Use of a micro-encapsulated eucalyptus-medium chain fatty acid product as an alternative to zinc oxide and antibiotics for weaned pigs

Objective: To compare the effects of eucalyptus-medium chain fatty acids (E-MCFAs), zinc oxide (ZnO), and antibiotics on performance, nutrient digestibility, and serum chemistry parameters of nursery pigs. Materials and methods: Three experiments were conducted. Recently weaned barrows, weighing approximately 7 kg, were allotted to five treatments consisting of a basal diet or the basal diet supplemented with antibiotics (33 mg per kg tiamulin and 44 mg per kg lincomycin), ZnO (1500 or 2500 mg per kg), or 0.1% E-MCFAs (Experiments One and Two). In Experiment Three, 1% diatomaceous earth was added as a digestibility marker and the negative control was not used. Results: In Experiment One (n = 24), average daily gain (ADG) and average daily feed intake (ADFI) were lower (P < .05), while in Experiment Two (n = 18), ADG was lower (P < .05) for pigs fed the basal diet than for pigs fed any of the supplemented diets. In all three experiments, performance of pigs fed the four supplemented diets did not differ (P > .05). Apparent fecal digestibility of crude protein, calcium, phosphorus, energy, lysine, histidine, phenylalanine, and threonine was higher (P < .05) in the diet supplemented with E-MCFAs than in diets supplemented with ZnO or antibiotics (n = 6). Serum zinc, glutamic-oxaloacetic transferase, and glutamic-pyruvic transferase were higher for pigs fed the ZnO-supplemented diets than for pigs fed the other two treatments (n = 9). Implication: Eucalyptus-MCFAs can be successfully used as a growth promoter in diets fed to nursery pigs.