THE EFFECT OF ZINC IN THE DIET FOR WEANED PIGLETS AND THE POSSIBILITIES OF SUBSTITUTION - review
Bělková J., Václavková E., Horký P.
Zinc in the body affects growth, development, reproductive ability, blood formation and metabolism of nucleic acids, proteins and carbohydrates. It plays a significant role in the development of cartilage and bone and has a positive effect on the development of skin derivatives. It is an essential ingredient of more than 200 enzymes; it influences the activity and stability of many of them and can be considered a significant antioxidant factor. Zinc acts on the function of the glands and activates the hormonal activity of the pituitary gland. It is essential for cellular immunity and cell proliferation, wound healing, leukocyte formation and function. It affects phagocytosis and antibody production. The zinc concentration in blood and blood plasma responds to changes in diet. Resorption occurs in the small intestine and is significantly affected by chemical form and solubility. The usability of zinc negatively affects the excess of calcium, phosphorus, iron, copper, cadmium, lead and coarse fiber in the feed. Excretion of endogenous zinc takes place via saliva, pancreatic and intestinal juices and bile, with a large amount of excretion by colostrum and milk. Zinc not resorbed and zinc excreted into the digestive tract leaving in the feces. The need for zinc is relatively high in juveniles with high growth rates. The underlying symptoms of the deficiency are reduced feed intake, decrease of growth, changes in skin, mucous membranes, impaired healing of wounds, weakening of immune functions and reproductive disorders.
Zinc and its compounds have a number of positive effects that make piglets better offset by changing the feed, environment, and weaning stress. The use of high therapeutic doses of zinc oxide in feed for weaned piglets has hitherto been a common practice that has allowed pig farmers to stimulate growth while keeping diarrhea and disease under control in a critical period after weaning. However, zinc also has a number of negative effects to be taken into account when used in high doses.
Key Words: Zinc, zinc oxide, pig, piglet, weaning