叶片出口角对离心泵性能曲线形状的影响

采用FLUENT,在多重参考坐标系下,利用有限体积法对雷诺时均Navier-Stokes方程进行数值离散,选用标准k-ε湍流模型和SIMPLEC方法求解,对4台不同比转速离心泵在不同叶片出口角下的内部流场进行了叶轮和蜗壳的多工况耦合数值模拟,研究了叶片出口角对离心泵扬程曲线和效率曲线的影响并进行了实验验证.研究给出了性能曲线随叶片出口角变化的规律并指出叶片出口角的改变对高比转速泵的扬程和效率曲线形状影响最为明显.研究结果对离心泵的选型和性能改进具有一定的指导意义.     

同翅目几种食用昆虫记述及营养分析

本文首次记载了同翅目中的４种食用昆虫,包括２种暗类和２种介壳虫,对云南少数民族食用这几种昆虫的习俗进行了描述,并对其中３种食用昆地主要营养成分和评价。分析结果表明,３种食用昆虫都含有丰富的蛋白质和氨基酸,粗蛋白质含量都在５０％以上,还吸脂肪、微量元素和维生素等成分,具有很好的营养价值。     

乳铁蛋白在动物防御系统中的作用

<正>乳铁蛋白(LF)最初在牛乳中发现,后来发现这种蛋白质也广泛地存在于猪、鼠、人及其它哺乳动物的唾液、泪液、支气管粘液、胆汁、胰液等外分泌液以及嗜中性粒细胞次级颗粒和血浆中。正常生理条件下LF在血浆中含量很低,而富含于各种外分泌液和嗜中性粒细胞的次级颗粒中。     

不同制粒温度对植酸酶活性的影响及畜禽饲养对比试验研究

试验将含有制粒专用植酸酶制剂的日粮样本在4种温度条件下进行制粒．制粒后的饲料应用植酸酶国标法进行酶活测定,结果表明：制粒专用植酸酶在调制温度70℃左右、蒸汽压力不高的情况下酶活基本未丧失,性能比较理想：当制粒温度达到80℃以上时,酶活明显降低,但总体保持在500U／kg以上．制粒用植酸酶仍具有较好的耐热性能。经过动物饲养试验表明．肉鸡和育肥猪饲养对照组和处理组之间的平均日增重和料肉比差异都不显著（p〉0．01）,这说明在添加制粒专用植酸酶后．对磷酸氢钙的量进行调整并不会影响肉鸡和育肥猪的生长性能．且同样能达到普通植酸酶在粉状饲料中的应用效果。     

中药新制剂菌痢消颗粒对猪鸡细菌性下痢的疗效观察

以人工复制细菌性下痢的猪、鸡为模型,采用不同剂量的菌痢消颗粒进行了疗效观察.从疗效来看,高、中剂量组的有效率显著高于阳性对照组(P≤0.05).从治愈率来看,菌痢消颗粒高、中剂量组与低剂量组和阳性对照组差异显著(P≤0.05),高、中剂量组治愈率差异不显著(P＞0.05).结果表明,菌痢消颗粒能安全、有效地治疗猪、鸡细菌性下痢.     

Regulation of fibroblast growth factor 9 on the differentiation of goat intramuscular adipocytes

It has been found that fibroblast growth factor receptor (FGF-FGFR) signaling can regulate the expression of adipocyte differentiation genes. FGF9 is one of the members of FGFs that mainly binds receptors FGFR2 and FGFR3. FGF9 is highly expressed in the adipose tissue of humans and mice, but there are few reports on the role of FGF9 in goat intramuscular adipocyte differentiation. Therefore, this study explored the effect of FGF9 on adipocyte differentiation through cell culture, interference, and overexpression. The expression of receptors FGFR1–FGFR4 in adipocyte differentiation and their effects on differentiation were detected to screen receptor gene of FGF9. Finally, the interaction between FGF9 and the receptor was tested by cotransfection. Our results showed that FGF9 interacts with FGFR2 to inhibit goat intramuscular adipocyte differentiation by regulating peroxisome proliferator-activated receptor gamma (PPARγ) and preadipocyte factor 1 (Pref1), which is a data support for subsequent pathway research.     

Association of a missense mutation in the luteinizing hormone/choriogonadotropin receptor gene （LHCGR） with superovulation traits in Chinese Holstein heifers

Background: Upon binding luteinizing hormone in the ovary, the luteinizing hormone/choriogonadotropin receptor (LHCGR) is necessary for follicular maturation and ovulation, as well as luteal function. We detected mutations in the LHCGR gene and evaluated their association with superovulation. Methods: Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing, we examined polymorphisms in LHCGR and the genotypes associated with superovulation traits in 127 Chinese Holstein heifers. Results: A G/T polymorphism (ss52050737) in exon 11 was significantly associated with the total number of ova and the number of transferable embryos. Conclusions: LHCGR may be a new predictor for superovulation in Chinese Holstein heifers.     

绵羊PRLR基因内含子9和外显子10多态性与产羔数的关系研究

本研究采用PCR-SSCP技术对绵羊催乳素受体(PRLR)基因内含子9和外显子10部分核苷酸多态性及其与小尾寒羊、中国美利奴(新疆型)绵羊多胎品系、肉用品系、体大品系、萨福克、无角陶赛特、中国美利奴(新疆型)和德国肉用美利奴产羔数间的关系进行了分析。结果发现:①在绵羊PRLR基因内含子9的第259 bp处,存在C→T转换,BB基因型的小尾寒羊平均产羔数分别较AA和AB基因型提高0.81和0.87只(P0.05);②在绵羊PRLR基因外显子10的第304 bp处存在一个G→A转换,该突变导致PRLR基因第387位氨基酸残基由Glu突变为Lys,并使中国美利奴(新疆型)多胎品系中AB基因型的平均产羔数较AA和BB基因型增加0.58和0.80只(P0.05);③在绵羊PRLR基因外显子10第571、585和606bp处分别存在G→A、C→G和C→T突变;其中前2处突变分别导致PRLR基因的第476位氨基酸由Ala突变为Thr,第480位氨基酸由Ser突变为Arg。其中第571 bp处突变导致小尾寒羊AB基因型的平均窝产羔数显著高于AA基因型的窝产羔数,增加0.8只(P0.05)。以上结果提示,PRLR基因可能是控制小尾寒羊和中国美利奴(新疆型)绵羊多胎品系产羔数的主效基因或与之存在紧密的遗传连锁。     

中国苜蓿审定登记品种叶形态特征及变异分析

利用CI-202型叶面积仪研究29个我国审定登记苜蓿品种(Medicago sativa L.)的叶长、叶宽、叶面积、叶周长、叶长/叶宽和叶形指数。结果表明:地方苜蓿品种和育成品种在叶形态方面存在着较大的差异,前者的叶片较后者小;二者叶片形状相似;在6个指标中,叶长宽比变异最大,叶周长变异最小;地方品种的叶面积、叶长、叶周长和叶长宽比的变异系数均高于育成品种,其他2项指标则低于后者;在育成品种中,中兰1号的变异最大,甘农3号苜蓿最小;在地方品种中,蔚县苜蓿的变异最大,河西苜蓿最小;该结果将为今后培育苜蓿新品种提供理论基础。     

Feeding behaviour in chickens given diets containing medium chain triglyceride

1. The effect of dietary medium chain triglyceride (MCT) on short‐term food intake was compared with the effect of long chain triglyceride (LCT) in chickens. Maize oil was used as the LCT while glyceryl tricaprylate (C 8) and glyceryl tricaprate (C 10) were used as MCT. Cumulative food intake was determined during the 6 h after the start of feeding.

2. Chicks were given diets containing 200 g C 8/kg diet, 200 g C 10/kg diet or 200 g LCT/kg diet in experiment 1. As early as 30 min after feeding, cumulative food intake in both MCT‐supplemented diets decreased significantly compared with the diet containing LCT.

3. To determine if endogenous cholecystokinin (CCK) was responsible for the decrease in food intake caused by MCT, birds were injected with the CCK‐A receptor antagonist devazepide (DVZ, 1 mg/kg BW) before diet presentation. DVZ had no effect on food intake with either LCT‐ or MCT‐supplemented diets.

4. In experiment 3, chicks were given a choice between either diets containing LCT and C 8, LCT and C 10, or C 8 and C 10 to confirm whether or not the palatability of the diets was influenced by the dietary fat sources. There was no difference in food intake between C 8 and C 10‐supplemented diets. However, chicks preferred the LCT‐supplemented diet compared with either of the diets containing MCT.