Effects of physical form of starter and forage provision to young calves on blood metabolites,liver composition and intestinal morphology

This study evaluated the effects of physical form of starter feed and forage provision on the performance, blood metabolites, liver composition and intestinal morphology of dairy calves. Individually housed calves (n = 52; body weight = 41.5 ± 2.5 kg) were randomly allocated (n = 13 per treatment) to one of the following four treatments: (i) ground starter feed (GS; mean particle size = 0.72 mm in diameter), (ii) textured starter feed (TS; mean particle size = 3.61 mm in diameter, including steam‐flaked corn and barley), (iii) pelleted starter feed (PS; mean particle size = 4.53 mm in diameter) and (iv) ground starter feed with chopped alfalfa hay (GS + AH; mean particle size = 1.02 mm in diameter). The calves fed GS + AH diets had greater (p < 0.01) starter intake, final body weight and average daily gain compared with the other groups, while GS and TS groups both had greater (p < 0.01) starter intake than the PS group. Feed efficiency was found to be better (p < 0.05) in the TS group than in the GS or PS group, but not different from the GS + AH one. Compared with the other groups, the GS + AH group had the highest (p < 0.01), while the PS one had the lowest (p < 0.01) concentrations of blood glucose and triglyceride. The calves fed GS + AH had the highest blood concentrations of total protein, globulin, triiodothyronine (T3), thyroxin (T4), T3 : T4 ratio (p < 0.05) and levels of fat and glycogen in the liver (p < 0.01) compared with the other groups. The highest (p < 0.05) liver glycogen contents were observed in the GS + AH and TS groups. The duodenum, ileum and jejunum in the calves fed GS + AH exhibited a greater muscle layer thickness (p < 0.05) compared with the other groups. Based on the results obtained, the addition of dietary forage to starter diets positively influenced performance, liver composition and intestinal morphology in developing calves.     

辐照对瓜实蝇遗传区性品系成虫肠道微生物的影响

为研究辐照对瓜实蝇肠道微生物群落多样性和结构组成的影响,以100 Gy137Cs辐照来自瓜实蝇遗传区性品系(GSS)的5、8、11和13日龄的雌、雄成虫,并采用Illumina MiSeq测序技术分别对其肠道菌群进行测序分析。结果表明,瓜实蝇雌雄成虫的肠道中存在19个主要的菌属,包括17个属名已知,1个属名未知和1个属不可培养。其中,17个已知属分别属于4个细菌门,即变形菌门(Proteobacteria)(占总量的50%~98%)、厚壁菌门(Firmicutes)(占总量的2%~47%)、拟杆菌门(Bacteroidetes)(占总量的1%~16%)和1个至今微生物界还未确定的稀少菌门(unclassified rare phyla)(总量1%)。此外,辐照降低了瓜实蝇肠道中的微生物多样性以及优势菌的丰富度,且这种影响与瓜实蝇的性别和成虫日龄无关。本研究结果为评估和修复辐照对瓜实蝇的损伤提供了参考。     

黄芩对肉鸡生长性能及回盲肠微生物菌群的影响

本试验旨在研究不同添加水平黄芩对肉鸡生长性能及回盲肠微生物菌群的影响。选取健康体重相近的1日龄肉鸡500羽,随机分为5组,每组5个重复,每个重复20羽,在基础日粮中分别添加0%(空白对照组)、0.1%、0.2%、0.4%黄芩以及1.0%抗生素(阳性对照组),试验期6周,测定1～21 d、22～42 d、1～42 d的日增重、料重比、免疫器官指数和回盲肠中乳酸菌和肠杆菌数量。结果表明,1～21 d时,各处理组日增重较空白对照组均有所增加,其中处理2增加显著(P0.05);与阳性对照组相比,各处理组的胸腺指数均显著提高(P0.05);盲肠乳酸菌数量均显著高于空白对照组(P0.05),回肠中乳酸菌数量有增加趋势。22～42 d时,与空白对照组相比,各处理组的日增重、免疫器官指数及回盲肠中乳酸菌和肠杆菌数量差异均不显著(P0.05)。结论:日粮中添加黄芩在1～21 d一定程度上可以促进肉鸡生长,改善肠道微生物菌群,其中添加0.2%黄芩效果较好。     

Effects of dietary supplementation of a commercial prebiotic Previda® on survival,growth, immune responses and gut microbiota of Pacific white shrimp,Litopenaeus vannamei

A 35‐day feeding trial was conducted to evaluate growth, bacterial populations of the gastrointestinal tract (GIT) and immune responses of Litopenaeus vannamei fed diets containing the commercial prebiotic Previda^®. Diets were formulated to contain Previda^® at 0, 0.2, 0.5, 1.0 or 1.6 g kg^?1 by weight. At the end of the study, differences in weight gain and survival among treatments were not significant (P > 0.05), but denaturing gradient gel electrophoresis analysis revealed that the microbial communities in the GIT changed significantly with the inclusion of dietary Previda^® at different levels. Previda^® was therefore able to selectively modify the microbial communities in the shrimp's GIT. Although individual bacterial species were not identified, enteric populations in shrimp fed the prebiotic at similar levels of inclusion were genetically similar. In addition, shrimp fed Previda^® at 1.6 g kg^?1 responded significantly (P < 0.05) better immunologically with respect to hemocyte phagocytic capacity, haemolymph protein, hyaline cell counts and haemolymph glucose compared with shrimp fed the basal diet. Although shrimp were not exposed to virulent pathogens in this study, the observed upregulation of some of imm‐une responses upon prebiotic supplementation indicates that an improved outcome of such challenges may be anticipated in Previda^®‐fed shrimp under commercial conditions.     

Diversity and activity of cellulolytic bacteria,isolated from the gut contents of grass carp (Ctenopharyngodon idellus) (Valenciennes) fed on Sudan grass (Sorghum sudanense) or artificial feedstuffs

Herbivorous grass carp (Ctenopharyngodon idellus) has a powerful capability to digest cellulose from aquatic plants, depending on the cellulase complex produced by the cellulolytic bacterial community in the gastrointestinal (GI) tract. However, it remains uncertain which bacteria taxa may actively participate in the digestion of food fibre. In this study, a total of 499 cellulolytic bacteria from the gut content of grass carp fed on Sudan grass (242 strains) and artificial feedstuffs (257 strains) were randomly isolated and characterized using carboxymethyl‐cellulose, microcrystalline cellulose and cellobiose agar media. The results showed that more than half of the isolates were capable of degrading carboxymethyl‐cellulose and cellobiose, while the remaining isolates were restricted to microcrystalline cellulose decomposition, exclusively. The cellulolytic bacterial community was dominated by Aeromonas, followed by Enterobacter, Enterococcus, Citrobacter, Bacillus, Raoultella, Klebsiella, Hydrotalea, Pseudomonas, Brevibacillus and some unclassified bacteria, as revealed by 16S rDNA sequence analysis. Notably, grass carp fed on grass with high‐fibre content harboured a higher diversity of cellulolytic bacteria than the ones fed on low‐fibre feedstuffs. Our results provided evidence for a positive correlation between the content of food fibre and the diversity of cellulolytic bacteria in grass carp intestines. Thus, improving growth conditions and cellulase activities for GI cellulolytic microorganisms in grass carp intestines are critical for effective utilization of feedstuffs containing high fibre levels.     

不同纤维源对成年鹅肠道组织形态变化的影响

本试验旨在研究不同纤维源对成年扬州鹅肠道组织形态变化的影响。选用18只健康、体重相近的25周龄扬州鹅公鹅,随机分为3组,即:稻壳粉组、苜蓿草粉组、羊草粉组,每组6只。试验期28 d,试验期末将试验鹅处死并留取各肠段组织,称重并观察肠道组织形态。结果表明:①不同纤维源对十二指肠和空肠长度影响差异不显著(P>0.05),稻壳草粉组回肠长度显著高于苜蓿草粉组与羊草粉组(P<0.05),苜蓿草粉组与羊草粉组差异不显著(P>0.05)。②稻壳粉组十二指肠绒毛高度、绒毛宽度、隐窝深度、肌层厚度均显著高于苜蓿草粉组与羊草粉组(P<0.05),其中苜蓿草粉组隐窝深度、V/C与羊草粉组差异显著(P<0.05);稻壳粉组与羊草粉组空肠绒毛高度显著高于苜蓿草粉组(P<0.05),隐窝深度显著低于苜蓿草粉组(P<0.05),稻壳粉组与羊草粉组间均差异不显著(P>0.05),稻壳粉组肌层厚度显著高于苜蓿草粉组(P<0.05);羊草粉组回肠绒毛高度显著高于苜蓿草粉组与稻壳粉组(P<0.05),3组间绒毛宽度差异显著(P<0.05),且以稻壳粉组最大,羊草粉组V/C显著高于苜蓿草粉组和稻壳粉组(P<0.05),羊草粉组肌层厚度显著低于苜蓿草粉组与稻壳草粉组(P<0.05)。由此可知,不同纤维源可显著影响25周龄扬州鹅肠道组织形态。     

肠道微生物宏基因组文库构建及酯解酶基因筛选

利用宏基因组学方法,以人肠道微生物样品为原材料,构建了1个约30 000个克隆的fosmid文库.以三丁酸甘油酯为底物,通过功能筛选,获得1个酯解酶阳性克隆.对该阳性克隆构建亚克隆,挑选具有酯解酶活性的阳性亚克隆进行测序分析,最终获得1个肠道微生物来源的酯解酶基因(GenBank登录号:JQ972699).结果表明,文库克隆的平均插入片段约为40 kb,没有重复插入片段克隆.获得的酯解酶基因推演蛋白与Pyramidobacter piscolens W5455的patatin样磷脂酶同源性最高,氨基酸一致性为95％.生物信息学分析结果表明该基因可能通过Vd型分泌方式进行分泌并发挥功能.本研究是通过构建人肠道微生物宏基因组大片段文库并结合重组子功能筛选获得酯解酶的首次报道,可为食品工业提供新的酯解酶来源和筛选方法.     

Effects of three major protein sources on performance,gut morphology and fermentation characteristics in broilers

ABSTRACT

1. This study determined the effects of three protein sources (PS), each at two digestibility crude protein (DCP) levels, on performance, gut morphology and fermentation characteristics in the hindgut of broilers.

2. It was hypothesised that broilers fed ingredients high in indigestible CP, i.e. rapeseed meal (RSM) or maize gluten (MG), could potentially cause reduced growth, impaired gut health, and more protein fermentation products in caecal digesta. Increasing the DCP level in each of the indigestible CP diets may compensate for these detrimental effects.

3. In total, 288 one-d-old male Ross 308 broilers were used in a completely randomised 3 × 2 factorial design, with six replicate pens per treatment. Three PS: soybean meal (SBM), rapeseed meal (RSM) or maize gluten (MG), and two DCP levels: 15.8 and 17.2% were used.

4. Broilers fed SBM had increased feed intake and BWG and improved FCR compared with those fed RSM and MG diets. Broilers fed high DCP had better performance compared with those on low DCP. No significant effects of PS or DCP level were found on gastrointestinal tract development, caecal ammonia or volatile fatty acid concentrations.

5. Broilers fed SBM had longer villi, smaller crypts and increased villus height to crypt depth ratio compared with those fed RSM and MG diets. Broilers fed RSM diet had a lower caecal pH, and had 16.5% and 14.9% more branched chain fatty acid contents in caecal digesta compared with those fed SBM and MG diets, respectively, indicating more proteolytic fermentation.

6. Replacing SBM by RSM and MG negatively affected growth performance and gut morphology. Hindgut protein fermentation was substantially increased in RSM fed birds.

7. To a certain extent, retarded growth performance in RSM and MG fed birds could be counterbalanced by increasing the dietary level of digestible CP.     

不同粪菌悬液处理方式对猪粪菌移植过程中细菌活性及活菌组成的影响

旨在探究不同粪菌液处理方法对其菌群活性及存活菌群物种组成的影响,为猪粪菌移植（FMT）的优化应用提供参考。本研究共设置7个试验组制备粪菌液：静置制备新鲜粪菌液组（FS）、静置制备粪菌液于-80℃冷冻1周组（FFS）、离心制备新鲜粪菌液组（FC）、离心制备粪菌液于-80℃冷冻1周组（FFC）、液氮冷冻粪便24 h静置制备粪菌液组（NS）、甘油+液氮冷冻粪便24 h静置制备粪菌液组（GNS）和液氮冷冻粪便24 h静置制备粪菌液于-80℃冷冻1周组（NFS）,在37℃厌氧培养箱中平板培养48 h后,进行菌落计数。从FS、FFS、FC和FFC 4组中根据菌落形态随机挑取87个单菌落纯化后进行16S rRNA基因全长测序。结果表明,静置和离心两种方法制备新鲜粪菌液时,粪菌活性存在显著差异,离心组显著低于静置组（P<0.05）。但冷冻粪便使用静置和离心两种方法制备的菌悬液,其粪菌活性无显著差异（P>0.05）。无论是静置还是离心方法制备粪菌液,新鲜和冷冻两种不同处理方式下的粪菌活性均无显著差异（P>0.05）,且对活菌的组成也无显著影响。使用静置法制备粪菌液时,FS、NS、GNS和NFS组间粪菌活性无显著差异（P>0.05）。综上表明,静置方法制备粪菌液时,超低温冷冻保存对粪菌活性及其活菌组成均无显著影响,这为大样本、长距离猪粪菌移植技术的应用提供了重要试验参考。     

蚯蚓粪基质与肥料添加量对辣椒穴盘育苗效果的研究

将蚯蚓粪和蛭石按2∶1(v/v)的比例组成复合基质,然后添加不等量的CO(NH2)2和KNO3,用于辣椒穴盘育苗。结果表明:通过添加适量的肥料,可以明显提高复合基质的电导率(EC值),改善辣椒的出苗率和幼苗叶片叶绿素含量,显著促进幼苗植株的生长发育。根据壮苗指数,筛选出最佳肥料添加量是CO(NH2)20.2 kg/m3和KNO30.8 kg/m3。研究结果为利用蚯蚓粪替代草炭培育辣椒健壮穴盘苗提供了科学施肥依据。