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Evaluation of the subchronic toxicity of kefir by oral administration in Wistar rats
Abstract
Introduction: Kefir is obtained by fermentation of milk with complex microbial populations present in kefir grains. Several health-promoting benefits have been attributed to kefir consumption. Objective: The objective of this work was to conduct a subchronic toxicity study, offering the rats normal or high-doses of kefir and evaluating growth, hematology and blood chemistry, as well as assessing bacterial translocation and the integrity of the intestinal mucosa of animals. Methods: Wistar rats were randomly divided into three groups (n = 6/group): control group received 0.7 mL of water, kefir group received 0.7 mL/day of kefir, (normodose), and Hkefir group received 3.5 mL/day of kefir (fivefold higher dose). Feeding was carried out by gavage. The animals were housed in individual cages and maintained under standard conditions for 4 weeks. Results: The normodose and high-dose of kefir supplementation did not harm the animals since growth, hematology and blood chemistry in rats, as well as the potential pathogenicity in tissues were within normal limits, demonstrating that consumption of normodose and highdose of kefir are safe. In addition, administration of the normodose of kefir reduced cholesterol levels and improved the intestinal mucosa of the rats. Conclusion: These results demonstrate that the consumption of kefir is safe. Importantly, while damages are not seen for the high-dose, the normodose consumption is recommended due to the pronounced beneficial effects, as safety is concerned.
... This kind of bond diversity in the kefiran structure might be responsible for biophysical stability of the kefir grains; which means the kefir grains do not change in terms of microbial composition, as well as biological activity, in which it will sustain during shelf-life of kefir brew [5,26,28]. ...
... Kefir grains after fermentation process, have a size larger than original starter grains before fermentation by up to 25% [28]. Besides, after fermentation, kefir grains form very small biological masses of new grains; which indicate that the kefir multiplication and growth in the milk is continuous [35,37] has revealed some theories beyond kefir multiplication; They explained the theory behind the forming of new small grains and increasing the size of kefir grains; that it is mainly due to self-aggregation on each other species of Lactobacillus upon each other such as L. kefiranofaciens, L. Kazachstania and L. turicensis, as well as to auto and co-aggregation of lactobacilli and yeast with each other Also they mentioned; that LAB and AAB support the production of polysaccharide as well as the ability of biofilm formation. ...
... The intestinal microflora and immune system stimulation; have an important role in the modulation of cancer cell development [28,42]. ...
Symbiosis is a coordination pattern within different microorganisms, which are capable of readjusting the imbalance of the intestinal microbiota; as a consequence of unhealthy lifestyles. A diet that rich in sugar, salt, and saturated fat is the main cause for change in the microbial equilibrium; which is responsible for gut homeostasis, that contribute to several universal epidemic diseases. Kefir grains constrain an invisible world within them; that are clusters of complex symbiotic system of beneficial microbial mixture consisting mainly of bacteria and yeasts, which is considered as a probiotic. Kefir brew is a nutraceutical dairy product, that is produced during the fermentation process as a result of the action of probiotics on the milk. Kefir brew has an ability to modulate the intestinal microbiota balance, and enhance its action. Routinely consumption of kefir brew attains a great promotion to the human health. In this review, we will discuss the mechanism by which consumption of kefir brew probiotics will modulate this imbalance system and accordingly restrain these diseases. Furthermore, we will highlight the symbiotic system of kefir brew and its significant actions on the human body; including the ability to promote the immune system in order to inhibit tumor formation or cancer progression.
... Every day, after fermentation, the grains were separated from the fermented milk by filtration using a plastic sieve and 0.7 ml of milk was administrated in each animal by gavage always at the same hour in the morning. This volume is considered secure for animal consumption, based on toxicity tests [21]. Probiotic supplementation was started 28 days before induction of periodontitis and the use of probiotics did not exceed 39 days [1]. ...
... MK is empirically prepared and no universal parameters have been defined for fermentation time [21]. Urdaneta et al. [36] and Güven et al. [37] state that fermentation time may vary from 24 to 96 h, with 24 h being the most appropriate, due to the acidity of fermented milk and the maintenance of relevant properties like taste, smell and consistence. ...
... The screening of incubation time with micro-Raman spectroscopy of L. kefiri, one of the most predominant microbiological species in MK, reached a higher intensity peak from the 4th day of fermentation. From this period onwards, there is a comparatively greater similarity of the L. kefiri spectrum of the MK samples as described by Gerbino et al. [21] as well as an increased intensity with higher fermentation times. This increase in intensity would lead us to choose the kefir with seven days of fermentation. ...
Periodontitis is a chronic inflammatory disease that affects the tooth-supporting tissues. This study evaluated the anti-inflammatory and antiresorptive effects of milk kefir (MK) on periodontitis in rats. Micro-Raman spectroscopy was performed on MK at different fermentation times to verify the presence of Lactobacillus kefiri. From these results, Wistar rats were divided into the following groups: C (Control); EP (experimental periodontitis); K1 (animals that received MK with one day of fermentation); K1+EP; K4 (animals without EP using MK with four days of fermentation) and K4+EP. MK was administered 28 days before EP induction and during the disease development period (11 days). On day 28, in the EP groups, periodontitis was induced. The animals were euthanized on day 39. The hemimaxillae were removed and the following parameters were evaluated: micro-Raman analysis of the presence of inflammation; histomorphometric analysis to quantify alveolar bone loss and immunohistochemistry for IL-6, TNF-α, IL-Iβ and IL-10 in the periodontal ligament. Micro-Raman analysis showed that four days fermentation MK has a higher intensity spectrum of L. kefiri. Furthermore, the administration of this probiotic reduced the intensity of the inflammation spectrum when compared to one day fermentation MK. It was observed that the animals from the K4+EP group showed significant reduction of alveolar bone loss, as well as a lower IL-6, TNF-α and IL-Iβ immunoexpression and a higher IL-10 immunoexpression, when compared to EP groups. We conclude that MK has anti-inflammatory and antiresorptive effects on periodontitis in rats and that these effects are fermentation time dependent.
... One collected blood samples and fasting glycaemia tests, HbA1C, triglycerides, total cholesterol and High Density Lipoprotein-HDL and Low Density Lipoprotein-LDL. Rosa et al. [45] carried out a study with the objective of verifying the toxicity of kefir, administered orally in normal doses and overdose, in addition to evaluating parameters of body weight, chemical blood hematology, bacterial translocation and integrity of the intestinal mucosa. Three groups of six animals were divided; control group received 0.7 mL/day of water; kefir group received 0.7 mL/day of kefir and Hkefir group received 3.5 mL/day of kefir administrated by tube-feeding for 4 weeks. ...
... In the analysis carried out on digital media, 10% of the sources presented this information. Rosa et al. [45] analyzed in their study that the administration of kefir in normal doses and overdose did not affect animals, body weight, hematological indicators, blood chemistry and potential pathogenicity in tissues, demonstrating that the consumption of kefir in normal doses and overdose is safe, in addition to reducing cholesterol levels and improving the intestinal mucosa of animals. In the research conducted on digital media, this topic did not appear on websites and blogs, however in scientific literature, the studies show that kefir does not present any harm in overdoses. ...
... In the research conducted on digital media, this topic did not appear on websites and blogs, however in scientific literature, the studies show that kefir does not present any harm in overdoses. When analyzing kefir antimicrobial activity, Tussolini et al. [45] found that 90% of 20 strains had antimicrobial action against the Staphylococcus aureus strain; the action against Salmonella typhimurium was 85%, and the action of Escherichia coli 95%. Therefore, it was possible to analyze that strains of lactic acid bacteria isolated from kefir grains have the capacity to inhibit pathogenic microorganisms. ...
The amount of available information in the media grows continuously and, frequently, it does not have a basis in the scientific literature. In the area of food and nutrition, the contents are available on social media profiles, websites and blogs, which usually appoint some foods as “superfoods” – able of curing diseases or inhibiting their development – or, on the other hand, classifying other foods as the cause of damage to health. Kefir-based products can be classified in the first category, being considered a “superfood” by the media. Thus, the aim of this study is to search for information about kefir in digital media and to evaluate such information based on scientific articles. The contents were collected from 50 websites or blogs, using Google as a search tool. The data obtained were divided into 25 positive categories and 5 negative categories. One made a comparison with the scientific literature. Analyzing the information about kefir, the majority has a scientific basis, however, digital media put the research data in a superficial way, without clear information to readers.
... r increase cellular damage. This is supported byPereira et al. (2013) in his study, in which he stated, kefir reduces total lipids in serum in a dose-dependent way. This may be related to other components of the blood serum such as ALT which increases at higher doses of water kefir and meanwhile decreases until an optimum concentration is achieved.Rosa et al. (2014) emphasizes the mechanism of how water kefir affects the gastrointestinal tract, particularly the intestinal mucosa, compared to a control group treated with normal saline. According to their study, the animals treated with kefir manifested well defined mucosa, villi and intestinal crypts. The villi were greater in height and wider in wi ...
... arly the intestinal mucosa, compared to a control group treated with normal saline. According to their study, the animals treated with kefir manifested well defined mucosa, villi and intestinal crypts. The villi were greater in height and wider in width. The animals also exhibited a thicker mucosal layer indicating a healthy gastrointestinal tract.Rosa et al. (2014) also explained in their study that bacterial translocation is the "passage of viable bacteria from the gastrointestinal tract through mucosal epithelium to other tissues". If such phenomenon transpires, the liver is the first organ to be compromised due to its direct connection through the portal blood. Further results of their study st ...
... Hence, the utilization of probiotic may prevent the consumption of the cell's natural storage of antioxidant systems (Castex et al. 2009 as mentioned byCan et al., 2012). Aside from this, kefir also competes with pathogenic bacteria for adhesion sites and further strengthens the immunological barrier function of the intestine(Rosa et al., 2014). ...
This study evaluated the hepatoprotective effect of water kefir in sprague-dawley rats. Four treatment groups were administered with sugar solution and varying doses of water kefir (Sugar solution, 1, 2 and 3 ml respectively) for seven days. After which, sub-lethal dose of acetaminophen (640 mg/kg) was given to induce hepatocellular injury. The effects of water kefir were measured based on the aspartate aminotranferase (AST) and alanine aminotransferase (ALT) levels. According to the results, water kefir promotes hepatoprotective effect by significantly decreasing (p<0.05) the levels of AST and ALT enzymes beyond the normal values. Furthermore, there is a significant difference between the different dosages administered among the treatment groups. The dosage of fermented water kefir which provided the greatest hepatoprotective effect is 3 ml and 2 ml for AST and ALT respectively. The results of the study show that as the concentration of water kefir increases, the AST level of blood samples decreases. On the other hand, the results for ALT assay tests yielded an optimum concentration of 2 ml. The more prominent effects of water kefir in AST levels suggest that its mechanism of action is to protect the mitochondria from oxidative stress induced by acetaminophen toxicity, hence maintaining its integrity inside the mitochondrial membrane.
... En este contexto, identificar y promover la implementación de métodos alternativos que puedan reducir, refinar y reemplazar (3R) el uso de animales de laboratorio en la investigación es urgente y desafiante [1]. Esta necesidad se hace más notoria con el continuo crecimiento de los productos naturales en el mercado, por ejemplo el uso de S. maxima y Kéfir como suplemento dietético [2][3][4]. Por otro lado en la biotecnología la manipulación de ovocitos, incluyendo los folículos preantrales, es usada para estudiar el fenómeno de la foliculogénesis y sus requerimientos metabólicos en cultivo in vitro [5][6][7][8] y con el propósito de tratar la infertilidad [9]. ...
... En relación al extracto de Kéfir, algunos estudios describen toxicidad subcrónica sin cambios histopatológicos [3,35]. Esto puede confirmarse por la disminución de la sobrevivencia folicular con la concentración de 200 µg.mL ...
S. maxima and Kéfir are known and used for their antioxidant and immunostimulant properties. This study aimed to evaluate the natural extracts of these two agents with the technique of manipulation of oocytes included in preantral follicles (MFP), because the technique can replace the use of laboratory animals and could also harmonize the laws that try to reduce and improve the use of animals for the study of new drugs and to integrate good laboratory practices. The natural extracts studied were obtained from S. maxima and Kefir, both substances are known in the market for their antioxidant and immunostimulating activity. Both were evaluated in suspensions of 10, 50, 100 and 200 µg.mL-1. The results show that Spirulina produced a decrease in survival, development, and follicular diameter. While Kefir did not show positive or negative influences on the growth and development of preantral follicles, only the concentration of 200 µg.mL-1 decreased follicular survival. The MFP technique proved to fit into the 3R policy (replacement, reduction, and refinement) and allowed to evaluate cytotoxicity, showing that the technique can be used as a safety test in natural extracts.
... The lower values of total cholesterol in the groups that received kefir show that kefir beverages are probiotic and have hypocholesterolemic effects [24] as demonstrated in other studies with milk kefir and water kefir [25,26]. ...
... Although values for triglycerides [27,32] and glucose [25] decreased in some studies on probiotic microorganisms, we did not experience this in our study. ...
Objective
To compare the effects of fermented kefir on the nutritional, physiological, and biochemical parameters of rats.
Methods
Grains of milk kefir (whole and skimmed) and water kefir (brown sugar) were used. The chemical composition analysis was performed on substrates and fermented beverages. The rats were evaluated for weight gain, body mass index, as well as their food, water, kefir, and calorie intake. We also evaluated their energy efficiency coefficient, weight of organs, in addition to their serum, and hepatic biochemistry.
Results
Fermentation increased the acid content index owing to degradation of lactose and brown sugar. The animals consumed more kefir, reducing the intake of chow and water. Kefir did not alter body and organ weight, while improving the lipid profile.
Conclusion
Water kefir with brown sugar was more effective in improving the lipid profile.
... Sağlık üzerine olan faydalarından ve hastalıkları önleme özelliklerinden dolayı kefir oldukça önemli bir diyet ürünü haline gelmektedir [16,18,34,35]. Bu gün kefir kolaylıkla marketlerden elde edilmekte ve insan diyetine kolayca adapte edilebilen çeşitli formlarda ticari olarak satılmaktadır. ...
... Bu çalışmada, Diniz ve ark., (2014) [35] referans alınarak, 8 hafta süre ile D-GAL ile uyarılmış sıçanlarda kefirin etkileri değerlendirildi. Bu aşamada 70 kg'lık bir insanın (erkek) günlük 200 ml (düşük doz) ve 1000 ml (5 kat yüksek doz) kefir tüketimine denk gelen düşük doz (0.7 ml/gün) ve yüksek doz (3.5 ml/gün) olacak şekilde sıçanlara iki ayrı doz uygulandı. ...
D-Galaktoz (D-GAL), oksidatif stresi arttırarak doğal yaşlanma sürecini
uyaran bir monosakkarittir. Bu çalışmada, yaşlanma ile ilişkili hasarlı modelde
oksidatif stres üzerine günlük kefir tüketiminin etkisi araştırıldı. Sıçanlara 8 hafta
boyunca D-GAL (300 mg/kg/5 gün), Düşük doz Kefir (DKFR) (0.7 ml/kg/5 gün) ve
Yüksek doz Kefir (YKFR) (3.5 ml/kg/5 gün) uygulandı. Bu süre sonunda elde
edilen beyin dokusu örneklerinde Glutatyon (GSH) ve Lipid peroksidasyonu (LPO)
düzeyleri ile Süperoksit dismutaz (SOD) ve Asetilkolin esteraz (AChE) aktiviteleri
ölçüldü. Kontrol grubuna kıyasla D-GAL grubunda GSH düzeyleri ve SOD
aktivitelerinde anlamlı bir azalma gözlendi, ancak LPO düzeyleri ve AChE
aktiviteleri arttı (p <0.05). Kefirin her iki dozunda da D-GAL verilen gruba kıyasla
LPO düzeyleri azaldı (p <0.05). D-GAL grubuna kıyasla, D-GAL verilen düşük doz
kefir grubunda SOD aktivitesi arttı, AChE aktivitesi azaldı (p <0.05). Aynı zamanda
histopatolojik bulgular da kefirin taklitçi yaşlanma modelinde koruyucu bir etki
göstererek oksidatif stresi azalttığını destekledi. Bu sonuçlar kefirin özellikle beyin
dokusunda yaşlanma ile uyarılmış oksidatif streste faydalı etkilere sahip
olabileceğini gösterdi.
... The randomised, double-blind, placebo-controlled trial by Da Silva Ghizi et al. (95) was the only one to use individualised dose per kilogram (1·6 ml/kg for males and 1·9 ml/kg for females), calculated on the basis of studies by Reagan-Shaw et al. (160) and Rosa et al. (161) . This dose was close to the lowest standardised doses used in other studies that showed benefits. ...
Increasing research has been conducted on the role of probiotics in disease treatment. Kefir, a safe, low-cost probiotic fermented milk drink, has been investigated in many in vitro and animal studies, although parameters for human therapeutic dose or treatment time have not yet been determined. To perform a scoping review of clinical studies that have used kefir as a therapeutic agent, compiling the results for perspectives to support and direct further research. This review was based on Joanna Briggs Institute guidelines, including studies on the effects of kefir-fermented milk in humans. Using the term KEFIR, the main international databases were searched for studies published in English, Spanish, or Portuguese until March 9, 2022. A total of 5835 articles were identified in the 4 databases, with 44 eligible for analysis. The research areas were classified as metabolic syndrome and type 2 diabetes, gastrointestinal health/disorders, maternal/child health and pediatrics, dentistry, oncology, women's and geriatric health, and dermatology. The many study limitations hampered generalization of the results. The small sample sizes, methodological variation, and differences in kefir types, dosage, and treatment duration prevented clear conclusions about its benefits for specific diseases. We suggest using a standard therapeutic dose of traditionally prepared kefir in milliliters according to body weight, making routine consumption more feasible. The studies showed that kefir is safe for people without serious illnesses.
... Interestingly, although kefir is consumed by millions of people around the globe with no AE reported so far, the literature contains sparse information on the safe levels of kefir intake in animal trials [115]. A 4-week kefir administration in rats, either with a normal (0.7 mL/day/animal) or a high (3.5 mL/day/animal) dose, did not show harmful effects on animals as determined by growth, hematology, blood chemistry or potential pathogenicity analyses in tissues [116]; however, the microbial composition of kefir was not determined to correlate its safe use with the presence of L. kefiranofaciens. Additionally, administration of kefir, with L. kefiranofaciens as the most abundant species, improved the survival rate in a fly model for Alzheimer's disease without any side effects [117]. ...
One of the main lactic acid bacterial species found in the kefir grain ecosystem worldwide is Lactobacillus kefiranofaciens, exhibiting strong auto-aggregation capacity and, therefore, being involved in the mechanism of grain formation. Its occurrence and dominance in kefir grains of various types of milk and geographical origins have been verified by culture-dependent and independent approaches using multiple growth media and regions of the 16S rRNA gene, respectively, highlighting the importance of their combination for its taxonomic identification. L. kefiranofaciens comprises two subspecies, namely kefiranofaciens and kefirgranum, but only the first one is responsible for the production of kefiran, the water-soluble polysaccharide, which is a basic component of the kefir grain and famous for its technological as well as health-promoting properties. L. kefiranofaciens, although very demanding concerning its growth conditions, can be involved in mechanisms affecting intestinal health, immunomodulation, control of blood lipid levels, hypertension, antimicrobial action, and protection against diabetes and tumors. These valuable bio-functional properties place it among the most exquisite candidates for probiotic use as a starter culture in the production of health-beneficial dairy foods, such as the kefir beverage.
... Based on the subchronic toxicity study, all the kefir treated mice survived until the end of the treatment period without demonstrating any abnormal behaviours or any toxicology symptoms. This finding is in agreement with Diniz et al. (2014) who have stated that normodose and highdose of kefir supplementation did not cause any significant changes in growth, serum biochemistry, haematology, and histopathology analysis upon oral administration in Wistar rats [76]. Besides, the adverse effects of drugs and chemicals can be detected from the change in body weight [77,78]. ...
Background
In recent years, researchers are interested in the discovery of active compounds from traditional remedies and natural sources, as they reveal higher therapeutic efficacies and improved toxicological profiles. Among the various traditional treatments that have been widely studied and explored for their potential therapeutic benefits, kefir, a fermented beverage, demonstrates a broad spectrum of pharmacological properties, including antioxidant, anti-inflammation, and healing activities. These health-promoting properties of kefir vary among the kefir cultures found at the different part of the world as different media and culture conditions are used for kefir maintenance and fermentation.
Methods
This study investigated the microbial composition and readily found bioactive compounds in water kefir fermented in Malaysia using 16S rRNA microbiome and UHPLC sequencing approaches. The toxicity effects of the kefir water administration in BALB/c mice were analysed based on the mice survival, body weight index, biochemistry profile, and histopathological changes. The antioxidant activities were evaluated using SOD, FRAP, and NO assays.
Results
The 16S rRNA amplicon sequencing revealed the most abundant species found in the water kefir was Lactobacillus hilgardii followed by Lactobacillus harbinensis, Acetobacter lovaniensis, Lactobacillus satsumensis, Acetobacter tropicalis, Lactobacillus zeae, and Oenococcus oeni. The UHPLC screening showed flavonoid and phenolic acid derivatives as the most important bioactive compounds present in kefir water which has been responsible for its antioxidant activities. Subchronic toxicity study showed no toxicological signs, behavioural changes, or adverse effects by administrating 10 mL/kg/day and 2.5 mL/kg/day kefir water to the mice. Antioxidants assays demonstrated enhanced SOD and FRAP activities and reduced NO level, especially in the brain and kidney samples.
Conclusions
This study will help to intensify the knowledge on the water kefir microbial composition, available phytochemicals and its toxicological and antioxidant effects on BALB/c mice since there are very limited studies on the water kefir grain fermented in Malaysia.
... These findings clearly show that both the normal and high dose of kefir is safe for consumption. The results highlight that although no damage was observed in the mucosa due to the high consumption dose of kefir, the normal dose is recommended due to the most pronounced beneficial effects [130]. ...
Kefir is a dairy product that can be prepared from different milk types, such as goat, buffalo, sheep, camel, or cow via microbial fermentation (inoculating milk with kefir grains). As such, kefir contains various bacteria and yeasts which influence its chemical and sensory characteristics. A mixture of two kinds of milk promotes kefir sensory and rheological properties aside from improving its nutritional value. Additives such as inulin can also enrich kefir's health qualities and organoleptic characters. Several metabolic products are generated during kefir production and account for its distinct flavour and aroma: Lactic acid, ethanol, carbon dioxide, and aroma compounds such as acetoin and acetaldehyde. During the storage process, microbiological, physicochemical, and sensory characteristics of kefir can further undergo changes, some of which improve its shelf life. Kefir exhibits many health benefits owing to its antimicrobial, anticancer, gastrointestinal tract effects, gut microbiota modulation and anti-diabetic effects. The current review presents the state of the art relating to the role of probiotics, prebiotics, additives, and different manufacturing practices in the context of kefir's physicochemical, sensory, and chemical properties. A review of kefir's many nutritional and health benefits, underlying chemistry and limitations for usage is presented.
... Kefir is a potential probiotic fermented milk that has been gaining prominence in the scientific literature due to its therapeutic activity and ease of production at home (Rosa et al., 2014). The peculiarity of kefir compared to other fermented milks lies in the metabolic activity of a complex mixture of bacteria (lactic and acetic acid-producing) and yeast (lactose fermenters and non-lactose fermenters) that live in symbiotic association (Leite et al., 2013). ...
... Despite the recent emergence of kefir among probiotic foods, there is little information in the literature about the safe level of consumption of kefir, the amount that should be consumed, the time it takes to show beneficial effects, etc. Based on increasing kefir consumption worldwide, research on these dietary ingredients is urgently required (Rosa et al. 2014). While the majority of the research was conducted in humans and on mice, no studies were found on insects. ...
This study examined the effect of kefir, yogurt, and milk on egg production and development in Drosophila melanogaster Meigen. Kefir, yogurt, and milk were added to the Drosophila culture medium. First they were fed to mature individuals and then these females laid eggs on medium containing kefir, yogurt, and milk. Later the development of eggs and larvae was examined. The experiments were conducted on two generations, the F1 generation reared with additives in the media and F2 without the additives. The effects of these substances on the basic stages of development were also examined. In the experimental groups, the numbers of eggs and larvae decreased considerably in both the F1 and F2 generations. The comparison between the experimental groups themselves also showed a difference. In both generations, development of eggs into third instar larvae was reduced and metamorphosis was delayed. In addition, morphological abnormalities were observed in the larvae. Overall the results showed that kefir, yogurt, and milk affected egg and larva development negatively and this negative effect continued in the F2 generation. The continuation of this negative effect in the F2 generation, which was not exposed to various milk additives, is an interesting finding. These results indicate that the nutrients from the milk and the milk products used were neither utilized by nor beneficial for this insect.
Over the past decades, an increase of male infertility through the decrease of sperm count has been noted. It has been suggested that environmental factors and lifestyle could a negative impact over sperm quality. Among these factors, the consumption of foods high in fat, which leads to overweight and obesity, can negatively influence fertility. The present study was designed to highlight the protective effect of Kefir, natural probiotic, against the decline in sperm quality related to fat high diet. Thirty adult rats were divided into four groups: Control (1 ml/100 g of body weight (bw) of semi‐shimmed cow milk), KM (1 ml/100 g bw of Kefir milk), HFD (1 ml/100 g bw of semi‐shimmed cow milk + high‐fat diet) and KM/HFD (1 ml/100 g bw Kefir milk + high‐fat diet). After 60 days of treatment, sperm quality, biochemical assays of lipids profil, blood cell count and histological examination in testis were assessed. The results described an improved of sperm density (64.28 106 ml vs 54.14 106 ml), viability (70.50% vs 55.33%), mobility (65.40% vs 63.60%) and morphological abnormalities (52% vs 25%) in the KM/HFD group compared to HFD group. In the same group, the lipid profil (Triglycerides (128.39 mg/dl vs 102.85 mg/dl), C‐LDL (13.65 mg/dl vs 15.32 mg/dl) and C‐HDL (23.21 mg/dl vs 19.15 mg/dl)) was corrected compared to HFD group. The histological observation of testis revealed a normal spermatogenesis compared to seminiferous tubules of HFD group, which showed a serious disruption and damage of testicular epithelium exerted by the high‐fat diet. These findings corroborated the previous beneficial effect of Kefir and brought new insights into its beneficial effect against deteriorated spermatogenesis in obese adult rats.
This work was aimed at evaluating the biological safety of a Lactobacillus plantarum 22 LMC strain with probiotic potential, isolated from the caecum mucosa of Creole pigs. A pre-clinical study was conducted to evaluate the effect of the probiotic candidate in an acute oral single-dose model 1012 CFU mL-1. Female and male Sprague Dawley rats were used divided into a group of five animals of each sex per treatment (3): viable L. plantarum cells (1), heat-inactivated cells of the same microorganism (2) and saline solution as a negative control (3) for 14 days; subsequently proceeded to euthanasia. Pathological and microbiological studies of the main organs were carried out. Some hematological and biochemical indices were determined. No toxic effects attributable to the administration of the probiotic were found; body weight was shown to be characteristic for the species and there were no alterations in organ weight. No macroscopic, histopathological and bacterial translocation variations were observed in the organs evaluated. The hematological and blood biochemical studies showed normal values for the species. It is concluded that the L. plantarum 22 CML strain was shown to be biologically safe at the single evaluated dose.
Background
Metabolic syndrome (MS) occurs when different metabolic and hemodynamic components change simultaneously, being one of the factors related to high mortality rates in patients with cardiovascular diseases. This study investigated the effects of the probiotic kefir on anthropometric and physiological parameters in human subjects with MS.
Methods
forty-eight patients diagnosed with MS were assigned into two groups in this randomized, double-blind, placebo-controlled clinical trial. Kefir group (KG) and control group (CG) drank kefir beverage and curd (1.6 mL/kg for men or 1.9 mL/kg for women) for 12 weeks, respectively. Blood pressure, anthropometric, and biochemical parameters (fasting glycemia, glycated hemoglobin (HA1c), total cholesterol (TC), high density lipoprotein (HDLc), triglycerides (Tg), oxidized LDL cholesterol (oxLDL), high-sensitivity C-reactive protein (hs-CRP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinophosphokinase (CPK), γ-Glutamyl Transferase (γ-GT), urea nitrogen, urea, and creatinine were evaluated before and after treatment. The risk of cardiovascular events for the next ten years was calculated through the Framingham Score method.
Results
Kefir intake decreased blood pressure, fasting glycemia, LDLc, non-HDLc, Tg, and oxLDL, and increased HDLc levels in women. Kefir also reduced the risk of cardiovascular events for the next ten years, although anthropometric parameters remained unchanged.
Conclusions
Kefir intake improved blood pressure, fasting glucose, and lipid levels, reducing oxLDL and the risk of developing cardiovascular events in the next ten years. These results suggest regular kefir intake may have positive effects on MS treatment.
Due to the increased interest shown in kefir, the present study examined its effects on some developmental characteristics in Drosophila. To compare the results related to kefir, another fermented product, i.e., yogurt, and the raw material of kefir, i.e., milk, were included in the experiment. All three foods were fed to Drosophila by addition to the medium. The results showed that the three foods delayed development in generations F1 and F2. In both generations, the number of adults was lower than that of the control group, but the comparison of the foods among themselves showed no significant difference. Moreover, the negative effect continued in generation F2. Phenotypically abnormal individuals were observed in the experiments, but there was no significant difference. Furthermore, the sex ratio changed in all the groups, including the control group. In the experimental group fed kefir, the sex ratio changed in favor of females, whereas in the other groups, it changed in favor of males. Whether the milk and milk products were fermented did not change the effect on Drosophila, but unexpectedly it delayed development, reduced the number of adults, and changed the sex ratio. It can be concluded that the three foods delayed development and altered the sex ratio in Drosophila.
Giardiasis, caused by the protozoan Giardia intestinalis, is one of the most common intestinal diseases worldwide and constitutes an important problem for public health systems of different countries. Kefir is a probiotic beverage obtained through fermentation of milk with "kefir grains"which consisting mainly of bacteria and yeasts that coexist in a complex symbiotic association. In this work, we studied the ability of kefir to protect mice from a G. intestinalis infection, and characterized the host immune response to this probiotic in the context of the intestinal infection. Six to eight weeks old C75BL/6 mice were separated into 4 groups: C (control mice), K (mice receiving 1/100 dilution of kefir in drinking water for 14 days), G (mice infected orally with 4x107 trophozoites of G. intestinalis at day 7), and GK (kefir-treated G. intestinalis-infected mice), and were sacrificed at 2 and 7 days post-infection (pi). Kefir administration was able to significantly reduce the intensity of Giardia infection at 7 days pi. An increase in CD4+ T cells percentage at 2 days pi was observed in Peyer's patches (PP) of mice belonging to G group compared with C and K groups, meanwhile in GK group, the percentage of CD4+ T cells in PP was similar to controls. At 2 days pi, a reduction in the percentage of B220+ MHC-II medium in PP was observed in infected mice compared with the other groups. At 7 days pi, Giardia-infected mice showed a reduction in RcFε+ cells compared with C group, suggesting a downregulation of inflammatory response. However, in K and GK groups, the percentages of RcFε+ cells did not differ from controls. An increment in IgA+ cells was observed in the lamina propria of K group compared with to control at 2 days pi. Interestingly, the diminished number of IgA+ cells registered in G group at 7 days pi, was restored by kefir feeding although the increase of IgA+ cells was no longer observed in K group at that time. No significant differences in CXCL10 expression were registered between groups, in concordance with the absence of inflammation in small intestinal tissue. Interestingly, a slight reduction on CCL20 expression was observed in G group suggesting that G. intestinalis might downregulate its expression as a way to evade inflammatory immune response. On the other hand, a trend to an increase in TNF-α expression was observed in K group, meanwhile GK group showed a significant increment in its expression. Moreover, kefir receiving-mice (K and GK groups) showed an increment in the expression of IFN-γ, the most relevant Th1-cytokine, at 2 days pi. Our results demonstrated that feeding with kefir reduces G. intestinalis infection and promotes the activation of different mechanisms of humoral and cellular immunity down-regulated by parasitic infection, which contributes to protection.
The objective of this study was to evaluate the functional properties of lactic acid bacteria (LAB) isolated from Tibetan kefir grains. Three Lactobacillus isolates identified as Lactobacillus acidophilus LA15, Lactobacillus plantarum B23 and Lactobacillus kefiri D17 that showed resistance to acid and bile salts were selected for further evaluation of their probiotic properties. The 3 selected strains expressed high in vitro adherence to Caco-2 cells. They were sensitive to gentamicin, erythromycin and chloramphenicol and resistant to vancomycin with MIC values of 26 µg/ml. All 3 strains showed potential bile salt hydrolase (BSH) activity, cholesterol assimilation and cholesterol co-precipitation ability. Additionally, the potential effect of these strains on plasma cholesterol levels was evaluated in Sprague-Dawley (SD) rats. Rats in 4 treatment groups were fed the following experimental diets for 4 weeks: a high-cholesterol diet, a high-cholesterol diet plus LA15, a high-cholesterol diet plus B23 or a high-cholesterol diet plus D17. The total cholesterol, triglyceride and low-density lipoprotein cholesterol levels in the serum were significantly (P
This study reports the effects of probiotics and α-tocopherol administration on microbial flora of rat gastrointestinal tract in a model system containing aspirin, ethanol and ammonia which are causative agent of gastric mucosal injury in animal and clinical studies. Sixty rats were used and randomly divided into three groups as Control (C), Probiotic mix culture (P) and α-Tocopherol (T). C, P and T groups received skim milk, probiotic mix culture and α-tocopherol for 14 days, respectively. Then, each group was also divided into four subgroups as aspirine, ethanole, ammonia and non-treated group. On day 15, aspirin, ammonia and ethanol were administrated to three subgroups, respectively. Non-treated subgroup just received saline in equal volume. In the 1, 5, 10 and 14th day of the feeding, fecal samples were taken from rats and lactic acid and coliform bacteria were determined. On day 15, rat intestine was taken out and examined for microbial flora. The results indicated that probiotic mix culture and α-tocopherol application had no significant effects on microbial flora of rat intestinal tract through 14 days of intake. In addition, there was not considerable difference in microbial flora in the jejunum, ileum and caecum for C, P and T groups with or without administration of aspirin, efhanol and ammonia.
This study was carried out to evaluate the effects of Arctium lappa L. (burdock) on the liver of adult male Wistar rats as measured by light microscopy and biochemical parameters. The rats received the extract in water bottles at doses of 10 or 20 g/L daily for 40 days. There were no significant changes in the plasma levels of albumin, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyl transferase (GGT), total protein, total cholesterol, urea, uric acid, triacylglycerol, calcium, phosphorus, chlorine and direct bilirubin. The morphological analysis did not reveal histopathological alterations in liver tissue. Both biochemical and morphological data did not indicate A. lappa toxicity.
The manufacturing processes have been reported to influence the properties of probiotics with potential impact on health properties. The aim was to investigate the effect of different growth media and inactivation methods on the properties of canine-originated probiotic bacteria alone and in combination mixture.
Three established dog probiotics, Lactobacillus fermentum VET9A, Lactobacillus plantarum VET14A and Lactobacillus rhamnosus VET16A, and their combination mixture were evaluated for their adhesion to dog mucus. The effect of different growth media, one reflecting laboratory and the other manufacturing conditions, and inactivation methods (95°C, 80°C and UV irradiation) on the mucus adhesion of the probiotic strains was characterized. Evaluation of dog probiotics was supported by cell visualization using transmission electron microscopy (TEM). Higher adhesion percentage was reported for probiotic strains growing in laboratory rather than in manufacturing conditions (P < 0·05). Inactivation by heat (95°C, 80°C) decreased the adhesion properties when strains were cultivated in soy-based growth media compared with those grown in MRS broth (P < 0·05). TEM observations uncovered differences in cell-surface components in nonviable forms of probiotic strains as compared with their viable forms.
Manufacturing process conditions such as growth media and pretreatment methods may significantly affect the adhesive ability of the tested strains.
Growth conditions, growth media, pretreatment methods and different probiotic combinations should be carefully considered for quality control of existing probiotics and for identification of new probiotics for dogs. These may also have an impact on health benefits for the host.
Elevated blood cholesterol is an important risk factor associated with atherosclerosis and coronary heart disease. The search for mediators that fine-tune cholesterol homeostasis has revealed lactic acid bacteria (LAB) to be potentially beneficial. The aim of the present study was to identify and characterize probiotic strains with bile salt hydrolase activity from kefir grains and evaluate their potential use as cholesterol-reducing probiotics in rats. Two isolates, Lp09 and Lp45, obtained from kefir grains were identified as Lactobacillus plantarum via molecular typing methods. Lactobacillus plantarum Lp09 and Lp45 exhibited excellent tolerance to low pH levels and high bile salt concentrations and showed potential bile salt hydrolase activity, bile salt deconjugation activity, and cholesterol coprecipitation ability. Additionally, the potential effect of Lb. plantarum Lp09 and Lp45 on plasma cholesterol levels was evaluated in Sprague-Dawley rats. Rats in 3 treatment groups were fed different experimental diets: a high-cholesterol diet, a high-cholesterol diet plus Lb. plantarum Lp09, or a high-cholesterol diet plus Lb. plantarum Lp45 for 4 wk. Total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels in serum as well as cholesterol and triglyceride levels in liver were significantly decreased in the LAB-treated rats compared with rats fed a high-cholesterol diet without LAB supplementation. Also, both fecal cholesterol and bile acid levels were significantly increased after LAB administration. No significant changes were detected in high-density lipoprotein cholesterol levels. These results suggest that the Lb. plantarum Lp09 and Lp45 strains present the potential to be explored as probiotic agents for the management of hypercholesterolemia.
Evaluate the effect of flaxseed, olive and fish oil on the lipid profile, preservation of villosities and lymphocyte migration in the intestinal mucosa of Wistar rats.
Thirty Wistar male rats were divided into four groups, which received the AIN-93M diet, with changes only to their lipid source: flaxseed, olive, fish, and soy oil (control group). The serum was separated for the biochemical parameter analysis. A histological evaluation was performed in the ileal portion.
The group which was fed fish oil presented lower values when compared to the other treatments for Total Cholesterol, High-density Lipoprotein Cholesterol and Triacylglycerol (p<0.05). The animals treated with fish and olive oils presented better intestinal villosities preservation. Less deposition of lymphocytes was observed in the flaxseed group (p<0.001).
This study demonstrated that flaxseed, olive and fish oils present different responses than soy oil for the intestinal mucosa preservation and lymphocyte proliferation in Wistar rats.
Kefir and its insoluble polysaccharide, kefiran, were both tested for antimicrobial and cicatrizing activities against several bacterial species and Candida albicans using an agar diffusion method. Comparator antimicrobials were also tested. Cicatrizing experiments were carried out on Wistar rats with induced skin lesions and Staphylococcus aureus inoculation, using a topical application of a 70% kefir gel. Both kefir and kefiran showed some activity against all organisms tested; the highest activity was against Streptococcus pyogenes. Cicatrizing experiments using 70% kefir gel had a protective effect on skin connective tissue and 7 days treatment enhanced wound healing compared with 5 mg/kg of neomycin-clostebol emulsion.
Kefir is a microbial symbiont mixture that produces jelly-like grains. As a widely used neutraceutical, however, the therapeutic applicability of kefir is not certain. In order to investigate the pharmacological effects of kefir, we used a mouse asthma model, in which airway inflammation and airway remodeling was produced by ovalbumin sensitization and challenge. BALB/c mice sensitized and challenged to ovalbumin, were treated with kefir (50mg/kg administered by intra-gastric mode) 1h before the ovalbumin challenge. Kefir significantly suppressed ovalbumin-induced airway hyper-responsiveness (AHR) to inhaled methacholine. Intra-gastric administration of kefir significantly inhibited the increase in the total inflammatory cell count induced by ovalbumin, and the eosinophil count in bronchoalveolar lavage fluid (BALF). Type 2 helper T cell (Th2) cytokines, such as interleukin-4 and interleukin-13, and total immunoglobulin E (Ig E) levels, were also reduced to normal levels in bronchoalveolar lavage fluid. Histological studies demonstrate that kefir substantially inhibited ovalbumin-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. Kefir displayed anti-inflammatory and anti-allergic effects in a mouse asthma model and may possess new therapeutic potential for the treatment of allergic bronchial asthma.
To assess the safety of Bifidobacterium pseudocatenulatum G4 in BALB/c mice that involves examination of bacterial translocation, changes in the internal organs and histology of the intestinal lining.
Forty male BALB/c mice were randomly assigned into five groups (n = 8). Three groups were orally fed with 50 microl of three different concentrations of B. pseudocatenulatum G4 (2 x 10(4), 1 x 10(8) and 1 x 10(11) CFU day(-1)) for 4 weeks. One group was orally administered with 50 microl of 1 x 10(8) CFU B. longum BB536 per day for 4 weeks and last group was used as a nonbifidobacterial treatment control, which received 50 microl of skim milk. The administered strains did not affect the general health of mice and incapable of carrying out translocation to blood or liver. There were no significant differences in the internal organ (liver, heart, kidney and spleen) indices, serum enzymes of liver (aspartate aminotransferase, alkaline phosphate, alanine aminotransferase) and kidney (urea and creatinine) and histology (villi height, crypts height, mucosa thickness and epithelial cell height) of caecum, ileum and colon.
Administration of high dose of up to 1 x 10(11) CFU B. pseudocatenulatum G4 per day to mice did not show any health threatening symptoms.
Bifidobacterium pseudocatenulatum G4 is none pathogenic to BALB/c mice and could be safe probiotic for human consumption.
Kefir is considered to be probiotic, beneficially affecting the host through its effects in the intestinal tract. Despite numerous studies that have examined the actions of probiotics on the host organism, few have analyzed the effects on intestinal enzymes. The aim of this present study is to report data on the effects of kefir on enzymes and proteins present in the intestine. In this study, female rats were fed for 22 days with 2 types of diets, standard and kefir-supplemented. Food intake and body weight were recorded daily. The glucose, uric acid, cholesterol, triacylglycerols, and alkaline phosphatase activity were measured in the serum. Rat body weights were similar in both groups (control and kefir). No significant differences were found in the weight of the organs examined. An intestinal enzymatic analysis was carried out, and the results showed an increase of this activity in addition to the uptake of d-galactose by brush border membrane vesicles. Glycemia was significantly lower in the kefir group. The present findings indicate that kefir, in the conditions studied, could benefit protein digestion and reduce glycemic index.
Kefir is a fermented milk drink produced by the actions of bacteria and yeasts contained in kefir grains, and is reported to have a unique taste and unique properties. During fermentation, peptides and exopolysacchar- ides are formed that have been shown to have bioactive properties. Moreover, in vitro and animal trials have shown kefir and its constituents to have anticarcinogenic, antimutagenic, antiviral and antifungal properties. Although kefir has been produced and consumed in Eastern Europe for a long period of time, few clinical trials are found in the scientific literature to support the health claims attributed to kefir. The large number of microorganisms in kefir, the variety of possible bioactive compounds that could be formed during fermenta- tion, and the long list of reputed benefits of eating kefir make this fermented dairy product a complex probiotic.
Purpose
– The purpose of the paper is to show that traditionally, kefir was obtained by fermenting milk with kefir grains. Wide variation in microflora of kefir grains makes it difficult to obtain an optimal and uniform starter culture necessary for obtaining a quality kefir. Reviewed literature on microbiological and technological innovations in kefir production would enrich the scientific knowledge resulting in production of kefir with superior physical, chemical, nutritional, therapeutic and sanitary qualities.
Design/methodology/approach
– An attempt is made to highlight the microbiological and technological aspects of kefir production with regard to the microflora of kefir grains, suitability of different types of milk, treatment of milk, starter inoculation and incubation, packaging, storage and post‐production treatment of kefir as well as methods of preservation of kefir grains.
Findings
– Diverse microflora of kefir grains is the prime cause for the wide variation in kefir quality. Production of kefir is based on symbiotic relation between lactic acid bacteria and yeasts and the type of milk, their heat‐treatment, size of inoculating starters and temperature of incubation influence their metabolic activities. Application of a suitable combination of lactic acid bacteria and yeasts would enable production of kefir with more uniform product with specific properties Packaging of kefir in a suitable container and storage at low temperature are suggested to retain its qualities.
Originality/value
– Fermentation of milk with a suitable starter combination consisting of lactic acid bacteria and yeasts rather than application of kefir grains during the production of kefir would be more scientific to yield a product with enhanced nutritional and therapeutic qualities.
Milk proteins have received increasing attention as potential ingredients of health-promot-ing functional foods targeted at diet-related chronic diseases, such as cardiovascular dis-ease, diabetes type two and obesity. To this end, growing interest has been focused on physiologically active peptides derived from milk proteins. These peptides are inactive within the sequence of the parent protein molecule and can be liberated by gastrointestinal digestion of milk, fermentation of milk with proteolytic starter cultures or hydrolysis by pro-teolytic enzymes. Milk protein-derived peptides have been shown under in vitro and in vivo conditions to exert a number of activities affecting the digestive, endocrine, cardiovascular, immune and nervous systems. A great variety of naturally formed bioactive peptides have been found in fermented dairy products, such as yoghurt, sour milk and cheese. Recently, industrial-scale technologies suitable for the industrial production of bioactive milk pep-tides have been developed. In addition, a few commercial food products supplemented with milk protein-derived bioactive peptides have been launched on limited markets. Some of these products carry clinically documented benefits, in particular for reduction of mild hypertension. The multifunctional properties of milk peptides appear to offer considerable potential for the development of many similar products in the near future.
Propionate is produced along with acetate and butyrate as a result of fermentative activity of gut microflora on dietary fiber. It has long been known to exhibit hypophagic effects in ruminants, however, its potential physiological roles in non-ruminants as well as humans remained unnoticed over the years. In view of various studies pointing towards the hypophagic as well as hypocholesterolemic effects of propionate in humans, it may act as an important factor in amelioration of obesity, a lifestyle disease arising due to energy imbalance and growing at a startling rate globally. Short chain fatty acids have recently been ascribed as ligands to G-protein coupled receptors (GPRs) 41 and 43. Thus, propionate along with acetate may also be involved in the regulation of adipogenesis and adipokine release mediated via GPRs. The present review summarizes the evidence which collectively raise the possibility of propionate as a dietary factor to depress appetite and combat the obesity epidemic.
Kefir is a traditional fermented milk that is carbonated, has a sharp acidic taste, yeasty flavour and contains a low percentage alcohol (less than 2% (v/v)). The beverage is manufactured by fermenting milk with Kefir grains, comprised of microorganisms, polysaccharides and milk proteins. The microbial population of Kefir grains primarily include lactic acid bacteria (LAB), namely lactococci and lactobacilli, yeasts, Acetobacter and filamentous fungi. Kefir exhibits antimicrobial activity in vitro against some fungi, and Grampositive and Gram-negative bacteria. Although the exact cause of this inhibition in Kefir is not known, the ability of LAB to inhibit the growth of closely related bacteria is well known. This inhibition of pathogenic and spoilage microbes may be due to the production of organic acids, hydrogen peroxide, acetaldehyde, diacetyl, carbon dioxide or bacteriocins. Acid is not the only contributor to the antimicrobial activity of Kefir and Kefir grains, and bacteriocins may play a role in the inhibitory activity. The bacteriocin producer Lactobacillus plantarum ST8KF, isolated from Kefir and Kefir grains, produces a bacteriocin 3.5 kDa in size. The mode of activity of bacteriocin ST8KF (bacST8KF) is thought to be bacteriostatic in exponential cultures of Enterococcus faecalis E88, Lactobacillus casei LHS, Lactobacillus curvatus DF38, Lactobacillus sakei DSM 20017, Lactobacillus salivarius 241 and Listeria innocua F and LMG 13568. The peptide is sensitive to proteolytic enzymes and does not adsorb to the surface of the producer cell. The bacteriocin is stable between pH 2.0 and 10.0, and for 20 min at 121°C. Maximum bacteriocin activity was observed in modified MRS medium supplemented with glucose or saccharose, meat extract, KH2PO4, glycerol, thiamine or cyanocobalamin, or in modified MRS medium without tri-ammonium citrate. Maximum levels of adsorption of bacST8KF (80%) to Lb. casei LHS and Lb. sakei DSM 20017 were recorded. Adsorption (80%) of the bacteriocin to Lactobacillus paraplantarum ATCC 700211T and Streptococcus caprinus ATCC 700066, which are not sensitive to the bacteriocin was also recorded. Optimal adsorption to E. faecalis E88 was recorded at 25°C at pH 2.0, and to L. innocua LMG 13568 at 4°C, 10°C and 25°C at pH 6.0. Potassium ions, MgCl2, Tris, NH4- citrate, Na-acetate, Na2CO3, EDTA and SDS led to decreased adsorption to both sensitive strains, while NaCl and mercaptoethanol resulted decreased adsorption to E. faecalis E88, but not to L. innocua LMG 13568. Methanol resulted in lower levels of adsorption to L. innocua LMG 13568 but not to E. faecalis E88. Triton X-100 and Triton X-114 increased the adsorption of bacST8KF by 40%, and ethanol and chloroform had no effect on bacteriocin adsorption. The growth of Lb. plantarum ST8KF and L. innocua LMG 13568 in a mixed culture resulted in an increase of bacST8KF production. Cells treated with bacST8KF secreted DNA and galactosidase. As bacST8KF remains stable under a variety of conditions, the bacteriocin may have application, if awarded GRAS (generally regarded as safe) status, in various food products as a natural additive or preservative. The genes encoding bacteriocin production are located on a 3.9 kilo base (kb) plasmid. Curing of the plasmid resulted in a mutant strain of Lb. plantarum ST8KF, and the Lb. plantarum strains ST8KF(+) and ST8KF(-) differed with regards to antibiotic resistance and carbohydrate fermentation reactions. The wild type and the cured strain were incorporated into Kefir grains during mass cultivation. The survival of the bacST8KF sensitive Enterococcus mundtii ST4SA added to the milk during Kefir production using the enriched mass cultured grains was monitored using fluorescent in situ hybridization. Enterococcus mundtii ST4SA was present in higher numbers in the ST8KF(-) Kefir system when compared to the ST8KF(+) system. It can, therefore, be concluded that Lb. plantarum ST8KF(+) contributes to the antimicrobial activity of Kefir through the production of bacteriocin ST8KF. Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2006.
The objective of this study was to evaluate the effects of Lactobacillus plantarum MA2, an isolate from Chinese traditional Tibet kefir, on cholesterol-lowering and microflora of rat in vivo. Rats were fed on cholesterol-enriched experimental diet, supplemented with lyophilized L. plantarum MA2 powder, with a dose of 10(11) cells/day per mice. The results showed that L. plantarum MA2 feeding significantly lowered serum total cholesterol, low-density lipoprotein cholesterol, and triglycerides level, while there was no change in high-density lipoprotein cholesterol. In addition, liver total cholesterol and triglycerides was also decreased. However, fecal cholesterol and triglycerides was increased significantly (P < 0.05) in comparison with the control. Also, L. plantarum MA2 increased the population of lactic acid bacteria and bifidobacteria in the fecal, but it did not change the number of Escherichia coli as compared to control. Moreover, pH, moisture, and organic acids in the fecal were also measured. The present results indicate the probiotic potential of the L. plantarum MA2 strain in hypocholesterolemic effect and also increasing the probiotic count in the intestine.
The general safety of immune-enhancing lactic acid bacteria (LAB) strains Lactobacillus rhamnosus HN001 (DR20), Lb. acidophilus HN017, and Bifidobacterium lactis HN019 (DR10) was investigated in a feeding trial. Groups of BALB/c mice were orally administered test LAB strains or the commercial reference strain Lb. acidophilus LA-1 at 2.5 x 10(9), 5 x 10(10) or 2.5 x 10(12) colony forming units (CFU)/kg body weight/day for 4 weeks. Throughout this time, their feed intake, water intake, and live body weight were monitored. At the end of the 4 week observation period, samples of blood, liver, spleen, kidney, mesenteric lymph nodes, and gut tissues (ileum, caecum, and colon) were collected to determine: haematological parameters (red blood cell and platelet counts, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration); differential leukocyte counts; blood biochemistry (plasma total protein, albumin, cholesterol, and glucose); mucosal histology (epithelial cell height, mucosal thickness, and villus height); and bacterial translocation to extra-gut tissues (blood, liver, spleen, kidney and mesenteric lymph nodes). DNA finger printing techniques were used to identify any viable bacterial strains recovered from these tissues. The results demonstrated that 4 weeks consumption of these LAB strains had no adverse effects on animals' general health status, haematology, blood biochemistry, gut mucosal histology parameters, or the incidence of bacterial translocation. A few viable LAB cells were recovered from the tissues of animals in both control and test groups, but DNA fingerprinting did not identify any of these as the inoculated strains. The results obtained in this study suggest that the potentially probiotic LAB strains HN001, HN017, and HN019 are non-toxic for mice and are therefore likely to be safe for human use.
Docosahexaenoic acid (DHA) is an omega-3 fatty acid which has been demonstrated to exhibit anti-inflammatory effects. The objective of this study was to determine the effect of DHA on phagocytic and chemotactic activities of peritoneal macrophages obtained from rats. DHA was dissolved in 1 ml of corn oil at dose of 36 mg/kg/day and given via oral gavage for 4 weeks. Control rats received 1 ml/day corn oil as vehicle. At the end of the treatment period, peritoneal macrophages were isolated and chemotactic and phagocytic activities were assayed. Chemotactic and phagocytic activities were reduced in rats fed with DHA. These results demonstrated the effect of DHA in modulating immune activities of rat peritoneal macrophages.
The evaluation of organ weights in toxicology studies is an integral component in the assessment of pharmaceuticals, chemicals, and medical devices. The Society of Toxicologic Pathology (STP) has created recommendations for weighing organs in GLP general toxicology studies lasting from 7 days to 1 year. The STP recommends that liver, heart, kidneys, brain, testes, and adrenal glands be weighed in all multidose general toxicology studies. Thyroid gland and pituitary gland weights are recommended for all species except mice. Spleen and thymus should be weighed in rodent studies and may be weighed in non-rodent studies. Weighing of reproductive organs is most valuable in sexually mature animals. Variability in age, sexual maturity, and stage of cycle in non-rodents and reproductive senescence in female rodents may complicate or limit interpretation of reproductive organ weights. The STP recommends that testes of all species be weighed in multidose general toxicology studies. Epididymides and prostate should be weighed in rat studies and may be weighed on a case-by-case basis in non-rodent and mouse studies. Weighing of other organs including female reproductive organs should be considered on a case-by-case basis. Organ weights are not recommended for any carcinogenicity studies including the alternative mouse bioassays. Regardless of the study type or organs evaluated, organ weight changes must be evaluated within the context of the compound class, mechanism of action, and the entire data set for that study.
Guidelines for Ethical Conduct in the Care and Use of Nonhuman Animals in Research
APA. Guidelines for Ethical Conduct in the Care and Use of
Nonhuman Animals in Research. Am Psychol Assoc 2012.
Seleksi bakteri asam laktat penghasil eksopolisakarida
- K Appetiteal-Awwaly
- A Manab
AppetiteAl-Awwaly K, Manab A. Seleksi bakteri asam laktat
penghasil eksopolisakarida. J Ternak Tropika 2007; 6 (2): 79-87.
Antimicrobial and healing activity of kefir and kefiran extract
- K L Rodrigues
- Lrg Caputo
- Jct Carvalho
- J Evangelista
- J M Schneedorf
Rodrigues KL, Caputo LRG, Carvalho JCT, Evangelista J,
Schneedorf JM. Antimicrobial and healing activity of kefir and
kefiran extract. Int J Antim Agents 2005; 25 (5): 404-8.