title: Subtherapeutic levels of antibiotics in poultry feeds and their effects on weight gain, feed efficiency, and bacterial cholyltaurine hydrolase activity.
abstract: A radiochemical method was developed to estimate cholyltaurine hydrolase potentials and rates of cholyltaurine hydrolysis in chicken intestinal homogenates. This method was used to monitor the effects of antibiotic feed additives on cholyltaurine hydrolase activity. Avoparcin, bacitracin methylenedisalisylic acid, efrotomycin, lincomycin, penicillin G procaine, and virginiamycin improved rate of weight gain and feed conversion of chicks and decreased cholyltaurine hydrolase activity in ileal homogenates relative to those of nonmedicated control birds. The results provided the first evidence that feeding selected antibiotics at subtherapeutic levels can affect bile acid-transforming enzymes in small-intestinal homogenates. The inverse relationship between growth performance and cholyltaurine hydrolase activity raises the possibility that specific inhibitors of this enzyme may promote weight gain and feed conversion in livestock and thereby reduce or eliminate the need for antibiotic feed additives.
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001414:Bacitracin / Q000494:pharmacology; D001419:Bacteria / Q000201:enzymology*; D001835:Body Weight / Q000187:drug effects; D002645:Chickens / Q000254:growth & development / Q000382:microbiology / Q000502:physiology*; D005503:Food Additives / Q000494:pharmacology; D007421:Intestine, Small / Q000201:enzymology / Q000382:microbiology; D008297:Male; D011112:Polymyxin B / Q000494:pharmacology; D011728:Pyridones / Q000494:pharmacology; D013656:Taurocholic Acid / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D005503:Food Additives; D011728:Pyridones; D001414:Bacitracin; C012954:efrotomycin; D013656:Taurocholic Acid; D011112:Polymyxin B