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Weaned pigs, Diet complexity, Zinc oxide, Carbadox


The positive effect of pharmacological levels of zinc (Zn) from zinc oxide (ZnO), is well documented. Zinc at 3000 mg/kg has been shown to be as effective as carbadox (CARB) in the weaned pigs’ diet. Recent research has demonstrated an unexpected effect on weaned pig performance from adding 3000 mg/kg of Zn from ZnO to simple diets. Normally, pigs fed complex diets with specialty ingredients outperform pigs fed simple diets, primarily because of increased feed intake. However, performance of pigs fed simple diets with added ZnO has been equal to performance of pigs fed complex diets with or without added ZnO (SWINE 2000-9 and SWINE 2000-10). Improvement in pig performance was not to the same degree with the addition of 3000 mg/kg Zn to a complex diet as to a simple diet. The results of some research suggests that 3000 mg/kg of Zn may be close to a toxic level in some instances. This experiment was designed to obtain data at a lower Zn level (2000 mg/kg). Of interest was whether 2000 mg/kg Zn from ZnO would give equal performance to 55 mg/kg CARB. Also of interest was in 2000 mg/kg Zn would elict an improvement in performance from pigs fed the complex diet as well as pigs fed the simple diet. If the response to 2000 mg/kg was the same for both types of diets, this would suggest that added Zn was marginally toxic when included at 3000 mg/kg but not at 2000 mg/kg in a complex diet. If the response to Zn was found only in the simple diet, it would suggest the differences in responses to Zn previously observed for simple and complex diets was due to an interaction between Zn levels and feed ingredients affecting feed intake.

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South Dakota State University


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