In vitro evaluation of probiotic properties and selenium bioaccumulation of lactic acid bacteria isolated from poultry gastrointestinal, as an organic selenium source.

The purpose of this study was to examine the probiotic characteristics and selenium (Se) bioaccumulation potential of five Lactobacillus strains in vitro. Lactobacillus acidophilus, L. delbrueckii subsp. lactis, L. reuteri, L. gallinarum, and L. animalis were among the strains employed. As significant aspects of probiotics, identification, and evaluation of their survival potential in the gastrointestinal system were undertaken. Although all experimental Lactobacillus strains bioaccumulated Se (IV) concentrations in media culture, three Lactobacillus strains (L. animalis, L. gallinarum, and L. acidophilus) bioaccumulated the highest Se concentrations (23.08, 8.62, and 8.51 mg/g, respectively) after culture in the presence of 1.5 mg/ml sodium selenite. By disc diffusion, all isolates were evaluated for antibiotic susceptibility against six antibiotics, including ciprofloxacin, ampicillin, methicillin, streptomycin, tetracycline, and trimethoprim-sulfamethoxazole. Many of the isolates tested positive for resistance to some of the antibiotics utilized. The L. reuteri and L. gallinarum were found to be resistant to about 50% of the antibiotics that were tested. In terms of acid tolerance, L. animalis showed significant resistance at acidic pH by 1.72 log unit reduction whereas L. delbrueckii and L. galliinarum showed significant sensitivity at acidic pH (P > 0.05). Bile tolerance was addressed as an important aspect of the safety assessment for probiotics. There were variances in acid and bile tolerance among species, although all of them tolerated stress conditions to an acceptable degree. Upon comparing the various species, it was observed that L. gallinarum exhibited a significant decline in growth, as evidenced by a decrease of 1.39 log units in cell viability. On the other hand, L. acidophilus and L. animalis demonstrated remarkable bile tolerance, with 0.09 and 0.23 log unit reduction respectively (P < 0.05). These results suggest that L. animalis, L. gallinarum, and L. acidophilus, can be good candidates to evaluate them in vivo in further investigations due to their tolerance to acid, and bile, antibiotic resistance, and strong ability to bioaccumulate Se in chickens.

Effect of Lactobacillus sp. and yeast supplementation on performance and some blood attributes in deoxynivalenol-challenged broiler chickens.

An experiment was conducted to evaluate the effect of different concentrations of probiotic (Lactobacillus sp.) and yeast (Saccharomycese cerevisiae) on performance, organ attributes and blood traits in broiler chickens. A total of 360 one-day-old female broiler chickens (Hubbard)® were allocated to 9 treatments and four replicates (10 birds per replication). The trail was performed in a completely randomized design (3 × 3 factorial arrangement) to examine the interaction effect of three concentrations of Lactobacillus sp. (0, 0.2 and 0.4 g/kg) and yeast (0, 0.75 and 1.5 g/kg) in deoxynivalenol (DON)-contaminated diets. The results showed that consumption of Lactobacillus sp. and yeast in DON-contaminated diets did not have a significant effect on broiler performance except for feed intake during starter period which was enhanced by yeast administration (P < 0.05). Increasing the Lactobacillus sp. content also reduced (P = 0.05) the proportional liver weight. Administration of Lactobacillus sp. to DON diets increased total protein, albumin and globulin concentrations (P < 0.05). Calcium and creatinine were influenced by yeast and Lactobacillus sp., respectively. Yeast (1.5 g/kg) and Lactobacillus sp. (0.2 g/kg) and combination of two additives (1.5 × 0.2) led to lower triglyceride concentration compared to DON group (P < 0.05). The DON diet increased aspartate amino transferase (AST) and lactate dehydrogenase (LDH) enzymes concentrations; while, inclusion of 0.4 g/kg Lactobacillus sp. to DON diet decreased AST and LDH enzymes concentrations (P < 0.05). In conclusion, administration of Lactobacillus sp. and yeast could not influence the performance of DON-fed birds; but these additives could reduce negative effects of DON on enzyme activities and some blood attributes.

Selenium-Enriched Saccharomyces cerevisiae Reduces the Progression of Colorectal Cancer.

Colorectal cancer is one of the most common causes of mortality in the world while malnutrition is responsible for one third of the problem. Selenium has been recommended for prevention of colorectal cancer. The present study was conducted to investigate the effect of selenium-enriched Saccharomyces cerevisiae in reducing colorectal cancer progression in rats. Five groups of 170-200-g weight rats (n = 40) including healthy and cancer controls, Saccharomyces cerevisiae, selenium, and selenium-enriched Saccharomyces cerevisiae-treated groups were examined. All animals except healthy control group received 40 mg 1,2-dimethylhydrazine (DMH) per kilogram weight of rat twice a week. The healthy group received normal saline, and synchronously, selenium group received soluble selenium (4 mg/mL), Saccharomyces cerevisiae and selenium-enriched groups received yeast with the density of 5 × 108 CFU/mL by daily gavage. All treatments were carried out for 5 weeks after the last injection. Animals were autopsied, and aberrant crypt foci (ACF) of ejected colon were studied in the 40th week. Microscopic sections were prepared for hematoxylin and eosin. Furthermore, immunohistochemical staining of CD31, BCL2, and P53 antibodies was performed. Macroscopic and microscopic evaluations showed that DMH had the least destructive effect in selenium-enriched Saccharomyces cerevisiae group compared to other groups. Selenium-enriched Saccharomyces cerevisiae reduces colorectal cancer progression by various mechanisms such as reduction in the number and size of ACF and alteration in the function of the proteins such as P53, BCL2, and CD31.

Dietary administration of beta-mercapto-ethanol treated Saccharomyces cerevisiae enhanced the growth, innate immune response and disease resistance of the rainbow trout, Oncorhynchus mykiss.

The effects of dietary whole cell yeast (Saccharomyces cerevisiae), n-3 HUFA-enriched yeast and treated yeast cells with beta-mercapto-ethanol (2ME) on immunity, growth performance and disease resistance to Yersinia ruckeri were investigated in Oncorhynchus mykiss. During 30 days, juvenile rainbow trout were fed diets supplemented with different forms of yeast at 5 × 10(7) CFU g(-1) or a control diet. After the feeding trial, remaining fish of each treatment were challenged by pathogenic Yersinia ruckeri and kept under observation for 14 days to record clinical signs and daily mortality rate. Yeast supplementation in all treatment groups significantly promoted the growth performance compared to control group. A significantly increase was also observed in immune responses in juvenile fish fed 2ME-treated yeast diet. More ever, the lowest fish mortality was obtained in this treatment group. The present results show that a diet supplemented with 2ME-treated yeast stimulates the immune system and growth of juvenile rainbow trout thus enhancing their resistance against Y. ruckeri.