In this research paper we describe the technological properties of beneficial lactic acid bacteria (LAB) obtained from a dairy production chain and the development of a fermented milk produced with Lactobacillus casei MRUV6. Fifteen LAB isolates (Lactobacillus sp., Pediococcus sp. and Weissela sp.) presented acidifying abilities (pH ranges from 0.73 to 2.11), were able to produce diacetyl (except by 5 isolates) and exopolysaccharides, and two were proteolytic. L. casei MRUV6 was selected for producing a fermented milk, stored up to 35 d at 4 and 10°C. Counts on MRS agar with added vancomycin (10 mg/l) and MRS agar with added bile salts (1.5% w/v) ranged from 9.7 to 9.9 log CFU/g, independently of the tested conditions, indicating stability and intestinal resistance of L. casei MRUV6, despite some significant differences (P < 0.05). The study demonstrated the technological potential of a potential probiotic candidate strain, L. casei MRUV6, to be used as a starter culture in the dairy industry.

To effectively mitigate antimicrobial resistance in the agricultural ecosystem, there is an increasing pressure to reduce and eliminate the use of in-feed antibiotics for growth promotion and disease prevention in food animals. However, limiting antibiotic use could compromise animal production efficiency and health. Thus, there is an urgent need to develop effective alternatives to antibiotic growth promoters (AGPs). Increasing evidence has shown that the growth-promoting effect of AGPs was highly correlated with the reduced activity of bile salt hydrolase (BSH), an intestinal bacterial enzyme that has a negative impact on host fat digestion and energy harvest; consistent with this finding, the population of Lactobacillus species, the major intestinal BSH-producer, was significantly reduced in response to AGP use. Thus, BSH is a key mechanistic microbiome target for developing novel alternatives to AGPs. Despite recent significant progress in the characterization of diverse BSH enzymes, research on BSH is still in its infancy. This review is focused on the function of BSH and its significant impacts on host physiology in human beings, laboratory animals and food animals. The gaps in BSH-based translational microbiome research for enhanced animal health are also identified and discussed.

The paucity of detailed X-ray crystallographic structures of integral membrane proteins arises from substantive technical obstacles in the overexpression of multimilligram quantities of protein, and in the crystallization of purified protein-detergent complexes (PDCs). With rare exception, crystal contacts within the lattice are mediated by protein–protein interaction, and the detergent surrounding the protein behaves as a disordered solvent. The addition and use of surfactants that display mesoscopic self-assembly behavior in membrane protein crystallization experiments presents a novel alternative strategy. Well-ordered crystals of the water channel human aquaporin-1 (hAQP1) that diffract to 4 Å resolution have been obtained with this approach.

The effect of feeding live Lactobacillus reuteri cells containing active bile salt hydrolase (BSH) on plasma cholesterol levels was studied in pigs. During an experiment lasting 13 weeks, twenty pigs were fed on a high-fat, high-cholesterol, low-fibre diet for the first 10 weeks, and a regular pig diet for the last 3 weeks. One group of animals received, twice daily, 11·25 (SD 0·16) log10 colony forming units of the potential probiotic bacteria for 4 weeks (from week 3 until week 7). From week 8 onwards, the treated group was again fed on the same diet as the control group without additions. The total faecal Lactobacillus counts were only significantly higher in the treated pigs during the first 2 weeks of L. reuteri feeding. Based on limited data, it was suggested that the administered Lactobacillus species had caused a temporary shift within the indigenous Lactobacillus population rather than permanently colonizing the intestinal tract. The probiotic feeding brought about significant lowering (P ≤ 0·05) of total and LDL-cholesterol concentrations in the treated pigs compared with the control pigs, while no change in HDL-cholesterol concentration was observed. The data for faecal output of neutral sterols and bile salts were highly variable between the animals of each group, yet they indicated an increased output in the treated pigs. Although the blood cholesterol levels went up in both groups during the 3 weeks following the Lactobacillus administration period, significantly lower serum total and LDL-cholesterol levels were observed in the treated pigs. During the final 3 weeks of normalization to the regular diet, cholesterol concentrations significantly decreased in both animal groups and the differences in total and LDL-cholesterol concentrations between the groups largely disappeared.