Abstract
Gastric cytology is frequently used in cetacean and sirenian health management and is a promising potential diagnostic for identifying gastric disease in pinnipeds.1,2 This study’s objective was to report preliminary pH and cytologic parameters for gastric fluid from northern elephant seal pups (NES; Mirounga angustirostris) undergoing rehabilitation. Thirty-two gastric fluid samples were collected from 22 fasted NES pups using an orogastric tube immediately prior to morning feeding. Gastric pH was measured by an electrode probe, and gastric fluid assessed via direct cytology with Wright-Giemsa staining. Cytologic evaluation was modeled after criteria recommended in cetaceans and sirenians, including cellularity, morphologic preservation, bacterial abundance, average white blood cells per high power field (WBC/HPF), and average epithelial cells per high power field (epithelial cells/HPF).2 Health status of sampled NES was classified as apparently normal, suspected systemic inflammation, or confirmed systemic inflammation based on physical exam, hematology, and serum amyloid A levels. Apparently normal NES (n=11) had a median gastric pH of 0.344 (min–max: 0.307–0.422), moderate cellularity and morphologic preservation, minimal bacterial abundance, a median of 17.3 average WBC/HPF (min–max: 1.2–32.6), and a median of 2.2 average epithelial cells/HPF (min–max: 0.4–4.5). By contrast, NES with confirmed systemic inflammation had significantly higher pH (median=0.429, min–max: 0.337–4.39, p-value=0.045) and average epithelial cells/HPF (median=9, min–max: 0.3–33.9, p-value=0.045). This study illustrates gastric fluid analysis has the potential to benefit the diagnosis and management of gastric disease in pinnipeds.
Acknowledgements
The authors thank the dedicated volunteers and staff of The Marine Mammal Center for their contributions to this study and their efforts in pinniped rehabilitation and conservation. The authors especially thank Barbie Halaska, Maggie Martinez, Carlos Rios, and Jen Soper for their help with cytology preparation and evaluation. Rescue and rehabilitation activities were conducted by The Marine Mammal Center under NOAA permit #18786-04 and clinical sampling under TMMC IACUC #2021-01-01.
*Presenting author
+Student presenter
Literature Cited
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2. Varela RA, Schmidt K, Goldstein JD, Bossart GD. Evaluation of cetacean and sirenian cytologic samples. Vet Clin North Am Exot Anim Pract. 2007;10(1):79–130.