15913
Serum IgG anti - brain antibody ( Ab ) levels of pnd21 SFvF1 offspring and SJL dams were higher than those of the FvSF1 offspring and FVB dams , but Hg only increased the titers of the FVB dams and their offspring .
 Hg
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Hg