Feed additives for swine: Fact sheets – carcass modifiers, carbohydrate-degrading enzymes and proteases, and anthelmintics

This is the second in a series of peer-reviewed practice tip articles, each including two or three fact sheets on feed additives for swine. The previous practice tip, published in the September-October issue of the Journal of Swine Health and Production, included fact sheets on acidifi ers and antibiotics (J Swine Health Prod. Future fact-sheet topics will include fl avors; high dietary levels of copper and zinc for growing pigs; mold inhibitors, mycotoxin binders, and antioxidants; phytase; phytogenic feed additives (phytobiotics-botanicals); and probiotics and prebiotics. Jacela JY, DeRouchey JM, Tokach MD, et al. Feed additives for swine: Fact sheets – carcass modifi ers, carbohydrate-degrading enzymes and proteases, and anthelmintics. There is increasing consumer demand for leaner and healthier pork products. Improvements in genetics, new technologies, and increased understanding of nutrition have become instrumental in helping producers meet this demand. Continued research also has led to the development of products that can be included in swine diets as carcass modifi ers. A dietary carcass modifi er is broadly defi ned as any component of the diet that alters the resulting carcass composition of pigs. Generally, the mechanism of action of carcass modifi ers is aimed at increasing protein and muscle deposi-tion while reducing fat deposition. These products vary in the mechanisms by which they modify carcass quality. In addition, not all carcass modifi ers are approved for use in pig diets, for public-health reasons. Understanding the modes of action and differences between these products is important for safe and effective use. What compounds are commonly used as carcass modifi ers? Carcass modifi ers available for use in swine include chromium, betaine, carnitine, conjugated linoleic acid, and ractopamine. Chromium. Chromium is an element essential for growth and development in animals. It plays an important function in metabolic processes involved in the regulation of glucose, proteins, lipids, and cholesterol. Chromium from organic complexes like chromium picolinate and chromium nicotinate is more readily absorbed than other inorganic forms, such as chromium chloride. A number of studies, 1-3 mostly utilizing chromium picolinate, have shown that adding chromium to pig diets during the growing-fi nishing period can improve growth performance or lean meat yield. However, the responses have not been consistently observed in all studies. 4-7 The exact physiological action of chromium that results in increased carcass leanness is not clear. One possible mechanism of action is improved insulin sensitivity of tissue, causing enhanced deposition of …