酵母培养物对肉仔鸡生长性能、肠黏膜结构及肠道菌群的影响

本试验旨在研究不同水平酵母培养物对肉仔鸡生长性能、肠黏膜结构及肠道菌群的影响.选取240只1日龄健康、体重相近的爱拔益加(AA)肉仔鸡,随机分为6个组,每组4个重复,每个重复10只鸡.对照组(Ⅰ组)饲喂基础饲粮,试验组(Ⅱ～Ⅵ组)分别饲喂在基础饲粮中添加0.05％、0.10％、0.15％、0.20％和0.25％酵母培养物的试验饲粮.试验期21 d.结果表明:1)Ⅴ、Ⅵ组肉仔鸡平均日增重和平均日采食量均显著高于Ⅰ组(P＜0.05),各组料重比差异不显著(P＞0.05).2)Ⅴ组肉仔鸡十二指肠、空肠和回肠绒毛高度及绒毛高度/隐窝深度显著高于Ⅰ组(P＜0.05),隐窝深度显著低于Ⅰ组(P＜0.05).3)Ⅴ组空肠、回肠和盲肠大肠杆菌数量显著低于Ⅰ组(P＜0.05),乳酸杆菌数量显著高于Ⅰ组(P＜0.05),各组双歧杆菌数量差异不显著(P＞0.05).结果提示,酵母培养物可调节肠道菌群和改善肠黏膜结构,进而提高生长性能.本试验条件下,l ～21日龄肉仔鸡饲粮酵母培养物的适宜添加水平为0.20％.     

Predisposing factors and prevention of Clostridium perfringens-associated enteritis

Clostridium perfringens is one of the major causes of intestinal disease in humans and animals. Its pathogenicity is contributed to by the production of a variety of toxins. In addition, predisposing environmental factors are important for the induction of C. perfringens-associated enteritis as shown by infection models. Environmental contamination, gastric and intestinal pH, intestinal microflora, nutrition, concurrent infections, and medical interventions may influence the intestinal colonization, growth, and toxin production by C. perfringens. Prevention of C. perfringens-associated enteritis may be mediated by the use of feed additives like probiotics, prebiotics, organic acids, essential oils, bacteriophages, lysozymes, bacteriocins, and antimicrobial peptides. Here we summarize and discuss published data on the influence of different environmental predisposing factors and preventive measures. Further research should focus on feed composition and feed additives in order to prevent C. perfringens-associated enteritis.     

家畜消化道菌群的分子生物学研究方法

消化道菌群多样性对于维持家畜机体健康起着至关重要的作用,因此,对家畜消化道中定植菌群的种类和功能进行分析就显得尤为关键。由于所有动物的消化道是厌氧环境,所以在体外的好氧环境中,有些菌种不易培养,而这些菌种信息的缺失,会导致消化道优势菌群的分析结果出现偏差。借助一些广泛应用的分子生物学研究方法,可以避免这种情况的发生。这些方法主要是测序法和定性定量分析法。测序法包括指纹图谱法和高通量测序法,定性定量分析法包括荧光原位杂交法和实时荧光定量PCR法。这些方法均基于分子生物学水平,可避免菌体培养步骤,直接分析消化道菌群的组成和功能。综述了上述方法的原理以及各自的优点和缺点,并对它们在动物消化道菌群多样性分析中的应用进行了讨论,以期为研究动物消化道微生物时不同分子生物学方法的选择和联合使用提供参考。     

黄牛瘤胃中多不饱和脂肪酸氢化的影响因素

为探索黄牛瘤胃中影响多不饱和脂肪酸氢化的因素,通过体外模拟瘤胃发酵的方法,研究不同补充料、瘤胃微生物、培养时间对瘤胃氢化作用的影响。结果表明：微生物培养时间所引起的变异占NH₃-N总变异的64.20%,是引起NH₃-N变化的主要影响因素;不同补充料、微生物区系和培养时间对挥发性脂肪酸(VFA)各组分的影响有显著差异;微生物培养时间与微生物区系的互作对丙酸、异丁酸和丁酸具有显著影响(V_{微生物×时间}分别为43.32**,1.56**和2.87**);乙酸、异戊酸、戊酸不受微生物区系、培养时间、不同补充料的影响;以膨化大豆为补充料时,NH3\|N的含量最高(19.49 mg/mL)且显著高于焙烤大豆;不同的原料和培养时间及其二者间的相互作用将对硬脂酸含量产生显著的影响(三者引起的变异占硬脂酸总变异的77.76%),而瘤胃微生物区系只在特定的培养时间才对硬脂酸含量产生显著影响;亚油酸(C18∶2)浓度只受到不同的瘤胃微生物的影响,不同的原料、培养时间和瘤胃微生物区系间的互作对反式油酸(C18∶1)浓度、亚麻酸(C18∶3)浓度均有显著或极显著的影响。     

硫磺改良盐碱土的微生物效应研究

【目的】探讨硫磺对盐碱土的改良效果。【方法】以不施肥(CK0)、施N、P(CK1)、施石膏(CK2)为对照,在施入N、P的基础上,分别施入75,150,225 kg/hm2硫磺,通过盆栽试验和大田试验,研究硫磺对宁夏平罗和陕西渭南地区盐碱地土壤微生物种类和含量及pH值和EC值的影响。【结果】盐碱土施入硫磺后微生物活性显著提高,微生物含量和种类均明显增加,pH值降低,EC值增加。硫磺对宁夏平罗碱性较大盐碱土各项指标的改善幅度均大于陕西渭南地区碱性较小而含盐量较高的土壤。【结论】硫磺对盐碱土具有明显的改良作用,且对碱性较大的盐碱土的改良效果尤佳。     

Growth,body composition,intestinal enzyme activities and microflora of juvenile Jian carp (Cyprinus carpio var. Jian) fed graded levels of dietary valine

This study investigated the effects of valine on growth, intestinal enzyme activities and microflora in juvenile Jian carp (Cyprinus carpio var. Jian). A total of 1200 fish with an average initial weight of 9.67 ± 0.03 g were fed diets containing 5.3 (unsupplemented control), 8.7, 11.8, 14.9, 18.7 and 20.1 g valine kg^?1 diet for 60 days. Results indicated that the specific growth rate, feed efficiency, body protein and lipid content of fish were significantly improved by the dietary valine (P < 0.05). The hepatopancreas weight and activities of trypsin, amylase, lipase, chymotrypsin, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) took the similar trends. Similarly, the optimum levels of dietary valine induced increases in the intestinal length, weight, folds height and activities of alkaline phosphatase, gamma‐glutamyl transpeptidase and creatine kinase. In contrast, the trends of muscle GOT activity and plasma ammonia content were opposite. Intestinal Aeromonas, Escherichia coli, Lactobacillus and Bacillus were changed by dietary valine supplementations. The dietary valine requirement for Jian carp (9.67–76.4 g) based on SGR was 13.7 g valine kg^?1 diet (4.0 g valine 100 g^?1 CP). Together, these results indicated that valine improved fish growth, digestive and absorptive ability.     

脂肪酸功能及其在养猪生产中应用的研究进展

脂肪酸是猪饲料中的一种重要营养成分,包括短链脂肪酸、中链脂肪酸和多不饱和脂肪酸等多种类型,它们除了提供能量外还对猪的肠道微生态、机体代谢、免疫机能、繁殖性能等具有调节作用。文章简述了不同饲料原料中脂肪酸的含量、脂肪酸的主要生物学功能及其在养猪生产中的应用效果,以期为养猪生产中合理应用油脂和脂肪酸提供依据。