Light and Electron Microscopy of Cells in Pig Colostrum, Milk and Involution Secretion

Abstract

Cells in pig colostrum, milk and involution secretion were identified using light and electron microscopy. Cell types identified were neutrophils, macrophages, epithelial cells, eosinophils and lymphocytes. The neutrophils predominated in colostrum and involution secretion, whereas in milk it was the epithelial cell. Macrophages and lymphocytes were present throughout lactation and so too were eosinophils which were always present in lower concentrations. Both neutrophils and macrophages were seen with phagocytic vacuoles containing either lipid, casein or cellular debris. The possible roles played by the phagocytic and lymphoid cells in the protection of the mammary gland of the sow and the gut of the neonate from pathogenic microorganisms is discussed.

An investigation of passive antibody and its effects on porcine epidemic diarrhea virus infection

“…72% in colostrum and 32 to 55% in milk (Evans et al, 1982). Under light and electron microscopy, Lee et al (1983) found that neutrophils and macrophages recovered from mammary secretions had phagocytic vacuoles containing lipid, casein, and cellular debris.…”

“…Later estimates of the number and proportion of cell types in mammary secretions vary widely (Evans et al, 1982;Hurley and Grieve, 1988;Magnusson, 1999;Lee et al, 1983;Schollenberger et al, 1986;Wuryastuti et al, 1993). suggested that this variation in cell numbers and types reflects both the developmental stage of the mammary gland and the physiological and/or immunological conditions of the sow.…”

Shedding of porcine reproductive and respiratory syndrome (PRRS) virus in mammary secrections of sows

“…In swine, secretions contain lymphocytes (T and B cells), phagocytes (neutrophils and macrophages), and epithelial cells. As shown in Table 1, estimates of the numbers and types of specific cells in porcine mammary secretions vary widely among researchers and between individual animals (23,33,53,55,86,102). Cell types and quantities are affected by stage of lactation and other individual conditions, but the piglet ingests an average of 500 to 700 million maternal cells daily (52).…”

“…T lymphocytes. Ten to 25% of cells found in swine colostrum are lymphocytes (23,33,52,53,55). Of these, 70 to 90% are T cells (50).…”

“…Of these, 70 to 90% are T cells (50). In contrast, less than 1 % of the cells in milk are T lymphocytes (23,33,50,51,53,54,86,87). The porcine T cell population has some unique features.…”