Comparitive Study On Morphology Of Hairs Between Melatonin Treated And Control American Mink

Mink(Neovison vison)is a seasonal molting animal.The adult mink has two moults in spring and autumn each year.Under natural conditions,the change of photoperiod is the first signal of molting,after the implantation of melatonin,mink’s start time of molting in autumn is ahead,Are there differences between melatonin treated and control American mink pelage morphological indexes?There is no detailed quantitative study at present.To compare morphological characteristics between the melatonin treated mink pelage and control mink pelage,we collected 10 pelts from melatonin treated female mink(pelted in August)and 10 pelts from control female mink(pelted in December).All mink were of the same breed(or color-type)and raised in the same mink farm.From each pelt,guard hair and underfur were sampled from four sites(neck,mid-back,buttock,and mid-belly).All the sampled hairs were made into cuticular impression organic glass and medulla pattern slide,and paraffin slice of skin tissues were made.Hair density of the four sites,straight length of underfur,length and diameter of hair,diameter of medulla,hair diameter near root,medulla-absent region length near hair root,flat-shaped scale pattern length near hair root was measured.Medullary index,proportion of medulla-absent and flat-shaped scale pattern near hair root,hair flatness,underfur crimp ratio was calculated.With the analysis of SPSS,we concluded that:(1)Expect the length and straight length of underfur in mid-belly,there was no significant difference in the length of guard hair and underfur,straight length of underfur,underfur crimp ratio,diameter of medulla,hair flatness,hair density in neck,mid-back,buttock and mid-belly between melatonin treated and control american mink,and they Pelage quality were similar for the melatonin treated and control American mink.(2)The diameter of underfur at neck,mid-back,buttock and mid-belly of control mink was extremely significant lower than the melatonin treated mink,medullary index of underfur at mid-back and buttock,mid-belly was(extremely)significan higher than the melatonin treated mink.The medulla-absent region length near hair root of underfur at neck,mid-back and buttock of control mink was significan higher than the melatonin treated mink.The proportion of medulla-absent near hair root of guard hair at neck and buttock of natural grown mink was significan higher than the melatonin treated mink,the proportion of medulla-absent near hair root of underfur at mid-back and buttock,neck and mid-belly of control mink was(extremely)significan higher than the melatonin treated mink.The hair diameter near root of guard hairand proportion of flat-shaped scale pattern near hair root of underfur at mid-belly of the natural grown mink significant lower than the melatonin treated mink,it shows that there are differences in the microscopic morphology of hair.(3)The guard hair and underfur what medulla-absent region length near hair root and proportion of medulla absent near hair root,diameter of underfur at the 4 sites,etc.,can be used to distinguish melatonin treated and natural grown mink pelage.