Oligosaccharides are low molecular weight carbohydrates between monosaccharides and poly-saccharides,which consist of 2 to 20 monosaccharides linked by glycosidic bonds.They have the effects of promoting growth,regula...Oligosaccharides are low molecular weight carbohydrates between monosaccharides and poly-saccharides,which consist of 2 to 20 monosaccharides linked by glycosidic bonds.They have the effects of promoting growth,regulating immunity,improving the structure of intestinal flora,and are anti-inflammatory and antioxidant.With the comprehensive implementation of the antibiotic prohibition policy in China,oligosaccharides as new green feed additive have been paid more attention.Oligosac-charides can be divided into the following 2 categories according to their digestive characteristics:one is easy to be absorbed by the intestine,called common oligosaccharides,such as sucrose and maltose oligosaccharide;the other is difficult to be absorbed by the intestine and has special physiological functions,called functional oligosaccharides.The common functional oligosaccharides include mannan oligosaccharides(MOS),fructo-oligosaccharides(FOS),chitosan oligosaccharides(COS),xylo-oligosaccharides(XOS)and so on.In this paper,we review the types and sources of functional oligo-saccharides,their application in pig nutrition,and the factors limiting their efficacy in recent years.This review provides the theoretical basis for further research of functional oligosaccharides,and the future application of alternative antibiotics in pig industry.展开更多
High sucrose content in traditional hawthorn leathers limits the potential consumption, particularly for elders and diabetics. In this study, sucrose-free hawthorn leathers were formulated with 75% fructooligosacchari...High sucrose content in traditional hawthorn leathers limits the potential consumption, particularly for elders and diabetics. In this study, sucrose-free hawthorn leathers were formulated with 75% fructooligosaccharides(FOS) and 25% xylooligosaccharides(XOS)(HLF75), which exhibited comparable morphology and sensory properties to the traditional ones. Then, the anti-obesity activity of HLF75 was investigated using high-fat diet(HFD) fed C57BL/6J mice. Comparing with traditional hawthorn leathers, HLF75 supplementation in HFD significantly decreased the levels of blood glucose and serum lipid. The histomorphologies of liver and subcutaneous fat tissues were ameliorated by HLF75, as well as the down-regulated m RNA expression levels of IL-1β, Nos2 and Cox-2 in the liver. M oreover, the protein levels of M y D88 and NF-κB in the liver were suppressed by HLF75 treatment with decreased F4/80-positive macrophage number. Ho wever, the expression levels of PI3K, phosphorylated-AKT(Thr308), and phosphorylated-m TOR(Ser2448) proteins related to glucose metabolism were increased in the liver. Moreover, fat synthesis-related gene expression in HLF75-fed mice was suppressed while expressions of lipolysis genes were improved. Thus, HLF75 supplementation alleviated HFD-induced obesity through the alleviation of inflammation and restoration of the disturbed glucose and lipid metabolism. Functional oligosaccharides could be effective sucrose substitutes in hawthorn leathers and enable their potential utilization as functional foods.展开更多
Thermophilic endo-chitinases are essential for production of highly polymerized chitooligosaccharides,which are advantageous for plant immunity,animal nutrition and health.However,thermophilic endo-chitinases are scar...Thermophilic endo-chitinases are essential for production of highly polymerized chitooligosaccharides,which are advantageous for plant immunity,animal nutrition and health.However,thermophilic endo-chitinases are scarce and the transformation from exo-to endo-activity of chitinases is still a challenging problem.In this study,to enhance the endo-activity of the thermophilic chitinase Chi304,we proposed two approaches for rational design based on comprehensive structural and evolutionary analyses.Four effective single-point mutants were identified among 28 designed mutations.The ratio of(GlcNAc)3 to(GlcNAc)2 quantity(DP3/2)in the hydrolysates of the four single-point mutants undertaking colloidal chitin degradation were 1.89,1.65,1.24,and 1.38 times that of Chi304,respectively.When combining to double-point mutants,the DP3/2 proportions produced by F79A/W140R,F79A/M264L,F79A/W272R,and M264L/W272R were 2.06,1.67,1.82,and 1.86 times that of Chi304 and all four double-point mutants exhibited enhanced endo-activity.When applied to produce chitooligosaccharides(DP≥3),F79A/W140R accumulated the most(GlcNAc)4,while M264L/W272R was the best to produce(GlcNAc)3,which was 2.28 times that of Chi304.The two mutants had exposed shallower substrate-binding pockets and stronger binding abilities to shape the substrate.Overall,this research offers a practical approach to altering the cutting pattern of a chitinase to generate functional chitooligosaccharides.展开更多
基金supported by the Hunan Provincial Natural Science Foundation of China(2022JJ40176)the National Natural Science Foundation of China(32202692)the China Agriculture Research System of MOF and MARA,Earmarked Fund for China Agriculture Research System(CARS-35).
文摘Oligosaccharides are low molecular weight carbohydrates between monosaccharides and poly-saccharides,which consist of 2 to 20 monosaccharides linked by glycosidic bonds.They have the effects of promoting growth,regulating immunity,improving the structure of intestinal flora,and are anti-inflammatory and antioxidant.With the comprehensive implementation of the antibiotic prohibition policy in China,oligosaccharides as new green feed additive have been paid more attention.Oligosac-charides can be divided into the following 2 categories according to their digestive characteristics:one is easy to be absorbed by the intestine,called common oligosaccharides,such as sucrose and maltose oligosaccharide;the other is difficult to be absorbed by the intestine and has special physiological functions,called functional oligosaccharides.The common functional oligosaccharides include mannan oligosaccharides(MOS),fructo-oligosaccharides(FOS),chitosan oligosaccharides(COS),xylo-oligosaccharides(XOS)and so on.In this paper,we review the types and sources of functional oligo-saccharides,their application in pig nutrition,and the factors limiting their efficacy in recent years.This review provides the theoretical basis for further research of functional oligosaccharides,and the future application of alternative antibiotics in pig industry.
基金supported by the National Natural Science Foundation of China (31630096)。
文摘High sucrose content in traditional hawthorn leathers limits the potential consumption, particularly for elders and diabetics. In this study, sucrose-free hawthorn leathers were formulated with 75% fructooligosaccharides(FOS) and 25% xylooligosaccharides(XOS)(HLF75), which exhibited comparable morphology and sensory properties to the traditional ones. Then, the anti-obesity activity of HLF75 was investigated using high-fat diet(HFD) fed C57BL/6J mice. Comparing with traditional hawthorn leathers, HLF75 supplementation in HFD significantly decreased the levels of blood glucose and serum lipid. The histomorphologies of liver and subcutaneous fat tissues were ameliorated by HLF75, as well as the down-regulated m RNA expression levels of IL-1β, Nos2 and Cox-2 in the liver. M oreover, the protein levels of M y D88 and NF-κB in the liver were suppressed by HLF75 treatment with decreased F4/80-positive macrophage number. Ho wever, the expression levels of PI3K, phosphorylated-AKT(Thr308), and phosphorylated-m TOR(Ser2448) proteins related to glucose metabolism were increased in the liver. Moreover, fat synthesis-related gene expression in HLF75-fed mice was suppressed while expressions of lipolysis genes were improved. Thus, HLF75 supplementation alleviated HFD-induced obesity through the alleviation of inflammation and restoration of the disturbed glucose and lipid metabolism. Functional oligosaccharides could be effective sucrose substitutes in hawthorn leathers and enable their potential utilization as functional foods.
基金supported by the National Key R&D Program of China[Grant No.2021YFC2103002]the National Natural Science Foundation of China[Grant No.32202720]+1 种基金The Agricultural Science and Technology Innovation Program(CAAS-ZDRW202304)the China Agriculture Research System of MOF and MARA(CARS-41).
文摘Thermophilic endo-chitinases are essential for production of highly polymerized chitooligosaccharides,which are advantageous for plant immunity,animal nutrition and health.However,thermophilic endo-chitinases are scarce and the transformation from exo-to endo-activity of chitinases is still a challenging problem.In this study,to enhance the endo-activity of the thermophilic chitinase Chi304,we proposed two approaches for rational design based on comprehensive structural and evolutionary analyses.Four effective single-point mutants were identified among 28 designed mutations.The ratio of(GlcNAc)3 to(GlcNAc)2 quantity(DP3/2)in the hydrolysates of the four single-point mutants undertaking colloidal chitin degradation were 1.89,1.65,1.24,and 1.38 times that of Chi304,respectively.When combining to double-point mutants,the DP3/2 proportions produced by F79A/W140R,F79A/M264L,F79A/W272R,and M264L/W272R were 2.06,1.67,1.82,and 1.86 times that of Chi304 and all four double-point mutants exhibited enhanced endo-activity.When applied to produce chitooligosaccharides(DP≥3),F79A/W140R accumulated the most(GlcNAc)4,while M264L/W272R was the best to produce(GlcNAc)3,which was 2.28 times that of Chi304.The two mutants had exposed shallower substrate-binding pockets and stronger binding abilities to shape the substrate.Overall,this research offers a practical approach to altering the cutting pattern of a chitinase to generate functional chitooligosaccharides.
