Is it possible to turn off message acknowledgment if it is not important for a particular communication scenario?

Sort of. In this situation, in general, you can improve throughput by setting the acknowledgment mode to permit duplicates, that is, by allowing the JMS server to avoid the overhead of the once-and-only-once guarantee:

  ...
  topicCon.createTopicSession(false, DUPS_OK_ACKNOWLEDGE);
  ...