Histochemical Studies of the Skin and Wool in Sheep Reared on High Molybdenum Diet

Abstract

Four Japanese Corriedale wethers were fed for 32 weeks in experimental conditions. Two of these were given 200mg ammonium molybdate per day per head and others were not given. The cortical segmentations were investigated at various levels from the skin surface. Evidence presented indicates that the administration of molybdenum (Mo) induces the irregularity in the cortical segmentation in the follicle of Mo treated sheep. Histochemical distributions of alkaline phosphatase and leucine aminopeptidase in the skin from these sheep were also studied.It was previously shown that an excess of Mo in pastures induces similar symptoms as copper deficient ones in sheep, such as anemia, depressed growth, bone disorder, depigmentation of wool and some abnormal wool fibers.1,2,3,4) It is the current view that the physical properties of wool, including crimp are largely due to the existence of cystine residues. It provides disulphide cross links holding the polypeptide chains in the massive condition in the fiber. Disulphide cross links are produced by oxidation of thiol groups, which occurs during keratinization stage in fiber formation. MARSTON5) found that the conversion of -SH to -SS-was incomplete in copper deficient sheep.While the role of copper in this situation is unknown, he suggested that copper seemes to play a role as a coenzyme in the oxidation of thiol groups. Recently, this idea has further supported by many other investigators.6,7) Moreover, it is well established that fine wool fibers have the bilateral structure constructed by ortho (basophilic) and para (acidophilic) cortical segments, which are different from each other in both chemical and physical properties.This has a close relationship to the crimp formation.8,9,10) Though many investigations have been published about the chemical composition 11,12,13) or the physical properties4,14) of the steely wool, there have been as yet little information about the effect of high Mo intake in sheep on the cortical segmentation at the lower level of the follicle.The purposes of this study were to show the cortical segmentation at various levels of wool follicles from sheep maintained on a high Mo diet and also to obtain some informations about the localization of alkaline phosphatase and of leucine aminopeptidase. They are often found in the metabolically active parts in the animal tissues and considered likely to linked with the transport of organic substances.

Experimental Copper Deficiency, Chromium Deficiency and Additional Molybdenum Supplementation in Goats – Pathological Findings

“…Several studies have reported effects of Cu deficiency and/or molybdenosis affecting skin, skeleton, cardiovascular system, liver, pancreas, gut and nervous system, in a variety of species, with different ages and durations of exposure [ 28 , 37 , 38 , 17 , 31 , 7 ].…”

“…Copper deficiency leads to achromotrichia in cattle [ 45 ] and molybdenosis results in depigmentation of the skin in cows [ 8 ], goats [ 37 , 38 ] and defective hair structure in sheep [ 28 ]. None of these changes were found in our study.…”