Lactic Acid Bacteria Research Articles

Identification, Safety Assessment, and Antimicrobial Characteristics of Cocci Lactic Acid Bacteria Isolated from Traditional Egyptian Dairy Products.

The main objective of this study is to isolate and identify lactic acid bacteria (LAB) from various Egyptian dairy products, examine their antibacterial and hemolysis potential, and ensure their safety when used as starter cultures in different dairy industries. Egyptian dairy products are often made without the use of commercial starter cultures, using raw milk and artisanal methods. The most popular traditional dairy products are Laban Rayeb and Zabady, as well as the cheese varieties of Ras, Domiati, and Karish. The microbial communities used for fermentation and the diversity of lactic acid bacteria are the most important factors that can affect the quality of these products. In order to investigate the diversity of cocci lactic acid bacteria in Egyptian dairy products, 70 samples of raw or fermented milk and cheeses were collected from traditional cheese-making factories, local markets, and farmhouses located in the Delta area of Egypt. Following this, the LAB were isolated from the samples. One hundred fifty-seven isolates of Gram-positive, catalase-negative, and cocci bacterial species were identified via rep-PCR, and some isolates were confirmed using pheS and 16S rRNA gene sequencing, as follows: Streptococcus infantarius subsp. infantarius (three isolates), Enterococcus hirae (three isolates), Enterococcus faecium (ninety-six isolates), Enterococcus faecalis (forty isolates), Enterococcus durans (six isolates), Lactococcus garvieae (one isolate), Pediococcus acidilactici (seven isolates), and Lactococcus lactis subsp. Lactis (one isolate). These findings validate that five strains have strong antibacterial activity against Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes, and one hundred thirty-four strains were safe for hemolysis. The five strains were selected as protective cultures, including Pediococcus acidilactici, Lactococcus lactis subsp. lactis, E. faecalis, and E. faecium.

Investigation of in situ and ex situ mode of lactic acid bacteria incorporation and the effect on dough extensibility, bread texture and flavor quality during shelf-life

Lactococcus lactis subsp. diacetylactis, Lactobacillus delbrueckii subsp. bulgaricus, and Lb. rhamnosus were evaluated for their efficiencies in preserving bread texture and flavor during shelf-life. The investigated LABs exhibited efficiency during preliminary screening in expressing selected enzymes (protease, xylanase, α-amylase, laccase, and glucose oxidase) and producing exopolysaccharide (EPS). Dough samples were supplemented with either sourdough starters containing live LAB cells or LAB cell lysates. Prolonged fermentation further enhanced the protective advantage of sourdough starter incorporation. During the 5-day shelf-life period, in situ enrichment with Lb. rhamnosus led to a mere 12.5–35.4 % hardness change and 13.8–20.7 % overall texture change. Furthermore, sourdough bread with live LAB cell supplementation displayed a more diverse and intense flavor profile, with high concentration of bread key odorants maintained during shelf-life, including 2,3-butanedione, 2-acetyl-1-pyrroline, and 3-methylbutanal. Meanwhile, no significant improvement was found in bread enriched with LAB cell lysates during shelf-life.

Inactivation kinetics of dairy phages using photocatalytic paint under diverse environmental conditions and radiation sources

This article investigates the efficacy of a photocatalytic paint for bacteriophages inactivation under various levels of incident radiation flux, relative humidity and radiation sources. Two phages that infect lactic acid bacteria were selected: J-1, infective of Lacticaseibacillus casei ATCC 27139, and M13-G1b, infective of Streptococcus thermophilus G1b. Phage suspensions were deposited on coated and uncoated plates and exposed to radiation typically used for indoor illumination (λ = 360–720 nm). A first-order inactivation kinetics was proposed with respect to the Plaque Forming Units per mL (PFU/mL) that correlates the inactivation constant with the operating conditions. The kinetic constant of this novel model combines a potential function for the incident radiation flux and a logistic function for the relative humidity. The results showed that as these variables increased, phage inactivation turned higher for both uncoated and coated plates. Photonic and quantum efficiencies were also calculated for both phages, when treated with photocatalytic paint under UV-A radiation. The photonic efficiencies were 8.03 × 1012 PFU/Einstein for J-1 and 4.05 × 1012 PFU/Einstein for M13-G1b, while the quantum efficiencies were 1.19 × 1013 PFU/Einstein for J-1 and 6.03 × 1012 PFU/Einstein for M13-G1b. Good agreement was obtained between predictions of the proposed kinetic model and experimental data, with a Root Mean Square Error of 4.43 % for J-1 and 2.98 % for M13-G1b. The developed model would be useful to predict phage inactivation under diverse combinations of operating conditions levels in environments of dairy plants, different from those tested in this work.

Gut Microbiota Dynamics and Phenotypic Changes Induced by Tetracycline in Drosophila melanogaster

Gut microbiota plays a crucial role in both physiological and pathological processes in humans and animals. Antibiotics, designed to combat bacterial infections, can induce alterations in the composition and abundance of the gut microbiota over prolonged exposure. This study addresses the limited understanding of the connections between gut microbiota and phenotypic profiles of metazoan species. We investigated the impact of early-life exposure to tetracycline in wild-type D. melanogaster, which were fed a standard diet, comparing them to a control group not exposed to tetracycline. The primary objective was to examine the consequences of early-life tetracycline exposure on gut microbiota and its implications for phenotypic profiles, including survival, locomotor activity, and reproduction in adult flies. Results revealed a significant reduction in lactic acid bacteria in adult flies exposed to tetracycline. However, tetracycline exhibited no interference with fly development, allowing them to maintain a normal lifespan. In adult flies, tetracycline significantly decreased the lifespan on day 35 at a concentration of 1000 µg/mL and reduced locomotion on day 27 at concentrations of 10 µg/mL and 1000 µg/mL. Remarkably, tetracycline did not impact the reproductive capabilities of the flies. This study demonstrates that while tetracycline led to a decline in lactic acid bacteria, locomotion, and lifespan in adult flies, it did not disrupt their development or reproductive processes.

The effects of applying cellulase and laccase on fermentation quality and microbial community in mixed silage containing corn stover and wet brewer's grains.

The purpose of this experiment was to explore the effect of adding cellulase and laccase on fermentation quality and microbial community in mixed silage of corn stover and wet brewer's grains. Try to a new approach for the proper preservation and utilization of the agro-industrial by-products (corn stover and wet brewer's grains). The experiment was divided into four groups: CK (control), C (cellulase, 120 U/g fresh matter [FM]), L (laccase, 50 U/g FM), CL (cellulase 120 U/g FW and laccase 50 U/g FM), and the chemical composition, fermentation quality, microbial population and microbial community in mixed silage of corn stover and wet brewer's grains after 30 day's fermentation were determined. Compared to control, the addition of cellulase significantly increased crude protein (CP), water-soluble carbohydrate (WSC), lactic acid bacteria (LAB) counts, while significantly decreased the neutral detergent fiber (NDF), acid detergent fiber (ADF) content (P < 0.05). Adding laccase significantly decreased the acid detergent lignin (ADL) content (P < 0.05). Combined application of cellulase and laccase significantly increased the CP, WSC content and LAB counts, while significantly decreased pH value, NDF, ADF and ADL content (P < 0.05), thereby improving fermentation quality. In addition, the application of cellulase and laccase increased the abundance of Firmicutes and LAB genera, and decreased microbial diversity level of the sample. The combined application of cellulase and laccase further improved fermentation quality and microbial community in mixed silage of corn stover and wet brewer's grains.

Exploring the physicochemical and microbiological properties of glutinous rice (Tapai pulut) fermented using Lactobacillus plantarum: A comprehensive characterization using 1H NMR

This study aimed to investigate the potential of producing lacto-fermented glutinous rice (Tapai pulut) to improve its physicochemical properties, metabolite compounds, and antibacterial activity of the end product. Glutinous rice was fermented with Amylomyces rouxii, and Lactobacillus plantarum 1 at 30 °C for 48 h. Lacto-fermented glutinous rice had significantly lower pH values and higher total lactic acid, soluble solid, glucose, and organic acid contents. The 1H NMR metabolomics profile revealed the presence of alcohols (7.67 mmol/L), sugars (208.16 mmol/L), organic acids (0.91 mmol/L) and amino acids (15.74 mmol/L), contributing to its antimicrobial activities and flavor profile. The lacto-fermented glutinous rice exhibited strong antibacterial activity against Bacillus cereus (18.20 mm), Staphylococcus aureus (18.92 mm), Listeria monocytogenes (15.42 mm), Escherichia coli (15.85 mm), and Salmonella typhimurium (12.23 mm). Meanwhile, the viable count of lactic acid bacteria (LAB) in the lacto-fermented glutinous rice was 9.49 log10 CFU/g. Based on sensory evaluation and positive feedback from panelists, lacto-fermented glutinous rice emerges as a promising probiotic food with potential health benefits for consumers.

Chemical, Textural and Antioxidant Properties of Oat-Fermented Beverages with Different Starter Lactic Acid Bacteria and Pectin.

Currently, starter cultures for fermenting plant-based beverages are not widely available commercially, but producers can use starter cultures for dairy products. Therefore, the aim of this study was to determine the physicochemical, rheological, antioxidant and sensory properties of oat beverages with/without pectin fermented by four different dairy starter cultures. The use of a mono-starter with Lactobacillus bulgaricus or Sreptococcus thermophilus allows for the efficient use of glucose, and more lactic acid is accumulated. The beverage with L. bulgaricus is characterised by high adhesion, syneresis and low cohesiveness, and it has high antioxidant activity and a low sensory profile. Using starter with L. bulgaricus, S. thermophilus and some Lactococcus for fermentation yields a product with high sensory capacity, forming a high-viscosity beverage matrix with low syneresis, high water retention, chewy texture and stickiness. It has been observed that the absence of lactococci and the presence of Lactobacillus casei, L. Rhamnosus and L. paracasei in the starter yields a product with high antioxidant activity, especially in the presence of pectin. The use of pectin significantly improves the viscosity and textural properties of oat yoghurt, enhancing the drink's flavour and giving it body. For many reasons, the use of different commercial starters in the dairy industry results in different viscosities of oat fermented beverages, forming a matrix with different textural, sensory and antioxidant properties.

Effect of Dry Aging of Pork on Microbiological Quality and Instrumental Characteristics

Meat aging is an important process that affects the quality of meat and is traditionally used mainly for beef. However, in recent years, there has been an increasing demand for pork products subjected to dry aging. The aim of this study was to compare selected parameters (microbiological quality, instrumental analyses of texture and color of meat, weight loss) of pork neck and loin with bone and skin together subjected to dry aging for 14 days. The microbiological profile (total viable psychrotrophic count, Enterobacteriaceae, psychrotrophic lactic acid bacteria, Pseudomonas spp.) on the surface of the meat with the skin and the lateral cutting surfaces without skin was compared on the first day after slaughter and after 14 days of dry aging. The results of this study demonstrated that dry aging did not significantly deteriorate the microbiological profile. Statistically significant weight losses were observed after 14 days of aging. The dry aging of pork had no significant effect on lightness (L*), redness (a*), and shear force. Significant differences were observed for yellowness (b*) and meat hardness (p &lt; 0.05).

The association between milk and dairy products intake and insomnia symptoms among Japanese adults in community-based cohort.

Objective: To examine the association between habitual intake of milk and dairy products and insomnia. Design: Cross-sectional study by using cohort study data among 60,633 participants (22,721 men and 37,912 women) aged 20-74 years in eastern Japan. The data of milk and dairy products intake, sleep status and other lifestyle habits were collected by self-administered questionnaires. The question about milk and dairy products included whole milk, low-fat milk, cheese, yogurt, and lactic acid bacteria beverages, and were assessed by frequency (< 1 time/week, 1-2 times/week, 3-6 times/ week, and ≥ 1 time/day). Sleep status was scored with the Athens Insomnia Scale. Results: Logistic regression analysis showed that adjusted odds ratio (OR) and 95% confidence interval (95% CI) for insomnia were statistically significantly lower for whole milk intake > 1 time/day compared to < 1 time/week in all (OR: 0.91; 95% CI: 0.86-0.96; P = 0.001). The similar results were shown for women (OR: 0.90; 95% CI: 0.85-0.97; P = 0.002), not for men. In contrast, the adjusted odds for insomnia were high in the group that had frequencies of 3-6 times/week of lactic acid bacteria beverages compared to <1 time/week (OR: 1.20, 95% CI: 1.11-1.29; P < 0.001 in all; OR: 1.36; 95% CI: 1.19-1.55; P < 0.001 in men; OR: 1.13; 95% CI: 1.03-1.24; P = 0.009 in women). Conclusions: This cross-sectional study of Japanese populations showed a tendency for no insomniacs to consume whole milk more frequently.

Evaluation of Different Lactic Acid Bacteria as Starter Cultures for Nono—A West African Fermented Dairy Product

Nono is a traditional cultured dairy product consumed across West Africa. In this study, five cultures isolated from Nigerian-produced nono and three purified lactic acid bacteria from the USDA-NRRL were examined for use in preparing nono starter cultures. Isolated cultures were characterized using microbiological and biochemical tests, including 16s rDNA sequencing to identify the genotype. Each isolated strain was cultured and inoculated into UHT milk (1% v/v) and allowed to ferment for 24 h at 25 °C. Fermented products were evaluated for pH, moisture content, water activity, and viscosity, and their descriptive sensory properties were noted. The isolate that resulted in sensory properties most similar to traditional nono was then used as the primary strain for subsequent starter culture blends made with the NRRL cultures. These blends were used for the fermentation of nono and compared with commercial nono samples. Isolates obtained from nono were as follows: Lactobacillus fermentum, Lactobacillus paracasei, and, surprisingly, Lactobacillus rhamnosus, which has not been previously reported as a part of the nono microflora. There was no significant difference in the physical parameters of nono made from the individual indigenous isolates and a similar pattern was observed for the organisms from NRRL, except that their total titratable acidity and viscosities were significantly (p &lt; 0.05) higher than those of the indigenous organisms. Compounded starter made with L. rhamnosus and NRRL cultures was then used to make nono that showed significantly (p &lt; 0.05) different pH and viscosity values than commercially purchased nono, while sensory evaluation showed that nono made from the new starter culture had a high overall consumer acceptance score.

The regulation of volatile flavor compounds in fermented meat products mediated by microorganisms: A review

Fermented meat products are widely consumed and favored by consumers because of their unique flavor and texture. Flavor formation is a complicated biochemical process, and microorganisms (mainly lactic acid bacteria, staphylococci, yeasts, and molds) play an essential role in flavor regulation. Elucidating the role of microorganisms in regulating the flavor formation of fermented meat products is critical for rationally designing microorganisms to improve the flavor quality of fermented meat products. Therefore, microorganisms, volatile compounds, and flavor-generating mechanisms of microorganisms in fermented meat products are summarized. This review also highlight correlations between microorganisms and flavor development and the effects of microorganisms on flavor development, which may provide important progress for the selection and application of microorganisms to improve the flavor of fermented meat products.

Effect of feed supplementation with Curcuma longa and Zingiber officinale spices on the zootechnical, biochemical, and microbiological parameters of broiler chickens

In recent years, there has been a significant trend to improve poultry zootechnical performances by biological methods to avoid the unwanted chemical growth factor's introduction into breeding process. Medicinal plants and their derivatives are good candidates to achieve this goal. Thus, this work aimed at evaluating the effect of poultry feed supplementation with the spices Curcuma longa and Zingiber officinale on the zootechnical performance, serological, and microbiological parameters of Ross 308 chicken. To achieve this purpose, 180 chicks divided into five groups and reared for 12 days. The experimental groups consisted of a control group receiving a conventional feed without antibiotics and four groups receiving a conventional feed with 0.5 and 1% turmeric and ginger doses, respectively. Results of the experiment revealed that supplementing the feed with 0.5% turmeric powder increased live weight, and average daily gain and decreased feed conversion compared to the other groups. Turmeric powder supplement (0.5 and 1%) affected blood serum parameters by decreasing triglyceride and aspartate aminotransferase (AST) concentrations. In comparison, the incorporation of 0.5% ginger in the diet decreased triglyceride concentrations, cholesterol, aspartate aminotransferases (ASAT), and alanine aminotransferases (ALAT). Cecum bacteriological analysis showed a total absence of coliforms, Salmonella sp., Clostridium sp., and lactic acid bacteria in the chick groups supplemented with different doses of turmeric and ginger (0.5 and 1%, respectively). Within this study’s limits, using these two studied spices as additives in poultry feed allowed us to conclude that supplementing with 0.5% turmeric powder positively impacted the evaluated parameters.

Administration of Lacticaseibacillus casei CSL3 in Swiss Mice with Immunosuppression Induced by Cyclophosphamide: Effects on Immunological, Biochemical, Oxidative Stress, and Histological Parameters.

The study aimed to evaluate the effects of supplementation with Lacticaseibacillus casei CSL3 in Swiss mice immunosuppressed with cyclophosphamide on immunological, biochemical, oxidative stress, and histological parameters. The animals were distributed into four groups (control, CSL3, cyclophosphamide, and CSL3 + cyclophosphamide), where two groups were treated with L. casei CSL3 (10 log CFU mL-1) for 30days, and two groups received chemotherapy (days 27 and 30-total dose of 250mgkg-1). Counts of lactic acid bacteria (LAB) and bile-resistant LAB in stool samples; blood count (erythrogram, leukogram, and platelets); serum total cholesterol levels; catalase enzyme activity; and thiobarbituric acid reactive substances (TBARS) levels in liver, kidney, and brain; IL-4 expression; IL-23, TNF-α, NF-κβ in the spleen; and histological changes in the liver, kidneys, and intestine were evaluated. The CSL3 + cyclophosphamide group showed a significant increase in bile-resistant LAB counts in feces (p = 0.0001), leukocyte counts, and expression of IL-23, TNF-α, and NF-κβ (p < 0.05) significantly reduced total cholesterol levels (p = 0.001) and protected liver damage of supplemented animals. For oxidative stress damage, the bacterium did not influence the results. It is concluded that the bacterium is safe at a concentration of 10 log CFU mL-1 and has probiotic potential due to its positive influence on the immune response and lipid metabolism.

Influence of Heat Treatment and Lactic Acid Fermentation on the Physical and Chemical Properties of Pumpkin Juice.

Pumpkin is a highly nutritious plant, rich in valuable nutrients that benefit human health. Due to the high perishability of this fruit, the production of pumpkin juice is a practical way to use it effectively. Recently, fermented vegetable juices have been used as a dairy alternative due to their nutritional and potential probiotic properties. This study investigated the fermentation of pumpkin juice using different strains of lactic acid bacteria (LAB), with and without heat treatment. The effects of fermentation on microbial growth, pH, acidity, extract, sugars, carotenoids, polyphenols, and antioxidant properties were analyzed. The heat-treatment process did not greatly impact the dry matter content, pH, acidity, extract, or sugar content. However, it led to a reduction in carotenoid and polyphenol levels. During fermentation, there was a consistent decrease in pH and an increase in total acidity, with no noticeable differences between bacterial strains regarding their influence on these parameters. The study revealed that there were no distinctions between LAB strains in their effects on pH, acidity, and carotenoid content in fermented pumpkin juice. Nonetheless, both L. sakei and L. plantarum proved to be effective in the fermentation process, with L. sakei demonstrating greater adaptability. The expected pH, acidity, and sugar content changes were consistently observed throughout the fermentation process. Overall, results confirm the efficacy of the used Lactobacillus strains in fermenting pumpkin juice and highlight the potential impact of heat treatment on the nutritional composition of the juice. The purpose of thermal processing of pumpkin juice, which is conducted with lactic acid fermentation, is crucial for the food industry. It extends the product's shelf life, improves its nutritional and taste profiles, and guarantees its microbiological safety.

Morphology of Bacteria and Fungi From The Fermentation of Asam Drien as a Local Food Ingredient of West Aceh

A typical food ingredient of the Aceh region, especially the western and southern, is Asam drien (language from the West Aceh region). Asam drien is made from durian fruit meat, usually due to the abundance of durian fruit, or because the durian fruit is of poor quality such as the taste of the bland fruit meat, then most of the people utilize the durian fruit into Asam drien which can be used as a seasoning for cooking. The purpose of this study was to identify the morphological characteristics of bacterial and fungal colonies in Asam drien processing, this study used a qualitative descriptive method for colony characteristics, and biochemical tests. The results of research on bacteria and fungi in Asam drien found 14 colonies from the entire fermentation both at home and in the laboratory, namely irregular and diffuse, elongated, round, and threaded shapes; colony color characteristics obtained only one color, namely cream color; characteristics of colony edges there are 5, namely: wavy, squiggly, smooth, serrated, and threadbare. Colony elevation characteristics obtained 2 forms, namely flat and raised. There are 2 types of colony surface characteristics, namely rough and smooth shiny. Then reisolated on selective media DeMan Rogosa Sharpe Agar (MRS Agar) for lactic acid bacteria. The results of observations found 11 colonies from the entire fermentation each consisting of 2 types of isolates Ka and Kb which are Gram-positive bacteria bacillus and coccus cell forms. As well as fungi that grow on Asam drien, namely the genus Rhizopus and the type of yeast found from the genus Saccharomyces. The catalase test on Asam drien bacteria is positive, has proteolytic, amylolytic, and cellulolytic potential, but is not able to hydrolyze fat and alcohol.

Phage defence loci of Streptococcus thermophilus-tip of the anti-phage iceberg?

Bacteriapossess (bacterio)phage defence systems to ensure their survival. The thermophilic lactic acid bacterium, Streptococcus thermophilus, which is used in dairy fermentations, harbours multiple CRISPR-Cas and restriction and modification (R/M) systems to protect itself against phage attack, with limited reports on other types of phage-resistance. Here, we describe the systematic identification and functional analysis of the phage resistome of S. thermophilus using a collection of 27 strains as representatives of the species. In addition to CRISPR-Cas and R/M systems, we uncover nine distinct phage-resistance systems including homologues of Kiwa, Gabija, Dodola, defence-associated sirtuins and classical lactococcal/streptococcal abortive infection systems. The genes encoding several of these newly identified S. thermophilus antiphage systems are located in proximity to the genetic determinants of CRISPR-Cas systems thus constituting apparent Phage Defence Islands. Other phage-resistance systems whose encoding genes are not co-located with genes specifying CRISPR-Cas systems may represent anchors to identify additional Defence Islands harbouring, as yet, uncharacterised phage defence systems. We estimate that up to 2.5% of the genetic material of the analysed strains is dedicated to phage defence, highlighting that phage-host antagonism plays an important role in driving the evolution and shaping the composition of dairy streptococcal genomes.

Antibiotic-resistant mutants of lactic acid bacteria: potential food control agents

Background: One of the most pressing challenges facing global agriculture today is the restoration of degraded farmland. Organic fertilisers are increasingly being used as a safer alternative to synthetic forms. The most promising form of environmentally friendly fertiliser is a bioconsortium based on different groups of microorganisms. Lactic acid bacteria (LAB) with high antifungal activity, isolated from Armenian dairy products, can form part of such a bioconsortium and protect plants from phytopathogens. In addition, LAB can be used as a preservative in the food industry due to its GRAS (generally recognised as safe) status. Objective: To obtain antibiotic-resistant pleiotropic lactic acid bacterial mutants with higher antifungal activity and broad-spectrum activity compared to natural strains. Methods: The objects of the study were LAB, whose antifungal activity was studied against phytopathogenic fungi of the genera Penicillium, Aspergillus, Alternaria and Fusarium, which cause crop/food spoilage. To increase antifungal activity, spontaneous pleiotropic mutants resistant to the streptomycin, kanamycin or rifampicin were obtained on the basis of original strains. Results: Among all the LAB tested, Lactobacillus bovis MDC 1061, L. paracasei MDC 10898 and L. buchneri BKM 1599 were selected for their antifungal activity. Based on the latter, 78 antibiotic-resistant mutants with different levels of antifungal activity were obtained. L. bovis MDC 1061 STR-25 and L. buchneri BKM 1599 RIF-7 mutants with up to 98% and 95% inhibition of fungal growth, respectively, were selected as potential food control agents. Conclusion: Antibiotic-resistant mutants L. bovis MDC 1061 STR-25 and L. buchneri BKM 1599 RIF-7 with high antifungal ability and a wide range of its effects were obtained. For the first time, the phenomenon of pleiotropic effect has been used in LAB to improve antifungal activity. After extensive study, these mutants can be used as promising components for creating an effective bioconsortium, as well as a preservative in food production, especially in the case of plant-based functional foods to protect against contamination by fungi. Keywords: lactic acid bacteria, pleiotropic mutants, antifungal activity

Probiotic strategies for mitigating heat stress effects on broiler chicken performance.

The primary objective of this study was to evaluate the effects of liquid (Fructose-added lactic acid bacteria, F-LAB) and commercial (Commercial LAB, C-LAB) probiotics sourced from Rye-Grass Lactic Acid Bacteria (LAB) on broiler chickens experiencing heat stress (HS). The research involved 240 broiler chicks, divided into six groups: control, F-LAB, C-LAB (raised at 24°C), HS, F-LAB/HS, and C-LAB/HS (exposed to 5-7h of 34-36°C daily). The study followed a randomized complete block design, with each group consisting of 40 chicks. F-LAB and HS/F-LAB groups received a natural probiotic added to their drinking water at a rate of 0.5ml/L, while C-LAB and HS/C-LAB groups were supplemented with a commercial probiotic at the same dosage. Control and HS groups received no probiotic supplementation. The duration of the study was 42days, with data collected on growth performance, feed intake, feed conversion ratio, and health parameters. Statistical analyses were performed using ANOVA, and significant differences between groups were determined using post hoc tests. The results revealed that without probiotic supplementation, heat stress led to a decrease in body weight gain, T3 levels, citrulline, and growth hormone levels, along with an increase in the feed conversion ratio, serum corticosterone, HSP70, ALT, AST, and leptin levels (p < 0.05 for all). Heat stress also adversely affected cecal microbiota, reducing lactic acid bacteria count (LABC) while increasing Escherichia coli and coliform bacteria (CBC) counts. However, in the groups receiving probiotic supplementation under heat stress (F-LAB/HS and C-LAB/HS), these effects were alleviated (p < 0.05 for all). Particularly noteworthy was the observation that broiler chickens supplemented with natural lactic acid bacteria (F-LAB) exhibited greater resilience to heat stress compared to those receiving the commercial probiotic, as evidenced by improvements in growth, liver function, hormonal balance, intestinal health, and cecal microbiome ecology (p < 0.05). These findings suggest that the supplementation of naturally sourced probiotics (F-LAB) may positively impact the intestinal health of broiler chickens exposed to heat stress, potentially supporting growth and health parameters.

Continental-scale insights into the sugarbeet diffusion juice microbiomes.

Bacterial contamination of raw diffusion juice poses unique challenges during the sugar extraction process. This study profiled bacterial communities by using full-length 16S rRNA amplicon sequencing and quantified the carbohydrate concentrations in raw diffusion juice samples received from sugar factory regions across the USA and Canada. Juice samples were collected at four time points during the 2021 and 2022 processing campaigns. Firmicutes was the dominant phylum from the raw diffusion juice samples collected during both campaigns and comprised 85.5% of total bacterial abundance. Lactic acid bacteria such as Leuconostoc and Lactobacillus were among the core genera which also dominated the bacterial community in raw diffusion juice. Positive correlations in the abundance of functionally and taxonomically related bacterial communities were identified. During the 2021 campaign, 44 bacterial genera were differentially abundant in raw diffusion juice extracted from sugarbeet roots in Periods 1 to 4. This number declined sixfold during the 2022 campaign to three genera. The concentration of raffinose in raw diffusion juice positively correlated to the relative abundance of Leuconostoc. Furthermore, an in vitro assay was performed to assess the growth dynamics of Leuconostoc mesenteroides in sucrose or raffinose-rich medium and observed the rapid consumption of both carbohydrates by this bacterium. This finding is important for deciphering microbial growth dynamics in raw diffusion juice that can be useful in minimizing sugar loss during the factory processing.IMPORTANCEFindings additionally provide baseline information that can be used to develop mitigation strategies that reduce losses due to microbial contamination of sucrose processing streams.

Impact of Golden Banana Puree (Musa acuminata) Enrichment on the pH, Lactic Acid Bacteria Count, and Viscosity of Kefir

The addition of golden banana puree (Musa acuminata) as a prebiotic has been hypothesized to enhance the growth of lactic acid bacteria in kefir. This study aimed to determine the effects of adding golden banana puree on the pH value, total lactic acid bacteria (LAB) count, and viscosity of kefir. The experiment was conducted using a Completely Randomized Design (CRD) with four treatments and three replications. The treatments included the addition of 0% (P0), 6% (P1), 8% (P2), and 10% (P3) banana puree. The observed variables were pH value, total LAB, and viscosity. Data were analyzed using Analysis of Variance (ANOVA), followed by Duncan's Multiple Range Test (DMRT) when a significant treatment effect was detected. The results indicated that the addition of golden banana puree had a very significant effect (P0.01) on the pH value, total LAB count, and viscosity of kefir. The study concluded that increasing the concentration of golden banana puree leads to a higher total LAB count and viscosity, while inversely lowering the pH value.