High-protein diets (HPDs) have the potential to reduce body weight, yet excessive protein intake can induce hepatic metabolic dysregulation and insulin resistance. L-theanine (LTA), a unique amino acid abundantly present in tea leaves, regulates protein metabolism under HPD conditions. However, its influence on glucose and lipid metabolism remains unclear. In this study, Sprague-Dawley rats were fed either a standard maintenance diet (20% of energy from protein) or HPDs containing 30%, 40%, or 50% of energy from protein, and were administered LTA at different doses (0, 100, 200, or 400 mg kg-1·body weight-1) for 40 days. A combination of physiological and biochemical assessments, metabolomics, proteomics, and Western blot techniques was used to investigate the regulatory effects and mechanisms of LTA on glucose and lipid metabolism under HPD conditions. The 30% HPD did not cause notable metabolic changes, whereas the 40% and 50% HPDs led to hyperinsulinemia and hepatic lipid accumulation by enhancing gluconeogenesis and fatty acid synthesis while inhibiting fatty acid β-oxidation. LTA alleviated insulin elevation, hepatic steatosis, and lipid droplet accumulation caused by the 40% and 50% HPDs. Mechanistically, LTA enhanced peroxisome proliferator-activated receptor alpha (PPARα) expression and increased acyl-CoA dehydrogenase medium chain (ACADM) expression to promote mitochondrial fatty acid β-oxidation, while decreasing acetyl-CoA carboxylase alpha (ACACA) and phosphoenolpyruvate carboxykinase 1 (PCK1) expression, thereby suppressing lipid synthesis and gluconeogenesis. These findings highlight the potential of LTA to mitigate HPD-associated metabolic alterations, supporting its application as a functional food ingredient for metabolic health management.

The protein levels in a diet are correlated with immunity but the long-term intake of excessive protein can compromise various aspects of health. L-theanine regulates immunity and protein metabolism; however, how its regulatory immunity effects under a high-protein diet are unclear. We used proteomics, metabonomics, and western blotting to analyze the effects of diets with different protein levels on immune function in rats to determine the role of L-theanine in immunity under a high-protein diet. The long-term intake of high-protein diets (≥40% protein) promoted oxidative imbalance and inflammation. These were alleviated by L-theanine. High-protein diets inhibited peroxisome proliferator-activated receptor (PPAR)α expression through the interleukin (IL)-6/signal transducer and activator of transcription (STAT)3 pathway and mediated inflammation. L-theanine downregulated anti-fatty acid-binding protein 5 (FABP5), inhibited the IL-6/STAT3 axis, and reduced high-protein diet-induced PPARα inhibition. Therefore, L-theanine alleviates the adverse effects of high-protein diets via the FABP5/IL-6/STAT3/PPARα pathway and regulates the immunity of normally fed rats through the epoxide hydrolase (EPHX)2/nuclear factor-kappa B inhibitor (IκB)α/triggering receptor expressed on myeloid cells (TREM)1 axis.

SCOPE:l-Theanine (LTA) is a non-protein amino acid that contributes to the flavor of tea and can regulate protein metabolism of healthy organisms. However, it is unknown whether it regulates protein metabolism in individuals on high-protein diets (HPDs).METHODS AND RESULTS:Here, Sprague-Dawley rats are fed HPDs with different protein supply ratios and administered a diverse dose of LTA for 40 days. Results show that HPDs with an energy supply ratio from protein >40% impair the liver and kidneys, elevate serum ammonia and urea nitrogen, induce amino acid (AA) catabolism, and promote fatty acid (FA) synthesis via FA-binding protein 5 (Fabp5) and acetyl-CoA carboxylase 1 (ACC1). LTA intervention alleviates HPD-induced hepatic and renal injury and improves serum biochemical indices. It increases hepatic free AA content and inhibits FA synthesis by downregulating Fabp5 and ACC1. It promotes protein synthesis by acting on the mammalian target of rapamycin (mTOR) pathway, thereby alleviating HPD-induced metabolic disorders.CONCLUSIONS:This study demonstrates that LTA mitigates kidney and liver damage induced by long-term excess HPDs by regulating protein metabolism.

以茶树品种'碧香早'夏季一芽二叶为原料,在传统红茶加工工艺基础上,将毛火初干后的闷堆工艺引入红茶加工的干燥工艺中,从感官品质、滋味品质成分和香气品质成分3方面探讨毛火初干后的闷堆处理对红茶品质的影响.结果 表明,与传统工艺加工的红茶相比,毛火初干后闷堆3h,能显著提高红茶品质,滋味醇爽,汤色红橙明亮,甜香显露;茶样中茶黄素质量分数显著增加(P＜0.05),由0.41％增加到0.62％;醇类香气物质总相对含量由52.25％上升到57.33％,酮类香气物质增加了具有果香的1,3,7-三甲基-3,7-二氢-1H-嘌呤-2,6-二酮、4-[2,2,6三甲基-7-氧杂二环[4.1.0]庚-1-基]-3-丁烯-2-酮和6-甲基-5-庚烯-2-酮.由此提示毛火初干后的闷堆工艺技术在提高红茶品质的生产实践中具有可行性.

高蛋白饮食可导致焦虑或抑郁自主行为,自主行为是判断是否具有焦虑或抑郁病症的重要方法.本研究通过对SPF级6周龄SD雄性大鼠进行40 d灌胃实验,采用旷场与明暗箱实验观察以及测定生理生化指标的方法,探究不同剂量L-茶氨酸(100、200、400 mg/(kg mb·d))对不同蛋白水平饮食(蛋白质供能比分别为20％、30％、40％、50％) SD大鼠行为变化的干预作用,以期为高蛋白饮食的多元化营养干预及L-茶氨酸深层次利用提供科学依据.结果 表明:与蛋白质供能比为20％的普通维持饲料组相比,蛋白质供能比为50％的高水平高蛋白饲料组的采食量、体质量显著减少(P＜0.05),大鼠在明箱中的停留时间显著缩短(P＜0.05),进入明箱的次数显著减少(P＜0.05),多巴胺、5-羟色胺、去甲肾上腺素质量浓度减少,但无显著差异,说明高水平高蛋白饮食可诱导大鼠抑郁行为.与高水平高蛋白饲料组相比,低剂量L-茶氨酸干预的高水平高蛋白饲料组大鼠体质量显著升高(P＜0.05),且在明箱的停留时间显著延长(P＜0.05);低、中剂量L-茶氨酸干预的高水平高蛋白饲料组大鼠在旷场箱的水平移动格数、后肢站立次数显著增加(P＜0.05);各剂量L-茶氨酸干预的高水平高蛋白饲料组大鼠进入明箱的次数显著增加(P＜0.05),且血清中多巴胺、去甲肾上腺素质量浓度显著升高(P＜0.05);同时低剂量L-茶氨酸干预的高水平高蛋白饲料组大鼠血清中5-羟色胺质量浓度显著升高(P＜0.05).综上,L-茶氨酸具有改善高蛋白饮食所致焦虑或抑郁SD大鼠自主行为的作用,其机制可能与单胺类递质的代谢相关.

以碧香早、金萱、黄金芽三个茶树品种一芽二叶的揉捻叶为原料,进行两两组配或三者组配,其他加工工艺条件相同.结果表明可提高红茶中的水浸出物、茶黄素、酚氨比、黄酮、可溶性糖的含量,进而提升红茶品质.其中,以碧香早、金萱、黄金芽三者茶鲜叶组配比例为3:3.5:3.5时效果最佳,与碧香早单一品种茶鲜叶加工的红茶相比,其滋味更醇厚,茶黄素、水浸出物、黄酮、可溶性糖含量显著增加(P<0.05),分别增加0.17％、2.14％、0.84％与0.75％,酚氨比显著提高2.35(P<0.05);其香气成分较碧香早单一品种红茶的香气成分多出11种;其四氢-α,α,5-三甲基-5-乙烯基呋喃-2-甲醇提高了3.11％、香叶醇提高了6.53％.

以茶树品种碧香早夏秋季一芽二叶茶鲜叶为原料,在红茶加工过程中,用微波初干工艺替代传统热风初干工艺,按不同微波强度、微波时间、摊叶厚度设置17组微波初干工艺处理,从感官品质、滋味品质成分和香气品质成分3个方面,探究了微波初干工艺对红茶品质的影响.结果表明,与传统热风初干工艺相比,采用微波强度600 W、微波时间3 min、摊叶厚度2 cm的微波初干工艺技术,所制红茶感官品质较好,红茶中的茶黄素、茶红素、总儿茶素、酯型儿茶素及表没食子儿茶素没食子酸酯(EGCG)、氨基酸、咖啡碱、可溶性糖的含量显著升高(P<0.05),茶多酚、茶褐素含量显著降低(P<0.05),香气品质成分由43种增加到50种,其中芳樟醇、苯乙醇等花果香香气成分的相对含量显著提高(P<0.05),并产生了(Z)-3,7-二甲基-2,6-辛二烯-1-醇、2,6,6-三甲基-1,3-环己二烯-1-甲醛、2,6,6-三甲基-1-环己烯-1-甲醛、丁香酚等甜香、花香成分.微波初干工艺有利于提高红茶品质.

此试验旨在利用现有神经性犬瘟热病例病料通过鸡胚培养的方法分离提取犬瘟热病毒,并研究出鸡胚培养犬瘟热病毒的最佳条件.同时提取的病毒可以用于后续抗体制备.试验共进行六次鸡胚培养,使用犬瘟热快速检测试纸进行鉴定,成功分离鉴定了 CDV病毒.结果表明:鸡胚培养犬瘟热病毒的方法是可行的,犬瘟热病料研磨液接种鸡胚的较佳接种部位是尿囊腔接种,每个鸡胚接种犬瘟热病料研磨上清液量最佳接种量0.25mL,但鸡胚培养犬瘟热病毒成功率较低,病毒液浓度不高.

以茶树品种碧香早夏季一芽一叶鲜叶为原料,在传统黄茶的摊放工艺中引入可激发花香品质形成的晒青和摇青工艺,探讨了利用晒青和摇青工艺技术加工花香型黄茶的可行性,以期为黄茶的提质加工和夏秋茶资源的综合利用提供参考.试验通过感官与理化品质分析,结果表明,在传统黄茶加工的摊放工序中科学融入晒青、摇青工艺技术,可加工出具有花香品质的夏季黄茶,相较于传统工艺黄茶,氨基酸、可溶性糖、茶黄素含量分别相对增加了3.90%、33.78%和19.05%,而茶多酚、酯型儿茶素含量相对分别降低了2.31%及2.88%,酚/氨比值、酯型儿茶素/总儿茶素比值分别降低了6.02%与10.77%,茶汤苦涩滋味减轻;同时香气品质成分更加丰富,正辛醛、水杨酸辛酯、苯甲醛、橙花基丙酮、4-[2,2,6-三甲基-7-氧杂二环[4.1.0]庚-1-基]-3-丁烯-2-酮等香气组分显现或相对含量提高.传统黄茶加工工艺中引入晒青和摇青,可加工有特色的花香型黄茶.

提高茶学硕士研究生人才培养质量既是茶产业高质量发展的客观需求,也是贯彻落实国家创新创业型精英教育的根本要求.本文根据新形势下茶产业对创新型高级专业技术人才知识和能力的客观需求,分析了当前我国茶学硕士研究生在招生、人才培养方案、课程教学、创新研究以及导师指导等方面存在的问题,探讨了提高生源质量、优化人才培养方案、创新教学内容与方法、完善研究创新条件、强化导师职能、健全保障制度等对策建议,以期为提高我国茶学研究生教育教学改革和人才培养质量提供参考.