ARTICLE 92 FEED & ADDITIVE MAGAZINE February 2026 Intestinal barrier integrity plays a central role in the health and productivity of lactating dairy cows, particularly during periods of heat stress and metabolic strain. Distillers dried grains with solubles (DDGS), traditionally valued for their protein and energy contribution, also deliver fermentation-derived bioactive compounds. These components position DDGS as a potential postbiotic feed ingredient, with implications for gut permeability, immune activation, and oxidative stress regulation in dairy nutrition. Intestinal barrier integrity is a key determinant of productivity and health in lactating dairy cows because it governs the balance between nutrient absorption and immune exclusion. The intestinal epithelium must permit efficient uptake of water, electrolytes, and nutrients while preventing translocation of luminal antigens, toxins, and microbial products into circulation. When barrier function is compromised, the resulting increase in intestinal permeability, commonly referred to as leaky gut syndrome, is associated with immune activation, oxidative stress, reduced feed efficiency, and lower milk yield, particularly during periods of heat stress and early lactation. Distillers dried grains with solubles (DDGS) are widely used in dairy rations due to their favorable protein, energy, and phosphorus content, yet their effects on gut function are inconsistently described. This variability reflects the complex nature of DDGS, which concentrate not only nutrients but also fermentation-derived microbial residues, unsaturated lipids, fiber fractions, and, in some cases, mycotoxins from the parent grain. We recently proposed that DDGS can be viewed as a functional food postbiotic because they supply non-living, microbial-derived bioactive components generated during fermentation and processing rather than live microorganisms. This framework encourages evaluation of DDGS beyond nutrient supply and toward their potential effects on immune signaling, microbial ecology, and intestinal barrier function. Specifically, this article links DDGS composition to the epithelial mechanisms that maintain or disrupt barrier integrity using the tight junction model illustrated in the accompanying figure. TIGHT JUNCTION ARCHITECTURE AND BARRIER FUNCTION The tight junction model illustrated in the accompanying figure below shows how epithelial barrier selectivity is maintained under homeostatic conditions and how oxidative and inflammatory stress can shift the system toward increased permeability. Tight junctions seal the apical lateral membranes of adjacent epithelial cells and collectively DDGS AS A POSTBIOTIC FEED INGREDIENT IN DAIRY COWS Dr. Alvaro Garcia Feeds Specialist and Nutritionist Dellait Animal Nutrition and Health
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