Partial Replacement of Molasses with Monosodium Glutamate–Condensed Molasses Soluble enhance growth performance by maintaining gut health in finishing pigs

A 10-week growth trial was conducted using three groups of 70 finishing pigs [210 head (Landrace × Yorkshire × (Duroc) with initial BW 53.92 ± 2.24 kg] to determine the effect of Monosodium Glutamate-Condensed Molasses Soluble (MSG-CMS) as a replacement for molasses on growth performance, nutrient digestibility, blood profiles, fecal microbiome composition, and meat quality in finishing pigs. For this, the pens of pigs (5 pigs/pen- 3 ♀and 2 ♂) were randomly allocated into 1 of 3 treatment groups in a completely randomized design with 14 replications/treatment. The dietary treatments were: TRT1, 4% Molasses; TRT2, 2% Molasses + 2% MSG-CMS; TRT3, 4% MSG-CMS. The test diets were fed in two phases: Phase 1, from week 0-5 and Phase 2, from week 5-10. Pigs fed the diet containing 4% MSG-CMS showed higher (P < 0.05) average daily gain and average daily feed intake during phases 1, 2, and the overall period compared with other treatments. However, final BW, gain-to-feed ratio, nutrient digestibility, backfat thickness, and lean meat percentage were not affected by dietary treatments. At week 10, pigs that received 4% MSG-CMS exhibited significantly higher (P < 0.05) blood insulin concentration, whereas no differences were detected in meat quality or carcass characteristics. Also, no differences were observed in alpha diversity indices among treatment groups. However, beta diversity analysis using unweighted UniFrac and Bray-Curtis PCoA demonstrated partial separation of microbial communities, with TRT3 showing a clearer clustering pattern. At the phylum level, TRT3 exhibited higher abundances of Firmicutes and Bacteroidota and a lower abundance of Proteobacteria. At the genus level, Prevotella and Lactobacillus were more abundant in TRT1, whereas Clostridium sensu stricto 1 was reduced in TRT3. LefSe analysis revealed enrichment of several fiber- and fermentation-associated taxa in TRT3, including unclassified Selenomonadaceae, Muribaculaceae, Treponema, and unclassified Ruminococcaceae. In summary, complete replacement of molasses with 4% MSG-CMS improved growth performance, without adversely affecting nutrient digestibility, gut microbial diversity, meat quality, or carcass characteristics, suggesting that MSG-CMS could serve as a potential alternative feed ingredient for improving the growth performance of finishing pigs.