Search

This study evaluated the cholesterol-alleviating effect and underlying mechanisms of chitosan-oligosaccharide (COS) in hypercholesterolemic hamsters. Male hamsters (n = 24) were divided into three groups in a random fashion, and each group was fed one particular diet, namely a non-cholesterol diet (NCD), a high-cholesterol diet (HCD), and an HCD diet substituting 5% of the COS diet for six weeks. Subsequently, alterations in fecal bile acids (BAs), short-chain fatty acids (SCFAs), and gut microflora (GM) were investigated. COS intervention significantly reduced and increased the plasma total cholesterol (TC) and high-density lipoprotein-cholesterol (HDL-C) levels in hypercholesteremic hamsters. Furthermore, Non-HDL-C and total triacylglycerols (TG) levels were also reduced by COS supplementation. Additionally, COS could reduce and increase food intake and fecal SCFAs (acetate), respectively. Moreover, COS had beneficial effects on levels of BAs and GM related to cholesterol metabolism. This study provides novel evidence for the cholesterol-lowering activity of COS.

The recent findings on β-casein (β-CN) A2 cattle’s milk variant have triggered global research interest, as it is claimed to be a safer choice for human health. Only a few studies have been performed to investigate the presence of β-CN A1 and A2 alleles of the CSN2 gene in dual-purpose Simmental and Angus cattle in Yunnan province, China. This present study aimed to genotype cattle producing A2 milk, predict the physicochemical properties, and quantify the isoform concentration of β-CN A2 protein. Blood samples were collected from 286 cattle (201 Simmental and 85 Angus breeds). Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) coupled with the sequencing method. Physicochemical properties were predicted using several webbased bioinformatics tools. A sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure β-CN A2 protein isoform concentration in fresh A2 milk. Allele frequencies of β-CN A2 were more dominant in Simmental (0.642) and Angus (0.835) than A1. The β-CN A1A2 genotype was most frequent in Simmental (44.8%), while A2A2 genotype was primarily found in Angus (70.6%). The predicted monoisotopic mass, molecular weight, isoelectric point (pI), net charge at pH 7, total number of atoms, instability index, and grand average of hydropathicity (GRAVY) of β-CN A2 were 23,567.23 Da, 23,582.30 Da, 5.24, –6.5, 3,357, 96.53, and –0.355, respectively. The β-CN A2 protein isoform concentration in Angus (17.8 ng/ml) was higher than in Simmental (16.7 ng/ml). Identifying β-CN A2 milk provides new insights for screening favorable alleles and establishing breeding programs based on marker-assisted selection.