How is fish a source of food for poultry animals?

Ukie the difference of the two is that the 
  research subject is a systematic investigation about 1 only person or thing or place etc in a particular ways  that  without   interventioning them personally, just a study only.
  research respondents also is a systematic investigation that study about the results in a survey or the one who is answered in a survey.

Nice thank you 
amacc east rizal