Effects of galacto-oligosaccharides on growth and gut function of newborn suckling piglets

Background: Most research on galacto-oligosaccharides(GOS) has mainly focused on their prebiotic effects on the hindgut,but their beneficial effects on the small intestine(SI) have received little attention.Since jejunum is the important place to digest and absorb nutrients efficiently,optimal maturation of the jejunum is necessary for maintaining the high growth rate in the neonate.Therefore,this study investigates the effect of the early intervention with GOS on the intestinal development of the jejunum.Methods: A total of 6 litters of neonatal piglets(10 piglets per litter; Duroc × Landrace × Large White) with an average birth weight of 1.55 ± 0.05 kg received 1 of 2 treatments based on their assignment to either the control(CON) group or the GOS(GOS) group in each litter.Piglets in the GOS group were orally administrated 10 mL of a GOS solution(reaching 1 g GOS/kg body weight) per day from the age of 1 to 7 d; the piglets in the CON group were treated with the same dose of physiological saline.All piglets were weaned on d 21.On d 8 and 21 of the experimental trial,1 pig per group from each of the 6 litters was euthanized.Results: The early intervention with GOS increased the average daily gains in the third week(P < 0.05).Decreased crypt depth was also observed in the jejunum of the piglets on d 21(P < 0.05).The early intervention with GOS increased the jejunal lactase activity on d 8,maltase activity and sucrase activity on d 21(P < 0.05).In addition,the early intervention with GOS also facilitated the mRNA expression of Sodium glucose co-transporter 1(SGLT1) on d 8 and the m RNA expression of Glucose transporter type 2(GLUT2) on d 21(P < 0.05).It was further determined that GOS up-regulated the m RNA expression of preproglucagon(GCG),insulin-like growth factor 1(IGF-1),insulin-like growth factor 1 receptor(IGF-1 R) and epidermal growth factor(EGF).GOS also up-regulated the protein expression of glucagon-like peptide-2(GLP-2) and EGF in the jejunum of the piglets.Furthermore,it was also found that GOS enhanced the protein expression of ZO-1 and occludin on d 8(P < 0.05),as well as increased the mRNA expression of TGF-β and decrease the mRNA expression of IL-12(P < 0.05).Conclusions: These results indicate that GOS have a positive effect on piglet growth performance in addition to decreasing the crypt depth and enhancing functional development in jejunum of suckling piglets.

Galacto-oligosaccharides improve barrier function and relieve colonic inflammation via modulating mucosa-associated microbiota composition in lipopolysaccharides-challenged piglets

Background:Galacto-oligosaccharides(GOS)have been shown to modulate the intestinal microbiota of suckling piglets to exert beneficial effects on intestinal function.However,the modulation of intestinal microbiota and intestinal function by GOS in intestinal inflammation injury models has rarely been reported.In this study,we investigated the effects of GOS on the colonic mucosal microbiota composition,barrier function and inflammatory response of lipopolysaccharides(LPS)-challenged suckling piglets.Methods:A total of 18 newborn suckling piglets were divided into three groups,the CON group,the LPS-CON group and the LPS-GOS group.Piglets in the LPS-GOS group were orally fed with 1 g/kg body weight of GOS solution every day.On the d 14,piglets in the LPS-CON and LPS-GOS group were challenged intraperitoneally with LPS solution.All piglets were slaughtered 2 h after intraperitoneal injection and sampled.Results:We found that the colonic mucosa of LPS-challenged piglets was significantly injured and shedding,while the colonic mucosa of the LPS-GOS group piglets maintained its structure.Moreover,GOS significantly reduced the concentration of malondialdehyde(MDA)and the activity of reactive oxygen species(ROS)in the LPS-challenged suckling piglets,and significantly increased the activity of total antioxidant capacity(T-AOC).GOS significantly increased the relative abundance of norank_f_Muribaculaceae and Romboutsia,and significantly decreased the relative abundance of Alloprevotella,Campylobacter and Helicobacter in the colonic mucosa of LPS-challenged suckling piglets.In addition,GOS increased the concentrations of acetate,butyrate and total short chain fatty acids(SCFAs)in the colonic digesta of LPS-challenged suckling piglets.GOS significantly reduced the concentrations of interleukin 1β(IL-1β),interleukin 6(IL-6),tumor necrosis factor-α(TNF-α)and cluster of differentiation 14(CD14),and the relative mRNA expression of Toll-like receptor 4(TLR4)and myeloid differentiation primary response 88(MyD88)in the LPS-challenged suckling piglets.In addition,GOS significantly reduced the relative mRNA expression of mucin2(MUC2),and significantly increased the protein expression of Claudin-1 and zonula occluden-1(ZO-1)in LPS-challenged suckling piglets.Conclusions:These results suggested that GOS can modulate the colonic mucosa-associated microbiota composition and improve the intestinal function of LPS-challenged suckling piglets.

Early-life galacto-oligosaccharides supplementation alleviates the small intestinal oxidative stress and dysfunction of lipopolysaccharide-challenged suckling piglets

Background:Galacto-oligosaccharides(GOS)are non-digestible food ingredients that promote the growth of beneficial bacteria in the gut.This study investigated the protective effect of the early-life GOS supplement on the piglets’gut function against the oxidative stress induced by lipopolysaccharide(LPS)-challenge.Methods:Eighteen neonatal piglets were assigned to three groups including CON,LPS and LPS+GOS groups.The piglets in CON group and LPS group received physiological saline,while those in LPS+GOS group received GOS solution for 13 d after birth.On d 14,the piglets in LPS group and LPS+GOS group were injected with LPS solutions,while the piglets in CON group were injected with the same volume of physiological saline.Results:The results showed that the early-life GOS supplement blocked the LPS-induced reactive oxygen species(ROS)secretion,malondialdehyde(MDA)production and the increase of pro-apoptotic factor expression.Meanwhile,the early-life GOS supplement improved the activities of antioxidant enzymes,disaccharidase enzymes activities,and digestive enzymes activities,and increased the mRNA abundance of the gene related to nutrient digestion and absorption and the relative protein expression of tight junction.The study also showed that the early-life GOS supplement improved the expression of Hemeoxygenase-1(HO-1)and NAD(P)H/quinone acceptor oxidoreductase-1(NQO-1),and activated the AMP-activated protein kinase(AMPK).Conclusions:These results suggested that GOS enhanced the gut function,reduced the ROS production and proapoptotic factors gene expression,and activated the AMPK signaling pathway in LPS-challenged piglets.

Gene Cloning and Molecular Characterization of a β-Glucosidase from Thermotoga Naphthophila RUK-10：an Effective Tool for Synthesis of Galacto-oligosaccharide and Alkyl Galactopyranosides

A novel thermostable β-glucosidase（Tnap0602） with β-galactosidase activity was cloned from Thermotoga naphthophila RUK-10 and overexpressed in Escherichia coli BL21（DE3） with the aid of pET28b（＋） vector. The recombinant β-glucosidase was purified to homogeneity by heat precipitation and Ni^2＋-affinity chromatography. The molecular weight of the recombinant enzyme was estimated to be 51 kDa by SDS-PAGE analysis. The optimum temperature for the hydrolyses of p-nitrophenyl-β-D-glucopyranoside and o-nitrophenyl-β-D-galactopyranoside by the recombinant β-glucosidase were both above 95 ℃, and the corresponding optimum pH value was found to be the same as 7.0. Thermostability studies show that the half-lives of the recombinant enzyme at 75, 80, 85 and 90℃ are respectively 84, 32, 14, and 3 h, and it is quite stable in a pH range of 5.0-10.0. The Km and Vmax values of the recombinant β-glucosidase for the hydrolysis of pNPGlu at 80 ℃ are 0.127 mmol/L and 18389.1 μmol·min^1·mg^-1, the corresponding values are 0.625 mmol/L and 6250 μmol·min^1·mg^-1 for the hydrolysis of oNPGal, respectively, The enzyme also display the hydrolysis activity for lactose and cellobiose. Galacto-oligosaccharide and alkyl galactopyranosides could be synthesized from Tnap0602 when lactose was used as the transglycosylation substrate, indicating that the thermostable β-glucosidase could be a candidate for industrial application.

Supplementation of milk formula with galacto-oligosaccharides improves intestinal micro-flora and fermentation in term infants

Background Oligosaccharides in human milk may protect infants by improving the intestinal micro-flora and fermentation. This study was to investigate effects of infant formula milk consisting of galacto-oligosaccharide (GOS) on intestinal microbial populations and the fermentation characteristics in term infants in comparison with that of human milk. Methods The test formula (Frisolac H,Friesland,Netherland) was supplemented with GOS at a concentration of 0.24 g/dl. Human milk and another formula without oligosaccharides (Frisolac H,Friesland,Netherland) were used as positive and negative control respectively. Growth,stool characteristics,and side effects of the recruited infants were recorded after 3 and 6 months’ follow-up,and the fecal species were collected for the analysis of intestinal micro-flora,short chain fatty acid (SCFA) and pH.Results At the end of 3- and 6-month feeding period,intestinal Bifidobacteria and Lactobacilli were significantly increased in infants fed with GOS supplemented formula and human milk when compared with infants fed with negative control formula; however,there was no statistically significant difference between GOS supplemented formula and human milk groups. Stool characteristics were influenced by the supplement and main fecal SCFA (acetic),and stool frequency were significantly increased in infants fed with GOS supplemented formula and human milk,while the fecal pH was significantly decreased as compared with that of negative control ( P <0.05). Supplementation had no influence on incidence of side effects (including crying,regurgitation and vomiting). Conclusions Supplementing infant formula with GOS at a concentration of 0.24 g/dl stimulates the growth of Bifidobacteria and Lactobacilli in the intestine and stool characteristics are similar to in term infants fed with human milk.

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.

Suitability of n-alkanes and chromium(Ⅲ) oxide as digestibility markers in calves at the end of the milk feeding period supplemented with a prebiotic

Prebiotics reveal positive effects on the growth performance of pigs and poultry,and might influence intestinal microflora.This,in consequence,could alter recovery rates of digestibility markers.In the current study,we evaluated the suitability of chromium(III)oxide(Cr_2O_3)and the synthetic alkanes ndotriacontane(C32)and n-hexatriacontane(C36)as external markers for digestibility estimation compared with the standard total collection method in calves supplemented with galactooligosaccharides.Eight male German Holstein calves(average age±SD=57±8 days)were divided into 2 milk replacer feeding groups(group receiving galacto-oligosaccharides[A]and control group[B]).Each of 2 groups of 4 individually fed calves received a distinct milk replacer with added markers for 14days.They were fed twice daily restrictively with milk replacer,concentrate and hay.After an adaptation period of 10 days,total faeces were collected.Faecal marker recoveries(FMR,means±SD)for C32 were(72±14)% for A and (80±12)% for B.Faecal marker recoveries for C36 was(82±15)% and (88±13)% for groups A and B,respectively.The FMR for Cr_2O_3was(102±11)%and(100±1)%for groups A and B,respectively.There were no significant differences between total collection organic matter digestibility and marker based organic matter digestibility when using Cr_2O_3and C36.But,when utilizing C32 to calculate nutrient digestibilities,results differed from the total collection method for organic matter,crude protein and ether extract.The results indicate that Cr_2O_3and C36 can be applied in digestibility studies with calves and give accurate estimates for OM and nutrient digestibilities without correction for FMR.