Sajid, Q. U. A.Wilk, M.Asghar, M. U.2024-11-072024-11-0720241230-1388https://doi.org/10.22358/jafs/166576/2023https://hdl.handle.net/11480/15189Protein quality plays a pivotal and dynamic role in the growth, productivity, and reproduction of ruminants. Increasing the proportion of dietary protein (CP) alone cannot balance the concentration of limiting amino acids (AA) in the duodenum of high -yielding dairy cows. However, supplying rumen -protected AA is believed to improve productivity and reproduction rates. Malabsorption of CP -rich meals in the rumen leads to high nitrogen (N) excretion through urine and faeces in the form of nitric oxide, nitrous oxide, ammonia and nitrate in the environment. Research data indicate that lysine and methionine are the two most limiting AA in the ruminant ration. Supplementing these limiting AA in ruminant diets is one of the most effective strategies to improve CP usage and reduce the negative impact of CP in the diet. Several in vivo and in vitro experimental studies have demonstrated that even low -quality dietary CP, when supplemented with rumen -protected AA (Met + Lys), exhibited a greater ability to reduce N2 or NH3 losses, while also supporting a decrease in enteric fermentation gas production and minimising soil or water pollution associated with animal production. However, further research is necessary to explore the molecular and genetic mechanisms underlying the effects of AA dietary supplementation on the rumen microbiota in ruminants.eninfo:eu-repo/semantics/openAccesscrude proteinenvironmentlimiting amino acidsrumen microbiotaruminantsReview Article33131210.22358/jafs/166576/20232-s2.0-85185600542Q3WOS:001155033000004N/A