[Histonet] Guniea pig anti-Doublecortin & Goat-Guinea pig secondary antibody on rat tissue

[ti fei]

it seems when I use guniea pig-anti-doublecortin (DCX) with secondary antibody from invitrogen goat-anti guinea pig Alexa 488 or 568. I always get staining on blood vessel-like structures. 
  
 Anyone has such experiences before? Do goat-anti-guinea pig IgG will cross react with rat IgG ?
 Or it is due to primary antibody problem - which is unlikely because the antibody has been used without a problem in other labs.