To maximize piglet growth, it is recommended that levels of crude protein be at 20-23% in pre-starters and 18-20% in starters. However, part of that crude protein will not be digested at the end of the ileum, and it will enter the large intestine together with the endogenous waste. This will promote the growth of the proteinsâ€™ fermenting bacteria and will affect other final products such as branched-chain fatty acids, ammonia, phenolic compounds, as well as biogenic indols and amines that could be potentially damaging and that could be involved in the post weaning diarrheaâ€™s aetiology. For that reason a diet low in protein as a prevention factor for piglet diarrhea has been suggested.
The digestibility of crude protein is seen to be compromised after weaning, so the selection of highly digestible ingredients with high absolute values is very important .
The use of trustable sources of lactic protein, animals and vegetable protein concentrates, with high digestibility values and low antinutritive factors is recommended. It is also important to determine the palatability and the combination of the different sources of protein with complimentary amino acid profiles in order to achieve the ideal protein mix.
Also, one should consider that certain ingredients can contain active substances or principles with beneficial effects apart from the simple nutrient supply (e.g. immunoglobulin, omega 3, bioactive proteins, etc).