Chazal tell us that Noah worked hard to keep all of the animals in the ark well fed. Most (or at least many) animals are carnivores or insectivores. Does that mean Noah in fact brought in animals to breed for food in addition to the pairs?
The animals before and after the flood were also all vegetarian. They only started to eat meat after the flood. Also, since the food supply in the ark was miraculous, Noach probably had a miraculous type of food (like the mannah in the dessert) that suited each animal as it needed. As we see in Bereishis 1:30
ל וּלְכָל חַיַּת הָאָרֶץ וּלְכָל עוֹף הַשָּׁמַיִם וּלְכֹל | רוֹמֵשׂ עַל הָאָרֶץ אֲשֶׁר בּוֹ נֶפֶשׁ חַיָּה אֶת כָּל יֶרֶק עֵשֶׂב לְ אָכְלָה וַיְהִי כֵן
30 And to all the beasts of the earth and to all the fowl of the heavens, and to everything that moves upon the earth, in which there is a living spirit, every green herb to eat," and it was so.
לכם יהיה לאכלה. ולכל חית הארץ: השוה להם הכתוב בהמות וחיות למאכל, ולא הרשה לאדם ולאשתו להמית בריה ולאכול בשר, אך כל ירק עשב יאכלו יחד כלם, וכשבאו בני נח התיר להם בשר, שנאמר (להלן ט ג) כל רמש אשר הוא חי וגו' כירק עשב שהתרתי לאדם הראשון, נתתי לכם את כל:
it will be yours for food. And to all the beasts of the earth: He equated cattle and the beasts to them [to man] regarding the food [that they were permitted to eat]. He did not permit Adam and his wife to kill a creature and to eat its flesh; only every green herb they were all permitted to eat equally. When the sons of Noah came, He permitted them to eat flesh, as it is said (below 9:3): “Every creeping thing that is alive, etc.” Like the green herbs, which I permitted to the first man, I have given you everything. — [from Sanh. 59b]
Ibn Ezra to Bereishis 6:20 says that if someone would suggest that some animals needed to be fed with meat in the teiva this would be dismissed as a valid question because even one who cannot find meat would eat grass and fruits when it is starving or hungry.
Radak (Genesis 6:21) is of the opinion that originally carnivorous animals were not carnivorous. Accordingly, there was no need to breed animals to feed other animals:
כיון שיבאו אליך להחיותם צריך שתזמן מכל מאכל לצרכך ולצרכם, והמאכל הוא הפירות והזרעים והעשבים, וגם החיות הטורפות יאכלו גם כן כמו האחרים, ולא אכלו בשר כמו שלא אכלו בתחלת הבריאה, כמו שכתבנו בפסוק ויעש אלהים את חית הארץ למינה
He states this in his commentary to Isaiah (11:6) as well.