Empleo potencial de Stevia rebaudiana en alimentación animal

The Natural Sweetener Stevia: An Updated Review on its Phytochemistry, Health Benefits, and Anti-diabetic Study

Stevia rebaudiana Bertoni is one of the significant high qualities of non-caloric sugar substitute sweetener plants against diabetes disease. Diabetes mellitus is one of the most common metabolic diseases caused by insulin secretion defects, insulin resistance in peripheral tissues, or both. Stevia rebaudiana is a perennial shrub of the Compositae family that is grown in several places around the world. It contains a plethora of different bioactive constituents which are responsible for several activities and sweetness. This sweetness is due to the presence of steviol glycosides which is 100-300 times sweeter than sucrose. Furthermore, stevia reduces oxidative stress, lowering the risk of diabetes. Its leaves have been used to control and treat diabetes and a variety of other metabolic diseases. This review summarizes the history, bioactive constituents of S. rebaudiana extract, pharmacology, anti-diabetic activity, and its application, especially in food supplements.

Stevia as a natural additive on gut health and cecal microbiota in broilers

Stevia mash (SM), leaves of Stevia rebaudiana Bertoni plant, is an additive used in poultry that enhances growth and health. Objective: to determine the effect of 1 % SM on productive parameters, gut health, and the cecal microbiome in broilers between the first 15 and 21 days old. One hundred sixty male, 1-day-old broilers (48.5 ± 2.5 g) were divided into Control (C) without SM and Treated (T) with 1 % SM on diet, during 15/21 days. Each subgroup had eight broilers/five repetitions/treatment. At day 15 or 21, all broilers were dissected, Fabricius Bursa and Gut removed and processed for histomorphometry, followed by Villi Height/Crypt Deep (VH/CD) ratio. Conversion Index (CI) was determined. The V3-V4 region of 16S rRNA gene was amplified from DNA obtained from pooled cecal contents and sequenced on Illumina Miseq PE 2 × 250 platform. Sequence processing and taxonomic assignments were performed using the SHAMAN pipeline. Both T groups have better VH/CD Ratios than C groups (p ≤ 0.05). In guts, increased plasmatic and goblet cells number and thicker mucus layer were found in T15 and T21. All groups received SM showed early immunological maturity in Fabricius Bursa. IC was similar between all treatments. Faecalibacterium, Ruminococcus torques group, and Bacteroides were the major genera modulated by SM addition. At 15 and 21 days old, SM exerts a impact on diversity and evenness of the cecal microbiome.  Conclusion: SM (1 %) produced early immunologic maturity on Fabricius Bursa, increased intestinal functionality, and modified the microbiota, increasing beneficial microbial genera and microbial diversity.

The use of plant extracts and bacteriophages as an alternative therapy approach in combatting bacterial infections: the study of lytic phages and Stevia rebaudiana

Introduction

In the light of the problem of antibiotic resistance, the use of combined alternative therapies in combatting bacteria-related disorders has gained popularity. Bacteriophages are one element implemented in new combination therapy. Stevia rebaudiana is known to have antimicrobial activity and regarded as potentially having a synergistic effect with bacteriophages. Therefore, possible interactions of lytic bacteriophages (MS2, T4 and Phi6) with acetone and methanol S. rebaudiana extracts (SRa and SRm) in the bacterial environment were examined.

Material and Methods

The interactions were tested using a microdilution method, phage-extract co-incubation assay, static interaction (synography) and dynamic growth profile experiments in a bioreactor.

Results

The interactions of the tested factors in a static environment differed from those in a dynamic environment. Dynamic conditions altered the effect of the extracts in a concentration-dependent manner. How different the effect of the SRa extract was to that of the SRm extract on bacterial growth in a dynamic environment depended on the species of the phage and bacterial host. The greatest differences were observed for E. coli strains and their phages, whereas Pseudomonas syringae and the Phi6 phage reacted very similarly to both extracts. Differences also emerged for the same extract in different E. coli strains and their phages.

Conclusion

Every extract type should be tested on a case-by-case basis and experiment outcomes should not be generalised before gathering data. Moreover, many varied experiments should be performed, especially when examining such multifactorial mixtures. The tested mixtures could potentially be used in multidrug-resistant bacterial infection treatments.

The Content of Phenolic Compounds in Stevia rebaudiana (Bertoni) Plants Derived from Melatonin and NaCl Treated Seeds

Stevia is a plant with many beneficial properties. It contains not only steviol glycosides, which are used as non-caloric natural sweeteners, but also a number of metabolites with antioxidant properties. This study examined the content of both phenolic acids and flavonoids in stevia leaves as an effect of treating seeds with melatonin and conducting germination in NaCl conditions. The results of our research indicated higher amounts of phenolic acids compared to flavonoids in stevia leaves. Among these acids, isochlorogenic, rosmarinic, and chlorogenic acids were accumulated in the largest amounts, regardless of the germination conditions. For 5 and 100 µM of melatonin treatments, the content of both phenolic acids and flavonoids increased. However, in salinity conditions (50 mM NaCl), 500 µM of melatonin had the most favorable effect on the synthesis of phenolic acids. The phenolic acids in that case reached a level three-times higher than that in the samples with the same melatonin concentration but without NaCl. We also found that the content of phenolic compounds varied depending on the age of the leaves. To the best of our knowledge, this is the first study to describe the effect of melatonin and NaCl on the synthesis on phenolic acids and flavonoids in stevia.

Steviol Glycosides Supplementation Affects Lipid Metabolism in High-Fat Fed STZ-Induced Diabetic Rats

A number of health-promoting properties of Stevia rebaudiana Bertoni and its glycosides, including the antihyperglycemic activity, have been found. The mechanisms of the antidiabetic action of stevia have not been fully understood. The aim of this study was to evaluate the effects of supplementary steviol glycosides on high-fat fed streptozotocin-induced diabetic rats with particular attention to lipid metabolism. The experiment was conducted on 70 male Wistar rats, of which 60 were fed a high-fat diet for 8 weeks followed by intraperitoneal injection of streptozotocin, to induce type 2 diabetes. Afterwards, rats were divided into six groups and fed a high-fat diet supplemented with pure stevioside or rebaudioside A, at two levels (500 or 2500 mg/kg body weight (b.w.)) for 5 weeks. Three additional groups: diabetic untreated, diabetic treated with metformin, and healthy, served as respective controls. Blood and dissected internal organs were collected for hematological, biochemical, and histopathological tests. It was found that dietary supplementation with steviol glycosides did not affect blood glucose, insulin, and insulin resistance indices, antioxidant biomarkers, but normalized hyperlipidemia and affected the appetite, as well as attenuated blood liver and kidney function indices, and reduced tissular damage in diabetic rats. Steviol glycosides normalize lipid metabolism and attenuate internal organs damage in diabetes.

Stevia Rebaudiana Bertoni, a Source of High-Potency Natural Sweetener-Biochemical and Genetic Characterization

Stevia rebaudiana is a natural sweetener herb that is increasingly used in herbal medicines in the food and cosmetics industries. Molecular methods can be combined with morphological techniques to identify stevia genotypes as a starting material to produce more reliable bioproducts. This study evaluated the level of the genetic and biochemical diversity in various stevia genotypes using HPLC (high performance liquid chromatography) analysis and random amplified polymorphic DNA (RAPD) markers. Stevia genotypes collected from different locations of the world showed clear variations at the biochemical and genetic level in Polish climate conditions. The influence of the genotypes on the content of steviol glycosides, antioxidants, phenols, flavonoids, and tannins was analyzed using phytochemical assays. Genotypes from Morocco, Poland, Egypt, and Nigeria can be defined as samples of higher quality compared to other genotypes analyzed in terms of the amount of steviol glycosides. Considering the rebaudioside A/stevioside ratio as a selection criterion, genotypes from Australia, China, India, and Pakistan should be considered to be valuable in terms of suitability for obtaining new varieties. The present results of RAPD marker analysis indicated differential banding pattern and considerable polymorphism among all ten stevia genotypes. Genotypes from Morocco, Egypt, Poland, Nigeria, China, and India, as genetically different, can be selected for further stevia breeding programs.