Hematology, Plasma Chemistry, and Hormonal Status as Health Indices in Newly Captured Beluga Whales (Delphinapterus leucas)
Abstract
The current research was performed under the project "Western-Okhotsk beluga population health assessment" and "The White Whale Programme" and aimed to evaluate the applicability of the hematological and endocrinological approaches for objective health assessment of wild and adapting to captivity beluga whales. Forty-two presumably healthy beluga whales (18 males, 24 females; body length: 212–450 cm), captured in the Okhotsk Sea in 2014 for commercial purposes, were surveyed. Examination took place on the day of capture (32 whales, "newly captured") and on the 15th to 20th day of captivity (17 individuals, "adapting"). Adult animals were released immediately after examination; juveniles/sub-adults were kept. The time between the start of animals' drive and blood sampling varied between 30–120 min. Routine blood tests were carried out manually at the field camp. Serum and plasma samples were obtained by centrifugation of blood, fast-frozen to -80°C, and kept frozen at -10 to -20°C until analyzed. Biochemical tests were performed in a certified veterinary laboratory "Shans-Bio" (Moscow). Hormonal assays were done at the IPEE Russian Academy of Science using enzyme immunoassay commercial kits "Immunotech" and "Hema" (Moscow). The data obtained were grouped and analyzed according to animal's age, sex, and duration of captivity. Assigning to a certain age class was based on skin coloration and body length.1
Hematological parameters of "newly captured" belugas are presented in Table 1, biochemical and hormonal data in Table 2. Compared to the adults, immature animals demonstrated significantly higher lymphocyte and monocyte count, higher levels of ALP, CK, calcium/phosphorus index, and lower ESR, fibrinogen, globulins, and the De Ritis ratio.
The "adapting" whales showed significant hematological changes: decrease in RBC, WBC content, Hb, eosinophils, lymphocytes, absolute amount of monocytes, and sharp increase in ESR, neutrophils count against the steady left shift with further increase in bands (up to 15%). Biochemical tests revealed reliable elevation of fibrinogen, with decrease in creatinine content and ALP activity. Hormonal tests displayed tendency to further elevation of cortisol concentrations.
Research results are discussed in the presentation in comparison with the available literature data on hematology, serum chemistry, and endocrinology of captive2,3 and free-ranging beluga whales1,4,5,6.
The simultaneous use of the acknowledged cetacean hematological and biochemical inflammatory indices7 together with other diagnostic approaches to health assessment in the wild and adapting to captivity beluga whales is reasonable. At the same time, the potential for practical application of the existing reference values of captive beluga whales for health monitoring of newly captured individuals is limited due to the remarkable modulation of hematological (in the broad sense) parameters of the latter caused by stress, parasitic invasions, diet, and other factors. It is preferable to rely either on standards specially developed for free living whales from local populations, or (in case of adapting to captivity animals) on individual dynamics of the indices. The data, presented in Tables 1 and 2, may be used (on conditions of compatibility of the blood sampling terms) as preliminary reference during the health assessment surveys of newly captured beluga whales at least from the Western-Okhotsk population.
Table 1. Hematological indices of newly captured beluga whales
|
Indices
|
Units
|
N
|
X ± σ
|
95% CI
|
Range
|
|
RBC
|
1012/l
|
32
|
3.1 ± 0.63
|
2.9–3.3
|
1.9–4.3
|
|
Hb
|
g/l
|
32
|
190.4 ± 25.9
|
181.0–200.0
|
106.4–225.7
|
|
MCH
|
pg
|
32
|
63.5 ± 12.4
|
59.0–68.0
|
41.7–84.7
|
|
ESR
|
mm/h
|
30
|
26.2 ± 16.0
|
20.2–32.2
|
0–53.5
|
|
WBC
|
109/l
|
32
|
11.4 ± 4.4
|
9.8–12.9
|
3.1–26.6
|
|
Neutrophils (total)
|
%
|
32
|
42.5 ± 9.3
|
39.1–45.8
|
17.0–57.5
|
|
109/l
|
32
|
4.6 ± 1.5
|
4.1–5.2
|
1.1–8.3
|
|
Eosinophils
|
%
|
32
|
25.7 ± 11.7
|
21.5–30.0
|
3.0–48.0
|
|
109/l
|
32
|
3.0 ± 2.3
|
2.2–3.8
|
0.3–12.6
|
|
Lymphocytes
|
%
|
32
|
28.5 ± 7.8
|
25.7–31.3
|
12.0–48.0
|
|
109/l
|
32
|
3.3 ± 1.7
|
2.7–3.9
|
0.5–8.9
|
|
Monocytes
|
%
|
32
|
3.2 ± 1.8
|
2.6–3.8
|
1.0–8.0
|
|
109/l
|
32
|
0.4 ± 0.2
|
0.3–0.4
|
0.1–0.9
|
Legend: N - number of examined individuals; X - mean arithmetic; σ - standard deviation; CI - confidence interval; MCH - mean cell hemoglobin; ESR - erythrocyte sedimentation rate.
Table 2. Serum chemistry and hormonal indices of newly captured beluga whales
|
Indices
|
Units
|
N
|
X ± σ
|
95% CI
|
Range
|
|
ALT
|
IU/l
|
30
|
2.4 ± 1.8
|
1.8–3.1
|
1.0–9.0
|
|
AST
|
IU/l
|
30
|
75.5 ± 34.1
|
62.8–88.3
|
35.0–231.0
|
|
AST/ ALT
|
|
30
|
39.6 ± 19.0
|
32.5–46.7
|
10.6–78.0
|
|
Bilirubin
|
Total
|
µmol/l
|
30
|
2.4 ± 1.8
|
1.8–3.1
|
1.0–10.9
|
|
Direct
|
µmol/l
|
30
|
0.7 ± 0.5
|
0.5–0.9
|
0.1–2.4
|
|
Indirect
|
µmol/l
|
30
|
1.7 ± 1.5
|
1.2–2.3
|
0.5–8.5
|
|
CK
|
IU/l
|
30
|
175.6 ± 122.9
|
129.7–221.5
|
28.0–638.0
|
|
GGT
|
IU/l
|
30
|
21.2 ± 10.3
|
17.3–25.0
|
6.5–42.5
|
|
Urea
|
mmol/l
|
30
|
24.1 ± 4.8
|
22.3–25.9
|
15.5–35.7
|
|
Creatinine
|
µmol/l
|
30
|
170.7 ± 47.2
|
153.1–188.3
|
95.0–311.0
|
|
Urea/creatinine ratio
|
|
30
|
78.6 ± 22.5
|
70.2–87.0
|
49.7–134
|
|
LDH
|
IU/l
|
30
|
441.3 ± 138.7
|
389.5–493.1
|
256.0–728.0
|
|
ALP
|
IU/l
|
30
|
216.5 ± 192.6
|
144.6–288.4
|
73.0–1093.0
|
|
Glucose
|
mmol/l
|
30
|
6.6 ± 1.7
|
5.9–7.2
|
3.7–10.5
|
|
Triglyceride
|
mmol/l
|
30
|
2.2 ± 0.67
|
1.9–2.4
|
1.4–3.9
|
|
Cholesterol
|
mmol/l
|
30
|
5.4 ± 1.7
|
4.7–6.0
|
3.2–9.6
|
|
Total protein
|
g/l
|
30
|
83.8 ± 14.8
|
78.3–89.3
|
57.0–119.0
|
|
Albumin (biochem.)
|
g/l
|
30
|
40.4 ± 7.7
|
37.5–43.2
|
27.0–60.0
|
|
Albumin (SPEP)
|
g/l
|
25
|
46.2 ± 6.2
|
43.9–49.0
|
32.8–60.2
|
|
Globulin (biochem.)
|
g/l
|
30
|
42.8 ± 13.5
|
37.8–47.8
|
27.0–60.0
|
|
α1-globulin
|
g/l
|
25
|
3.3 ± 1.6
|
2.6–4.0
|
1.3–10.0
|
|
α2-globulin
|
g/l
|
25
|
10.5 ± 2.62
|
9.4–11.6
|
4.4–16.3
|
|
β1+2-globulin
|
g/l
|
25
|
4.2 ± 1.43
|
3.6–4.8
|
1.8–7.9
|
|
γ-globulin
|
g/l
|
25
|
27.5 ± 7.7
|
24.3–30.7
|
12.9–44.9
|
|
Albumin/globulin ratio
|
|
30
|
1.1 ± 0.5
|
0.9–1.2
|
0.5–2.3
|
|
Fibrinogen
|
g/l
|
30
|
1.06 ± 0.45
|
0.9–1.2
|
0.4–2.0
|
|
Sodium
|
mmol/l
|
30
|
165.0 ± 23.5
|
156.2–173.8
|
120.0–216.0
|
|
Potassium
|
mmol/l
|
30
|
4.6 ± 0.8
|
4.3–4.9
|
3.2–6.6
|
|
Sodium/potassium ratio
|
|
30
|
36.4 ± 3.8
|
35.0–37.8
|
28.5–44.1
|
|
Calcium
|
mmol/l
|
30
|
2.7 ± 0.1
|
2.5–2.9
|
2.0–4.2
|
|
Phosphorus
|
mmol/l
|
30
|
2.4 ± 0.6
|
2.2–2.6
|
1.6–3.9
|
|
Calcium/phosph. ratio
|
|
30
|
1.2 ± 0.2
|
1.1–1.3
|
0.8–1.7
|
|
Iron
|
mmol/l
|
30
|
41.7 ± 18.7
|
34.7–48.7
|
15.6–109.1
|
|
Cortisol
|
nmol/l
|
30
|
223.0 ± 81.2
|
192.7–253.3
|
107.2–424.9
|
|
T4 total
|
nmol/l
|
30
|
113.0 ± 41.9
|
97.4–128.6
|
27.2–227.3
|
|
T4 free
|
pmol/l
|
26
|
29.5 ± 13.5
|
24.1–35.0
|
12.4–74.0
|
|
T3 total
|
nmol/l
|
30
|
3.4 ± 1.1
|
2.9–3.8
|
2.3–5.9
|
|
T3 free
|
pmol/l
|
26
|
5.3 ± 2.2
|
4.4–6.2
|
2.6–11.9
|
Legend: N - number of examined individuals; X - mean arithmetic; σ - standard deviation; CI - confidence interval; MCH - mean cell hemoglobin; ESR - erythrocyte sedimentation rate.
Acknowledgements
The authors thank fieldwork participants Alexey Paramonov and Maria Solovyeva, Alexander Morozovskiy's capture team for accommodation and assistance with sampling; Ocean Park Corporation Hong Kong for funding data collection expedition, hematology and plasma chemistry analyses; Russian Geographic Society for funding hormonal tests.
* Presenting author
Literature Cited
1. St. Aubin DJ, Deguise S, Richard PR, et al. Hematology and plasma chemistry as indicators of health and ecological status in beluga whales, Delphinapterus leucas. Arctic. 2001;54:317–331.
2. Bossart GD, Reidarson TH, Dierauf LA, Duffield DA. Clinical pathology. In: Dierauf LA, Gulland FMD, eds. CRC Handbook of Marine Mammal Medicine. 2nd ed. Boca Raton, Florida: CRC Press; 2001:383–436.
3. Cornell LH, Duffield DA, Joseph BE, Stark B. Hematology and serum chemistry values in the beluga (Delphinapterus leucas). J Wildl Dis. 1988;24:220–224.
4. Norman SA, Goertz CEC, Burek KA, et al. Seasonal hematology and serum chemistry of wild beluga whales (Delphinapterus leucas) in Bristol Bay, Alaska, USA. J Wildl Dis. 2012;48:21–32.
5. St. Aubin DJ, Geraci JR. Adaptive changes in hematologic and plasma chemical constituents in captive beluga whales, Delphinapterus leucas. Canadian Journal of Fisheries and Aquatic Sciences. 1989;46:796–803.
6. Tryland M, Thoresen SI, Kovacs KM, Lydersen C. Serum chemistry of free-ranging white whales (Delphinapterus leucas) in Svalbard. Vet Clin Pathol. 2006;35:199–203.
7. Reidarson TH, Duffield D, McBain J. Hematology of marine mammals. In: Weiss DJ, Wardrop KJ, eds. Schalm's Veterinary Hematology. 6th ed. Wiley-Blackwell. 2010:950–957.