The “Digestion-Antibacterial” Axis Concept Rebuilds New Barriers for Gut Health in Nursery Piglets — In-Depth Analysis of the Groundbreaking Presentation by Researcher Hu Youjun of NIC at the Fourth Weiwei Forum

Conventional crude protein or apparent digestibility measures fail to accurately reflect the fate of dietary protein in the gastrointestinal tract of piglets. Undigested protein that reaches the distal ileum undergoes microbial putrefaction, producing toxic metabolites such as ammonia, hydrogen sulfide, and biogenic amines, which damage the intestinal barrier and trigger inflammation and diarrhea.

Accurate Measurement of Gastrointestinal Protein Digestion: IDP

NIC The team discovered a new evaluation system for protein utilization. IDP ( InDigestible Protein , indigestible protein in the terminal ileum). Researcher Hu Youjun presented several recent studies: Aarhus University, Denmark M.N. Engelsmann Wait ( 2022 ) It was found that low protein digestibility in early-weaned piglets increases the ileal IDP Redundancy; especially 40 Within the first few days of life, the digestibility of protein in piglets is 40-60% ， NIC(2025) Their research was also the first in China to confirm this conclusion. What implications do these findings have for cost reduction and efficiency gains in industry? We argue that conventional nutritional studies may have overestimated the protein utilization efficiency of pre-weaning piglets and, in examining factors influencing growth performance and diarrhea incidence, have underestimated ileal… IDP Instead of addressing the harms, they have devoted considerable effort to functional regulatory substances, which can be described as putting the cart before the horse. Erinle Wait ( 2025 ) confirmed that feeding the diet resulted in high IDP of piglets, fecal score ( FCS ) In the 6 When the temperature reaches its peak, the diarrhea rate increases significantly; high IDP At the same time, elevated concentrations of protein fermentation metabolites in the cecum exacerbate the inflammatory response, ultimately reducing average daily gain and 56 Age in days and body weight. IDP Predicting piglet production performance is superior to traditional dietary protein indicators. Therefore NIC It is believed that regulation of the digestive axis should be the foundation of healthy management during the post-weaning nursery phase. Meanwhile, acidifiers NIC Continuously improve the acid-binding capacity of feed ingredients ( ABC ) Database (updated to version 4 edition), and developed a “model for selecting digestive acidity in piglets” 2.0 The application can predict the effectiveness of different acidifier combinations based on protein levels, acidity, and the rearing stage, and it also offers customized formulation services. In short, precise regulation IDP and ABC Maintaining gut balance is one of the key technical approaches for preventing and controlling post-weaning diarrhea.

Low protein digestibility in early-weaned animals may increase IDP redundancy.

Ethan B. Stas, Mike D. Tokach, Joel M. DeRouchey, Jason C. Woodworth, Robert D. Goodband, and Jordan T. Gebhardt, 2024

Traditional acidifiers ( NIC Digestive acids, classified within the acid world category, are the most direct regulatory tool for compensating for insufficient gastric acid secretion in piglets. The core functions of digestive acids include: lowering the pH in the stomach pH to 3.5–4.0 By activating pepsinogen; promoting protein denaturation to expose peptide bond sites; and stimulating the duodenum to release secretin, thereby enhancing pancreatic juice secretion. Researcher Hu Youjun emphasized that the digestive action of acid may play a crucial and irreplaceable role in initiating enzymatic degradation of plant proteins, addressing their anti-digestibility.

Acid initiates the digestion of intact proteins in the stomach.

Differences in the secondary structure of various protein sources directly affect their efficiency of enzymatic digestion. Zein ( zein ) Due to its high content of hydrophobic residues and glutamine, it readily forms helical aggregates in alcohol–water environments, adopting a triple superhelical structure that is inaccessible to digestive enzymes. Soybeans 7S β- Glycinin subunits can also naturally assemble into amyloid aggregates. NIC The team used in vitro digestion combined with electron microscopy and Fourier-transform infrared spectroscopy ( FTIR ), for the first time directly revealing the synergistic effect of acidifiers and proteases in profoundly disrupting the microstructure of soybean meal. Scanning electron microscopy showed that raw soybean meal has a smooth surface, retaining its natural layered texture; after adding enzyme preparations alone or simulating digestion with in vitro gastrointestinal fluids, the SEM images indicated a slight increase in structural looseness, but no complete disintegration was achieved. When the acidifier is combined with acidic protease ( 30U/g ) After co-processing, the soybean meal particles undergo deep fragmentation and disintegration. ——1.5% Acidulant + The protease group exhibits a loose, flocculent structure with the highest porosity; 3.0% The group is piled up in powder form. Encouragingly, ASB-TP A significant dose-dependent effect was observed in the in vitro digestion of soybean meal. —— As the addition level increases, both the content of acid-soluble protein and the gradient of crude protein digestibility rise, and these factors exhibit a synergistic effect with acidic proteases, serving as key drivers for enhancing the digestibility of soybean meal. Subsequent in vitro protein digestibility assays and measurements of acid-soluble protein content further confirmed the acid-amplification effect during soybean meal digestion.