Lysine is used widely in livestock production due to the shortage of feed protein resources. L-lysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus. However, there are few articles about L-lysine·H2SO4 product regarding intestinal morphology and liver pathology of broiler chickens. In this article, we focus on the absorption and metabolism of L-lysine·H2SO4 revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H2SO4. To evaluate the tolerance of broilers for L-lysine·H2SO4, 240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0, 1%, 4%, 7% or 10% L-lysine·H2SO4 (L-lysine content = 55%). Supplementation of 1% L-lysine·H2SO4 in the diet had no negative effects. However, 4%, 7% or 10% L-lysine·H2SO4 supplementation produced negative responses on broiler performance, carcass characteristics, blood biochemistry, and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet. Our results show that supplementation with 1% L-lysine·H2SO4 had no negative effects on performance, carcass characteristics, blood biochemistry, intestinal morphology and liver pathology in broilers, but supplementation with 4%, 7% or 10% L-lysine·H2SO4 produced a negative response, particularly with respect to intestinal morphology and liver pathology.

(1) This study explored Lacticaseibacillus rhamnosus MS27, a newly isolated strain, as a potential probiotic candidate for alleviating the onset and severity of ulcerative colitis (UC). (2) L. rhamnosus MS27 was isolated and subjected to biochemical identification, antibiotic sensitivity testing, and antibacterial activity assessment. Dextran sulfate sodium (DSS) colitis model mice were used to evaluate its alleviating effects. In this study, 16S rRNA microbiome and eukaryotes reference transcriptome analyses were conducted to investigate its impact on intestinal microbial ecology and potential molecular mechanisms. (3) L. rhamnosus MS27 exhibits high acid tolerance at pH 3.23 and maintains a high viable bacterial count for 24 h. It can utilize sucrose, lactose, maltose, inulin, esculin, salicin, and mannitol but not raffinose, and it is sensitive to carbenicillin, erythromycin, tetracycline, chloramphenicol, clindamycin, and penicillin. It effectively increases the abundance of beneficial microbes, particularly Akkermansia, Muribaculaceae, and Limosilactobacillus reuteri (p < 0.05), while significantly reducing microorganisms linked to human pathogens causing diarrhea and gastroenteritis (p < 0.05). Transcriptomic analysis demonstrated that the expression levels of Igkv16-104 and C1qtnf3 were significantly downregulated in the presence of L. rhamnosus MS27 treatment compared to DSS treatment alone (p < 0.05). Further analysis revealed significant differences in genes related to immune functions, antigen presentation, and immune cell markers, indicating potential protein–protein interaction networks, particularly among genes of the major histocompatibility complex (MHC). (4) L. rhamnosus MS27, as a novel strain, demonstrates a significant capacity to alleviate inflammatory phenotypes. L. rhamnosus MS27 exhibits distinctive metabolic characteristics in lactic acid utilization, acetic acid and oleic acid production. Furthermore, it contributes to systemic homeostasis regulation by modulating Turicibacter to link intestinal microbiota composition with host immune function.