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Manuscript Details

Postbiotic and Parabiotic Feed Additives in Livestock and Poultry Nutrition: Review on Mechanisms, Health Effects, and Performance Outcomes

Abdelrahim Abubakr*, and Asawir Alamin

Department of Animal Nutrition, College of Animal Production, 1660 University of Bahri, Khartoum, Sudan

Malaysian J. Anim. Sci. 2026 29(1): 11-48

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The livestock and poultry industries need antibiotic growth promoter alternatives that remain effective during feed processing and storage, where live probiotics may lose viability under heat and pressure. Postbiotics - preparations of inanimate microorganisms and/or their components - and parabiotics (paraprobiotics) have therefore emerged as promising non-live feed additives. This review summarizes evidence on the mechanisms of action and applications of postbiotics and parabiotics in poultry and ruminants, emphasizing microbiota modulation, intestinal barrier function, immunomodulation and performance outcomes, and comparing these products with conventional probiotics. Lactic acid bacteria, Bifidobacterium, Saccharomyces cerevisiae and Aspergillus oryzae are producer strains that generate bioactive metabolites. In poultry, dietary postbiotics typically increase lactic acid bacteria, reduce Enterobacteriaceae counts and gut pH, and improve villus height and villus:crypt ratio, often accompanied by improved weight gain and feed conversion, particularly under heat stress or enteric challenge. In layer pullets orally challenged with 1 mL of a 10? CFU/mL Salmonella Enteritidis inoculum, a Saccharomyces-derived postbiotic reduced cecal colonization from about 4.49 to 3.35 log CFU/g, demonstrating a measurable pre-harvest food safety benefit. In ruminants, Lactiplantibacillus plantarum RG14 postbiotics increased ruminal propionic acid concentration by about 18% (31.81 vs. 37.56 mM), enhanced cellulolytic bacteria, and improved rumen papillae development and expression of antioxidant and tight junction genes in post-weaning lambs. The review also considers safety and regulation, highlights the need for harmonized ISAPP-aligned definitions and product characterization, and notes that non-replicating preparations are intrinsically safer and more stable than live probiotics but remain strongly dependent on source strain, inactivation method, dose and delivery matrix. Overall, postbiotics and parabiotics are promising tools to support sustainable, antibiotic-reduced animal production when integrated into well-designed feeding programs.