Food and specific macronutrient limitation in an assemblage of predatory beetles

Habitats vary in food resources with carnivores often being prey limited, but it is unclear whether habitats facilitate a nutritionally balanced diet. Two paradigms in nutritional ecology, ecological stoichiometry and nutritional geometry, predict that carnivores are limited mainly by protein or lipid, respectively. Using the carabid beetle Anchomenus dorsalis and 10 other predatory beetles from agricultural fields, we developed and tested two simple procedures for quantifying macronutrient‐specific habitat conditions without requiring information about the natural prey. Both procedures assume that predators forage for nutrients rather than specific prey. Our results show that 10 of 11 species were food limited. Five species were lipid limited and one species was protein limited in the field. Co‐existing predator species showed considerable segregation of fundamental macronutritional niches. A linear relationship between specific nutrient limitation and the target lipid:protein (L:P) intake ratio indicates that species with high L:P target are more protein limited while species with low L:P target are more lipid limited. The study illustrates how species within a natural assemblage vary in nutritional niche and in specific nutrient limitation.     

Effects of increased atmospheric CO2 on nutritional contents in poplar (Populus pseudo-simonii [Kitag.]) tissues and larval growth of gypsy moth (Lymantria dispar)

Changes in the concentrations of phytochemical compounds usually occur when plants are grown under elevated atmospheric CO₂. CO₂-induced changes in foliar chemistry tend to reduce leaf quality and may further affect insect herbivores. Increased atmospheric CO₂ also has a potential influence on decomposition because it causes variations in chemical components of plant tissues. To investigate the effects of increased atmospheric CO₂ on the nutritional contents of tree tissues and the activities of leaf-chewing forest insects, samples of Populus pseudo-simonii [Kitag.] grown in open-top chambers under ambient and elevated CO₂ (650 μmol mol^?1) conditions were collected for measuring concentrations of carbon, nitrogen, C : N ratio, soluble sugar and starch in leaves, barks, coarse roots (>2 mm in diameter) and fine roots (<2 mm in diameter). Gypsy moth (Lymantria dispar) larvae were reared on a single branch of experimental trees in a nylon bag with 1 mm × 1 mm grid. The response of larval growth was observed in situ. Elevated CO₂ resulted in significant reduction in nitrogen concentration and increase in C : N ratio of all poplar tissues. In all tissues, total carbon contents were not affected by CO₂ treatments. Soluble sugar and nonstructural carbohydrate (TNC) in the poplar leaves significantly increased with CO₂ enrichment, whereas starch concentration increased only on partial sampling dates. Carbohydrate concentration in roots and barks was generally not affected by elevated CO₂, whereas soluble sugar contents in fine roots decreased in response to elevated CO₂. When second instar gypsy moth larvae consuming poplars grew under elevated CO₂ for the first 13 days, their body weight was 30.95% lower than that of larvae grown at ambient CO₂, but no significant difference was found when larvae were fed in the same treatment for the next 11 days. Elevated atmospheric CO₂ had adverse effects on the nutritional quality of Populus pseudo-simonii [Kitag.] tissues and the resultant variations in foliar chemical components had a significant but negative effect on the growth of early instar gypsy moth larvae.     

Effects of increased atmospheric CO2 on nutritional contents in poplar (Populus pseudo-simonii [Kitag.]) tissues and larval growth of gypsy moth (Lymantria dispar)

Changes in the concentrations of phytochemical compounds usually occur when plants are grown under elevated atmospheric CO₂. CO₂-induced changes in foliar chemistry tend to reduce leaf quality and may further affect insect herbivores. Increased atmospheric CO₂ also has a potential influence on decomposition because it causes variations in chemical components of plant tissues. To investigate the effects of increased atmospheric CO₂ on the nutritional contents of tree tissues and the activities of leaf-chewing forest insects, samples of Populus pseudo-simonii [Kitag.] grown in open-top chambers under ambient and elevated CO₂ (650 μmol mol^-1) conditions were collected for measuring concentrations of carbon, nitrogen, C : N ratio, soluble sugar and starch in leaves, barks, coarse roots (>2 mm in diameter) and fine roots (<2 mm in diameter). Gypsy moth (Lymantria dispar) larvae were reared on a single branch of experimental trees in a nylon bag with 1 mm 1 mm grid. The response of larval growth was observed in situ. Elevated CO₂ resulted in significant reduction in nitrogen concentration and increase in C : N ratio of all poplar tissues. In all tissues, total carbon contents were not affected by CO₂ treatments. Soluble sugar and nonstructural carbohydrate (TNC) in the poplar leaves significantly increased with CO₂ enrichment, whereas starch concentration increased only on partial sampling dates. Carbohydrate concentration in roots and barks was generally not affected by elevated CO₂, whereas soluble sugar contents in fine roots decreased in response to elevated CO₂. When second instar gypsy moth larvae consuming poplars grew under elevated CO₂ for the first 13 days, their body weight was 30.95% lower than that of larvae grown at ambient CO₂, but no significant difference was found when larvae were fed in the same treatment for the next 11 days. Elevated atmospheric CO₂ had adverse effects on the nutritional quality of Populus pseudo-simonii [Kitag.] tissues and the resultant variations in foliar chemical components had a significant but negative effect on the growth of early instar gypsy moth larvae.     

核、质基因对肺形侧耳菌丝生长、营养成分及基因表达的影响

本研究通过杂交构建肺形侧耳同核异质菌株N1M1、N1M2和同质异核菌株N1M1、N2M1,比较菌丝形态与生长速度、营养成分以及常见的细胞核基因与线粒体基因的表达量,分析线粒体基因对肺形侧耳菌丝的影响,探讨线粒体基因与核基因的相互作用。由菌丝生长情况可知N1M1和N1M2菌丝形态相似,生长速度差异不显著,N1M1和N2M1菌丝形态差异大,生长速度差异极显著,在菌丝形态与生长速度上细胞核基因作用大于线粒体基因。进一步检测菌株中的主要营养成分发现必需氨基酸与总水解氨基酸含量差异显著,菌株N1M2蛋白含量显著高于N1M1,N1M1维生素C含量是N1M2的1.67倍,菌株N2M1多糖和蛋白含量显著高于N1M1,铁和维生素C含量显著低于N1M1。所以细胞核基因、线粒体基因都能影响肺形侧耳营养成分含量。检测同核异质菌株N1M1、N1M2的7个细胞核常见基因的表达情况发现,N1M2菌丝中6个细胞核基因的表达量都显著高于N1M1,这表明肺形侧耳线粒体基因的不同会影响核基因的表达;同质异核菌株N1M1、N2M1的14个线粒体普通编码蛋白基因表达差异显著,这说明线粒体基因的表达量会因核基因的不同有所差异。综上,肺形侧耳线粒体基因和细胞核基因能够相互影响,共同作用于生命活动。     

常春二乔玉兰春夏季开花节律及营养效应研究

为系统掌握常春二乔玉兰春夏季开花物候节律,探讨其与营养物质的关系,本研究以6年生常春二乔玉兰为试验材料,观测其年生长发育节律、春夏季开花物候特性以及茎段营养物质的含量变化。结果表明：（1）每年12月始至翌年2月下旬为常春二乔玉兰休眠期。2月下旬花芽膨大生长,并于3月开始春季开花,花期持续约20 d。4月进行营养生长,5月完成花芽分化。5月底部分花芽膨大并于6月开始开花,夏季花期持续约20 d。7~9月为未膨大花芽的发育滞缓期。此外,少量夏季开放的花的基部侧芽再次分化形成花芽。10~12月随着落叶的开始,树体逐渐进入休眠期。（2）常春二乔玉兰营养生长后分化的花芽能够花开两季。春季开花为先花后叶,开花率为100%,开花同步率较高,雌、雄蕊发育正常,为可育花。夏季开花为花叶同放,开花率约为30%,且开花同步率较低,开放的花内雌、雄蕊发育异常,为不育花。（3）春季开花期间可溶性糖和可溶性蛋白呈下降趋势,淀粉含量于开花后期下降;夏季开花期间可溶性糖和淀粉总体呈先降后升趋势,而可溶性蛋白总体呈下降趋势。综上所述,常春二乔玉兰春、夏季开花期内开花模式存在一定差异,其显著节律特征与营养物质含量变化有关,推测低水平的可溶性糖及高水平的淀粉和可溶性蛋白有利于春季开花的启动,而低水平的可溶性蛋白及高水平的可溶性糖和淀粉含量则有利于夏季开花的实现。     

Meta-analysis of spineless cactus feeding to meat lambs: performance and development of mathematical models to predict dry matter intake and average daily gain

Spineless cactus is a useful feed for various animal species in arid and semiarid regions due to its adaptability to dry and harsh soil, high efficiency of water use and carbohydrates storage. This meta-analysis was carried out to assess the effect of spineless cactus on animal performance, and develop and evaluate equations to predict dry matter intake (DMI) and average daily gain (ADG) in meat lambs. Equations for predicting DMI and ADG as a function of animal and diet characteristics were developed using data from eight experiments. The dataset was comprised of 40 treatment means from 289 meat lambs, in which cactus was included from 0 to 75% of the diet dry matter (DM). Accuracy and precision were evaluated by cross-validation using the mean square error of prediction (MSEP), which was decomposed into mean bias, systematic bias and random error; concordance correlation coefficient, which was decomposed into accuracy (C_b) and precision (ρ); and coefficient of determination (R²). In addition, the data set was used to evaluate the predicting accuracy and precision of the main lamb feeding systems (Agricultural and Food Research Council, Small Ruminant Nutritional System, National Research Council and Institut National de la Recherche Agronomique) and also two Brazilian studies. The DMI, CP intake (CPI), metabolizable energy (ME) intake and ADG increased when cactus was included up to 499 g/kg DM (P<0.001). In contrast, animals fed high levels of cactus (>500 g/kg DM) had a decreased DMI, CPI and NDF intake, but increased feed efficiency (P<0.001) and similar ADG compared with those without cactus addition. The DMI was positively correlated with initial BW, final BW, concentrate and ADG, while it was negatively correlated with cactus inclusion and ME of the diet. On other hand, ADG was positively correlated with DMI, initial and mean BW and concentrate, and it was negatively correlated with cactus inclusion. The two developed equations had high accuracy (C_b of 0.95 for DMI and 0.94 for ADG) and the random error of MSEP was 99% for both equations. The precision of both equations was moderate, with R² values of 0.53 and 0.50 and ρ values of 0.73 and 0.71 for DMI and ADG, respectively. In conclusion, the developed equation to predict DMI had moderate precision and high accuracy, nonetheless, it was more efficient than those reported in the literature. The proposed equations can be a useful alternative to estimate intake and performance of lambs fed cactus.     

An Acinetobacter baumannii,Zinc-Regulated Peptidase Maintains Cell Wall Integrity during Immune-Mediated Nutrient Sequestration

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黑木耳子实体粉代替部分膳食对高脂模型小鼠营养性肥胖预防作用

本文旨在研究黑木耳粉代替部分膳食对模型小鼠预防营养性肥胖的作用功效。试验选择5周龄健康ICR雄性小鼠48只,随机分为正常对照组(CK)、高脂组(HFD)、阳性药物对照组(PD)和黑木耳粉添加组(AH)。连续饲喂9周,检测小鼠的各项生理生化指标。结果表明：与HFD组相比,AH组小鼠体重、附睾脂肪指数显著降低(P<0.05);Lee’s指数、血清葡萄糖(GLU)含量、甘油三酯(TG)含量和肝脏指数含量极显著降低(P<0.01),血清高密度脂蛋白胆固醇(HDL-C)和肝脏HDL-C含量极显著提高(P<0.01);染色结果观察到AH组小鼠肝脏中脂肪细胞减小,脂质含量降低;附睾脂肪体积减小,附睾细胞形状较规则。高通量测序分析发现,黑木耳粉干预有效改善了小鼠肠道中的变形菌门、螺杆菌属与拟杆菌属的相对丰度。研究结果表明黑木耳有显著预防小鼠营养性肥胖的功效,为黑木耳的开发利用提供依据。     

术前预后营养指数和血清转铁蛋白与老年髋部骨折患者术后切口愈合的关系及其预测价值分析

摘要 目的：研究术前预后营养指数（PNI）和血清转铁蛋白（TRF）与老年髋部骨折（HF）患者术后切口愈合不良（PWH）的关系及其预测价值。方法：选取2020年1月～2022年3月南京市中医院收治的252例接受手术治疗老年HF患者,根据术后切口愈合情况分为PWH组（n=27）和非PWH组（n=225）。收集患者基础资料、术前PNI和血清TRF水平。采用多因素Logistic回归分析老年HF患者术后PWH的影响因素,受试者工作特征（ROC）曲线分析PNI和血清TRF水平对老年HF患者术后PWH的预测价值。结果：252例老年HF患者术后出现27例PWH,其中24例切口长时间不愈合,3例切口裂开。与非PWH组比较,PWH组体质量指数（BMI）和白蛋白、淋巴细胞计数（LC）、PNI、血清TRF水平更低,糖尿病比例和术中出血量更高（P＜0.05）。多因素Logistic回归分析显示,BMI≥18.5 kg/m²（OR=0.648,95％CI：0.457～0.919）、PNI（OR=0.954,95％CI：0.932～0.976）、血清TRF（OR=0.484,95％CI：0.307～0.761）升高是老年HF患者术后PWH的保护因素,糖尿病（OR=2.651,95％CI：1.182～5.948）、术中出血量增加（OR=1.013,95％CI：1.005～1.021）是危险因素（P＜0.05）。ROC曲线分析显示,PNI和血清TRF水平单独与联合预测老年HF患者术后PWH的曲线下面积（AUC）分别为0.808、0.770、0.871,灵敏度分别为70.37％、55.56％、92.59％,特异度分别为80.65％、85.81％、70.32％。二者联合预测老年HF患者术后PWH的AUC大于二者单独预测（P＜0.05）。结论：术前PNI和血清TRF水平降低是老年HF患者术后PWH的危险因素,二者联合对老年HF患者术后PWH的预测价值较高。     

Effect of diet composition and lysine supply on growth and body composition in juvenile turbot (Psetta maxima)

A 10-week feeding trial was conducted to study the effect of feeding level and dietary lysine concentration on growth, protein and lysine retention, and body composition in juvenile turbot. Maintenance requirement for lysine and the efficiency of lysine utilisation were determined as well. Two experimental diets were formulated based on fishmeal or wheat gluten as main protein sources, containing 6.4 g (Diet A, control) and 4.5 g lysine per 100 g CP (Diet B), respectively. Diets were fed once daily at six feeding levels (per day 0.3%, 0.6%, 0.9%, 1.2%, and 1.5% of body weight [BW] and ad libitum) to a total of 432 fish of 48 g initial BW. No differences in the growth parameters were observed between diets at the same feeding level, except a lower feed to gain ratio (p < 0.05) at the highest feeding level at Diet B. Whole-body composition was not affected by diet, whereas muscle protein concentration was significantly lower for fish fed Diet B. Amino acid concentration in whole-body protein was affected by dietary treatment and fish fed Diet B showed lower concentrations of all essential amino acids. In fish muscle protein, lysine, methionine, leucine, isoleucine, and valine concentrations were significantly lower in Diet B. Efficiency of lysine utilisation for growth (k_lys) was determined by linear regression analysis and amounted for 0.69 for Diet B. The maintenance lysine requirement defined at zero lysine retention was 6.5 mg · kg^?0.8 · d^?1. Lysine intakes at zero protein retention were 13.0 mg and 12.9 mg · kg^?0.8 · d^?1 for Diet A and B, respectively. Growth and nutrient retention were similar for both diets and, therefore, a lysine deficiency in Diet B did not occur. In conclusion, a proportion of 330 g wheat gluten per kg feed did not influence growth performance and maintenance requirement for lysine in juvenile turbot. However, the effect of diet composition on the amino acid profile of body protein might be relevant for the derivation of the amino acid requirement from protein retention.