Suppression of ovarian progesterone production in dairy cows using an implant of GnRH-agonist (deslorelin) for the purpose of evaluating progesterone metabolism

OBJECTIVE: To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. METHODS: Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2alpha) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20alpha-OH and 20beta-OH) were monitored for a period of 5 weeks. RESULTS: Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). CONCLUSIONS: These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4.     

野外放归大熊猫肠道菌群变化的研究

对四川卧龙中国保护大熊猫研究中心的一只野外放归亚成体大熊猫肠道菌群的组成和季节变化规律进行了研究,同时与其圈养双胞胎兄弟的肠道菌群进行了比较。从放归大熊猫粪便中分离出17种肠道菌,优势菌群为肠杆菌、肠球菌和乳杆菌。与圈养大熊猫相比,放归大熊猫肠道菌群中优势菌群的种类未发生改变,但是肠球菌数量增加,肠杆菌和乳杆菌的数量减少。研究发现放归大熊猫肠道菌群中的肠杆菌和肠球菌的数量随季节变化有较大波动,乳杆菌的数量随季节变化波动不大;而圈养大熊猫三种优势菌的数量随季节变化波动都不大。     

Modulation of broilers’ caecal microflora and metabolites in response to a potential probiotic Bacillus amyloliquefaciens

Studies have found that a dietary supplement of Bacillus amyloliquefaciens improved the growth performance, increased the nutrient digestibility of hosts and modulated the intestinal microflora. A total of 360 1‐day‐old Ross broilers were randomly divided into three treatments: a control group with a basal diet, an antibiotic group with a basal diet and added colistin sulphate, and a probiotics group with a basal diet and added Bacillus amyloliquefaciens. The HiSeq high‐throughput sequencing analysis of 16S rRNA was used to investigate the differences in birds’ caecal microflora, and metabolomics was used to analyse changes in caecal metabolites. Results showed that the supplementation of Bacillus amyloliquefaciens significantly improved the BW and ADG compared with the control birds. Results of sequencing indicated that (i) 645, 670, 596 unique operational taxonomic units (OTUs) were found in birds supplemented with Bacillus amyloliquefaciens on day 7, 21 and 42, separately, (ii) due to the diversity and relative abundance of the birds’ caecal microflora, the OTUs of the caecal microflora clustered according to age and treatment, except on day 42, (iii) among the six predominate families (Ruminococcaceae, Lachnospiraceae, Enterobacteriaceae, Erysipelotrichaceae, Lactobacillaceae and Rikenellaceae), the supplementation of Bacillus amyloliquefaciens significantly increased Enterobacteriaceae on day 42, (iv) Bacillus amyloliquefaciens increased the relative abundance of Faecalibacterium and Ruminococcus on day 21, increased the Faecalibacterium and Blautia and decreased the Ruminococcus on day 42. The metabolomics of caecal metabolites showed that the dietary Bacillus amyloliquefaciens changed the caecal metabolites involved of amino acid metabolism and glyceride metabolism, and the antibiotics changed the caecal metabolites that were related to carbohydrates and amino acid metabolism on day 21.     

瘤胃液移植在反刍动物中的研究进展

瘤胃液移植是一种将健康供体动物的瘤胃液转移给受体动物的技术。目前，针对瘤胃液移植的报道还相对有限，但越来越多的研究结果显示，瘤胃液移植可以影响反刍动物的干物质采食量、产奶量等，还具有重建瘤胃菌群结构的潜力。本文综述了瘤胃液移植的方法及实践中的应用研究，分析其对反刍动物生长性能、瘤胃发酵、瘤胃微生物区系的影响以及在治疗某些疾病方面的作用，为反刍动物瘤胃液移植的研究提供参考。     

微生物菌群培养组学在动物医学中的应用

实验室条件下可培养的微生物约占自然界中微生物总数的1%，这限制了人们对99%未知微生物的认识和利用，而研究表明，那些“不可培养的微生物”是可以被开发和利用的，未能被纯培养的微生物才是未知微生物的主体。微生物培养组学探索利用多种培养条件和长时间的培养，结合基质辅助激光解吸电离飞行时间质谱法（MALDI-TOF-MS）和16S核糖体RNA（rRNA）测序可以大规模鉴定各种微生物，同时利用全基因组测序和宏基因组测序手段对未知微生物进行深入分析。本文综述了国内外近年来微生物菌群培养组学在反刍动物胃肠道、禽类盲肠及家畜鼻腔微生物菌群研究中的最新进展，探讨将动物体内菌群培养组学方法应用于动物疾病防治领域的可行性。作为一个新兴的研究方法，尽管该培养组学还存在一些不够成熟的方面，但它的发展前景十分广阔，微生物菌群培养组学方法和其他研究方法的互补已经逐渐成为发展兽医微生物学新的突破口。     

EM菌在水产养殖中的应用概述

为了能改善水质、渔业增殖和修复生态环境,EM菌的应用得到了广泛的关注,成为近几年研究的热点。鉴于此,本研究系统梳理了EM菌的定义及来源,综述了国内外近几十年EM菌在水产养殖中的作用效果及其作用机理,阐述了影响EM菌作用效果的因素等;发现EM菌在调控微生物生态结构、降低水环境中有害物质、提高免疫、增重增产等方面有着显著的效果,但EM菌技术的基础理论研究还比较薄弱,且生产技术及应用过程等还存在着不足。因此今后应提高生产技术,建立和提高筛选系统,并开发EM菌在水产养殖研究和应用的新领域,为水产养殖创造更大的经济价值,并为可持续养殖提供可能。     

Effect of Dietary Lactobacillus fermentum from Pig on Growth Performance,Nutrient Apparent Digestibility,Faecal Microflora Number and Serum Immune Indices in Weaned Piglets

This experiment was conducted to study the effects of Lactobacillus fermentum on growth performance, nutrient apparent digestibility, faecal microflora number and serum immune indices of weaned piglets.A total of 160 weaned piglets with an average age of (30±2) days and averge body weight of (7.85±0.68) kg were randomly distributed into 4 groups with 4 replicates per group and 10 piglets per replicate feeding basal diet, 0.1%, 0.2%, and 0.3% Lactobacillus fermentum supplementation diets, respectively.The experiment lasted for 35 d.The results showed that, compared with the control group, the average daily gain, the feed conversion ratio, the apparent digestibility of crude protein, calcium and total phosphorusin of Lactobacillus fermentum groups were all increased in varying degrees.The optimum supplemental level of Lactobacillus fermentum should be 0.2%, and at this level, the average daily gain was significantly increased by 8.70% (P<0.05), the F/G was decreased by 4.62% (P<0.05), the apparent digestibility of crude protein, calcium and total phosphorus were significantly increased (P<0.05), the number of faecal E.coli was significantly decreased (P<0.05), and the serum IgG was significantly increased by 8.39% (P<0.05).The results indicated that Lactobacillus fermentum supplementation could improve the immune function, growth performance, the apparent digestibility of crude protein, calcium and total phosphorus and reduce the number of faecal E.coli of weaned piglets.     

Evaluation the effect of subchronic feeding of transgenic cotton line (CKC1) on the faecal microbiota of albino rabbits

Recent studies have demonstrated a strong relationship between the intestinal microbiota and the host health. As such, consumers are increasingly becoming more concerned about the potential effect of certain foods/feeds, particularly of transgenic origin on the gut microbiota. Although the European Food Safety Authority has recommended in their guidelines, to study the effect of transgenic food/feed on host-microbiota, yet, few studies have focused on the evaluation of such effects mainly due to culturing difficulties. Therefore, this study was intended to evaluate the potential adverse effects of transgenic diet consumption on some specific gut microflora (Lactobacillus group, Bifidobacterium genus, Escherichia coli subgroup and Enterococcus genus) of rabbits. A total of forty-eight rabbits were randomly assigned into four groups and fed a diet containing a variable proportion of transgenic cottonseeds at 0, 20, 30 and 40% inclusion level, respectively. Changes in the specific or total faecal bacterial population were monitored at five different experimental stages (i.e. 0, 45, 90, 135 and 180 days) using both the traditional plate count method (TM) and quantitative real-time PCR (qPCR). No significant differences (p > .05) were observed concerning numbers of specific bacteria or total bacteria between the control and experimental groups, though qPCR showed numerically higher values in terms of 16S rRNA gene copies as compared to the values obtained from TM. However, such numerical differences were biologically insignificant (p > .05). Similarly, no significant variations were noticed in the calculated B/E (log₁₀ copies of Bifidobacterium per g faces/log10 copies of E. coli genome per g faeces) ratios in all the groups. All the ratios were in the range of 1.24 to 1.30 throughout the experiment, indicating a good balance of intestinal microflora and greater resistance to intestinal disorders. It is therefore concluded that feeding transgenic cottonseeds could not adversely affect the gut microflora of rabbits during a long-term study.     

Stress steroid levels and the short-term impact of routine dehorning in female southern white rhinoceroses (Ceratotherium simum simum)

Rhinoceros populations in Africa are under severe threat as a result of surging poaching rates and risk-mitigation strategies are continuously adapted in an attempt to ensure the survival of the species. This study compared faecal glucocorticoid metabolite (fGCM) levels of two age classes of limited free-ranging female white rhinos with fGCM levels of adult free-ranging female white rhinos. Subsequently, fGCM alterations in the limited free-ranging animals were monitored following routine dehorning as a measure of the animals’ short-term physiological stress response. Baseline fGCM levels differed significantly between tested groups, with both free-ranging and limited free-ranging adult animals showing significantly higher fGCM levels compared with limited free-ranging juvenile females. In contrast, baseline fGCM levels did not differ significantly between limited free-ranging and free-ranging adult individuals. Routine dehorning procedures resulted in a short-term stress response expressed by a significant increase in fGCM levels 48 h post-dehorning, with stress steroid levels returning to pre-dehorning concentrations 72 h after the procedure.