Analyzing Bacillus thuringiensis crystal protein 5B against gastrointestinal nematodes

Liz Kass


Gastrointestinal parasites are becoming resistant to current anthelmintic (deworming) treatments, threatening the welfare and production of livestock animals. Gastrointestinal nematodes (GIN) lead to devastating impacts to their host, weight loss, anemia, reduced feed intake, lethargy and in severe cases, death. These health implications GIN cause lead to economic consequences for formers/producers by lowering production. 

This study analyzes the anthelmintic therapies of Bacillus thuringiensis (Bt) crystal protein (Cry) 5B on GIN. Fifteen sheep were separated into three different treatment groups (n=5) control, Cry5B 10mg/kg and Cry5B 40mg/kg. To assess the anthelmintic properties of Bt Cry5B, fecal egg counts (FEC) were gathered daily after Cry5B treatment until the abomasum of the sheep were collected to quantify the remaining worm burden. After Cry5B treatment FEC and worm burdens drastically decreased in the 40mg/kg treatment group and decreased in the 10mg/kg treatment group.  These results concluded there are anthelmintic properties of Bacillus thuringiensis crystal protein 5B against GIN, but further research will be needed to implement Bt Cry5B as an anthelmintic.