The Effect of Quantitative Feed Restriction Duration on Growth Performance and Carcass Characteristics of Broiler Chickens

The growth productivity of broilers is influenced by improving growth performance through improving body weight, average daily gain, and feed conversion rate. The objective of the study was to determine the effect of quantitative feed restriction duration on growth performance and carcass characteristics of broilers. A total of 144 day-old broiler chicks were reared in a deep litter system until slaughter at 42 days. Chicks were randomly allocated to three treatments which were replicated three times with 16 birds per replicate. The three treatments were the control (T1), one week of feed restriction (T2), and two weeks of feed restriction (T3). Birds were fed with starter, grower and finisher diets. The average daily gain (ADG), average daily feed intake (ADFI), and the feed conversion ratio (FCR) were computed for each week. Carcass weight and internal organs weights were measured. The body weight gained by the birds in T1 was similar to the birds that were restricted for a week. The treatments had a significant effect on the average daily gain in weeks 4, 5, and 6. The ADG for T2 was higher (P < 0.05) at week 5 after 1 week of restriction, than T1 and T3. The feed conversion ratio was significantly higher in T3 after 2 weeks of restriction. In T2 and T3, feed intake was significantly lower than in birds fed ad libitum at week 4 at the start of the treatment. There was no significant effect on the relative weights of heart weights, liver, gizzard, feet, and heads among the treatment groups except for intestine weight which was lower (P < 0.05) in T1 than T2 and T3. It was concluded that broilers that were restricted for one week had a positive result in growth performance. Feed restriction had minimal effect on the organ weights of broiler chickens.

Intoxication Induced by Urea Containing Diets in Broiler Chickens: Effect on Weight Gain, Feed Conversion Ratio, Hematological and Biochemical Profiles

Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, and hematological and biochemical profiles. A total of 48 broiler chicks were randomly allotted into 4 groups, designated Groups 1, 2, 3 and 4 of 12 birds each. Birds in Groups 2, 3 and 4 were fed on diets containing urea at the levels of 1%, 2.5% and 4%, respectively. Birds in Group 1 served as control and were not exposed to urea. Experimentation period was for 3 weeks and experiment was terminated when birds were 42 days of age. Body weight of all intoxicated birds at the various intervals was significantly decreased in comparison with that of the untreated control. Compared with control, all intoxicated broilers manifested significant (P ≤ 0.05) decrease in all hematological parameters involving erythrocytic and total leucocytic counts, Hemoglobin (Hb) and Packed Cell Volume (PCV) on a dose- and time-pattern. In comparison with the control levels, biochemical profile of the intoxicated birds disclosed significant decrease in blood glucose level and significant increase in serum uric acid, urea, Alkaline Phosphatase (ALP) and Lactate Dehydrogenase (LDH) levels. Based upon the present data, it was concluded that the addition of urea to broiler diets bears serious sequences concerning the general health condition, performance, weight gain, and hematological and biochemical profiles.

Effects of Feeding Time on the Growth Performance and Variation of RNA/DNA Ratio of the Chinese Soft-shelled Turtle, Pelodiscus sinensis

The present study was to investigate the effects of feeding time on growth of the Chinese soft-shelled turtle. The experiment was carried out with a photoperiod of 12L （light）： 12D （dark） with lights on at 06：00 and off at 18：00. Turtles were maintained at a temperature of 32 - 0.2 ℃ in tanks throughout the length of the experiment. The turtles in group 1 to group 6 were fed respectively at 00：00, 04：00, 08：00, 12：00, 16：00 and 20：00 with 60 turtles each （Initial body weight 88.27 - 0.09 g）. Acrophases of postprandial RNA/DNA ratio in liver in each group was shown between 5h and 7h after feeding. A positive linear correlation could be seen between specific growth rate （SGR） and RNA/ DNA：SGR=t.1586RNA/DNA-0.7097 （r = 0.9328, P = 0.0066）. The results indicated that the values at the acrophases of about 6h after feeding might be used as an instantaneous growth index in the Chinese soft-shelled turtle. The turtles in group 1 grew better than group 3, group 4, group 5, group 6, because they ate more, but they ate more and grew slower than group 2, whose feed conversion rate was also higher. Meanwhile, the SGR and feeding rate of turtles fed at 12：00 were the lowest from the six groups （P 〈 0.05）. Turtles fed in group 1, group 2 and group 6 developed more heavy final body weight （FBW）, higher feeding rate and SGR than the other three groups. This probably suggested that turtles fed in scotophase grew better than that fed at photophase in total.

Linkage between the intestinal microbiota and residual feed intake in broiler chickens

Background:Intestinal microbiota plays a key role in nutrient digestion and utilization with a profound impact on feed efficiency of livestock animals.However,the intestinal microbes that are critically involved in feed efficiency remain elusive.Methods:To identify intestinal bacteria associated with residual feed intake(RFI)in chickens,male Cobb broiler chicks were individually housed from day 14 to day 35.Individual RFI values were calculated for 56 chickens.Luminal contents were collected from the ileum,cecum,and cloaca of each animal on day 35.Bacterial DNA was isolated and subjected to 16S rRNA gene sequencing.Intestinal microbiota was classified to the feature level using Deblur and QIIME 2.High and low RFI groups were formed by selecting 15 and 17 chickens with the most extreme RFI values for subsequent LEfSe comparison of the difference in the microbiota.Spearman correlation analysis was further performed to identify correlations between the intestinal microbiota composition and RFI.Results:No significant difference in evenness,richness,and overall diversity of the microbiota in the ileum,cecum,or cloaca was observed between high and low RFI chickens.However,LEfSe analysis revealed a number of bacterial features being differentially enriched in either high or low RFI chickens.Spearman correlation analysis further identified many differentially enriched bacterial features to be significantly correlated with RFI(P<0.05).Importantly,not all short-chain fatty acid(SCFA)producers showed a positive association with RFI.While two novel members of Oscillibacter and Butyricicoccus were more abundant in low-RFI,high-efficiency chickens,several other SCFA producers such as Subdoligranulum variabile and two related Peptostreptococcaceae members were negatively associated with feed efficiency.Moreover,a few closely-related Lachnospiraceae family members showed a positive correlation with feed efficiency,while others of the same family displayed an opposite relationship.Conclusions:Our results highlight the complexity of the intestinal microbiota and a need to differentiate the bacteria to the species,subspecies,and even strain levels in order to reveal their true association with feed efficiency.Identification of RFI-associated bacteria provides important leads to manipulate the intestinal microbiota for improving production efficiency,profitability,and sustainability of poultry production.

Analysis of York Pigs Feeding Behavior Using Stepwise Regression and Principal Component Regression

A statistical analysis was conducted on the feeding behavior of 106 York breeding pigs.Pearson correlation analysis,principal component correlation analysis and multiple stepwise regression equation methods were applied to establish regression equations of the York breeding pigs total feed intake per time and average feed intake per time with corrected fat thickness,feed conversion rate,and corrected daily gain.The results showed that:①there were three peak feed intake periods for the pigs,and the correlation coefficient between the feed intake and the corrected fat thickness of the pigs in the 24 h period was positive or negative,that is,increasing the number of feeding times and the feed intake was not necessarily conducive to the fat thickness accumulation,but the breeding goal of fat thickness could be achieved by controlling the feeding times and feed intake;②the average feed intake of pigs in the 60-90 kg body weight stage was 30%-50%higher than that of the 30-60 kg body weight stage,but the number of feeding times decreased,the peak feeding time was more concentrated,and the feeding duration per time was 3.0 min longer,indicating that as the weight of pigs increased,the feed intake increased significantly;and③the stepwise regression equations and the principal component equations showed that the feeding behavior of York pigs in the 30-90 kg growth stage was not only affected by the feeding time within 24 h,but also by environmental factors such as temperature and humidity.The feeding behavior of York pigs is a complex process of interaction between environmental factors and animal factors.

Optimal Supplement Dosage of Double-Low Rapeseed Meal in Concentrated Feed of Fattening Lambs

[ Objective] To determine the optimal supplement dosage of double-low rapeseed meal in concentrated feed of fattening lambs. [ Method] A total of 120 Tibetan lambs at the age of 50 d were selected and divided randomly into four groups. The lambs in these four groups were fed with diets respectively supplemented the double-low rapeseed meal of 50,100,150 and 200 g/kg. Their diets had the same nutritional levels of energy and protein. The experimental period was 120 d. [ Result] Daily gain, feed conservation ratio and economic benefits were largely increased in the lambs fed with the diets supplemented the double-low rapeseed meal of 150 g/kg （Daily gain, P 〈 0.01 ）. However, the daily gain and feed conservation ratio were largely decreased in the lambs fed with the diets supplemented the double-low rapeseed meal of 200 g/kg. Moreover, serum levels of transaminase and thyroxine were not significantly different between the four groups. [ Conclusion] The optimal supplement dosage of the double-low rapeseed meal is 150 g/kg in fattening lambs.

A novel integrated step-feed biofilm process for the treatment of decentralized domestic wastewater in rural areas of China

For wastewater treatment in rural areas, a novel three-stage step-feed wastewater treatment system, combined with a drop-aeration biofilm process, was tested in the laboratory to investigate its performance in removing suspended solids （SS）, chemical oxygen demand （COD）, NH4＋-N, total nitrogen （TN）, and total phosphorus （TP）. The removal rates of SS, COD and NH4＋-N were 90%, 80%, and 90% in efluent concentrations less than 10 mg/L, 50 mg/L and 8 mg/L, respectively. The TP removal rate was less satisfactory. The C/N ratio in the raw wastewater was often less than 3.5, and the removal efficiency of TN was therefore limited. A carbon-release batch experiment was carried out to measure the feasibility of enhancing denitrification at low influent C/N ratios. The result showed that the C/N could be over 9.0 in the supernatant. Polymerase chain reaction denaturing gradient gel electrophoresis technology was used to reveal the changes in the bacterial community during different stages of the integrated step-feed biofilm process. The results showed that banding patterns and the distribution of dominant bands for the same experimental period in different aerobic zones were similar. Phylogenetic analysis indicated that lanes 10, 11 and 12, which presented three aerobic zones at the same operation period, had the closest phylogenetic relationship among the lanes.

Feeding Effect of Growing-Finishing Pigs under Fine Division of Feeding Stages

In order to study the feeding effect of fine division of feeding stages on the growing-finishing pigs,96 healthy Duroc × Landrace ×Yorkshire hybrid commercial pigs with similar age in days,size,and body weight about 15 kg,half boars and half sows,randomly divided into3 treatments( each treatment repeated 4 times,and each repetition 8 pigs). According to the body weight division standard,three stages,four stages,and five stages of feeding were adopted separately. The daily ration of with different nutrition levels was used,body weight and feed consumption were measured,and effects of different feeding methods on body weight increase,feed utilization,and economic benefits of growing-finishing pigs. The results showed that compared with the three-stage feeding,the body weight of five-stage and four-stage feeding increased by 4. 18%( P < 0. 01) and 2. 41%( P < 0. 05),respectively,and the body weight of five-stage feeding increased by 1. 74%( P < 0. 05) compared with that of four-stage feeding; the daily feed consumption of five-stage and four-stage feeding increased 3. 10%( P < 0. 01) and 1. 70%(P <0. 01),respectively,and the daily feed consumption of five-stage feeding was 1. 37% higher than that of four-stage feeding. The feed cost of five-stage feeding and four-stage feeding increased 3. 32%( P < 0. 01) and 1. 61%( P < 0. 05) separately,and the feed cost of five-stage feeding was 1. 69% higher than that of four-stage feeding( P < 0. 01). The income from average body weight increase of five-stage and fourstage feeding increased by 5. 47%( P < 0. 01) and 3. 59%( P < 0. 01) respectively,and the benefit of average body weight increase of fivestage feeding was 1. 81% higher than that of four-stage feeding( P > 0. 05). The crude protein consumption from average body weight increase of five-stage and four-stage feeding decreased by 2. 28%( P < 0. 01) and 1. 68%( P < 0. 01),respectively; the crude protein consumption from average body weight increase of five-stage feeding was 0. 67% lower than that of four-stage feeding; the feed conversion ratio of five-stage feeding,four-stage feeding,and three-stage feeding was 2. 92,2. 93,and 2. 95 respectively. The results showed that compared with the threestage feeding,the four-stage and five-stage feeding could significantly increase the body weight of the growing-finishing pigs,improve the feed utilization level and improve the economic benefits,and the effect of five-stage feeding was better than the four-stage feeding.

Influence of fish meal quality on growth,feed conversion rate and protein digestibility in shrimp (Penaeus chinensis ) and red seabream (Pagrosomus major)

The effect of fishmeal quality on growth,feed conversion ratio and protein digestibility was studied in a growth experiment with shrimp and red seabream.The shrimp and fish were fed three diets varing in the quality of the fishmeal used in the respective feeds: low quality fish meal,good quality fish meal,and Peru fish meal.The experiment lasted for 2 months.The shrimp and fish fed the feed with good quality fish meal showed significantly better feed conversion ratio,weight gain rate,protein digestibility than the other groups.

进水分配比对分段进水PN/A工艺脱氮性能影响

以预脱碳污水和市政污水作为目标污水,建立了好氧段分段进水的新模式,通过调整进水分配比来优化好氧段C/N,以期实现短程硝化-厌氧氨氧化(PN/A)工艺在实际工况下的稳定运行.采用4组以好氧/缺氧/好氧/缺氧(O/A/O/A)模式运行的序批式反应器(SBR),R1、R2、R3及R4以进水分配比(预脱碳污水:市政污水)分别为1:0、2:1、1:1及1:2的分段进水模式运行.结果表明,R1未能实现PN/A工艺,总氮去除率(NRE)仅为60.2%.随着进水分配比不断下降,R2、R3、R4分别在第34,30及36d实现PN/A工艺,NRE分别达到71.8%、80.3%及74.1%.其中R3系统处理性能最好且最稳定,厌氧氨氧化贡献率达到83.9%.污泥沉降性与粒径最佳.此外,高通量结果显示氨氧化菌(Nitrosomonas)和厌氧氨氧化菌(Candidatus_Kuenenia)丰度分别为2.74%和12.17%,且与好氧异养菌(AHB)形成了良好的协同作用.因此,分段进水模式在进水分配比为1:1时有利于实现稳定的PN/A工艺,此时各功能微生物可得到较好富集与平衡.

基于工程应用的CW-GMAW熔滴过渡形态表征

综述了涉及工程应用的冷丝熔化极气体保护焊(Cold wire gas metal arc welding,CW-GMAW)熔滴过渡形态特征。结果表明,在大电流、强规范、富氩混合气体保护下,CW-GMAW工艺的熔滴过渡形态呈喷射过渡;当电流较小、电弧电压较低时,可能为滴状过渡,甚至在弧压很低时,呈现短路过渡形态。该工艺电弧发生偏向冷丝的位移,弧长变短甚至发生短路,与冷丝送进速率比增高及冷丝在电弧中产生大量金属蒸气时弧柱电阻下降有关。在具有富氩混合保护气体的相同工艺参数下,CWGMAW转变电流比GMAW降低了4%~7%。焊接工艺参数对CW-GMAW和GMAW工艺熔滴过渡形态的影响规律大致相近,但前者因涉及冷丝送进速率比和电极焊丝送进速度,以及它们的匹配等,使焊接电流的影响更为复杂。

零鱼粉饲料与高鱼粉饲料饲喂下凡纳对虾饲料利用效率相关性状的遗传评估

为探讨选育零鱼粉需求凡纳对虾(Penaeus vannamei)品种的可能性,解决目前鱼粉短缺、饲料成本居高不下的问题,本研究在零鱼粉饲料(蛋白含量占38%)和高鱼粉饲料(鱼粉含量占25%,蛋白含量占42%)饲喂条件下进行凡纳对虾饲料利用效率相关性状的遗传评估。选择30个家系进行40 d的单尾饲养实验,结果显示,饲喂高鱼粉饲料对虾的平均增重率(62.00%)和平均饲料效率比(124.00%)明显高于饲喂零鱼粉饲料(23.50%和49.40%)。对虾摄食量和增重率在零鱼粉饲料和高鱼粉饲料饲喂下的遗传力在0.458±0.140到0.699±0.155之间,饲料效率比在零鱼粉饲料和高鱼粉饲料饲喂下的遗传力分别为0.186±0.098和0.341±0.110。由于没有剖分出共同环境效应,遗传力都存在一定程度高估,因此,零鱼粉饲料饲喂下的饲料效率比的遗传变异并不高。摄食量和增重率在2种饲料间的遗传相关分别为0.580±0.171和0.676±0.155,表示这2个性状存在中等的基因型与饲料互作效应。饲料效率比在2种饲料间的遗传相关仅为0.299±0.304,表示该性状存在严重的基因型与饲料互作效应。综上结果来看,使用零鱼粉饲料不利于凡纳对虾的养殖及选育工作的开展。

畜禽饲料效率性状遗传研究进展

饲料效率是评价畜牧生产效率高低的一项重要指标,它是畜禽育种研究的重要性状之一。在过去几十年里,肉蛋奶产量等畜禽生产性状已经取得显著遗传进展。随着饲料成本的逐年提高,近几年饲料效率性状逐渐受到育种工作者的高度关注。欧美国家已陆续将饲料效率作为育种目标纳入综合选择指数,我国也开始相关研究并取得了研究进展。本文介绍了饲料效率的概念、常用衡量指标、遗传参数估计,并综述了国内外常见畜禽饲料效率性状的研究进展,为进一步解析畜禽饲料效率性状遗传机制和优化育种方案提供参考。

杂多酸离子液体催化剂的制备及其合成可降解聚酯PES的催化性能

为了分析杂多酸离子液体催化剂的催化性能,以Fe为中心杂原子、Mo为配位原子,制备了杂多酸阴离子,并将其与1-羟丙基-3-甲基咪唑溴盐通过离子交换反应制备功能化杂多酸离子液体催化剂([HO-(CH_(2))_(2)-mim]_(5)[Ti(H_(2)O)FeMo_(11)O_(39)])。利用FT-IR、UV、XRD和TGA对所制催化剂进行结构表征与性能测试,通过正交试验优化工艺参数,探讨投料比、催化剂用量、酯交换反应温度和时间对其催化性能的影响。结果表明:所制催化剂结构正确,热性能良好,并具有较好催化效果。最佳工艺条件为:投料比2,催化剂质量分数1.0%,反应温度220℃,反应时间5 h,该条件下PES收率为75.32%。

北京鸭对博落回散的耐受性试验

为了探究北京鸭对博落回散的耐受性,为博落回散在饲料中的安全添加剂量提供数据支持,试验将210只1日龄北京鸭分为5组,对照组饲喂不添加任何药物的基础日粮,30,90,150,300 mg/kg组分别饲喂含30,90,150,300 mg/kg博落回散的基础日粮,连续饲喂42 d,分别在14,28,42日龄早晨投料前称量北京鸭的体重,测定各组鸭在1~14、15~28、29~42、1~42日龄的生长性能;分别在14,28,42日龄采集血液,测定各组血常规与血清生化指标;42日龄时屠宰各组北京鸭,采集器官测定器官指数,进行病理解剖并观察组织病理学变化,评价北京鸭对不同剂量博落回散的耐受性。结果表明:与对照组相比,30,90,150 mg/kg组1~42日龄间的日增重和饲料转化率显著提高(P<0.05),300 mg/kg组呈下降趋势但差异不显著(P>0.05);各组在14日龄时血常规与血清生化指标差异不显著(P>0.05);在28,42日龄时,30,90,150 mg/kg组白细胞数、红细胞数、血红蛋白含量与对照组差异不显著(P>0.05),300 mg/kg组与对照组差异显著(P<0.05);300 mg/kg组肝脏重和肝脏指数显著高于对照组(P<0.05)。90,150,300 mg/kg组均有1只北京鸭死亡,对照组有2只死亡;150 mg/kg组有1只北京鸭肝脏颜色偏黄,300 mg/kg组有4只北京鸭肝脏肿大、颜色偏黄,发生轻度脂肪变性、肝细胞肿大、胞浆内发现近圆形空泡等病理变化。说明在饲料中添加30~90 mg/kg的博落回散可安全有效地促进北京鸭生长,当添加量为300 mg/kg时,北京鸭表现不耐受,生长性能下降,饲料转化率降低,并表现出肝脏损伤。

料液比对搅拌型UHT核桃酸奶品质特性的影响

超高温瞬时灭菌技术(ultra high temperature,UHT)在植物乳制品领域的应用备受关注。然而,关于UHT对植物乳制品品质特性的影响并未探明。为解决植物基酸奶在灭菌过程中存在的蛋白过度变性和微生物残留问题,研究了1∶8、1∶10、1∶12、1∶14、1∶16共计5个料液比梯度的核桃酸奶,探讨了UHT处理下不同料液比对搅拌型核桃酸奶品质的影响。研究结果显示,在不同料液比下,核桃酸奶的pH和酸度在发酵过程中表现出一致的趋势。料液比为1∶12时,核桃酸奶具有最高的硬度、稠度和持水性,分别为211.37 g、464.51 g·s和83.54%,相对于其他料液比有效地改善了核桃酸奶的品质特性。料液比为1∶8时,核桃酸奶具有最小的粒径,为37.63μm。综上,通过对核桃酸奶进行UHT处理并使用适宜的料液比,可以明显地改善核桃酸奶的品质特性。研究结果可为搅拌型核桃酸奶产品的生产提供关键的实验数据和理论支持,并为相关领域的学术研究和工业应用提供参考。

陈化粮对雏鸡生长性能和免疫指标的影响及乳酸杆菌的恢复作用

在模拟制备黄曲霉毒素超标陈化粮的基础上,探究陈化粮对雏鸡料肉比、免疫器官指数和血细胞数量的影响以及乳酸杆菌的恢复作用。选用160只白来航雏鸡,随机分为4组,分别为对照组、高剂量黄曲霉毒素组、低剂量黄曲霉毒素组、高剂量黄曲霉毒素+乳酸杆菌组,攻毒时间为28 d。结果发现,与对照组相比,黄曲霉毒素对雏鸡日增重有显著的阻滞作用;与对照组相比,低剂量黄曲霉毒素组和高剂量黄曲霉毒素组料肉比极显著升高,而添加乳酸杆菌对雏鸡料肉比具有显著的恢复作用(P<0.05)。与对照组相比,黄曲霉毒素对鸡血细胞生成和免疫器官发育具有显著的阻滞作用(P<0.05),导致血细胞合成受阻和免疫器官发育滞后,而乳酸杆菌对鸡血细胞生成和免疫器官发育具有一定的恢复作用。

补料比及反冲推头倾角对Y型管内高压成形质量的影响研究

目的解决5A02铝合金Y型管在内高压成形过程中易出现破裂和内凹缺陷的问题,以获得最佳成形质量的管件,对成形中的补料比和反冲推头倾角进行研究。方法使用内高压成形机进行实验,分析了管件的表面质量、管件壁厚分布情况,研究了补料比和反冲推头倾角对Y型管成形质量的影响。选取端面倾角大小分别为0°、13.5°、27°的反冲推头进行实验,设计了1.5∶1、2∶1、2.5∶1和3∶14组补料比进行对比分析。结果比较3种不同反冲推头成形得到的管件,通过对支管成形效果的分析,确定13.5°为最佳反冲推头倾角;补料比在1.5~2.5时可成形出Y型管,补料比为2∶1时,Y型管成形质量最好。为获得成形质量高的Y型管,需选择补料比为2∶1的加载路径和端面倾角为13.5°的反冲推头进行实验。结论采用合适的反冲推头端面倾角,既可以使Y型管获得理想高度的支管,又可有效地抑制成形中期支管出现的破裂缺陷;选择合理的补料比可以避免过渡圆角内凹缺陷,也可以改善Y型管的壁厚分布情况,进一步提升管件最终的成形质量。

片烟加料均匀性快速评价方法研究

采集不同加料比例下的片烟近红外光谱(Near-infrared spectrum,NIR)数据,采用多元散射校正(Multiplicat-ive scatter correction,MSC)结合二阶导数和卷积平滑(Savitzky-golay smoothing,S-G)对光谱数据进行预处理,光谱范围选择7500~4000 cm^(-1),采用偏最小二乘法构建加料比例预测模型并对模型进行内部交叉验证和外部验证。结果表明,该模型的R^(2)=0.999,RMSE=0.026,交叉验证R^(2)=0.976,RMSE=0.138,外部验证预测值和真值残差绝对值介于0~0.3,模型预测性能好,预测精度高,说明利用近红外技术可快速预测烟丝样品的加料比例,实现卷烟加工过程中加料均匀性的快速检测。

基于竞聚率设计制备组成均匀的聚羧酸减水剂

基于实验得到的聚羧酸减水剂(PCE)共聚单体的竞聚率数据,采用控制转化率和补加活泼单体相结合的方法,结合理论计算和实际测定结果,确定了活泼单体丙烯酸(AA)补加时间及补加量,使其在共聚过程中始终与大单体异丁烯基聚乙二醇醚(MAPEG)组成保持基本不变,以保证聚合反应不同时间段生成的共聚物组成和结构与设计值一致。为系统研究控制工艺的准确性和可靠性,将其与传统投料工艺反应过程中所得产物的组成对比,考察了控制共聚物组成对分散性能的影响。结果表明,基于竞聚率的控制工艺制备PCE过程中,分段补加消耗较快的AA抑制了AA和MAPEG在共聚物瞬时组成的变化幅度,共聚物的平均酸醚比[n(AA)/n(MAPEG)]分别为2.8、3.8、4.8,基本接近设计酸醚比(3.0、4.0、5.0);其制备的PCE平均主链长度及主链上羧基含量、大单体含量较高,使PCE覆盖面积和吸附层厚度增大,从而提升了水泥净浆初始流动度和流动保持性能。