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白羽番鸭生长曲线拟合比较分析 总被引：7，自引：0，他引：7
试验测定不同性别法国白羽番鸭早期体重,用Logistic、Von Bertalanffy和Gompertz 3种非线性生长模型拟合其生长曲线。研究结果表明,白羽番鸭公鸭、母鸭4周龄前生长缓慢,后期公鸭生长快于母鸭;通过比较拟合优度（R2）、残差平方和（E）和进行适合性χ2检验结果发现,Gompertz模型拟合效果最佳。进一步比较不同性别Gompertz模型拟合参数,结果发现公鸭与母鸭相比,有较高的初始体重、极限体重、最大周增重和拐点体重,较低的初始生长速度。公鸭拐点周龄为7.03周,较母鸭的5.37周龄晚;公鸭4周龄前相对生长率小于母鸭,4周龄后则超过母鸭,绝对生长率差异较大。 相似文献
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不同填饲量对北京鸭生长性能、血清生化指标和肝脏组织学的影响 总被引：1，自引：0，他引：1
本试验旨在研究不同填饲量对北京鸭生长性能、血清生化指标及肝脏组织学的影响。试验选取96只35日龄健康、体重相近的雄性北京鸭,随机分成8个组,每组6个重复,每个重复2只鸭,试验期为7 d。对照组试鸭自由采食,平均日采食量为(259.55±18.59)g,填饲组试鸭在35日龄和36日龄时分别填饲260和300 g/d的玉米-豆粕型饲粮,之后5 d各填饲组填饲量保持不变,分别为300、330、360、390、420、450、480 g/d。结果表明:1)除300 g/d填饲组外,其他填饲组北京鸭试验末重和平均日增重显著高于对照组(P<0.05)。试验末重和平均日增重随填饲量的提高而逐渐提高,当填饲量为420 g/d以上时,试验末重和平均日增重基本保持稳定(P>0.05)。填饲组料重比与对照组相比差异不显著(P>0.05)。以平均日增重为评定指标,采用直线折线模型进行估算的最适填饲量为414.2 g/d。2)不同填饲量对北京鸭血清葡萄糖浓度、血清谷草转氨酶活性没有显著影响(P>0.05),450 g/d填饲组血清γ-谷氨酰基转移酶活性显著高于对照组(P<0.05),其他填饲组与对照组相比差异不显著(P>0.05)。血清甘油三酯、总胆固醇浓度和谷丙转氨酶活性随填饲量的提高而逐渐升高,且差异显著(P<0.05)。3)填饲使得北京鸭肝脏细胞肿大,胞浆中充满大量大小不等的脂肪滴。由此可见,填饲能够快速增加北京鸭的脂肪沉积,但填饲量超过420 g/d时,北京鸭生长性能基本保持稳定。 相似文献
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为研究乌嘴白羽优质肉鸭产肉性能的动态变化规律,本实验选取360只鸭(公、母各半),其中公、母各分3个重复组,每组60只。测定0~10周龄的体重,3~10周龄的胸肌重、腿肌重,并运用Logistic、Gompertz、Bertalanffy 3种非线性生长模型进行曲线拟合分析。结果表明:3种曲线模型对优质肉鸭体重拟合效果均较好,拟合度均在0.997以上,Gompertz模型拟合最佳(公鸭R2=0.999,母鸭R2=0.998);成熟体重公、母鸭分别为3127.8、2919.1 g,拐点周龄分别为4.2、3.9周,最大周增重分别为402.7、392.0 g;除Gompertz模型不能对胸肌重、腿肌重进行拟合,其他2种模型拟合度均在0.95以上,其中Logistic模型拟合最佳(胸肌公鸭R2=0.992,母鸭R2=0.973;腿肌公鸭R2=0.992,母鸭R2=0.973);胸肌公、母鸭极限重量分别为345.4、279.0 g,拐点周龄分别为7.2、6.6周,最大周增重分别为73.2、63.0 g;腿肌公、母鸭极限重量分别为203.0、178.6 g,拐点周龄分别为3.9、3.6周,最大周增重分别为34.7、37.1 g。本研究结果可为乌嘴白羽优质肉鸭的选育、饲养管理以及种质资源的开发利用提供理论依据。 相似文献
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连城白鸭肉用新品系早期生长规律及生长曲线拟合的研究 总被引：1，自引：0，他引：1
对0～9周龄的连城白鸭肉用新品系早期生长发育情况进行了测定和分析,并运用Gompertz模型对其生长曲线进行拟合与分析。结果表明:Gompertz模型能很好地模拟连城白鸭肉用新品系生长曲线,拟合度(R2)高(公鸭:R2=0.9998,母鸭:R2=0.9997),进一步对拟合参数分析,发现连城白鸭肉用新品系公鸭极限体重为2423.6g,拐点体重为891.7g,拐点周龄为3.5周;母鸭极限体重为2099.2g,拐点体重为772.3g,拐点周龄为3.2周。 相似文献
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半番鸭及其亲本生长曲线拟合与杂种优势分析 总被引：2，自引：1，他引：1
实验测定了樱桃谷鸭、白羽番鸭、苏牧麻鸭、白羽番鸭♂×樱桃谷鸭♀(樱番鸭)、白羽番鸭♂×苏牧麻鸭♀(苏番鸭)早期体重数据,发现樱番鸭杂种优势率为12.8%,苏番鸭为22.04%。用Logistic、Von Bertalanffy和Gompertz3种非线性生长模型拟合其生长曲线,通过比较拟合优度、复相关指数和进行适合性χ2检验,发现Gompertz模型拟合效果最好。比较5组鸭Gompertz模型拟合参数,结果表明:在亲本鸭组中白羽番鸭初始重较樱桃谷鸭和苏牧麻鸭高,初始生长速度、最大周增重较这2个亲本组低,拐点时间也比其晚。2个杂交组最大周增重、成熟速度、极限体重、拐点体重、初始重和拐点时间都有很大提高,存在明显的杂种优势。 相似文献
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《中国家禽》2019,(10)
试验旨在研究饲粮中添加丁酸梭菌对填饲北京鸭生长性能、免疫功能和血液抗氧化指标的影响。选取1日龄健康北京鸭300只,随机分成5个组,每组6个重复,每个重复10只鸭。对照组饲喂基础饲粮,试验组在基础饲粮中分别添加100 mg/kg丁酸梭菌(低剂量组)、200 mg/kg丁酸梭菌(中剂量组)、400 mg/kg丁酸梭菌(高剂量组)以及150 mg/kg金霉素(抗生素组)。从第37天开始,对所有北京鸭进行人工填饲,每6 h填饲一次,共填饲5 d,于第42天清晨屠宰取样并检测相关指标。结果表明:①37日龄时,丁酸梭菌组和抗生素组的体重均显著高于对照组(P0.05),但42日龄时,各组之间的体重差异不显著(P0.05)。②与对照组相比,饲粮中添加中剂量的丁酸梭菌可以显著提高填饲北京鸭血清中IgA、IgG、C3和C4的含量(P0.05)。③与对照组相比,饲粮中添加中剂量和高剂量的丁酸梭菌显著降低填饲北京鸭血清中IL-6和IL-17的含量(P0.05)。④与对照组相比,只有中剂量组的丁酸梭菌显著提高填饲北京鸭血清中SOD活性(P0.05),且均显著降低血清中CORT、ROS和MDA的含量(P0.05)。由此可见,丁酸梭菌和填饲都可以使北京鸭的体重增加,但丁酸梭菌可以有效缓解填饲应激引起的机体氧化应激和炎性反应,并提高机体免疫功能,200 mg/kg的添加效果最佳。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献
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Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献