It is said in many of the world´s great scriptures that one should not kill. We are all one Godly energy force that depend on oneanother and have the same value, no matter how big, small, mundane or enlightened one soul may be. We need to take heed to this general rule of no killing. This means animals as well. In the Jain religion it is forbidden to even eat root vegetables among other things because of the multitude of microorganisms that grow on it and their priests wear cotton muslin masks over their mouths as to not breath in and thus kill airborne microorganisms. In my opinion it isn´t necessary to worry yourself of such microorganisms which are of a much lower level of conciousness as we were born to breath the air and born to eat, but having such a higher level of conciousness we need to make educated and compasionate decisions and do what we know is right. Animals have a sense of community and family. They feel love, happiness, sorrow, pain and soforth. Humans have never inflicted so much pain on animals as now. We need to not inflict pain directy or indirectly on any animals. If you can do this you can live with less guilt.