Doctor of Philosophy (PhD)


School of Animal Science

Document Type



The objectives of this research were to determine 1) the effect of anise oil (AO) in pigs after exposure and re-exposure by dietary additions to sow and nursery diets; and 2) the maximum level of AO that could be fed to broilers and its effect on in-vitro growth of Clostridium perfringens (ClP); 3) to determine the effect of AO and diet type on growth performance of broilers after a challenge with ClP; and 4) to determine the effect of AO fed to broilers under commercial conditions. The results indicated that exposing lactating pigs to AO through the sow diet had a positive effect on pig feed intake after weaning, improved nursery feed efficiency, and had a positive influence on growth performance. Feeding broilers more than 4000 ppm AO in their diet reduced broiler feed intake, and more than 2500 ppm AO reduced growth. In an in-vitro Exp., the antibiotic Bacitracin and anticoccidial Salinomycin completely inhibited ClP growth, and AO linearly reduced ClP growth to undetectable levels. Thus, AO could have antimicrobial activity against ClP in-vitro. During a challenge with ClP (d 10 with 2 x 109 CFU/ml), broiler feeding AO reduced broilers ADFI and ADG during the first 10 days. Necropsy of all broilers indicated that feeding AO reduced the lesions of the jejunum (LS) related to ClP challenge. In a second ClP challenge (3 x 106 CFU/ml, on d 10 and 13), fish meal (FM) improved growth performance of broilers and had no effect on LS related to ClP challenge compared broilers fed vegetable protein. Feed intake was not affected by AO in this study. Broilers were fed a 3-phase feeding program in a floor pen study, and the treatment diets were antibiotic free, antibiotic added, or AO (1000 ppm). Feeding AO had a similar effect to feeding antibiotic added diet on growth performance of broilers. In summary, AO stimulated pig feed intake after weaning and growth performance after re-exposure. Also, AO had antimicrobial activity against ClP growth in-vitro, reduced jejunum lesions related to ClP in-vivo, and can be an alternative to antibiotics fed as growth promotants for broilers.



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Committee Chair

Bidner, Thomas