Milk fat depression in cows fed high-grain diets has been related to an increase in the concentration of trans-10 C 18:1 and trans-10,cis-12 conjugated linoleic acid (CLA) in milk. These fatty acids (FA) are produced as a result of the alteration in rumen biohydrogenation of dietary unsaturated FA. Because a reduction in ruminal pH is usually observed when high-concentrate diets are fed, the main cause that determines the alteration in the biohydrogenation pathways is not clear. The effect of pH (6.4 vs. 5.6) and dietary forage to concentrate ratios (F:C; 70:30 F:C vs. 30:70 F:C) on rumen microbial fermentation, effluent FA profile, and DNA concentration of bacteria involved in lipolysis and biohydrogenation processes were investigated in a continuous culture trial. The dual-flow continuous culture consisted of 2 periods of 8 d (5 d for adaptation and 3 d for sampling), with a 2 × 2 factorial arrangement of treatments. Samples from solid and liquid mixed effluents were taken for determination of total N, ammonia-N, and volatile fatty acid concentrations, and the remainder of the sample was lyophilized. Dry samples were analyzed for dry matter, ash, neutral and acid detergent fiber, FA, and purine contents. The pH 5.6 reduced organic matter and fiber digestibility, ammonia-N concentration and flow, and crude protein degradation, and increased nonammonia and dietary N flows. The pH 5.6 decreased the flow of C 18:0 , trans-11 C 18:1 and cis-9, trans-11 CLA, and increased the flow of trans-10 C 18:1 , C 18:2n-6 , C 18:3n-3 , trans-11,cis-15 C 18:2 and trans-10,cis-12 CLA in the 1 h after feeding effluent. The pH 5.6 reduced Anaerovibrio lipolytica (32.7 vs. 72.1 pg/10 ng of total DNA) and Butyrivibrio fibrisolvens vaccenic acid subgroup (588 vs. 1,394 pg/10 ng of total DNA) DNA concentrations. The high-concentrate diet increased organic matter and fiber digestibility, nonammonia and bacterial N flows, and reduced ammonia-N concentration and flow. The high-concentrate diet reduced trans-11 C 18:1 and trans-10 C 18:1 , and increased C 18:2n-6 , C 18:3n-3 and trans-10,cis-12 CLA proportions in the 1 h after feeding effluent. The increase observed in trans-10,cis-12 CLA proportion in the 1 h after feeding effluent due to the high-concentrate diet was smaller that that observed at pH 5.6. Results indicate that the pH is the main cause of the accumulation of trans-10 C 18:1 and trans-10, cis-12 CLA in the effluent, but the trans-10,cis-12 CLA proportion can be also affected by high levels of concentrate in the diet.

Previous studies have indicated that supplementation with probiotic bacteria may improve lipid metabolism. The present study was aimed at investigating the effects of a mixture of three strains of Lactobacillus plantarum (CECT 7527, CECT 7528 and CECT 7529) on cholesterollowering efficacy in hypercholesterolaemic patients. A total of sixty volunteers (thirty participants in the placebo group and thirty counterparts in the L. plantarum group), aged 18-65 years old, participated in a controlled, randomised, double-blind trial. The study group received one capsule daily containing 1·2 £ 10 9 colony-forming units of Lactobacillus strains in a unique dose; the placebo group consumed the same product without bacteria for 12 weeks. A significant reduction of 13·6 % in plasma total cholesterol (TC) levels was observed after 12 weeks of consumption in the L. plantarum group when compared with the placebo group. The lipidic outcomes were also analysed based on TC values at baseline: low initial values (LIV, 2000 -2500 mg/l) v. high initial values (HIV, 2510 -3000 mg/l). In the HIV group, the L. plantarum treatment showed a reduction after 12 weeks of consumption compared with the placebo group in TC, LDL-cholesterol (LDL-C) and oxidised LDL-C (17·4, 17·6 and 15·6 %, respectively). In the LIV, the L. plantarum treatment only showed a reduction after 12 weeks of consumption when compared with the placebo group in TC (9·4 %). The present results showed that the biofunctionality of L. plantarum (CECT 7527, CECT 7528 and CECT 7529) is proportional to the cardiovascular risk of the patient, having a better effect in patients with higher levels of cholesterol.

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Combined, these characteristics suggest that these strains could be excellent candidates for reducing high blood cholesterol levels.

BACKGROUND: Cardiovascular disease, global leading cause of morbi-mortality, deserve a special attention of efficacious and safe treatments. Development of new principles based on the intestinal microbiome has been revealed as a promising approach. OBJECTIVE: To assess the effects of a combination of three Lactobacillus plantarum strains on low-density lipoprotein cholesterol (LDL-C) and other lipid parameters in hypercholesterolemic adults. METHODS: In this double-blind, placebo-controlled, randomized trial, 60 patients (mean age 51.8 y, BMI 26.2 kg/m 2 , LDL-C 167.5 mg/dL) not receiving lipid-altering treatment were treated either with a L. plantarum-containing probiotic (LpPRO) or placebo (PLBO) single capsule daily for 12 weeks. Lipid and safety parameters were assessed at screening/baseline, 6 and 12 weeks of treatment, and after a 4-week follow-up period. RESULTS: At 12 weeks, compared to PLBO, the LpPRO group had significantly (p < 0.001) larger reductions in LDL-C (24.4 vs. 9.8 mg/dL), total-C (33.7 vs. 10.6 mg/dL), LDL-C/high-density lipoprotein cholesterol (HDL-C) ratio (0.8 vs. 0.3), oxidized LDL (7.5 vs. 1.0 U/L) and triglycerides (29.1 vs. 4.1 mg/dL). HDL-C was also significantly (p < 0.001) increased in LpPRO vs. PLBO (2.9 vs. 0.4 mg/dL). CONCLUSIONS: The L. plantarum combination reduced LDL-C and improved other lipid parameters, suggesting its potential for hypercholesterolemia treatment.