Metabolomic analysis of amino acid metabolism in colitic rats supplemented with lactosucrose

Serum biochemical parameters and amino acids metabolism are altered in piglets by early-weaning and proline and putrescine supplementations

The study was to investigate the effect of early-weaning stress and proline (Pro) and putrescine (Put) supplementations on serum biochemical parameters and amino acids (AA) metabolism in suckling and post-weaning pigs. Blood and small intestinal mucosa were harvested from suckling piglets at 1, 7, 14, and 21 d of age and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age, as well as from piglets received oral administration of Pro and Put from 1 to 14 d old. In suckling piglets, the serum glucose, albumin and total cholesterol levels were increased (P < 0.05) with increasing age, whereas the serum globulin, urea nitrogen (BUN), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) levels were lowered (P < 0.05). The concentrations of most serum AA and the AA transporters related gene expressions were highest in 7-d-old piglets (P < 0.05), whereas the phosphorylation status of the mammalian target of the rapamycin (mTOR) signaling pathway in the small intestine increased in piglets from 1 to 21 d old (P < 0.05). Weaning at 14 d old increased (P < 0.05) the BUN and triglycerides levels in serum, as well as jejunal solute carrier family 7 member 6 (SLC7A6), ileal SLC36A1 and SLC1A1 mRNA abundances at d 1 or 3 post-weaning. Weaning also inhibited (P < 0.05) the phosphorylation levels of mTOR and its downstream ribosomal protein S6 kinase 1 (S6K1) and 4E-binding protein-1 (4EBP1) in the small intestine of weanling pigs. Oral administration of Put and Pro decreased (P < 0.05) serum ALP levels and increased (P < 0.05) intestinal SLC36A1 and SLC1A1 mRNA abundances and mTOR pathway phosphorylation levels in post-weaning pigs. Pro but not Put treatment enhanced (P < 0.05) serum Pro, arginine (Arg) and glutamine (Gln) concentrations of weaning-pigs. These findings indicated that early-weaning dramatically altered the biochemical blood metabolites, AA profile and intestinal mTOR pathway activity, and Pro and Put supplementations improved the AA metabolism and transportation as well as activated the intestinal mTOR pathway in weanling-pigs. Our study has an important implication for the broad application of Pro and Put in the weaning transition of piglets.

Novel and emerging prebiotics: Advances and opportunities

Consumers are conscientiously changing their eating preferences toward healthier options, such as functional foods enriched with pre- and probiotics. Prebiotics are attractive bioactive compounds with multidimensional beneficial action on both human and animal health, namely on the gastrointestinal tract, cardiometabolism, bones or mental health. Conventionally, prebiotics are non-digestible carbohydrates which generally present favorable organoleptic properties, temperature and acidic stability, and are considered interesting food ingredients. However, according to the current definition of prebiotics, application categories other than food are accepted, as well as non-carbohydrate substrates and bioactivity at extra-intestinal sites. Regulatory issues are considered a major concern for prebiotics since a clear understanding and application of these compounds among the consumers, regulators, scientists, suppliers or manufacturers, health-care providers and standards or recommendation-setting organizations are of utmost importance. Prebiotics can be divided in several categories according to their development and regulatory status. Inulin, galactooligosaccharides, fructooligosaccharides and lactulose are generally classified as well established prebiotics. Xylooligosaccharides, isomaltooligosaccharides, chitooligosaccharides and lactosucrose are classified as "emerging" prebiotics, while raffinose, neoagaro-oligosaccharides and epilactose are "under development." Other substances, such as human milk oligosaccharides, polyphenols, polyunsaturated fatty acids, proteins, protein hydrolysates and peptides are considered "new candidates." This chapter will encompass actual information about the non-established prebiotics, mainly their physicochemical properties, market, legislation, biological activity and possible applications. Generally, there is a lack of clear demonstrations about the effective health benefits associated with all the non-established prebiotics. Overcoming this limitation will undoubtedly increase the demand for these compounds and their market size will follow the consumer's trend.

Effective production of lactosucrose using β-fructofuranosidase and glucose oxidase co-immobilized by sol-gel encapsulation

The production of lactosucrose is hampered by the costly use of β-fructofuranosidase, which shows poor stability and a low efficiency in transfructosylation activity. Immobilization could improve enzyme stability and realize the cyclic utilization at a reduced cost. In order to eliminate the by-product inhibition and improve the transfructosylation efficiency, β-fructofuranosidase and glucose oxidase were co-immobilized by sol-gel encapsulation and the subsequent production efficiency of lactosucrose was investigated. The as-prepared immobilized bi-enzymes retained 85.39% of their initial activity at an enzyme concentration of 1.47 mg/g·sol during immobilization and showed great operational stability (maintaining 78.5% of their initial activity) after 15 consecutive reuses. The yield of lactosucrose synthesized by immobilized bi-enzymes reached 160.8 g/L under the optimized conditions, which was relatively higher than previous reported results. Moreover, the yield of lactosucrose synthesized by immobilized bi-enzymes was significantly improved as compared to that synthesized by immobilized β-fructofuranosidase. HPLC and NMR spectrum results confirmed the presence of lactosucrose during immobilized bi-enzymes catalysis. Furthermore, a relatively high purity of lactosucrose was obtained (87.4% determined by HPLC) after separation with Diaion UBK535 calcium ester resin, and the optimal conditions for separation of lactosucrose were investigated. These results indicated that the co-immobilization of β-fructofuranosidase-glucose oxidase was helpful to improve the production of lactosucrose with low costs, which can be used in continuous lactosucrose production in food industry in advantages of high stability and reusability. And the as-prepared lactosucrose with high purity can be applied to many kinds of food as functional additives.

Based on the Metabolomic Approach the Energy Metabolism Responses of Oriental River Prawn Macrobrachium nipponense Hepatopancreas to Acute Hypoxia and Reoxygenation

Hypoxia represents a major physiological challenge for prawns and is a problem in aquaculture. Therefore, an understanding of the metabolic response mechanism of economically important prawn species to hypoxia and re-oxygenation is essential. However, little is known about the intrinsic mechanisms by which the oriental river prawn Macrobrachium nipponense copes with hypoxia at the metabolic level. In this study, we conducted gas chromatography-mass spectrometry-based metabolomics studies and assays of energy metabolism-related parameters to investigate the metabolic mechanisms in the hepatopancreas of M. nipponense in response to 2.0 O₂/L hypoxia for 6 and 24 h, and reoxygenation for 6 h following hypoxia for 24 h. Prawns under hypoxic stress displayed higher glycolysis-related enzyme activities and lower mRNA expression levels of aerobic respiratory enzymes than those in the normoxic control group, and those parameters returned to control levels in the reoxygenated group. Our results showed that hypoxia induced significant metabolomic alterations in the prawn hepatopancreas within 24 h. The main metabolic alterations were depletion of amino acids and 2-hydroxybutanoic acid and accumulation of lactate. Further, the findings indicated that hypoxia disturbed energy metabolism and induced antioxidant defense regulation in prawns. Surprisingly, recovery from hypoxia (i.e., reoxygenation) significantly affected 25 metabolites. Some amino acids (valine, leucine, isoleucine, lysine, glutamate, and methionine) were markedly decreased compared to the control group, suggesting that increased degradation of amino acids occurred to provide energy in prawns at reoxygenation conditions. This study describes the acute metabolomic alterations that occur in prawns in response to hypoxia and demonstrates the potential of the altered metabolites as biomarkers of hypoxia.

Effects of feeding frequency on meat quality traits and Longissimus muscle proteome in finishing pigs

Sixty-four barrows with an initial body weight of 59.8 ± 2.1 kg were allocated to one of the two feeding frequency regimes (had free access to diet and fed two meals per day). Pigs had free access (FA) to feed were fed on an ad libitum basis during the 8-week experimental period. Pigs fed twice daily (M2) were allowed to consume their meals in 2 h. Pigs fed twice daily had lower average daily feed intake (p < 0.01) and average daily gain (p < 0.1), but a greater G:F (p < 0.05) than FA pigs. Lower perirenal fat deposition, hot carcass weight, intramuscular fat content (p < 0.05) and dressing percentage (p < 0.1) were found in M2 pigs compared with FA pigs. Activities of citrate synthase, β-hydroxylacyl-CoA dehydrogenase and lactate dehydrogenase were greater in the Longissimus muscle (LM) of M2 pigs compared with FA pigs (p < 0.05). Proteomic analysis revealed that expression abundances of proteins involved in glucose metabolism, energy production and lipid utilization were upregulated, but expression levels of proteins participating in protein and amino acid metabolism, stress response and redox homeostasis were downregulated in the LM of M2 pigs than those in FA pigs (p < 0.05). In conclusion, the less meal frequency impairs growth rate, has marginal effects on carcass and meat quality traits and affects expression abundances of proteins in the LM of finishing pigs.

Chlorogenic acid ameliorates intestinal mitochondrial injury by increasing antioxidant effects and activity of respiratory complexes

Dietary polyphenols are thought to be beneficial for human health by acting as antioxidants. Chlorogenic acid (CGA) is abundant in plant-based foods as an ester of caffeic acid and quinic acid. In this study, we investigated the effects of CGA on mitochondrial protection. Our results demonstrated that pretreatment with CGA ameliorated the intestinal mitochondrial injury induced by H2O2; membrane potential was increased, mitochondrial swelling, levels of reactive oxygen species, contents of 8-hydroxy-2-deoxyguanosine, and cytochrome c released were decreased. The beneficial effects of CGA were accompanied by an increase in antioxidant and respiratory-chain complex I, IV, and V activities. In trinitrobenzene-sulfonic acid-induced colitic rats indicated that CGA supplementation improved mitochondria ultrastructure and decreased mitochondrial injury. Our results suggest a promising role for CGA as a mitochondria-targeted antioxidant in combating intestinal oxidative injury. Daily intake of diets containing CGA, such as coffee and honeysuckle, may be useful for prevention of intestinal diseases.

Efficient Biosynthesis of Lactosucrose from Sucrose and Lactose by the Purified Recombinant Levansucrase from Leuconostoc mesenteroides B-512 FMC

Lactosucrose, a rare trisaccharide formed from sucrose and lactose by enzymatic transglycosylation, is a type of indigestible carbohydrate with a good prebiotic effect. In this study, lactosucrose biosynthesis was efficiently carried out by a purified levansucrase from Leuconostoc mesenteroides B-512. The target gene was cloned and expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity by nickel affinity and gel filtration chromatography. The effects of pH, temperature, substrate concentration, substrate ratio, and enzyme amount on lactosucrose biosynthesis were studied in detail, and the optimized conditions were determined to be pH 6.5, 50 °C, 27% (W/V) sucrose, 27% (W/V) lactose, and 5 U mL(-1) of the purified recombinant enzyme. Under the optimized reaction conditions, the maximal lactosucrose yield reached 224 g L(-1) after reaction for 1 h. Therefore, L. mesenteroides levansucrase could be considered a potential candidate for future industrial production of lactosucrose.

Growth performance, serum biochemical profile, jejunal morphology, and the expression of nutrients transporter genes in deoxynivalenol (DON)- challenged growing pigs

BACKGROUND

Fusarium infection with concurrent production of deoxynivalenol (DON) causes an increasing safety concern with feed worldwide. This study was conducted to determine the effects of varying levels of DON in diets on growth performance, serum biochemical profile, jejunal morphology, and the differential expression of nutrients transporter genes in growing pigs.

RESULTS

A total of twenty-four 60-day-old healthy growing pigs (initial body weight = 16.3 ± 1.5 kg SE) were individually housed and randomly assigned to receive one of four diets containing 0, 3, 6 or 12 mg DON/kg feed for 21 days. Differences were observed between control and the 12 mg/kg DON treatment group with regards to average daily gain (ADG), although the value for average daily feed intake (ADFI) in the 3 mg/kg DON treatment group was slightly higher than that in control (P<0.01). The relative liver weight in the 12 mg/kg DON treatment group was significantly greater than that in the control (P<0.01), but there were no significant differences in other organs. With regard to serum biochemistry, the values of blood urea nitrogen (BUN), alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate amino transferase (AST) in the 3 treatment groups were higher than those in the control, and the serum concentrations of L-valine, glycine, L-serine, and L-glutamine were significantly reduced in the 3 treatment groups, especially in the 12 mg/kg DON group (P<0.01). Serum total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) were markedly decreased after exposure to DON contaminated feeds (P<0.01). The villi height was markedly decreased and the lymphocyte cell numbers markedly increased in the 3 DON contaminated feeds (P<0.01). The mRNA expression levels of excitatory amino acid transporter-3 (EAAC-3), sodium-glucose transporter-1 (SGLT-1), dipeptide transporter-1 (PepT-1), cationic amino acid transporter-1 (CAT-1) and y(+)L-type amino acid transporter-1 (LAT-1) in control were slightly or markedly higher than those in the 3 DON treatment groups.

CONCLUSIONS

These results showed that feeds containing DON cause a wide range of effects in a dose-dependent manner. Such effects includes weight loss, live injury and oxidation stress, and malabsorption of nutrients as a result of selective regulation of nutrient transporter genes such as EAAC-3, SGLT-1, PepT-1, CAT-1 and LAT-1.

A diet with lactosucrose supplementation ameliorates trinitrobenzene sulfonic acid-induced colitis in rats

Chronic intestinal inflammation contributes to an increased risk of colon cancer.

Metabolomics study of metabolic variations in enterotoxigenic Escherichia coli-infected piglets

This study aimed to explore the metabolic profiling in the serum of enterotoxigenic Escherichia coli (ETEC) infected piglets.

Lactosucrose attenuates intestinal inflammation by promoting Th2 cytokine production and enhancing CD86 expression in colitic rats

Some oligosaccharides have immunoregulatory and anti-inflammatory functions in the intestine. This study investigated the immunoregulatory effect of lactosucrose (LS) on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitic rats. Alkaline phosphatase activity was increased but myeloperoxidase activity was decreased in the LS-TNBS group, as compared with the TNBS group (colitis rats without receiving LS). LS supplementation stimulated IL-4 and IL-10 production, while up-regulating CD86 expression in dendritic cells. LS supplementation reduced the ratio of CD80/CD86 and the ratio of IFN-γ/IL-4 compared to the TNBS group. Moreover, IFN-γ was significantly correlated with CD80 (r = 0.764, p < 0.01), whereas IL-4 was significantly correlated with CD86 (r = 0.489, p < 0.05). These results indicated that LS attenuated colitis by promoting the production of Th2-type cytokines and rebalancing the ratio of Th1/Th2 and that enhanced IL-4 production is correlated with enhanced CD86 expression in the gut. Therefore, LS is a functional food for patients with inflammatory bowel disease.

Metabolomic analysis of amino acid and energy metabolism in rats supplemented with chlorogenic acid

This study was conducted to investigate effects of chlorogenic acid (CGA) supplementation on serum and hepatic metabolomes in rats. Rats received daily intragastric administration of either CGA (60 mg/kg body weight) or distilled water (control) for 4 weeks. Growth performance, serum biochemical profiles, and hepatic morphology were measured. Additionally, serum and liver tissue extracts were analyzed for metabolomes by high-resolution (1)H nuclear magnetic resonance-based metabolomics and multivariate statistics. CGA did not affect rat growth performance, serum biochemical profiles, or hepatic morphology. However, supplementation with CGA decreased serum concentrations of lactate, pyruvate, succinate, citrate, β-hydroxybutyrate and acetoacetate, while increasing serum concentrations of glycine and hepatic concentrations of glutathione. These results suggest that CGA supplementation results in perturbation of energy and amino acid metabolism in rats. We suggest that glycine and glutathione in serum may be useful biomarkers for biological properties of CGA on nitrogen metabolism in vivo.

Dietary arginine supplementation enhances intestinal expression of SLC7A7 and SLC7A1 and ameliorates growth depression in mycotoxin-challenged pigs

This study tested the hypothesis that dietary L-arginine supplementation confers beneficial effects on growing pigs fed a mold-contaminated diet. The measured variables included: (1) the average daily weight gain and feed:gain ratio; (2) activities of total superoxide dismutase, glutathione peroxidase, diamine oxidase, as well as amino acid and D-lactate concentrations in serum; (3) intestinal morphology; (4) expression of the genes for SLC7A7 (amino acid transporter light chain, y(+L) system, family 7, member 7), SLC7A1 (cationic amino acid transporter, y(+) system, family 7, member 1), SLC1A1 (neuronal/epithelial high affinity glutamate transporter, system XAG, member 1), SLC5A1 (sodium/glucose cotransporter, family 5, member 1) in the ileum and jejunum. Mycotoxins in feedstuffs resulted in an enlarged small intestine mass, oxidative injury in tissues, and reduced growth performance in pigs. Dietary arginine supplementation enhanced (P < 0.05) expression of jejunal SLC7A7 and ileal SLC7A1, in comparison with the control and mycotoxin groups. In addition, supplementing 1% L-arginine to the mycotoxin-contaminated feed had the following beneficial effects (P < 0.05): (1) alleviating the imbalance of the antioxidant system in the body; (2) ameliorating intestinal abnormalities; and (3) attenuating whole-body growth depression, compared with the mycotoxin group without arginine treatment. Collectively, these results indicate that dietary supplementation with L-arginine exerts a protective role in pigs fed mold-contaminated foods. The findings may have important nutritional implications for humans and other mammals.