A Shrewsbury man has pleaded not guilty to charges that he traveled to the Dominican Republic to have sex with underage girls. Conrad Gallant, 62, entered his plea on Friday in federal court in Worcester, according to court records. He faces charges including sexual exploitation of children and engaging in illicit sexual conduct in foreign places. Gallant allegedly traveled to the county to have sex with minors at least four times between February 2011 and his arrest last March. He is being held without bail.