21563
METHODS : Separate groups of male C57BL / 6J mice discriminated 0 . 56 , 1 , or 1 . 78 mg / kg of nicotine base .
 Chemical: nicotine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: nicotine