Nigella sativa L. (NS) is an Asian plant containing bioactive compounds such as thymoquinone, which has been linked to antimicrobial, anti-inflammatory and gastro-protective activities. Extracts of NS improve performance and reduce enteropathogen colonization in other species, but studies with swine are scarce. The aim of this study was to test an NS extract as an alternative antibiotic feed supplement for its effects on wildtype populations of E. coli and Campylobacter and a challenge strain of Salmonella Typhimurium and evaluate its effect on growth performance in weanling pigs. For this purpose, a total of 72 three-week-old weaned Yorkshire × American Landrace crossbreed piglets were randomly distributed into two study groups (n = 36). Each study group contained a control group (CON, no added extract), a NS1 group (NS extract at 1.5g/kg diet) and a NS2 group (NS extract at 4.5g/kg diet). The NS extract was given by oral gavage on the first study group, and it was incorporated in the feed on the second study group. The piglets body weight (BW) was recorded at the beginning and end of the study to evaluate animal growth and the feed conversion ratio (FCR). Gut samples were collected at the end of the study (9 days) from the jejunum, cecum and rectum.
As a result, wildtype E. coli jejunal and rectal populations from both NS supplemented groups were lower than the control. However, wildtype Campylobacter and Salmonella typhimurium were unaffected by NS treatment. Feed efficiency improved linearly over the 9 days in pigs treated with NS1 and NS2, possibly due to the high glutamine/glutamic acid content of the NS extract.
In conclusion, the oral administration of a NS extract to weanling pigs improved feed conversion during the 9-day trial and significantly reduced levels of naturally occurring E. coli in the jejunal and rectal content. These results warrant further research to investigate the role that glutamine/glutamic acid may play in NS supplementation and the potential of NS to control specific enteropathogenic E. coli infections in weanling pigs and to improve pig performance during grower and finisher phases of pig production.
Petrujkic, B. T., Beier, R. C., He, H., Genovese, K. J., Swaggerty, C. L., Hume, M. E., Crippen, T. L., Harvey, R. B., Anderson, R. C., and Nisbet, D. J. Nigella sativa L. as an alternative antibiotic feed supplement and effect on growth performance in weanling pigs. Journal of the Science of Food and Agriculture 98, no. 8 (2018): 3175-3181. https://doi.org/10.1002/jsfa.8823