Galacto-oligosaccharides Research Articles

Evaluation of Prebiotic Properties of Galactooligosaccharides Produced by Transgalactosylation Using Partially Purified β-Galactosidase from Enterobacter aerogenes KCTC2190.

Transgalactosylation reaction is the penultimate step in the production of galactooligosaccharides (GOSs) which has prominent applications in the treatment of disorders. In the present study, partially purified β-galactosidase from Enterobacter aerogenes KCTC2190 was used for the synthesis of prebiotic GOSs. GOSs were produced using lactose as substrate. Structural elucidation of collected fractions of GOSs by liquid chromatography electrospray ionization mass spectrometry exhibited the appearance of major peaks of produced GOSs at m/z 241.20, 481.39, 365.11, 527.17, and 701.51 respectively. GOSs facilitated the growth of potential probiotic strains (Lactobacillus delbrueckii ssp. helveticus, Bifidobacterium bifidum, and Lactiplantibacillus plantarum) and liberated propionate and butyrate as principal short-chain fatty acids which established its prebiotic potency. Synbiotic combinations exhibited good antioxidant activities. Synbiotic combinations also exhibited antimicrobial activities against pathogenic microorganisms namely Staphylococcus aureus and Escherichia coli. Synbiotic combinations of GOSs and the respective probiotic microorganisms were able to decrease viable human bone cancer cells (MG-63).

Whey Derivatives and Galactooligosaccharides Stimulate the Wound Healing and the Function of Human Keratinocytes through the NF-kB and FOXO-1 Signaling Pathways.

Skin repair requires the activation of keratinocytes and is mediated by controlled inflammation and cell migration and proliferation, ending with the regeneration of well-differentiated cell layers. Whey derivatives contain galactooligosaccharides (GOS), which have potential beneficial effects on wound healing due to their activity as toll-like receptor ligands, although their direct nonprebiotic effects in the skin have not yet been described. In this study, we investigated the effects of different whey-derived products and purified GOS on a human keratinocyte cell line. We found that the inflammatory cytokine interleukin-8 (IL-8) was upregulated by nuclear factor kappa B (NF-kB) signaling triggered by whey derivatives and GOS and that wound healing was accelerated by promoting cell migration and the loss of E-cadherin in the absence of epithelial–mesenchymal transition. Interestingly, the treatments enhanced the mitochondrial function in association with the translocation of the Forkhead Box O1 (FOXO-1) transcription factor. Finally, we detected the increased expression of the differentiation markers induced by GOS and whey derivatives. All together, our results show that GOS-containing products can promote wound closure and skin health by direct activity on keratinocyte functions. Among the preparations tested, the fermented compound produced by autochthonous microorganisms was the most active in modulating keratinocyte activity, supporting the biological value of whey derivatives for health.

Lactobacillus plantarum Combined with Galactooligosaccharides Supplement: A Neuroprotective Regimen Against Neurodegeneration and Memory Impairment by Regulating Short-Chain Fatty Acids and the c-Jun N-Terminal Kinase Signaling Pathway in Mice.

Probiotics and prebiotics have received attention in alleviating neurodegenerative diseases. Lactobacillus plantarum (L. plantarum) 69-2 was combined with galactooligosaccharides (GOS) and supplemented in a d-galactose (d-gal)-induced neurodegeneration and memory impairment mice model to explore its effects on the brain and the regulation of short-chain fatty acids. The results showed that the L. plantarum-GOS supplementation inhibited d-gal-induced oxidative stress and increased the brain's nuclear factor erythroid 2-related factor 2 (Nrf2) levels. Butyrate, a metabolite of the gut microbiota regulated by L. plantarum combined with GOS, inhibits p-JNK expression, downregulates pro-apoptotic proteins expression and the activation of inflammatory mediators, and upregulates synaptic protein expression. This might be a potential mechanism for L. plantarum 69-2 combined with GOS supplementation to alleviate d-gal-induced neurodegeneration and memory impairment. This study sheds new light on the development of aging-related neuroprotective dietary supplements based on the gut-brain axis.

Reusability of immobilized β-glucosidase on sodium alginate-coated magnetic nanoparticles and high productivity applications

The purpose of this study is to detect the impact of the covalent immobilization of β-glucosidase (β-Glu) from Thermatoga maritima on sodium alginate-based magnetically recyclable iron nanoparticles (SA-Fe3O4 MNPs) for boosting robustness, facile retrieval, and recycling of enzyme. We developed a novel green method to amend the transformation of lactose to galacto-oligosaccharides (GOS). The interaction of the Immobilized β-Glu and SA-Fe3O4 MNPs were characterized by SDS-PAGE, Transmission electron microscope (TEM) and FT-IR spectroscopy. After immobilization, the ideal pH maintained 7.0, the optimum temperature (temp.) increased to 85 °C and deceptive Km and Vmax raised by 65 and 41%, respectively. Immobilization provided low activation energy and enhanced pH and heat stability. The SA-Fe3O4 MNPs maintained the effectiveness of enzyme by 39.52% up to the 6th cycle of reuse and the hydrolysis power exceed 28.13% of lactose to GOS. Conclusively, thermal stability, improved pH, and excellent reusability over β-Glu make SA-Fe3O4 MNPs a viable option for long-term GOS production as well as other industrial uses.

Recent Advances in the Production, Analysis, and Application of Galacto-Oligosaccharides

Galacto-oligosaccharides (GOS) are the prebiotic constituents with various functional qualities that promote the optimal proliferation of gut microbiota and are consequently beneficial to human health. GOS are not absorbed by humans and animals, but they play numerous health-related positive roles in the human body. Currently, their production has occupied much attention due to the increasing demand for functional foods. It could be produced by enzymatic and chemical approaches. Many microbial enzymes have been utilized for GOS production but the main source of these enzymes is lactose. Moreover, characterization of GOS structures is also a necessary and critical effort for understanding their mechanism of action. Hence, this review is written to understand the extensive but related features for the synthesis of GOS which includes: the enzymatic production of GOS through various enzymes and the types of enzymes such as free, immobilized, recombinant, crude, and purified enzymes that are involved in their synthesis, the techniques used in the purification of GOS, the analysis and quantification of GOS through various practices, and the functional properties of GOS are also discussed in this review. It also aims to combine new findings with current information in order to improve understanding of GOS formation and other factors related to its functionality.

Prebiotics, Probiotics, and Postbiotics in the Prevention and Treatment of Anemia.

Iron deficiency anemia (IDA) is very common and affects approximately 1/3 of the world’s human population. There are strong research data that some probiotics, such as Lactobacillus acidophilus and Bifidobacterium longum improve iron absorption and influence the course of anemia. Furthermore, prebiotics, including galactooligosaccharides (GOS) and fructooligosaccharides (FOS), increase iron bioavailability and decrease its destructive effect on the intestinal microbiota. In addition, multiple postbiotics, which are probiotic metabolites, including vitamins, short-chain fatty acids (SCFA), and tryptophan, are involved in the regulation of intestinal absorption and may influence iron status in humans. This review presents the actual data from research studies on the influence of probiotics, prebiotics, and postbiotics on the prevention and therapy of IDA and the latest findings regarding their mechanisms of action. A comparison of the latest research data and theories regarding the role of pre-, post-, and probiotics and the mechanism of their action in anemias is also presented and discussed.

Effects of Fermented Milk Containing Bifidobacterium animalis Subsp. lactis MN-Gup (MN-Gup) and MN-Gup-Based Synbiotics on Obesity Induced by High Fat Diet in Rats.

Given the probiotic effects previously found in Bifidobacterium animalis subsp. lactis MN-Gup (MN-Gup) and its great application potential in dairy products, this study aimed to investigate the effects of fermented milk containing MN-Gup or MN-Gup-based synbiotics on high fat diet (HFD)-induced obesity in rats. Galacto-oligosaccharides (GOS) and xylo-oligosaccharides (XOS) were selected as the tested prebiotics in MN-Gup-based synbiotics due to their promotion of MN-Gup growth in vitro. After nine weeks of HFD feeding, the obese rats were intervened with fermented milk containing MN-Gup (MN-Gup FM) or its synbiotics (MN-Gup + GOS FM, MN-Gup + XOS FM) for eight weeks. The results showed that the interventions could alleviate HFD-induced body weight gain, epididymal fat deposition, adipocyte hypertrophy, dyslipidemia and inflammation, but GOS and XOS did not exhibit significant synergies with MN-Gup on those alleviations. Furthermore, the interventions could regulate the HFD-affected gut microbiota and microbial metabolites, as shown by the increases in short chain fatty acids (SCFAs) and alterations in obesity-related bile acids (BAs), which may play important roles in the mechanism underlying the alleviation of obesity. This study revealed the probiotic effects of MN-Gup on alleviating obesity and provided the basis for MN-Gup applications in the future.

Preliminary Evaluation of Potential Properties of Three Probiotics and Their Combination with Prebiotics on GLP-1 Secretion and Type 2 Diabetes Alleviation

Type 2 diabetes (T2D) is a disease of global concern characterized by hyperglycemia and insulin resistance. Many studies found that glucagonlike peptide-1 (GLP-1) is an incretin hormone that can alleviate hyperglycemia and T2D. Recently, probiotics and their combination with prebiotics have been found to show great potentials of blood glucose regulation and T2D alleviation. Given the important role of GLP-1 in T2D, screening probiotics with the capacity of promoting GLP-1 secretion is of great help for providing a novel application of T2D treatment. In the current study, we evaluated the effects of three probiotics, namely, Lactobacillus paracasei LC-37 (LC-37), Bifidobacterium animals MN-Gup (MN-Gup), and Bifidobacterium longum BBMN68 (BBMN68), and their combination with prebiotics on promoting GLP-1 secretion using NCI-H716 cells. The results showed that LC-37 and MN-Gup could stimulate more GLP-1 secretion in NCI-H716 cells, but BBMN68 had no significant effect. Further evaluation suggested that the two combinations of LC-37 with isomaltooligosaccharide (IMO) and MN-Gup with galactooligosaccharide (GOS) had the best performance on promoting GLP-1 secretion in vitro. Subsequently, the effects of the two combinations on promoting GLP-1 secretion and alleviating T2D were investigated in vivo using high fat diet (HFD) and streptozotocin (STZ) treated rats. The results showed that the two combinations could significantly reduce fasting blood glucose levels, improve insulin resistance, and modulate serum lipid profiles in HFD/STZ-treated rats. These results will help understand the potential of promoting GLP-1 secretion of LC-37 and MN-Gup and provide theoretical basis for their applications in fermented milk or other foods.

Sodium alginate and galactooligosaccharides ameliorate metabolic disorders and alter the composition of the gut microbiota in mice with high-fat diet-induced obesity

We aimed to investigate the effects of sodium alginate (SA) and galactooligosaccharides (GOS) on the metabolism and gut microbiota of high-fat diet (HFD)-fed obese mice. GOS and SA delayed high-fat diet-induced obesity, reduced the epididymal fat and liver indices, and improved the circulating lipid profile. Low- and high-dose GOS reduced weight gain by 48.8 % and 35.3 %, and low- and high-dose SA reduced it by 37.7 % and 34.4 %, respectively. GOS and SA reduced blood glucose concentration, probably by increasing the expression of glucose transporter 4. GOS and SA increased the expression of tight junction proteins (ZO-1 and occludin), reduced the D-lactic acid (D-LA) and lipopolysaccharide concentrations, and reduced the expression of toll-like receptors, consistent with improved intestinal barrier function. GOS and SA also increased the abundance of Bacteroidota, Bifidobacterium, and Lactobacillus; and reduced that of Patescibacteria in the gut. The abundance of Parabacteroides positively correlated with the circulating low-density lipoprotein-cholesterol (LDL-C) concentration; that of Lactobacillus negatively correlated with LDL-C, D-LA, and tumor necrosis factor-α concentration; and that of Bifidobacterium positively correlated with high-density lipoprotein-cholesterol concentration, according to Spearman correlation analysis. In conclusion, SA and GOS ameliorate obesity and the associated metabolic disorders in mice, and also modulate their gut microbial composition.

The Effect of Nutritional Intervention with Lactoferrin, Galactooligosacharides and Vitamin D on the Gut Microbiota Composition of Healthy Elderly Women.

Background: Nutritional supplements, such as bovine lactoferrin (bLF), have been studied for their immunomodulatory properties, but little is known of their effect on the gut microbiota composition of the elderly when supplemented alone or combined with other nutritional supplements such as prebiotics and micronutrients. In the present study, fecal samples from a double-blind, placebo-controlled nutritional intervention study were analysed. At baseline (T1), 25 elderly women were distributed into two groups receiving dietary intervention (n = 12) or placebo treatment (n = 13) for 9 weeks. During the first 3 weeks of the study (T2), the intervention group consumed 1 g/day bLF, followed by 3 weeks (T3) of 1 g/day bLF and 2.64 g/day active galactooligosaccharides (GOS), and 3 weeks (T4) of 1 g/day bLF, 2.64 g/day GOS and 20 μg/day of vitamin D. The placebo group received maltodextrin, in dosages matching those of the intervention group. Fecal bacterial composition was profiled using partial 16S rRNA gene amplicon sequencing. Short-chain fatty acids (SCFA) were determined in fecal water as were levels of calprotectin, zonulin, and alpha-1-antitrypsin, as markers of gastrointestinal barrier and inflammation. Results: A significant increase was observed in the relative abundance of the genus Holdemanella (p < 0.01) in the intervention group compared to the placebo at T1. During T2, Bifidobacterium relative abundance increased significantly (p < 0.01) in the intervention group compared to the placebo, and remained significantly higher until the end of the study. No other effect was reported during T3. Furthermore, concentrations of SCFAs and calprotectin, zonulin and alpha-1-antitrypsin did not change during the intervention, although zonulin levels increased significantly within the placebo group by the end of the intervention. Conclusions: We conclude that supplementation of bLF enhanced the relative abundance of Holdemanella in the fecal microbiota of healthy elderly women, and further addition of GOS enhanced the relative abundance of Bifidobacterium.

Effects of Galacto-Oligosaccharides Supplementation on Gut Comfort and Fecal Microbiota in Female Adults With Gut Complaints

ObjectivesThe prevalence of gastrointestinal (GI) discomfort is widespread and quality of life is strongly linked to a well-functioning GI tract. Over the years, many (dietary) solutions have been developed but the prevalence remains high. Prebiotic galacto-oligosaccharides (GOS) have been shown to support gut health in various target groups. Therefore, the objective of this study was to investigate the effect of 21 days consumption of 5.5g GOS on gut comfort in women (25–45 years old) with self-reported gut comfort complaints in a double blind randomized placebo controlled trial.MethodsHealthy Dutch women (n = 65) with a self-reported gut comfort component score (consisting of bloating, flatulence, stomach ache, constipation, and diarrhea, range: 0–15) of at least 6 were enrolled. For three weeks, participants received a daily powder with either 5.5g BiotisTM GOS or maltodextrin to be taken during the first meal of the day. Weekly, validated questionnaires were conducted to study the effect on gut comfort score, sleep, stress, and product tolerance. Furthermore, at start and after the intervention, stool samples were taken to study faecal microbiota.ResultsThis study demonstrates that on group average the daily consumption of 5.5g GOS as well as maltodextrin, for 3 weeks in healthy females (average age: 34 yrs) with self-reported gut comfort complaints, improved the gut comfort component score. No differences were found between the two interventions, which indicates that a large placebo-effect was in place. However, the consumption of GOS did result in a 3 times higher odds to improve the gut comfort component score after three weeks. Daily consumption of 5.5g GOS resulted in a shift in the overall microbiota composition, with a clear 85% increase of faecal Bifidobacterium, which was not observed for the control group. Finally, posthoc analysis showed that GOS tends to decrease flatulence and to improve quality of sleep at 21 days of consumption.ConclusionsDaily consumption of 5.5g GOS for 21 days among adult women 25–45 years with non-medical diagnosed gut complaints improved the gut comfort component score, but was not different from the control. However, consumption of GOS resulted in a higher odds to improve this score. Furthermore, the daily intake of 5.5g GOS significantly increased fecal Bifidobacterium.Funding SourcesFrieslandCampina, The Netherlands.

Determination of FODMAP Contents of Traditional Indian Regional Recipes

ObjectivesFermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAPs) are a large class of small non-digestible carbohydrates which are poorly absorbed in the small bowel. There is insufficient data on the FODMAP content of Indian foods which is a major barrier in the implementation of the low FODMAP diets to manage irritable bowel disease (IBS) in the Indian population. The objective of this study was to determine the FODMAP contents of commonly consumed traditional recipes from different regions of India.MethodsA database of selected recipes, was curated based on the information gathered from a 24 hour diet recall that was conducted among participants (n = 35) belonging to the different regions (north, south, west and east) of the country, and official websites of the state tourism departments. The popular websites of traditional regional recipe chefs were referred to create an exhaustive list of ingredients and methods of preparation of the selected regional recipes.. This was followed by determination of the FODMAP content, including the total FODMAP content, total lactose, excess fructose, mannitol, sorbitol, GOS (Galactooligosaccharide), fructan, total oligosaccharides content using the Monash Online FODMAP Calculator.ResultsThe FODMAP contents of n = 269 commonly consumed regional Indian recipes were analyzed. Among these recipes, 73.2% (n = 197) and 26.8% (n = 72) were observed to be high, and low in FODMAP content respectively. The major FODMAP group present in the average Indian diet was found to be oligosaccharides i.e fructans and GOS, followed by lactose. Wheat, onion, garlic, pulses and legumes were the major ingredients contributing to the high FODMAP content.ConclusionsTo our knowledge, this is the first study to document the detailed FODMAP content of 269 traditional Indian recipes along with their classification into low and high.This recipe database will form a basis for creating low FODMAP diet plans and can further be used in future dietary intervention research studies in Indian population.Funding SourcesNone.

556-P: The Relationship between Short-Chain Fermentable Carbohydrates (FODMAPs) , Gut Microbiome, and Glucose Intolerance: An Exploratory Analysis

Fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) are fermentable short-chain carbohydrates that include fructans, galactooligosaccharides (GOS) , lactose, excess fructose, mannitol and sorbitol. Low FODMAP diets in irritable bowel syndrome were associated with reductions in metabolically beneficial, short-chain fatty acids (SCFA) - producing bacteria. We examined the interactions between FODMAP, gut microbiota and glucose tolerance in this exploratory analysis. Twenty subjects underwent oral glucose tolerance tests (OGTT) with C peptide measurements. Ten were classified as normal glucose tolerant (mean ±SD 55±years, body mass index (BMI) 22.7­±2.5 kg/m2, 2-hour plasma glucose 5.7±1.0 mmol/L) and with impaired glucose tolerance (58±­5 years, BMI 23.5±2.9 kg/m2, 2-hour glucose 9.0±0.9 mmol/L) . FODMAPs and macronutrients were assessed from 3-day food diaries. Fecal samples were collected for microbiome analysis. Total FODMAPs were positively correlated to presence of Dorea (r=0.49, p=0.027) . For individual FODMAP items, lactose was positively correlated with Akkermansia (r=0.54, p=0.013) , Bifidobacterium (r=0.42, p=0.037) and negatively correlated with Shigella (r=0.35, p=0.031) in both groups. GOS were positively correlated with Lactobacillus (r= 0.21, p=0.006) and negatively with Shigella (r=0.28, p=0.043) . In the whole group, lower insulin resistance as shown by homeostasis model assessment HOMA2-IR was associated with higher abundance of Bifidobacterium logum (r=0.48, p=0.01) . HOMA2-beta showed correlation with Dorea (r=0.43, p=0.056) . FODMAPs increased the health-promoting microbiota (e.g. Dorea, Lactobacillus, Akkermansia, and Bifidobacterium) . These SCFA promoting microbiota were associated with lower insulin resistance and improved beta-cell function while suppressing the growth of opportunistic pathogens, such as Escherichia spp. Disclosure N. Chu: None. J. He: None. R.C. Ma: Research Support; AstraZeneca, Bayer AG, Novo Nordisk A/S, Pfizer Inc., Tricida, Inc. Other Relationship; Bayer AG, Boehringer Ingelheim International GmbH. A.P. Kong: Advisory Panel; Abbott, Kyowa Kirin Co., Ltd. Research Support; Boehringer Ingelheim. Speaker's Bureau; AstraZeneca, Bayer, Eli Lilly and Company, Sanofi. Stock/Shareholder; Aptorum Group Limited. Other Relationship; AstraZeneca, Novo Nordisk. J.C. Chan: Board Member; Asia Diabetes Foundation. Consultant; Bayer AG, Boehringer Ingelheim International GmbH, Celltrion, Merck Sharp &amp; Dohme Corp., Roche Diabetes Care, Viatris Inc. Research Support; Applied Therapeutics, AstraZeneca, Eli Lilly and Company, Hua Medicine, Servier Laboratories. Stock/Shareholder; GemVCare Ltd. E. Chow: Research Support; Hua Medicine, Medtronic, Powder Pharmaceuticals Inc. Speaker's Bureau; Novartis AG, Sanofi. Funding Health Medical Research Fund (17180431) Hong Kong College of Physicians Young Investigator's Research Grant

Effect of process parameters on the β-galactosidase hydrolysis of lactose and galactooligosaccharide formation in concentrated skim milk

The study aimed at evaluation of β-galactosidase activity for lactose hydrolysis (DH) and galactooligosaccharide (GOS) formation at 7 °C. β-galactosidase derived from K. lactis was more effective than B. lichenformis for DH and GOS formation in 16% lactose solution. β-galactosidase from K. lactis exhibited 96.61% DH and 7.28% GOS production after 12 h of reaction and hence was utilized for lactose hydrolysis in concentrated skim milk (40% total solids). Use of 9.53 U/mL enzyme resulted in significantly high DH (97.06%) after 12 h with 4.90 g/L of residual lactose. However, maximum GOS formation of 12.01% with 94.74% DH was obtained after 4 h. Further increase in reaction time up to 12 h resulted in breakdown of tri and tetrasaccharide GOS, thereby, reducing GOS content. Hence, reaction time of 12 h was finalized to obtain maximum DH along with additional benefit of GOS formation.

A Prebiotic Diet Alters the Fecal Microbiome and Improves Sleep in Response to Sleep Disruption in Rats.

Sleep disruption is a challenging and exceedingly common physiological state that contributes to a wide range of biochemical and molecular perturbations and has been linked to numerous adverse health outcomes. Modern society exerts significant pressure on the sleep/wake cycle via myriad factors, including exposure to electric light, psychological stressors, technological interconnection, jet travel, shift work, and widespread use of sleep-affecting compounds. Interestingly, recent research has identified a link between the microbiome and the regulation of sleep, suggesting that interventions targeting the microbiome may offer unique therapeutic approaches to challenges posed by sleep disruption. In this study, we test the hypothesis that administration of a prebiotic diet containing galactooligosaccharides (GOS) and polydextrose (PDX) in adult male rats improves sleep in response to repeated sleep disruption and during recovery sleep. We found that animals fed the GOS/PDX prebiotic diet for 4 weeks exhibit increased non-rapid eye movement (NREM) and rapid eye movement (REM) sleep during 5 days of sleep disruption and increased total sleep time during 24 h of recovery from sleep disruption compared to animals fed a control diet, despite similar baseline sleep characteristics. Further, the GOS/PDX prebiotic diet led to significant changes in the fecal microbiome. Consistent with previous reports, the prebiotic diet increased the relative abundance of the species Parabacteroides distasonis, which positively correlated with sleep parameters during recovery sleep. Taken together, these findings suggest that the GOS/PDX prebiotic diet may offer an approach to improve resilience to the physiologic challenge of sleep disruption, in part through impacts on the microbiome.

Performance and meat quality traits of slow-growing chickens stimulated in ovo with galactooligosaccharides and exposed to heat stress

In vivo performance, carcass and meat quality traits of slow-growing chickens stimulated in ovo with trans galactooligosaccharides (GOS) and exposed to heat stress were evaluated. On d 12 of egg incubation, 3,000 fertilized eggs (Hubbard JA57) were divided into prebiotic group (GOS) injected with 3.5 mg GOS/egg, saline group (S) injected with physiological saline (only to assess the hatchability rate) and an uninjected control group (C). After hatching, 600 male chicks (300 from GOS and 300 from C) were housed on floor pens (6 pens/treatment, 25 birds/pen) and reared under neutral (TN) or heat stress conditions (HS, 30°C from 36 to 50 d). BW, daily feed intake (DFI), daily weight gain (DWG), feed conversion rate (FCR), and mortality were measured. At 50 d of age, 15 randomly selected birds/treatment/environmental conditions were slaughtered and the pectoral muscle (PM) was collected for analyses. Hatchability was similar among groups. BW of the newly hatched chicks was lower (P < 0.01) in GOS compared to C. Final BW, DWG, DFI, and FCR were not affected (P > 0.05) by GOS. HS reduced final BW (−12.93%, P < 0.001). During finisher phase, DFI and DWG were lower (P < 0.001) and FCR was higher (P < 0.01) in HS compared to TN. Mortality was not affected (P > 0.05) by GOS and HS. Meat from GOS chickens had a higher (P < 0.01) pH and was darker (P < 0.05) compared to C. Proximate composition, cholesterol content, fatty acid profile, and intramuscular collagen properties of PM were not affected by GOS. The HS group showed a lower (P < 0.05) content of both collagen and monounsaturated fatty acids than TN group. Significant interactions between GOS and temperature were found for FA composition. In conclusion, the differences in performance have had an impact on the responses to HS in Hubbard chickens, but not on mortality rate. GOS did not relieve the negative effect of HS on chickens’ performance.

Prebiotic effect of galacto-oligosaccharides on the skin microbiota and determination of their diffusion properties.

Recently, prebiotics are attracting plenty of attention in the field of skin care, since it is found that they are able to support the balance of beneficial and harmful microorganisms on the skin, and accordingly prevent several skin conditions associated with microbial imbalance. Topical application of prebiotics, although insufficiently investigated, holds great promise in improving skin health. The purpose of this research was to determine the prebiotic potential of galacto-oligosaccharides (GOS) for skin microbiota and suitability for incorporation in different topical formulations, and finally, provide insights into their diffusion properties. The prebiotic effect of GOS was evaluated through the influence on the growth of Staphylococcus epidermidis and Staphylococcus aureus, the most common resident and pathogenic bacterium of the skin microbiota, respectively. Also, with the future use of GOS in cosmetic products in mind, the diffusion of GOS molecules from two different topical formulations, hydrogel and oil-in-water (O/W) gel emulsion, was monitored employing Franz diffusion cell and two systems-with cellulose acetate membrane and transdermal diffusion test model, Strat-M® membrane. Course of fermentation and the amount of diffused GOS molecules were monitored using high-performance liquid chromatography (HPLC). The in vitro results revealed that GOS at a concentration of 5% (w/v) has a pronounced stimulatory effect on S.epidermidis, while simultaneously showing an inhibitory effect on S.aureus, both in nutrient broth and cosmetic formulations. GOS trisaccharide and tetrasaccharide diffusion coefficients from O/W gel emulsion were calculated to be 5.61·10-6 cm2 s-1 and 1.41·10-8 cm2 s-1 , respectively. The diffusion coefficient of GOS trisaccharides from hydrogel was 3.22·10-6 cm2 s-1 , while it was not determined for tetrasaccharides due to low diffused concentration. Transdermal diffusion tests revealed that GOS incorporated in two formulations stays at the surface of the skin even after 24h. When applied in adequate concentration, GOS has the potential to be used as a skin prebiotic. Novel GOS enriched formulations, Aristoflex® AVC-based hydrogel and Heliogel™-based O/W gel emulsion, provided efficient diffusion and delivery of prebiotic GOS molecules to the skin surface.

Supplementation with galacto-oligosaccharides in early life persistently facilitates the microbial colonization of the rumen and promotes growth of preweaning Holstein dairy calves.

We aimed to determine the effects of dietary supplementation with galacto-oligosaccharides (GOS) on the growth performance, serum parameters, and the rumen microbial colonization and fermentation of pre-weaning dairy calves. The study comprised 2 phases of 28 and 42 d, respectively. During phase 1, 24 newborn female Holstein dairy calves were randomly allocated to consume a diet supplemented with 10 g/d GOS (GOS, n = 12) or not (CON, n = 12). Thereafter, during phase 2, the GOS group was further divided into 2 groups: one that continued to consume GOS (GOSC, n = 6) and one that no longer consumed GOS (GOSS, n = 6), alongside the CON group. Galacto-oligosaccharides increased the average daily gain (ADG), body weight, feed efficiency, and serum high-density lipoprotein-cholesterol concentration of dairy calves during phase 1 (P < 0.05). Supplementation with GOS for the entire study reduced the incidence of diarrhea and increased the serum total protein and Ca concentrations (P < 0.05) compared with the CON group. The effect of GOS supplementation persisted after it was stopped because the ADG and final body weight of the GOSS group were higher than those of the CON group (P < 0.05). Furthermore, the GOSS group showed a persistently lower incidence of diarrhea and greater colonization of the rumen with probiotics, at the expense of less beneficial bacteria, which would promote ruminal fermentation and microbial protein synthesis. These findings provide a theoretical basis for the rational application of prebiotics and have important practical implications for the design of early life dietary interventions in dairy calf rearing.

Profile diversity of galacto-oligosaccharides from disaccharides to hexasaccharides by porous graphitic carbon liquid chromatography-orbitrap tandem mass spectrometry

Galacto-oligosaccharides (GOS) are important prebiotic supplements for commercial nutraceutical food. The prebiotic efficacy of functional GOS is dependent on their chemical profile. Screening potential markers aids specifications and quality control of GOS materials. However, profiling analysis of GOS with a degree of polymerization (DP) ≥ 4 is still challenging. This study presents a porous graphitic carbon liquid chromatography-orbitrap tandem mass spectrometry-based method that characterized 58 linear and 10 branched GOS and detected 59 non-reducing GOS from DP2 to DP6. The results indicated that 15 major group components with DP2-DP5 accounted for more than 65% of total GOS content in GOS samples, while non-reducing GOS components accounted for only 2.8–7.6%. Substantial variations in components occurred in samples from different batches and sources. Structural and constitutive diversity were dominated by DP3-DP5. This method can help control the quality of GOS products and be used to investigate the structural and prebiotic-efficacy relationships.

Molecular dynamics simulation guided distal mutation of Thermotoga naphthophila β-glucosidase for significantly enhanced synthesis of galactooligosaccharides and expanded product scope

For efficient enzymatic production of health-beneficial galactooligosaccharides (GOSs), a glycone (−1)/aglycone (+2) subsite mutation strategy to engineer a thermophilic GH1 β-glucosidase (Tn0602) from Thermotoga naphthophila RKU-10 was introduced. Six single mutation variants (F226G, N246G, N246E, N222F, N222Y, G224T) and two double mutants (F226GF414S, F226GF414Y) were designed. The +2-subsite variant F226G produced 136 mM galactooligosaccharide 1.2-fold more than the wild type (115 mM). More significantly, a superimposed mutation of the −1/+2 subsites F226G/F414S gave a total GOS production of 314 mM (82.16% lactose conversion), 2.7-fold higher than the total GOS production of the wild type. Furthermore, the variant F226GF414S was profiled 241 mM of trisaccharide (galβ (1 → 3)/(1 → 4) lactose) and 73 mM tetrasaccharide (galβ (1 → 3)/(1 → 4) galβ (1 → 3)/(1 → 4) lactose). According to a 300-ns molecular dynamic simulation, the superimposed mutation increased GOS productivity and expanded the scope of products by changing the structural flexibility and reducing the steric hindrance of the substrate tunnel. Overall, our study successfully demonstrated that a − 1/+2 subsite mutagenesis method could be used in β-glucosidases Tn0602 to improve enzyme productivity and expand product scope, which could be a potential route to evolve retaining glycosidases towards the desired direction.