High starch diets attenuate the immune function of Micropterus salmoides immune organs by modulating Keap1/Nrf2 and MAPK signaling pathways.

Based on their good physiological functions and physical properties, carbohydrates are widely used in fish feed. However, excessive use of carbohydrates such as starch in fish feed may reduce the immunity of the fish and cause a series of health problems. In order to more clearly clarify the effects of different starch levels in feed on the immune organs of Micropterus salmoides, this study took the immune organs as the entry point and explored it from several perspectives, including differences in enzyme activity in plasma, changes in gene expression in immune organs, and resistance to pathogenic bacteria. The results showed that (1) high starch feed activates inflammatory responses in the spleen and head kidney through the MAPK signaling pathway. This leads to a decrease in the number of lymphocytes and weakens the resistance to pathogens; (2) high starch diet affects the antioxidant capacity of the trunk kidney by regulating the Keap1/Nrf2 pathway; (3) There was a strong correlation between gene expression patterns in the head kidney and lysozyme content in plasma. This implies that the high starch diet may regulate lysozyme production by affecting gene expression in the head kidney and further affect immune function. This study helps to reveal the interaction between starch and the immune system and provide scientific basis for the development of reasonable dietary recommendations and disease prevention.

Transcriptome analysis of the immunomodulatory effects of Salvia miltiorrhiza polysaccharide on hemocyte immune response in Procambarus clarkii.

Natural plant polysaccharide as immune modulator is considered an effective strategy for healthy aquaculture to reduce medicine treatment. Salvia miltiorrhiza polysaccharides (SMP) had applications to regulate immune activity and enhance antioxidant in vertebrates, but the potential function has been rarely reported in crustaceans. In this study, the immunological effects of SMP on hemocytes of Procambarus clarkii were analyzed. Results showed that total superoxide dismutase (T-SOD), phenoloxidase (PO) activity and respiratory burst were up-regulated after SMP treatment. After high-throughput sequencing, 2170 differentially expressed genes (DEGs) including 1294 up-regulated and 876 down-regulated genes were identified. KEGG function enrichment analysis indicated that DEGs are involved in crustaceans cellular immune-related signaling pathways, including lysosome, phagosome and endocytosis. Transcriptome mining and qRT-PCR showed that SMP up-regulated humoral immunity factors gene expression. Diets supplemented with 0.8% SMP significantly up-regulated the total number of hemocytes (THC), T-SOD and PO activity, improved the survival of crayfish after Citrobacter freundii infection. This study suggested that SMP could improve the cellular and humoral immunity of P. clarkii. Furthermore, this finding supplied a molecular foundation for further comprehending the immunopotentiator effects of plant polysaccharides in crustaceans.

Simulated Moving Bed Purification for Flavonoids from Tartary Buckwheat Shell.

Tartary buckwheat shell is an important by-product of Tartary buckwheat production. Previous studies shown that Tartary buckwheat shells are rich in flavonoids, which are responsible for their antioxidant properties. Due to lack of advanced separation technologies, the purification for Tartary buckwheat shell is still in the laboratory scale, and could not realize the industrialization production. According to the results of static adsorption experiment, AB-8 resin was selected for Tartary buckwheat shell flavonoids (TBSF) adsorption. The adsorption isotherm, resin adsorption thermodynamic and dynamic adsorption parameters were studied. And the adsorption of AB-8 resin for TBSF was determined as an endothermic process. Results of preparative chromatography experiment showed that TBSF could be efficiently purified by AB-8 resin. And the optimal parameters were: feed concentration 25 mg/mL, desorption flow rate 2.5 mL/min. Under these conditions, the TBSF were separated effectively. Results of liquid chromatography-mass spectrometer (LC-MS) indicated that there were seven kinds of flavonoids in Tartary buckwheat shell, which were mainly from the 40 and 60% of ethanol elution. Simulated moving bed (SMB) was applied for TBSF purification the first time in this study. The optimal conditions of SMB were as following: adsorption zone flow rate 7.0 mL/min, contaminant removal zone flow rate 17.9 mL/min, product elution zone flow rate 22.3 mL/min, regeneration zone flow rate 21.5 mL/min, water washing zone flow rate 27.5 mL/min, switching time 1260 S, and the purity and yield of TBSF was 90 ± 0.22% and 85 ± 0.28%, respectively. The IC50 values of α-glucosidase inhibition activities and DPPH scavenging activity of the purified TBSF were 57.09 ± 0.15 and 7.92 ± 0.23 µg/mL, respectively. The constituents of TBSF showed higher α-glucosidase inhibition activities and antioxidant than raw TBSF and rutin. The results suggest that SMB is a proper method for industrial production of TBSF, and SMB could be applied for other natural products purification.

An Overview of Plant Phenolic Compounds and Their Importance in Human Nutrition and Management of Type 2 Diabetes.

In this paper, the biosynthesis process of phenolic compounds in plants is summarized, which include the shikimate, pentose phosphate and phenylpropanoid pathways. Plant phenolic compounds can act as antioxidants, structural polymers (lignin), attractants (flavonoids and carotenoids), UV screens (flavonoids), signal compounds (salicylic acid, flavonoids) and defense response chemicals (tannins, phytoalexins). From a human physiological standpoint, phenolic compounds are vital in defense responses, such as anti-aging, anti-inflammatory, antioxidant and anti-proliferative activities. Therefore, it is beneficial to eat such plant foods that have a high antioxidant compound content, which will cut down the incidence of certain chronic diseases, for instance diabetes, cancers and cardiovascular diseases, through the management of oxidative stress. Furthermore, berries and other fruits with low-amylase and high-glucosidase inhibitory activities could be thought of as candidate food items in the control of the early stages of hyperglycemia associated with type 2 diabetes.