基于UHPLC-Q-TOF/MS的不同产地普洱生茶化学成分差异研究

为了更加全面地了解产地对普洱生茶品质与化学成分的影响,本研究选取来自临沧市、普洱市、西双版纳州三大产区12个茶山(自然村)的普洱生茶样品,采用超高效液相色谱-四级杆-飞行时间质谱(UHPLC-Q-TOF/MS)对不同产地普洱生茶的非挥发性代谢物表型进行了研究。结果表明:不同产地普洱生茶的化学成分在含量上具有较大差异,且具有明显的产地特征。采用主成分分析,可以对来自西双版纳自治州(包括勐腊县、勐海县、景洪市)、普洱市、临沧市3个地级行政区的普洱生茶进行有效区分,也可以对来自普洱茶产区的东南、西南、西北3个区域的普洱生茶进行有效区分。进一步鉴定了普洱生茶中79种主要成分,并对其在12个茶山(自然村)的普洱生茶中的含量分布,以及与不同产地普洱生茶滋味品质的关系进行了分析。本研究表明,基于UHPLC-Q-TOF/MS的茶叶非挥发性化学成分轮廓可以作为普洱生茶产地判别的依据。     

Effects of starvation,subsequent feeding and photoperiod on flesh quality in farmed cod (Gadus morhua)

The study was designed to investigate the effect of four cycles of 5 weeks starvation followed by 10‐week refeeding compared with daily feeding under either natural photoperiod or continuous light (LL) regime on body composition and flesh quality in Atlantic cod in sea cages, northern Norway. The fish were sampled for body composition and flesh quality parameters at the start of the trial, twice at the end of a 10‐week feeding period and twice at the end of a 5‐week starvation period. There was effect of both feeding and light regime on growth, the two starving groups losing weight during starvation and regaining weight during refeeding, and the group under LL being heavier. But, the mean overall growth did not vary between groups. Starvation/refeeding regime resulted in higher slaughter yield, but no overall effect was seen on hepatosomatic index, water content, water holding capacity (WHC), muscle pH, hardness or flesh colour compared with control groups. Continuous light increased gutted weight and slaughter yield, lowered WHC and depressed maturation compared with fish under natural light regime. Increased growth rate resulted in softer fillets and lower muscle pH.     

Effect of l‐ascorbyl‐2‐polyphosphate supplementation on growth performance,body composition,antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp,Litopenaeus vannamei

An 8‐week feeding trial was conducted to evaluate the effects of ascorbic acid (AsA), in the form of l ‐ascorbyl‐2‐polyphosphate (LAPP) on growth performance, body composition, antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp, Litopenaeus vannamei. Five practical diets (46% crude protein and 7.6% lipid) supplemented with graded levels of AsA (14.64, 48.55, 84.98, 308.36 and 639.27 mg kg^?1 diet) were fed to five replicate groups of L. vannamei (mean initial wet weight 0.57 g). No significant differences were found on growth performance among all treatments. However, whole body lipid content significantly decreased with dietary AsA levels increasing. Activities of total antioxidant capacity, glutathione reductase and glutathione peroxidase were significantly affected by dietary AsA levels. Shrimp fed LAPP‐free diet had higher malondialdehyde content than those fed the diets supplemented with LAPP. Dietary AsA levels higher than 308.36 mg kg^?1 diet increased the survival of shrimps after 1, 2 and 3 h of acute salinity change. Broken‐line regression analysis on survival after 3 h of salinity stress and second‐degree polynomial regression analysis on glutathione reductase data indicated that the optimal dietary AsA requirement of L. vannamei was estimated to be 306.39, 319.75 mg kg^?1 diet respectively.     

Characteristics and Functional Properties of Ovary from Squid Loligo Formosana

The characteristics and functional properties of the ovary from Loligo formosana were studied. Moisture (72.07 ± 0.24%) was dominant, followed by protein (18.64 ± 0.51%) and carbohydrate (7.44 ± 0.2%). Ash (1.39 ± 0.03%) and lipids (0.46 ± 0.5%) were found as the minor constituents. Albumin (79.02 ± 0.79%) was the major protein of the squid ovary, followed by glutelin-1 (8.31 ± 0.62%) and globulin (6.68 ± 0.08%). Nevertheless, prolamin and glutelin-2 constituted approximately 1% of the total proteins. Based on the electrophoretic studies, albumin had the largest band intensity. The squid ovary was rich in non-essential amino acids (52.26%) and high in hydrophobic amino acids (48.03%). It was also rich in polyunsaturated fatty acid (PUFA, 43.76 ± 0.84%), followed by saturated fatty acid (SFA, 39.36 ± 0.12%) and monounsaturated fatty acid (MUFA, 12.94 ± 0.55%). Ovary lipids had a high amount of docosahexaenoic acid (C22:6) (28.59%). At pH 3, the squid ovary powder (SOP) had the maximum solubility (96.39%), whereas the lowest solubility (38.33%) was observed at pH 9. The foaming capacity and stability of SOP were increased with increasing concentration up to 8% (p < 0.05). The globulin fraction showed the higher foaming capacity, as compared to albumin and glutelin-1 fractions. The squid ovary had good nutritional value and possessed excellent foaming properties. Therefore, the squid ovary could serve as a novel food additive or ingredient.     

Comparative survival and growth performance of European lobster larvae,Homarus gammarus,reared on dry feed and conspecifics

A bottleneck of crustacean larval culture concerns nutrition and associated cannibalism in communal rearing systems, which impact on larval survival, development and growth. For early‐stage European lobster, Homarus gammarus larvae, feeding ecology and body composition are largely unknown. We initiated four progressive feeding experiments (novel feed types, feeding regime and feed size and cannibalism effects) on growth and survival, to inform and update husbandry protocols. Performance of larvae offered a dry commercial feed was not significantly different compared with a conventional wet plankton feed of the same ration and size grade (both within 600–1,000 μm). Further experiments found that the same ration of dry feed offered six times daily improved development and growth, over the conventional regime of three times daily. Small‐grade dry feed (particles: 250–360 μm) improved larval performance compared with a larger feed (360–650 μm). Larvae were also fed different proportions of dry feed and/or conspecifics in both communal and individual rearing systems (the latter preventing cannibalism via segregation). Individually reared larvae, fed only dead conspecifics, displayed the greatest survival (80%) to postlarvae. This underlines the impact of cannibalism on survival and nutrition in H. gammarus larviculture. A final experiment analysed H. gammarus zoea 1 composition, identifying deficiencies in ash and carbohydrate in lobster feeds. This suggests a need for a species‐specific, formulated dry feed for H. gammarus larviculture. Our research represents the first investigation of H. gammarus larval composition and dietary requirements and highlights decreased growth potential associated with providing nutrition solely from generic commercial feed.     

洛阳市植烟区生态环境聚类及烟叶化学成分分析

[目的]分析不同生态环境烟叶的化学成分差异性及适宜性。[方法]以降雨、海拔和日照条件为因子,对洛阳市烟区生态环境进行系统聚类,并抽取34个样品分析了不同生态环境中烟叶的化学成分含量及适宜性。[结果]与2015年全国平均含量相比,洛阳市烟叶的总植物碱、总氮和钾含量较低,淀粉和游离氨基酸含量略高,样品间氯含量、钾氯比和糖碱比变异较大;聚类分析将洛阳市烟区划分为A、B、C、D 4类小生态环境烟区;A类烟区烟叶的总植物碱、氯含量相对较高,D类烟区烟叶的钾氯比、糖碱比和氮碱比相对较高;4类烟区烟叶的总植物碱、总氮、游离氨基酸含量和氮碱比适宜性较好,碳水化合物含量高出适宜范围,糖碱比例不协调,钾、氯含量偏低。[结论]总体来看,A类烟区烟叶化学成分适宜性最佳。     

哈尔滨地区大豆蚜及其天敌昆虫的多年种群动态和相关性分析

为明确大豆蚜种群数量与其天敌昆虫龟纹瓢虫[Propylea japonica(Thunberg)]、异色瓢虫[Harmonia axyridia(Pallas)]及花蝽(Orius sp.)的田间发生情况及二者的相关性,采用对角线五点取样、借助直接观察法,对哈尔滨地区大豆蚜及上述天敌昆虫的种群动态(2008-2014年)进行了系统调查。记录各年份大豆蚜种群数量峰值及峰值日后第6天各天敌昆虫的种群数量,并对大豆蚜与天敌昆虫的发生关系进行了相关分析。结果表明:6月为大豆蚜的田间始发期,7-8月为其田间猖獗期,9月为其消亡期。在大豆蚜的始发期和猖獗期,田间均有龟纹瓢虫(成虫和幼虫)、异色瓢虫(成虫和幼虫)及花蝽(成虫和若虫)的发生。龟纹瓢虫幼虫和异色瓢虫成虫的田间种群数量与大豆蚜的种群数量间均呈现显著相关性。     

Effects of Dietary Lipids on the Growth Performance,Survival, and Digestive Enzymes of Juvenile Cuttlefish,Sepia lycidas

This study was conducted to determine the effects of dietary lipids on the growth performance, muscle composition, and enzyme activities of the stomach, intestines, and liver of Sepia lycidas juveniles. Fish oil and soybean lecithin were selected as lipid sources to formulate six experimental diets containing lipid levels of 3.68, 4.15, 6.62, 8.09, 9.56, and 11.03%. The feed efficiency first declined and then rose, with the lowest value obtained in individuals fed the 8.09% lipid content diet; the protein efficiency ratio significantly decreased with an increased lipid level. The highest crude protein content and lowest crude lipid content were simultaneously obtained in individuals fed the 9.56% lipid content diet. The activities of pepsase, trypsin, and intestine lipase initially increased before decreasing. The highest activities of protease, trypsin, and lipase were obtained in individuals fed the 9.56% lipid content diet, while the highest activity of amylase was obtained in individuals fed the 6.62% lipid content diet. Hepatic glutamate pyruvate transaminase and glutamic oxaloacetic transaminase initially increased and then held steady, with the highest activities simultaneously obtained in individuals fed the 9.56% lipid diet. Our results suggest that dietary lipids at a level of 9.56% could be the optimal lipid requirement for S. lycidas to grow and maintain normal metabolism.     

饥饿不同时间后投喂对许氏平鮋生长及体成分的影响

在室内水温21.8~25℃条件下,将初始体质量为(8.87±0.16)g的许氏平鮋Sebastes schlegeli放养在50cm×50cm×100cm网箱中,饥饿0(S0)、3(S3)、6(S6)、9(S9)和12d(S12)后分别投喂30d、27d、24d、21d和18d,每组3个重复,测定其体质量、肥满度、脏体指数、肝体指数、摄食率、食物转化率及全鱼和肝脏主要生化组成的变化。结果表明:随着饥饿时间的延长,幼鱼体质量逐渐降低,各饥饿组鱼体质量显著低于同期对照组(P0.05)。恢复投喂后,S3组体质量、增重率(WGR)和特定生长率(SGR)显著高于对照组S0(P0.05),S6与S0组无显著差异(P0.05),而S9与S12组未能达到S0水平(P0.05)。S3组食物转化率(FCE)显著高于其余各组(P0.05),S9、S12组则显著低于对照组(P0.05)。饥饿状态下,各饥饿组鱼肝体指数与脏体指数显著小于S0组(P0.05));恢复投喂后各组肝体指数、脏体指数与对照组无显著差异。随着饥饿时间的延长,鱼体粗灰分含量显著升高(P0.05),水分与粗蛋白含量呈上升趋势(P0.05)。饥饿6d后,鱼体粗脂肪含量显著低于对照组,饥饿12d时粗脂肪含量比饥饿前降低了19.33%(P0.05)。恢复投喂后,各试验组间鱼体水分、粗蛋白、粗脂肪和粗灰分含量差异不显著(P0.05)。S9和S12组中肝脏粗脂肪含量显著低于S0组(P0.05)。     

Effects of dietary protein and lipid levels with different protein‐to‐energy ratios on growth performance,feed utilization and body composition of juvenile red‐spotted grouper,Epinephelus akaara

An 8‐week feeding trial was conducted to assess dietary protein and lipid levels on growth performance, feed utilization and body composition of juvenile red‐spotted grouper (7.85 ± 0.03 g fish^?1). Nine semi‐purified diets were formulated containing varying protein levels (440–520 g kg^?1, dry matter) and lipid levels (60–120 g kg^?1, dry matter). The weight gain of juvenile Epinephelus akaara was affected by dietary protein (p = .005) and its interaction with dietary lipid (p = .020). Viscerosomatic index, intraperitoneal fat ratio and whole‐body lipid level increased with increasing dietary lipid level (p < .001). Nitrogen retention was not affected by dietary protein and lipid, while lipid retention decreased with increasing dietary lipid level (p < .001). The plasma blood urea nitrogen increased with increasing dietary protein level (p = .003). This study showed that diet with 520 g kg^?1 protein and 60 g kg^?1 lipid with 30.58 mg kJ^?1 P:E provided a maximal growth for this species. Moreover, an increase in dietary lipid levels (from 60 to 90 g kg^?1) could reduce the protein requirement (from 520 to 480 g kg^?1) without affecting the growth performance, while higher fat deposition was observed in fish fed high‐lipid diets.