Study On Histomorphologic Development Of Hair Follicles And Gastrointestinal Tracts And Activities Of Gastrointestinal Digestive Enzymes In Young Fox

This study was carried out in order to clarify the development pattern of pelage in Foxes. The skin thickness, the number of primary hair follicle and secondary hair follicle, the ratio of hair activity and the follicle length and depth were studied histologically on a series of skin samples taken from back, belly, shoulder and hip, between 1 to 42 days old after birth (4/group). And then, the experiment was conducted to study the development pattern of gastrointestinal tract in silver foxes. The intestinal villi’s height, width, density, the number of goblet cells in the intestinal villi and intestinal crypt depth, as well as the height and density of the fundus gland were observed and measured. And then study on the activities of enzyme in digestive tract, pancreas and stomach. The results were summarized as follows:(1) The epidermis layer matured at 1d and the dermis layer matured at 7 days after birth. The primary hair follicle was matured at 7 days, its length and depth changed a little after then, however, they were significantly different at 42 days(P<0.05). The secondary hair follicle was seen at 14 days, and it grew fast at 14-28 days, then the length and depth change flattened after 28 days. The density and activity of primary follicle showed highest at 1st, and then gradually reduced. However, the density of secondary follicle increased along with the days up to 42 days old, and the S/P (secondary follicle/ primary follicle) was the biggest at the42 days, moreover, continue to increase. The pieces were observed at 35 days which 7 days before the follicle group formed.(2) The intestinal villi have but not completely developed at birth. The height of duodenal villi increased gradually, and showed the highest at 42 days, but the highest of villi in jejunum and ileum showed the longest at 21 days and 28 days. The width of intestinal villi and the number of the goblet cells increased with the cubs growing. In contrast, the density of intestinal villi reduced with the cubs growing. The depth of crypt in jejunum decreased after increased. The value of the depth reached the biggest at 35 days and the depth of duodenal and ileum crypt increasing all the time instead. The value of duodenal V/C(villi height/crypt depth) increased after decreased, however, the value of jejunum V/C was similar after 21 days, the ileal V/C decreasing all the time, and 32.15% fewer than born. The height and density of fundus gland creased first and then reduced. The fundus gland showed the highest at 35 days as 362.25μm, the density of which showed the maximum at 21 days as 52.77 /mm.(3) With the daily increased, the amylase activity in intestine and pancreas had a tendency to increase. When the primary, the activity of pancreatic amylase is low, and with the daily increased, which is increasing rapidly. The activity of trypsin in pancreas lower than in intestinal tract, trypsin activity of the blue foxes increased gradually with the cubs growing, but trypsin activity of the silver foxes decreased after increased with the cubs growing, overall it presented a gradually increasing trend. Pancreatic lipase activity was higher than intestinal lipase activity among different species, pancreatic lipase activity of the blue foxes increased with the cubs growing, duodenal lipase activity was higher than the jejunum and ileum lipase activity, the intestine was at a little change. Intestinal lipase activity of the silver foxes decreased after increased with the cubs growing, basically the change tended to be gentle after 21 days. The activity of the disaccharidase increased gradually with the cubs growing. The activity of the pepsase is low before 21 days after birth, and then increased with the cubs growing.The activity of pepsase in gastric mucosa is higher than gastric content from 1 day after birth to 42 days.(4) The development of these two species went similar after comparison analysis of these two, showing no significant differences. But the density of the primary hair follicle and the secondary hair follicle of blue foxes was higher than that in silver foxes, while the width of hair bulb and the depth of the hair follicle in blue foxes were smaller than that in silver foxes. The crypt depth of different intestine parts and the intestinal villi density in blue foxes were higher than that in silver foxes. The V/C value of blue foxes was lower than silver foxes. The stomach fundus gland development went the same way for these two species, increasing at first and decreasing later, with their maximum happening at day 35, but the highest growth happened before day 21 for silver foxes, while the highest growth happened after day 21 for blue foxes. The activity of amylopsin, pancrelipase and trypsinase in silver foxes was higher than that in blue foxes, while the enzyme activity in intestinum showed no obvious regularity. As the day went by, the pepsin activity in gastric mucosa increased at first, decreased later, while the pepsin activity in gastric contents showed gradually increasing trend.