Ontogeny of American paddlefish lymphoid tissues

Abstract

The temporal and spatial distribution of American paddlefish Polyodon spathula immune cell populations was determined using enzyme cytochemistry and immunohistochemistry. Monocytes and macrophages were present in the renal haematopoietic tissue, spleen, meningeal myeloid tissue, cardiac myeloid tissue and lamina propria of the spiral valve at 7 days post‐hatch (dph). Immature lymphocytes were present in the renal haematopoietic tissue, spleen, meningeal myeloid tissue, cardiac myeloid tissue, thymus and lamina propria of the spiral valve at 7 dph. Type A lymphocytes (T‐cell like) were demonstrated in the thymus by 21 dph. Type B immunoglobulin positive lymphocytes (B‐cell like) were present in the renal haematopoietic tissue, cardiac myeloid tissue and lamina propria of the spiral valve by 7 dph, the thymus at 21 dph, the spleen by 56 dph, and were not observed in the meningeal myeloid tissue of paddlefish aged 7–28 dph. Granulocytes were present in the renal haematopoietic tissue, thymus, spleen, meningeal myeloid tissue, cardiac myeloid tissue and lamina propria of the spiral valve by 7 dph. The spleens in 7–28 dph fish were predominately red pulp. Differentiation of leukocytic and erythrocytic compartments (white and red pulp, respectively) was not apparent in the spleen until 56 dph. Remarkable thymic cortical and medullary differentiation was not yet present at 28 dph, and the thymus was not sampled at 56, 84 or 112 dph. The cardiac myeloid tissue was not developed until 56 dph. Peyer’s patches were present in the lamina propria by 56 dph. Paddlefish lympho‐myeloid structures are therefore slow to develop, and vaccination procedures should be performed at 2–4 months post‐hatch.

The first finding of Hassall's corpuscles in the thymi of cultured sturgeons

“…The cortex is predominantly composed of closely packed lymphocytes. The medulla is composed of sparsely organised lymphocytes, macrophages, reticular cells and Hassall's corpuscles that have a disperse distribution (Fange 1986;Petrie-Hanson and Peterman 2005;Peterman and Petrie-Hanson 2006). …”

Effects of body mass and water temperature on routine metabolism of American paddlefish Polyodon spathula

“…Interest in culturing P . spathula for caviar in the U.S.A. has increased as a result of banned importation of beluga Huso huso (L. 1758) (Acipenseridae) caviar (Peterman & Petrie-Hanson, 2006). Zooplankton consumption estimates for P .…”

Immunohistochemical mapping of thymic microenvironment in sterlet (Acipenser ruthenus)

“…The epithelial cells constitute a fine epithelial intra-thymic network (Mohammad et al 2007;Gradil et al 2014), while closely packed lymphocytes dominate the cortex. The medulla consists of sparsely organised lymphocytes, macrophages, reticular cells, fibroblasts and dispersedly distributed Hassall's corpuscles (Bowden et al 2005;Petrie-Hanson and Peterman 2005;Peterman and Petrie-Hanson 2006;Salkova and Flajshans 2016).…”

“…The thymus is considered as the primary lymphoid organ in sturgeons, Acipenseridae (Petrie-Hanson and Peterman 2005;Peterman and Petrie-Hanson 2006). The thymus is a paired lymphoepithelial organ situated on the upper inside edge of the operculum in close proximity to the branchial cavity and pharyngeal epithelium (Bowden et al 2005;Salkova and Flajshans 2016).…”