A predictive score for retinopathy of prematurity by using clinical risk factors and serum insulin-like growth factor-1 levels

AIM：To detect the impact of insulin-like growth factor-1（IGF-1）and other risk factors for the early prediction of retinopathy of prematurity（ROP）and to establish a scoring system for ROP prediction by using clinical criteria and serum IGF-1 levels.METHODS：The study was conducted with 127 preterm infants.IGF-1 levels in the 1st day of life,1st,2nd,3rd and4th week of life was analyzed.The score was established after logistic regression analysis,considering the impact of each variable on the occurrences of any stage ROP.A validation cohort containing 107 preterm infants was included in the study and the predictive ability of ROP score was calculated.RESULTS：Birth weights（BW）,gestational weeks（GW）and the prevalence of breast milk consumption were lower,respiratory distress syndrome（RDS）,bronchopulmonarydysplasia（BPD）and necrotizing enterocolitis（NEC）were more frequent,the duration of mechanical ventilation and oxygen supplementation was longer in patients with ROP（P〈0.05）.Initial serum IGF-1 levels tended to be lower in newborns who developed ROP.Logistic regression analysis revealed that low BW（〈1250 g）,presence of intraventricular hemorrhage（IVH）and formula feeding increased the risk of ROP.Afterwards,the scoring system was validated on 107 infants.The negative predictive values of a score less than 4 were 84.3%,74.7%and 79.8%while positive predictive values were 76.3%,65.5%and71.6%respectively.CONCLUSION：In addition to BW〈1250 g and IVH,formula consumption was detected as a risk factor for the development of ROP.Breastfeeding is important for prevention of ROP in preterm infants.

Growth and energy budget of juvenile lenok Brachymystax lenok in relation to ration level

We evaluated the effect of ration level(RL) on the growth and energy budget of lenok Brachymystax lenok. Juvenile lenok(initial mean body weight 3.06±0.13 g) were fed for 21 d at five different ration levels: starvation,2%,3%,4% bwd(body weight per day,based on initial mean values),and apparent satiation. Feed consumption,apparent digestibility,and growth were directly measured. Specific growth rates in terms of wet weight,dry weight,protein,and energy increased logarithmically with an increase in ration levels. The relationship between specific growth rate in terms of wet weight(SGRw,%/d) and RL(%) was characterized by a decelerating curve: SGRw=-1.417+3.166ln(RL+1). The apparent digestibility coefficients of energy exhibited a decreasing pattern with increasing ration level,and there was a significant difference among different RLs. Body composition was significantly affected by ration size. The relationship between feed efficiency rate in terms of energy(FERe) and RL was: FERe=-14.167+23.793RL–3.367(RL)2,and the maximum FERe was observed at a 3.53% ration. The maintenance requirement for energy of juvenile lenok was 105.39 k J BW(kg)-0.80/d,the utilization efficiency of DE for growth was 0.496. The energy budget equation at satiation was: 100IE=29.03FE+5.78(ZE+UE)+39.56 HE+25.63 RE,where IE is feed energy,FE is fecal energy,ZE+UE is excretory energy,HE is heat production,and RE is recovered energy. Our results suggest that the most suitable feeding rate for juvenile lenok aquaculture for wet weight growth is 2.89% bwd,whereas for energy growth,the suggested rate is 3.53% bwd at this growth stage.

Study of Chinese Economic "Growth Drag" Caused by Land Resource in the Perspective of the Modified Two-Level CES Production Function

The purpose of the study is to measure the "growth drag" according to the characteristic of Chinese land resource.Romer model (2001) holds that every country is inevitably affected by the "growth drag" due to the limitation of land resource.So it's of profound strategic significance to measure the "growth drag" according to the character of Chinese land resource.Modified two-level CES production function was employed,and this paper modified the hypothesis of the model.The result indicates that the limitation of Chinese land resource casts shadow over the economic development of China,and the growth rate is 0.4618% lower than that without the limitation of land resource.Through implementing the land resource protection policy along with the technology improvement and the substitute effect of other factors to the land resource,China will keep a steady and balanced economic growth.

Growth and Biochmical Studies of Mrigal Fish (Cirrhinus mrigala) Fed Graded Levels of Oil

A 45-day experiment was carried out to evaluate the growth performance, digestive enzymes activity and biochemical response of Cirrhinus mrigala fed graded levels of oil. Three isonitrogenous purified diets （6%, 8% and 10% of oil） were formulated. A total of 108 juveniles of Cirrhinus mrigala （5.95±0.25） g were equally distributed in triplicate groups in nine plastic tanks of 100 L capacity and fed under natural light cycle. Growth performance of the fish significantly reflected the effect of inclusion levels of oil tested but the diet with 8% lipid had the best significant growth performance [% weight gain, Feed Conversion Ratio （FCR） and Specific Growth Rate （SGR）], across different experimental groups. Levels of secretion of digestive enzymes in the fish fed different experimental diets resulted in significant values of （p〈0.05） amylase and lipase, while Aspartate transaminase （AST）, Alanine transaminase （ALT）, Lactate dehydrogenase （LDH） and Malate dehydrognnase （MDH） values in the muscle and liver decreased significantly （F〈0.05） as the levels of oii in the diet increased. However, serum biochemical parameters did not record any significant difference 6o〉0.05） with the exception of the total lipid across diets. The study confirmed the inclusion effect of graded levels ofoil in juvenile Mrigal diet, but the inclusion should not be more than 8% to avert growth depression.

Expression of insulin-like growth factor-1 mRNA and protein level of corpora striata in ischemic side at the early stage of middle cerebral artery ischemia/reperfusion in rhesus monkeys

BACKGROUND： Insulin-like growth factor-I（IGF-1）, as one of the important members of growth factor family, participants in the regulation of many physiological functions and behaviors, having very strong neuroprotective effect. However, the expression of IGF-1 following cerebral ischemia/reperfusion is still disputed. OBJECTIVE： To observe the expression of IGF-1 and protein of corpora striata in ischemic side at the early stage of middle cerebral artery ischemia/reperfusion in rhesus monkey. DESIGN ： A completely randomized grouping design, controlled animal experiment SETTING ： Institute of Cerebrovascular Disease, Affiliated Hospital of Medical College of Qingdao University MATERIALS： ① Totally 17 rhesus monkeys , of either gender, aged 4 to 5 years, were enrolled . Seven rhesus monkeys observed with gene chip were randomly divided into 2 groups： sham operation group （n=3） and ischemia/reperfusion group 〈n=4〉. Ten rhesus monkeys observed with in situ hybridization and immunohistochemistry method were randomly divided into 2 groups： sham operation group 〈n=3 〉and ischemia/reperfusion group （n=7）. Rhesus monkeys observed under microscope were divided into 2 groups： sham operation group （n=6） and ischamia/reperfusion group （n=-11）.②Materials used in the experiment： cresyl violet （Sigma Company, America）; immunohistochemical reagent kit （ Huamei Bio-engineering Company）; In situ hybridization reagent kit （Boshide Bio-engineering Co.Ltd, Wuhan）; 12 800 dots chip （Boxing Company, Shanghai）. METHODS ： This experiment was carried out at the Institute of Cerebrovascular Disease, Affiliated Hospital of Medical College of Qingdao University from January 2001 to December 2003.① The onset area of middle cerebral artery was blocked for 2 hours, middle cerebral artery ischemia/reperfusion models were created.② After ischemia/reperfusion for 24 hours, cerebral tissue sections of rhesus monkeys were prepared and stained with cresyl violet. Image analysis was performed with 5001W image analysis software. Morphological change of corpora striata of operative side was observed in the rhesus monkeys between two groups. Total RNA was extracted from cerebral tissue. ③ Detection of gene chip： Cy3-duTP and Cy5-duTP were used to respectively perform reverse transcription labeling. The sample was reversely transcribed into cDNA, then hybridized with cDNA of cerebral tissue. Genes with the separate absolute value of cy3 and cy5〉800, cY3/cy5 〉 2（high expression） or 〈 0.5 （low expression） were found out. Those were genes with differential expression. ④ The expressions of IGF-1 mRNA and protein level of corpora striata in ischemic side of rhe- sus monkeys were detected between sham operation group and ischemia/reperfusion group at 9 and 24 hours after ischemia/reperfusion with in situ hybridization method and immunohistochemical method. Brown granules were IGF-1 protein positive cells. ⑤ Analysis of variance was used in the difference comparison of measurement data among groups. MAIN OUTCOME MEASURES ： ① Change of morphological structure of corpora striata at ischemic side in rhesus monkeys. ② Change of cerebral gene expression profiles at ischemia/reperfusion in rhesus monkeys between two groups.③ Expression of IGF-1 mRNA and protein level of corpora striata at ischemia/reperfu- sion in rhesus monkeys between two groups. RESULTS ： ① Pathological change ： Obvious pathological change of cerebral infarction appeared in the ischemia and reperfusion group, while there was no such pathological change in the sham operation group.② Change of gene expression profile ： There were 4480 genes with difference expression in the ischemia/reperfusion group and sham-operation group, in which, 260 genes had high expression and their absolute value was over 800, and 63 genes had low expression, cy3/cy5 of IGF-1 was 0.379, being relative low ex- pression. ③ IGF-1 mRNA and protein positive cell counts in corpora striata at cerebral ischemic side[IGF-1 mRNA： 〈9.72±1.18）,（9.11 ±0.76）,（14.77±0.60） counts/field：lGF-1 protein： （15.11 ±1.83）,（15.39±0.78）, （34.62±0.97）counts/field, P 〈 0.05-0.01]. CONCLUSION： IGF-1 mRNA and protein are lowly expressed in middle cerebral artery of rhesus monkeys at ischemia/reperfusion.

Influence of the Repeated Flooding on Growth and Development of Acorus calamus Vegetation in Water-level-fluctuation Zone of the Three Gorges Reservoir

[ Objective] The research aimed to study influence of the repeated flooding on growth and development of A. calamus in water-level-fluc- tuation zone of the Three Gorges Reservoir. [ Method] A. calamus plants were exposed to water under the dark conditions respectively in Septem- ber 2009 and September 2010. Then, they were taken away from the water, and grew in natural conditions in the following March and April respec- tively （ marked as S1, S2, S1 and S2）. The plant number was conducted statistics respectively. On May 7, the leaf number was made statistics. Length, width and rapid light responding curve of the leaf were determined. [ Result] Repeated flooding restrained significantly plant germination un- der the dark condition. Plant number in S1 and S2 groups decreased by 38.9% and 33.3% respectively compared with the control. It also reduced survival rate of the plant. Plant number in S2 group decreased by 16.7% （P 〈 0.05） compared with that of S2 group when they were taken away from the water. Both of flooding promoted elongation of the leaves, restrained leaves to grow wider, and also restrained leaf formation of the plants except for S1 and S1 groups. Total leaf length of a plant decreased markedly after the second flooding which in S1 and S2 groups were 50.6% and 36.9% respectively less than that after the first flooding. Total leaf number of the plant in S1and S2 groups reduced significantly, and they were only 63.1% and 38.5% respectively of the control. Compared with the first flooding, total leaf length of a plant in the control increased signifi- cantly and decreased remarkably in S2 group after the second flooding. Furthermore, light response ability of the relative electronic transfer rate （rETR） in S1 group wasn＇t significantly different from the control, and rETRmax, in S2 group was significantly less than the control. Moreover, non- photochemical quenching （NPQ） decreased remarkably in S1 and S2 groups. It indicated that A. calamus had good restore ability of the light re- sponse, but restoring of its heat dissipation capacity was slower. [ Conclusion] Repeated flooding inhibited plant growth and population recovery of A. calamus under the dark condition.

肥猪散对育肥猪生长性能、血清生化指标、抗氧化水平和生长激素水平的影响

为了解肥猪散对育肥猪生长性能、血清生化指标、抗氧化水平和生长激素水平的影响,试验选取160头体重相近的育肥猪,随机分为4组,对照组饲喂基础饲粮,试验1、2、3组分别在饲粮中添加1%、2%、4%肥猪散,试验期35 d。试验期间对育肥猪的生长情况进行测定和记录,检测第0、35天的血清生化指标、抗氧化水平和生长激素水平。结果显示:与对照组相比,试验1、2、3组增重和平均日增重极显著增加(P<0.01),试验2、3组平均日采食量显著增加(P<0.05),各组间的料重比差异不显著(P>0.05);使用肥猪散35 d后,试验1、2、3组血清尿素氮含量显著降低(P<0.05),葡萄糖含量极显著升高(P<0.01),超氧化物歧化酶活性有上升的趋势(0.05<P<0.10),皮质醇含量显著降低(P<0.05)。综上,育肥猪饲料中添加肥猪散具有提高生长性能,改善血清生化指标,提高抗氧化水平和生长激素水平的作用,推荐添加剂量为2%。

地方保护政策对中国新能源汽车市场推广的影响分析

加快建设全国统一大市场对推动中国新能源汽车产业发展具有重要意义,而各地频发的地方保护现象却成为阻碍新能源汽车市场推广的主要因素。以2010—2021年中国28个省(市、区)新能源汽车推广数量的面板数据作为研究样本,分析了地方保护政策对新能源汽车市场规模和市场占比的影响,以及产品市场发育程度在其中的调节和门槛效应。研究结果表明,地方保护政策对新能源汽车市场规模扩大和市场占比提升均有显著的抑制作用,产品市场发育程度在该影响过程中具有调节性作用,地方保护政策对市场规模的作用受到产品市场发育程度单一门槛效应的影响,而对市场占比的作用则受双重门槛效应的影响,呈现出先促进后抑制的倒“U”型特征。进一步研究显示,地方保护政策通过加深能源市场分割阻碍了新能源汽车市场推广。区域异质性表明,东部地区的地方保护政策对新能源汽车市场推广有显著的抑制作用,而中西部地区的保护政策则有助于市场规模的扩大;在有新能源汽车上市企业母公司的地区,地方保护政策的抑制作用更为明显;而在没有此类企业的地区,其抑制作用相对较弱。研究结论为打破中国新能源汽车产业中的地方保护主义、推动产业可持续发展提供了决策参考。

火针联合低压无针瘢痕内注射复方倍他米松治疗瘢痕疙瘩疗效及对生长因子水平、瘢痕状态的影响

目的观察火针联合低压无针瘢痕内注射复方倍他米松治疗瘢痕疙瘩的效果及对生长因子水平、瘢痕状态的影响。方法选取2021年1月—2022年2月来我院就诊100例瘢痕疙瘩患者,随机分为对照组、治疗组,每组各50例,对照组采用低压无针瘢痕内注射复方倍他米松,治疗组在对照组基础上加火针治疗,对比两组疗效、生长因子水平、瘢痕状态。结果治疗组治疗后总有效率较对照组为高(P<0.05);治疗组治疗后细胞生长因子β1(TGF-β1)、血小板源生长因子(PDGF)、表皮细胞生长因子(EGF)指标水平均较对照组为低,成纤维细胞生长因子(FGF)指标水平较对照组为高(P<0.05);观察组治疗后瘢痕状态评分均较对照组低(P<0.05)。结论火针联合低压无针瘢痕内注射复方倍他米松治疗瘢痕疙瘩疗效明显,可调节生长因子水平,还能改善瘢痕状态,促进其恢复,值得推广。

Implication of serum levels of interleukin-18 and nitric oxide in tumor growth and metastasis of non-small cell lung cancer

To study the effect of IL-18 and nitric oxide(NO) on the growth and metastasis of non-small cell lung cancer (NSCLC).Methods Serum IL-18 and nitrate and nitrite levels in 82 patients with NSCLC and 20 healthy control subjects were measured by using ELISA and Griess.Results The levels of serum IL-18 were (334.2±31.0)ng/L in NSCLC patients and (151.3±22.0)ng/L in control subjects,respectively.The levels of nitrate and nitrite were (237.1±21.0)μmol/L in NSCLC patients and (44.2±15.0)μmol/L in control subjects.The levels of serum IL-18 and nitrate and nitrite were not related with age,gender,histological types in patients with NSCLC.The levels of serum IL-18 was closely associated with TNM stage,lymph node metastasis and distal metastasis,but not with its degree and organ types of metastasis.There was a negative correlation between the levels of serum IL-18 and nitrate and nitrite.Conclusion Serum IL-18 and nitrate and nitrite levels may be useful to evaluate the prognosis of the patients with NSCLC.16 refs,2 tabs.

我国县域经济韧性的实践检验

县域是连接乡村与城市的重要纽带,是拉动城乡要素双向流动的中转站。通过测度2014—2020年我国2 074个县以及296个城市的经济韧性发现,城市经济韧性整体高于县域经济,当受到外部冲击后,县域经济韧性逆势上升;在产业方面,第三产业韧性高于第二产业,受到外部冲击后,第一产业韧性逆势上升,第二产业韧性波动较小,第三产业韧性下降明显;在区域方面,中西部地区的县域经济韧性较强,东部地区的城市经济韧性较强。此外,通过双向固定效应模型回归发现,经济增长和经济稳定对经济韧性均有显著的边际贡献,经济增长提高经济发展活力,经济稳定为降低韧性波动提供有益支撑。2020年受新冠疫情冲击,县域的经济增长对韧性的边际贡献有所下降,经济稳定对韧性的边际贡献显著提升;对县域而言,第三产业、东部地区、外围城市的经济增长显著,第一产业、第二产业、中西部地区的经济稳定显著。为实现县域经济韧性对我国经济的带动作用,要充分发展壮大县域经济,提高县域经济韧性,破解发展不平衡不充分的问题;要注重经济韧性的产业和区域差异,协调产业间及区域间经济发展协作关系;既要充分发挥增长对经济的带动作用,也要发挥经济稳定对降低经济波动作用,实现经济增长和经济稳定的平衡统一,促进经济高质量发展。

不同粗蛋白质水平对白王种鸽繁殖性能和乳鸽生长性能的影响

试验旨在探究“2+2”生产模式下不同粗蛋白质水平对白王种鸽繁殖性能和乳鸽生长性能的影响。试验选取产蛋性能相近的300日龄健康种鸽168对,随机分为4组,每组7个重复,每个重复6对种鸽,每对种鸽哺育2只乳鸽。试验Ⅰ组、Ⅱ组、Ⅲ组和Ⅳ组分别饲喂粗蛋白质水平为13.43%、15.04%、16.64%和18.25%的饲粮。试验期46 d,其中孵化期18 d (1~18 d),哺乳期28 d (19~46 d)。结果显示,试验Ⅱ组、Ⅲ组产蛋间隔显著低于试验Ⅰ组(P<0.05),试验Ⅲ组种蛋受精率显著高于试验Ⅰ组、Ⅳ组(P<0.05),试验Ⅲ组入孵蛋孵化率极显著高于试验Ⅰ组、Ⅱ组、Ⅳ组(P<0.01)。试验Ⅲ组乳鸽28日龄体重显著高于试验Ⅰ组(P<0.05),乳鸽屠宰率极显著高于试验Ⅰ组(P<0.01),乳鸽胸肌率显著高于试验Ⅰ组、Ⅱ组、Ⅳ组(P<0.05)。试验Ⅱ组、Ⅲ组、Ⅳ组窝料重比1极显著低于试验Ⅰ组(P<0.01)。研究表明,不同粗蛋白质水平影响了种鸽的繁殖性能、乳鸽的生长性能以及窝料重比,在“2+2”生产模式下,建议白王种鸽饲粮适宜粗蛋白质水平为16.64%。

扶正化浊汤联合甲状腺片治疗对甲状腺结节大小及疗效的影响

目的探讨扶正化浊汤治疗甲状腺结节(TN)对结节大小的影响。方法TN患者106例,随机均分为观察组和对照组,对照组给予左甲状腺素钠片常规治疗,观察组在对照组基础上同时增加扶正化浊汤治疗;于治疗前、治疗3个月时,对2组患者进行中医主症评分,采用彩色多普勒超声仪记录2组患者结节数目、最大直径、结节体积、血流阻力指数(RI)及搏动指数(PI),同时采集患者外周静脉血4 mL,检测促甲状腺激素(TSH)、游离三碘甲状腺原氨酸(FT3)、游离四碘甲腺原氨酸(FT4)及血管内皮生长因子(VEGF)水平,治疗3个月后评估2组患者的西医疗效,记录2组治疗期间恶心、呕吐、皮疹及口干等不良反应发生情况。结果治疗后3个月,2组中医主症评分均较治疗前下降,且观察组低于对照组(P<0.05);与对照组比较,2组TN患者治疗3个月后结节数目减少、结节最大直径和结节体积均降低,且观察组低于对照组,差异有统计学意义(P<0.05);治疗后3个月,观察组TSH低于对照组,FT 3、FT 4高于对照组(P<0.05);治疗3个月后,观察组VEGF、RI、PI低于对照组(P<0.05);观察组西医疗效和中医证候疗效中的临床痊愈和总有效率均高于对照组,差异有统计学意义(P<0.05);比较观察组与对照组不良反应发生率比较,差异无统计学意义(P>0.05)。结论扶正化浊汤治疗TN疗效显著,可有效减轻患者症状,减小结节数目及大小,调节甲状腺功能,改善血流状况,降低VEGF表达,且安全性高。

乙二胺四乙酸铁钠对肉仔鸡生长性能和组织中铜、锌和锰元素沉积的影响

试验旨在研究饲粮添加乙二胺四乙酸铁钠(NaFeEDTA)对肉仔鸡生长性能和不同组织中铜、锌和锰沉积的影响。试验按3(铁源)×3(添加铁水平)+1(不加铁对照组)双因子完全随机试验设计,将560只1日龄AA肉公鸡随机分成10组,每组7个重复,每个重复8只鸡,分别饲喂未添加铁的玉米-豆粕型基础日粮(对照组)和在此基础日粮中分别添加20、40和60 mg/kg铁(分别源于硫酸亚铁(FeSO_(4)·7H_(2)O)、饲料级NaFeEDTA和食品级NaFeEDTA的饲粮21 d。结果显示:与FeSO_(4)·7H_(2)O组相比,饲粮添加不同来源的NaFeEDTA对肉仔鸡生长性能无显著影响(P>0.05);食品级和饲料级NaFeEDTA组心脏中铜、胫骨中锌以及肝脏和胫骨中锰元素的含量显著提高(P<0.05)。由此可见,添加NaFeEDTA从整体上促进了肉仔鸡心脏中铜、胫骨中锌以及肝脏和胫骨中锰元素的沉积。

饲粮中性洗涤纤维水平对晋汾白猪生长性能、消化能力、肠道微生物以及代谢产物的影响

本试验旨在探究不同中性洗涤纤维(NDF)水平饲粮对晋汾白猪生长性能、抗氧化能力、消化能力、肠道微生物以及代谢产物的影响,为纤维的合理利用提供理论依据。选用体重为(19.72±0.37)kg的晋汾白猪80头,随机分成4组,每组5个重复,每个重复4头(公母各占1/2)。4组试验猪分别饲喂NDF水平为9.0%(不添加大豆皮,9N组)、13.5%、(添加9.35%大豆皮,13.5N组)、18.0%(添加18.64%大豆皮,18N组)和22.5%(添加28.03%大豆皮,22.5N组)的饲粮,以9N组为对照组。预试期7 d,正试期30 d。结果显示:1)与13.5N组相比,9N组、18N组和22.5N组的料重比显著降低(P<0.05)。2)22.5N组的血清总抗氧化能力显著高于9N组和18N组(P<0.05)。3)在结肠前段,13.5N组和22.5N组的纤维素酶含量显著高于18N组和9N组(P<0.05)。4)18N组和22.5N组的粗蛋白质表观消化率显著低于9N组和13.5N组(P<0.05)。5)结肠内容物中丙酸和异丁酸浓度以9N组的最高,丁酸和戊酸浓度以13.5N组最高。6)13.5N组、18N组和22.5N组的肠道微生物Alpha多样性指数均显著高于9N组(P<0.05);18N组结肠内容物中普雷沃氏菌属_9的相对丰度显著高于9N组和22.5N组(P<0.05),13.5N组结肠内容物中毛螺菌属的相对丰度高于9N组(P<0.05);同时,丙酸、异丁酸和异戊酸均与普雷沃氏菌属9存在显著或极显著正相关(P<0.05或P<0.01),丁酸与毛螺菌属存在极显著正相关(P<0.01)。7)13.5N组结肠内容物中γ-L-谷氨酰基-L-谷氨酸表达量高于其他3组。综上可知,饲粮NDF水平的适当提高降低了晋汾白猪的料重比,提高了机体的抗氧化能力,改善了机体的消化能力,增加了肠道微生物的多样性,改善了肠道健康,影响了机体的代谢产物,进而促进了机体健康发育。在本试验条件下,晋汾白猪饲粮中适宜的NDF水平为13.5%~18.0%。

不同施磷水平下外生菌根真菌对薄壳山核桃幼苗生长和磷吸收的影响

采用盆栽实验,比较了低磷(0.05 mmol·L^(-1))和正常施磷(0.50 mmol·L^(-1))下接种土生空团菌(Cenococcum geophilum Fries)和豆马勃属菌(Pisolithus sp.)以及未接菌的薄壳山核桃〔Carya illinoinensis(Wangenh.)K.Koch〕幼苗在净光合速率、干质量、营养元素吸收以及土壤酶活性的差异。结果显示:低磷条件下,土生空团菌和豆马勃属菌的幼苗菌根侵染率分别为39.9%和35.5%;正常施磷条件下,这2种真菌的幼苗菌根侵染率分别为41.4%和31.9%。总体上看,缺磷会抑制幼苗光合作用,减少干质量以及叶中全氮、全磷和全钾含量;接菌处理促进了幼苗光合作用,增加了干质量以及根、茎、叶中全氮、全磷和全钾含量。低磷条件下,接种豆马勃属菌对幼苗光合作用和干质量增加的提升效果显著优于接种土生空团菌,接种土生空团菌对幼苗营养元素吸收的提升效果总体优于接种豆马勃属菌。低磷条件下,接菌处理提高了土壤中β-葡萄糖苷酶、N-乙酰-β-葡萄糖苷酶和碱性磷酸酶活性,降低了亮氨酸氨基肽酶活性,且接种豆马勃属菌对土壤酶活性的提升效果优于接种土生空团菌。综合分析认为,外生菌根真菌对薄壳山核桃幼苗在低磷条件下的磷吸收和生长具有明显促进作用,不同菌种对薄壳山核桃幼苗生长和土壤酶活性的影响存在差异,在提高磷利用效率和宿主植株干质量方面表现出不同的优势。

饲粮蛋白质水平对舍饲育肥牦牛生长性能、养分表观消化率及血清生化指标的影响

试验旨在探究不同粗蛋白水平饲粮对冷季舍饲集中育肥牦牛生长性能、养分表观消化率及血清生化指标的影响。试验选取体况良好、体重(180.00±11.67)kg的公牦牛30头,随机分为3组,每组10个重复,每个重复1头牦牛。设计3个粗蛋白水平分别为12.5%(Ⅰ组)、15.5%(Ⅱ组)和18.5%(Ⅲ组)的全混合饲粮(TMR)。预试期30 d,正式试验期90 d。结果显示,Ⅰ组、Ⅱ组牦牛的总增重、平均日增重显著高于Ⅲ组(P<0.05);Ⅲ组牦牛的料重比显著高于Ⅰ组、Ⅱ组(P<0.05)。Ⅱ组、Ⅲ组牦牛的粗灰分表观消化率显著高于Ⅰ组(P<0.05)。Ⅲ组牦牛血清中谷丙转氨酶(ALT)活性显著高于Ⅱ组(P<0.05);Ⅲ组尿素氮(BUN)含量显著高于Ⅰ组、Ⅱ组(P<0.05)。研究表明,中蛋白质水平饲粮在牦牛育肥过程所呈现的育肥效果较好,冷季集中育肥牦牛推荐饲粮蛋白质水平为15.5%。

能量和蛋白水平对生长育肥阶段皖西白鹅生长性能、肠道酶活性及血液指标的影响

试验旨在探究皖西白鹅育肥阶段饲粮适宜的能量和蛋白水平。选用180只1日龄体重接近、健康的皖西白鹅,随机分为6组,每组5个重复,每个重复6只,采用2×3因子设计高代谢能(12.3 MJ/kg)、低代谢能(11.8 MJ/kg)以及高蛋白(16.3%)、中蛋白(15.3%)、低蛋白(14.3%) 6种不同能量和蛋白水平的饲粮。试验期63 d。结果显示:63日龄时D组(11.8 MJ/kg、16.3%)皖西白鹅日增重显著高于A组、C组、E组(P<0.05),料重比最低;D组肠道麦芽糖酶活性显著高于A组、B组、E组、F组(P<0.05);胰蛋白酶活性排序为D组>F组>A组>C组>B组>E组。研究表明,育肥阶段皖西白鹅饲粮适宜的代谢能、蛋白水平分别为11.8 MJ/kg、16.3%。

饲料蛋白质水平对图们雅罗鱼生长指标和鱼体成分的影响

文章旨在研究不同饲料蛋白质水平对图们雅罗鱼(Leuciscus waleckii tumensis)生长指标和鱼体主要体成分的影响。试验将630尾初始体重为(3.37±0.07)g的图们雅罗鱼随机分成6组,每组3个重复,每个重复35尾鱼。各组饲料蛋白质水平分别为30.12%(P1)、33.21%(P2)、36.17%(P3)、39.64%(P4)、42.19%(P5)、45.37%(P6),进行8周的网箱养殖生长试验。试验结果表明,不同蛋白质水平图们雅罗鱼的终末体重、增重率、特定生长率和饲料效率均有先增高后降低的趋势。随饲料蛋白水平的升高,鱼体粗蛋白质、水分和粗灰分差异不显著(P>0.05),粗脂肪含量有下降趋势,与高蛋白质水平组相比,低蛋白质水平组鱼体脂肪含量显著降低(P<0.05)。依据生长和体成分指标,用回归曲线拟合特定生长率和饲料效率综合评价,图们雅罗鱼蛋白质需求量为38.07%~38.52%。

饲粮蛋白质水平对藏羊生长性能、血清生化指标及肉品质的影响

试验旨在探究不同蛋白质水平饲粮对藏羊生长性能、血清生化指标和肉品质的影响。试验选用初始体重相近[(15.40±0.81)kg]且体况良好的2月龄高原型藏羊公羔90只,随机分为3个组,每组5个重复。各组分别饲喂蛋白质水平为12%(A组)、14%(B组)和16%(C组)的饲粮。整个试验分预试期7 d和正试期90 d。结果显示:①各组间的平均日增重、平均日采食量及料重比均差异不显著(P>0.05)。②A组的血清谷丙转氨酶活性高于B组(P>0.05)和C组(P<0.05),B组的血清葡萄糖含量显著低于其他两组(P<0.05),A组的血清总蛋白含量低于B组(P<0.05)和C组(P>0.05)。③C组的肌肉中糖原含量显著高于A组(P<0.05),C组的肌肉中苹果酸脱氢酶活性显著高于其他两组(P<0.05)。④C组的肌纤维直径显著高于B组(P<0.05),B组和C组的肌纤维密度显著高于A组(P<0.05),B组的肌纤维横截面积显著高于C组(P<0.05)。综上,饲粮蛋白水平为16%时,有利于增强藏羊的生长性能。在饲粮蛋白水平为14%时,有利于增强育肥期藏羊肌肉品质。