Abstract: Provided herein are supplements that include free amino acids L-glutamine or a salt thereof, L-leucine or a salt thereof, nd L-arginine or a salt thereof, and active IGF-1. The L-glutamine or salt thereof, L-leucine or salt thereof, and L-arginine or salt thereof can be present at a ratio of approximately 3:1:1. Also provided are compositions that include the supplement, such as a food product. The disclosure also includes, but is not limited to, methods for using the supplements, including improving the performance of an animal, improving a processing factor of an animal, or increasing intestinal health of an animal, where the method includes administering to the animal a food product that has the supplement.

Abstract: Provided herein are methods for treating an animal using a composition that includes active IGF. The methods include treating an animal at risk of having an infection caused by an infectious agent, treating an animal having an infection, and treating a symptom associated with an infection. In one embodiment, the infectious agent is a virus. In one embodiment, the administering includes daily administration of at least 0.05 nanograms of active IGF-1 per kilogram bodyweight of the animal daily (ng/kg), at least 0.1 ng/kg, at least 2 ng/kg, at least 5 ng/kg, or at least 10 ng/kg.