Hematology
Fish Health Management
Cold Blooded Vertebrates
• Primary site of hematopoiesis is anterior fourth
of the kidney
• Spleen is a accessory area of hematopoiesis as
well as the site for blood cell destruction
• Bone marrow, spleen and lymph nodes serve
this function warm blooded vertebrates
• Various types of blood cells in head kidney:
- Immmature
- Mature
- Red Blood Cells and White Blood Cells
Blood Cell Types
• Hemocytoblast- Stem Cell or blast cells,
- Most abundant in hemopoetic tissue of kidney,
rare in blood
• Erythrocytes- Red Blood Cells
- Carries Oxygen
• Leukocytes- White Blood Cells
- Blood Clotting
- Phagocytosis
- Inflammation Response
Erythrocytes
• Primary Function: Oxygen
transport
• Elongated elliptical cell: 13-16
m long by 7-10 wide m
• Nucleus centrally located,
elliptical in shape
• Polychromatins- Immature
erythrocytesless elliptical with blueish-gray
cytoplasm
Ghost Cells
• Artifact of
Sampling
Leukocytes
• Immune Response
• Coagulation
• Hard to differentiate
Lymphocytes
• Usually sparse in red
blood cells
• Spherical in shape, 710 m
• Eccentrically located
spherical nucleusstains reddish-purple
Neutrophils (Polymorphonuclear
Leukocytes)
• Only granulocytic
leukocyte present in
rainbow trout
• Origin and function of
theses cells not well
understood
• Accounts for 1-9% of total
leukocytes
• Average diameter is 9-13
m
• Multi-lobuated nucleus
(2-5 lobes)
Thrombocytes
• Occur in varying shapes
and size: elongated,
spiked, fusiform, and
spheroid.
• Elongated - 5-8 m long
• Spiked – streaked
cytoplasm on one end
• Fusiform- streaked
cytoplasm on both ends
• Spheroid- dense nuclei,
little or no cytoplasm
Monocytes and Macrophages
• Monocytes- large 9-25 m
• Indistinguishable from Macrophages once
in tissue
• Cytoplasm often has granules and a large
nucleus
• Macrophages not usually seen in blood
Kidney Imprint
• Various states of
hematopoiesis
Blood Sampling
Non-Lethal
• Mouth Catheterization
• Caudal Artery
• Heart
Lethal
• Sever Caudal Peduncle
• Sever Gill
Blood Assessment
• Three Indexes:
– Red Blood Cell Abundance
• Hemoglobin
• Hematocrit - Ratio of Packed RBC’s to total blood volume
• Variations in reading can be caused by species,
sex, age, temperature, clotting, water quality,
season
Hematocrit Readings
• Low
– Indicates anemia, gill damage,
osmoregulation impairment
• High
– Indicates stress, dehydration, hemoglobin
concentrations
Lab Procedure
•
•
•
•
•
Take blood from caudal artery
Use one tube for Blood Smear
Seal other 2 with CritoSeal at vacant end
Measure % of both
Tissue imprints
Tissue Imprints
• Cut a small piece of
Tissue
Fish 1
K
• Using forceps,
create imprints by
touching tissue to
slide in succession
L
S
Stain using Diff Quick
• Fix slides in Solution A (Methyl Alcohol) for
10 min
• Dip slides in Solution B 25 times
• Dip slides in Solution C 25 times
• Wash with DDI water. Dry and examine
the slides.