory

Problem

1. Spawning

2. Feeding


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MATUREMALE

MATUREFEMALE


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PacificSalmon Life

Cycle

Deposit eggs in grave nestsand die

if i h f


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Life History Theory ofSalmonid Species

Semelparity(Pacific Salmon) Iteroparity(Steelhead)

Emphasis Juvenilesurvival

Adult survival

Investment inSpawning

High Lower


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Problem

Spawning

Iteroparity Rates

< 2% inSnake/ColumbiaRiver

Historical rates-

unknown

PhysiologicalChanges?


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Problem (con).Steelhead and Feeding

Mature spawners

Stop feeding duringfinal sexualmaturation

If food is found instomach; eating out

of habit Kelts

Feed, rebuilding

strength to migrate


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Project Objectives

GeneralUnderstand the changes in tissue microstructureof the pyloric stomach in two reproductive phasesof steelhead (mature and kelt)

Specific

1. Characterizehistological profiles byidentifying pertinent tissue attributes

2. Developa method to evaluate tissuearchitecture in pre- and post reproductive


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Why Histology?

Insight on tissuelevel organization

Disease detectionand prevention

Static representation

of health


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Hypothesis

The length ofthe epithelialfolds and thearea of the

rugae isrelated to thesteelheadsability to feed,

digest andassimilate.


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Methodology (FishCollection)

Dworshak (Sexually Mature)

Not feeding

Controlled environment Steelhead representing sexually mature

phase of the adult spawning migration

Lower Granite Dam (Kelts) Rebuilding energy stores

Steelhead in their post-spawning

migration back to the Pacific Ocean


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Dworshak


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Methodology (Histology Pre1. Tissue fixed in

formalin2. Sectioned for

shipment (ColoradoHisto-Prep in Fort

Collins, CO.)3. Hematoxylin and

eosin was used forstaining of paraffin

embedded tissues


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Methodology(Measuring)

Measurements(Microscope Software-Calibrated m)

Area of RugaeThree

measurements perfish

Total data points =18

Length

3 ruga per fish


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1. Measure the base of the

ruga (dotted line).

2. Find the midpoint of the

line.

3. Calculate length.4. Calculate the width of

the line horizontally.

MeasuringArea of Ruga


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4. Label the quadrantscounterclockwise

5. Locate two suitable

folds

6. Locate the longest

and shortest (max/min)

EstablishingQuadrants


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7. Measure the cross

sectional area (l x w=a)

The optimum

magnification: 100-300.

MeasuringEpithelial

Folds


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Discussion

Average epithelial fold length in kelts ~ 50%longer than in mature spawners

Average rugae area in kelts ~ 55% larger than

mature spawners Variation within kelts

Migration Distance

Spawn Timing

Homogeneity within mature spawn

Holding tank

Documents

NSF REU Fisheries Bio Medical Presentation Summer 2011