Enzyme activity in the small intestine of goat kids during the period of passive immunity acquisition

Abstract

Enzyme activity of protein and carbohydrate degradation in small intestinal mucosa was investigated in goat kids fed with lyophilized bovine and goat colostrum. At 0, 7 and 14h of life 15 male newborns received 5% of body weight of lyophilized bovine colostrum and 14 goat colostrum, both with 55mg/mL of IgG. Duodenum, jejunum and ileum samples were collected at 18, 36 and 96h of life. Three animals were sampled at birth, without colostrum intake. Activity of aminopeptidase N and A, dipeptidil peptidase IV, lactase, maltase and sucrase was determined as one international unit per gram of tissue. Intracellular enzymatic activity of acid phosphatase was observed by histochemistry in tissue section. Only the activity of aminopeptidase A in the ileum was affected by treatment, with a greater value for LBC than for GC (P<0.05). The aminopeptidase N activity was the highest at 36h in the duodenum (P<0.05) and lowest at 96h in the jejunum (P<0.05). Dipeptidil peptidase IV activity was highest at 36h in the duodenum (P<0.05), lowest at 96h in the jejunum (P<0.05) and higher at 36h than at 96h in the ileum (P<0.05). Aminopeptidase A activity in the ileum was highest at 36h (P<0.05), followed by 18 and 96h of life (P<0.05). Lactase activity in the duodenum increased from 18 to 36h and from 36 to 96h in the jejunum (P<0.05). Maltase activity increased only in the duodenum from 18 to 96h (P<0.05). Sucrase activity in the jejunum decreased from 18 to 36h and from 36 to 96h in the ileum (P<0.05). At birth, activity of most enzymes was similar to that at later times (P<0.05). Histochemistry analyses showed a higher frequency of lysosomes with acid phosphatase activity in the duodenum, especially at 36h of life. In the jejunum, the presence of lysosomes with acid phosphatase activity was the highest at 96h, followed by 36 and 18h of life. In the ileum, all samples showed low presence of lysosomes with acid phosphatase activity. These results indicate that lyophilized bovine colostrum, as a heterologous source of antibodies or nutrients, is a possible alternative management tool for goats. The present work also suggests that in the first 4days of life, enzyme activity in the intestinal epithelium of goats is still not fully stimulated, which is an important characteristic for these animals that depend on macromolecule absorption to acquire passive protection after birth.