Improving the nutritional provision for pigs by considering digestive and fermentative characteristics of the feed ingredients

Determining the biological availability of nutrients in feed ingredients is the prerequisite to optimize the diet formulation and develop precision nutrition in swine production. However, the nutritional values demonstrated in current official feedstuff tables have some limitations, for example, no information about the digestive characteristics or fermentative capability, which are now still black box in the feed evaluation systems. While diets with various digestive and fermentative characteristics but similar nutritional values could result in distinct growth performance on pigs, new parameters including digestive and fermentative kinetics as supplemental indexes are expected to be helpful for precise feed formulation. Application of digestive kinetics can solve the problem of asynchronism release of glucose and amino acids from digestion, and ensure the glucose digested from starch meets the energy requirement of pigs including absorption of digested amino acids. Application of fermentative kinetics can make better combination of the fibrous ingredients, which are more common in agricultural by-products, and promote the healthy intestinal barrier with the mediation of microbiota. Therefore, in this review, we summarized the recent research advances on digestive and fermentative kinetics of the feed ingredients fed to pigs, particularly the strategies for their applications in facilitating balanced diet formulation for the whole gut and improving the nutritional provision for pigs.