Excellent work, even with results consistent with those that we verified in research that we conducted evaluating the reduction of protein in pig rations at different stages of production. However, I would like to make a few points which I consider relevant. First - it is important to consider that in the environment in the production unit, the animals are normally exposed to greater immunological challenge. In this case, protein reduction may compromise animal performance, since the reduction of non-essential amino acids, such as glutamate, aspartate, glycine, glutamine, by its recognized actions in the immune system, may limit the defense system of animals and consequently their performance. Second, it is known that the digestion of soy protein results in the production of various peptides, which are functional, with the action, for example, of increasing the phagocytic capacity of neutrophils.
My position was that in practical conditions where immunological challenges are greatest, and consequently the demand for a certain pool of amino acids is considered to be non-essential and increased, the possibility of protein reduction of the feed is limited.
In addition to this, it should be considered that gastrointestinal digestion of protein sources produces a variety of peptides with functional action that may favor the animal.