Calf intestinal mucin: isolation, partial characterization, and measurement in ileal digesta with an enzyme-linked immunosorbent assay.
The aim of this study was to develop a specific ELISA for calf intestinal mucin to quantify its contribution to ileal endogenous losses. Mucin was isolated from intestinal scrapings by cesium chloride density gradient ultracentrifugation. The isolated mucin had a high concentration of glutamic and aspartic acids, threonine, and serine (13.2, 11.2, 9.6, and 9.2 mol % of total amino acids assayed, respectively). The carbohydrates present were (mol % of total hexoses): galactose 42.1, N-acetylglucosamine 24.1, N-acetylgalactosamine 23.6, fucose 4.7, mannose 3.1, and sialic acids 2.4. Amino acids and carbohydrates represented 52.6 and 47.4% of the mucin by weight, respectively. A rabbit hyperimmune plasma was raised against purified mucin and used to set up an ELISA. The linear range of this assay was 20 to 640 ng/ml. The plasma cross-reacted with calf abomasal and colonic mucin. It showed no cross-reactivity with nonmucin components and no reactivity with intestinal mucin from other animal species except for the rat. Mucin accounted for approximately 3.5% of the dry matter output at the ileum of calves fed a substitute milk based on skim milk powder. This represented a flow of 3.4 g of mucin/kg of dry matter intake. Mucin flow increased when dietary protein was provided by cow's colostrum. Finally, the developed assay is a suitable tool to investigate the impact of dietary factors on the flow of mucin along the gut of preruminant calves.
Montagne
L
L
Unité Mixte de Recherche sur le Veu et le Porc, Institut National de la Recherche Agronomique, Rennes, France.
Toullec
R
R
Lallès
J P
JP
D000018:Abomasum / Q000737:chemistry; D000818:Animals; D000918:Antibody Specificity; D001224:Aspartic Acid / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D002417:Cattle / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D002586:Cesium; D002712:Chlorides; D004032:Diet; D004063:Digestion; D004797:Enzyme-Linked Immunosorbent Assay; D018698:Glutamic Acid / Q000032:analysis; D007082:Ileum / Q000737:chemistry; D007106:Immune Sera; D007422:Intestines / Q000737:chemistry*; D008892:Milk; D009077:Mucins / Q000032:analysis / Q000302:isolation & purification*; D012694:Serine / Q000032:analysis; D013912:Threonine / Q000032:analysis
D002241:Carbohydrates; D002712:Chlorides; D007106:Immune Sera; D009077:Mucins; D002586:Cesium; D013912:Threonine; D001224:Aspartic Acid; D018698:Glutamic Acid; D012694:Serine; C028019:cesium chloride