I”ve been following this tread and still remain true to my original assertation about the purpose of animals in the world. (That they were given to us to use in our lives as well as our service to Hashem).
Besides all of the halachos that we have in the Torah from the Korbonos that we (Korban pesach) and cohanimm must eat, plus the laws of shchitah, basar v’cholov and so we can also look at our Avos to see what their opinions were.
Avroham who not only shected an Ayil in place of his son (remember he was commanded to offer Yitzchok, it was afterward when he was commanded to stop that he looked up and saw the Ayil) but when he had 3 strangers come visit him after his bris milah, he shected 3 diffrent cows in order to give each one his own tounge. Seems to be excessive if we were not suppose to eat animals.
Yitzchok who wished to give over his brochos to Eisv commanded him to go and hunt an animal so that he would have a good meal and be in good spirits to give the brochos properly. Kind of takes away the moment if eating an animal is a bad thing. (ALSO One of the reasons also given was to give Aisov the mitzvah of Kivod Ov and make him more worthy to receive them. If eating meat is wrong, it’s kind of counter productive)
Yaakov who with the guidance of his mother shected goats to cover his hands and neck with skins and for his mother to cook in place of the meal that his father was expecting. So in a sence they added more animals giving up thier lives which when going under the guidance that eating animals is wrong would be a mitzvah boh L’avaeira.
None of them where in the Te’iva so I don’t know what debt the animal kingcome owed to them.