Interaction between the sequence of feeding of hay and concentrate,and boiling of barley on feed intake,the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares

The interaction between the sequence of feeding of hay and concentrate and the hydrothermal processing of barley in alleviating concentrate effects on intake, and hindgut fermentation in horses was tested. Six Arabian mares (4–10 years of age, 410 ± 35 kg body weight) were used to evaluate the effects of feeding sequence (FS) and type of barley (TB) on intake, and faecal volatile fatty acids (VFA), activities of α‐amylase (AA: EC 3.2.1.1), carboxymethyl cellulase (CMCase: EC 3.2.1.4), microcrystalline cellulase (MCCase: EC 3.2.1.91) and general filter paper degrading activity (FPD). Mares were offered a ration of air‐dried alfalfa and concentrate (70:30 as‐fed) in four subsequent periods of 14 days including 8 days of adaptation and 6 days of sampling. In each period and each meal, mares received concentrate either 30 min after (HC) or 30 min before (CH) alfalfa hay. Barley was either milled or boiled in water. Rectal samples were grabbed directly from rectum once per period. Mares subjected to CH had higher dry matter intakes than mares under HC regime. The acetate:propionate ratio (A:P ratio) in rectal content was higher with CH than HC. The AA activity was higher under CH than under HC. Mares fed boiled barley had lower rectal concentrations of VFA and propionate and a higher A:P ratio than mares fed milled barley. Furthermore, the rectal content showed a higher MCCase activity but a lower AA activity when mares were fed boiled compared with milled barley. Interactions between FS and TB were observed with respect to CMCase activity, and concentrations of propionate and valerate. In conclusion, the present results suggest that both, feeding concentrate before hay and boiling the barley, might improve the hindgut environment in Arabian mares, and that the two measures were mostly additive and sometimes even synergistic.     

Effect of hay type on cecal and fecal microbiome and fermentation parameters in horses

The effect of hay type on the microbiome of the equine gastrointestinal tract is relatively unexplored. Our objective was to characterize the cecal and fecal microbiome of mature horses consuming alfalfa or Smooth Bromegrass (brome) hay. Six cecally cannulated horses were used in a split-plot design run as a crossover in two periods. The whole plot treatment was ad libitum access to brome or alfalfa hay fed over two 21-d acclimation periods with subplots of sampling location (cecum and rectum) and sampling hour. Each acclimation period was followed by a 24-h collection period where cecal and fecal samples were collected every 3 h for analysis of pH and volatile fatty acids (VFA). Fecal and cecal samples were pooled and sent to a commercial lab (MR DNA, Shallowater, TX) for the amplification of the V4 region of the 16S rRNA gene and sequenced using Illumina HiSeq. The main effects of hay on VFA, pH, and taxonomic abundances were analyzed using the MIXED procedure of SAS 9.4 with fixed effects of hay, hour, location, period, and all possible interactions and random effect of horse. Alpha and beta diversities were analyzed using the R Dame package. Horses fed alfalfa had greater fecal than cecal pH (P ≤ 0.05), whereas horses fed brome had greater cecal than fecal pH (P ≤ 0.05). Regardless of hay type, total VFA concentrations were greater (P ≤ 0.05) in the cecum than in feces, and alfalfa resulted in greater (P ≤ 0.05) VFA concentrations than brome in both sampling locations. Alpha diversity was greater (P ≤ 0.05) in fecal compared with cecal samples. Microbial community structure within each sampling location and hay type differed from one another (P ≤ 0.05). Bacteroidetes were greater (P ≤ 0.05) in the cecum compared with the rectum, regardless of hay type. Firmicutes and Firmicutes:Bacteroidetes were greater (P ≤ 0.05) in the feces compared with cecal samples of alfalfa-fed horses. In all, fermentation parameters and bacterial abundances were impacted by hay type and sampling location in the hindgut.     

Mean retention time of digesta in the different segments of the equine hindgut

Six Thoroughbred horses were used to determine the mean retention time (MRT) of digesta in the different segments of the hindgut. The horses were fed timothy hay or silage in equal amounts (1.6% bodyweight [BW]/day) every 3 h/day. Hay or silage labeled with the rare earth elements cerium, dysprosium, neodymium, ytterbium, lanthanum, samarium and praseodymium, were fed to the horses 36, 30, 24, 18, 12, 6 and 3 h before slaughter, respectively. Just after slaughter, digesta samples in the different segments were collected and determined for the contents of the rare earth elements. Using these data, a method to calculate the MRT in the different segments was proposed. There were no significant differences between diets in the MRT of each segment. The averaged MRT of hay and silage in the cecum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon and small colon was 2.9, 3.1, 5.9, 1.0, 4.0, and 4.0 h, respectively. The dry matter weight of the digesta was related to the MRT in the right ventral colon (r = 0.94, P = 0.005), left ventral colon (r = 0.87, P = 0.03), left dorsal colon (r = 0.98, P < 0.001) and right dorsal colon (r = 0.95, P = 0.004), but it was not related to the MRT in the cecum and small colon.     

Intake, selection, digesta retention, digestion and gut fill of two coprophageous species, rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus), on a hay-only diet

A colonic separation mechanism (CSM) is the prerequisite for the digestive strategy of coprophagy. Two different CSM are known in small herbivores, the 'wash-back' CSM of lagomorphs and the 'mucous-trap' CSM of rodents. Differences between these groups in their digestive pattern when fed exclusively hay were investigated in six rabbits (Oryctolagus cuniculus) and six guinea pigs (Cavia porcellus). Intake, digestibility (by total faecal collection), solute and particle mean retention times (MRT, using Co-EDTA and Cr-mordanted fibres) were measured. Rabbits selected less fibrous parts of the hay than guinea pigs, leaving orts with higher content of neutral detergent fibre [NDF; 721 ± 21 vs. 642 ± 31 g/kg dry matter (DM) in guinea pigs]. They also expressed a lower NDF digestibility (0.44 ± 0.10 vs. 0.55 ± 0.05 of total), a similar particle MRT (15 ± 3 vs. 18 ± 6 h), a longer solute MRT (51 ± 9 vs. 16 ± 4 h), and a lower calculated dry matter gut fill (19.6 ± 4.7 vs. 29.7 ± 4.1 g DM/kg body mass) than guinea pigs (p < 0.05 for each variable). These results support the assumption that the 'wash-back' CSM, exhibited in the rabbits, is more efficient in extracting bacterial matter from the colonic digesta plug than the 'mucous-trap' CSM found in the guinea pigs. Related to metabolic body mass, rabbits therefore need a less capacious colon for their CSM where a more efficient bacteria wash-out is reflected in the lower fibre digestibility. A lighter digestive tract could contribute to a peculiarity of lagomorphs: their ability to run faster than other similar-sized mammals.     

Phylogenetic analysis of hindgut microbiota in Hokkaido native horses compared to light horses

The analysis of 16S rDNA sequence of bacteria in feces of Hokkaido native horses and light horses were performed to compare the hindgut microbiota between the two breeds. One hundred and four bacterial 16S rDNA clones (57 clones from four native horses and 47 clones from two light horses) were obtained. Only four sequences (3.8% of total sequences) showed 97% or more similarity to known species. The sequences were mainly affiliated with Cytophaga–Flavobacter–Bacteroides and low GC Gram‐positive bacteria (LGCGP). Proportion of LGCGP was higher in light horses. Other phyla including Verrucomicrobia, Spirochaetes and Archaea were detected only for native horses, suggesting high diversity of microbiota in native horses. In LGCGP, clusters related to known cellulolytic species were found only for native horses, while a cluster related to soluble sugar‐utilizing species was detected only for light horses. The library composition‐comparing software LIBSHUFF showed significant (P < 0.05) difference of fecal microbiota between the horse breeds. The number of Fibrobacter succinogenes‐related sequence and the frequency of detection of novel groups were found to be higher in native horses by selective amplification analysis. The results suggest that genetic diversity and population size of the F. succinogenes group are higher in the hindgut of native horses.     

Effects of sensor location during in situ measurements on pH in caecal digesta of the horse,and post-observational treatment of sensor data

Measurements of caecal pH are useful when studying the effect of a ration on the hindgut environment in horses. Frequent in situ measurements of caecal pH have been used to measure short-term changes in pH. However, this method also results in a large and complex data set. Transient random influxes of alkaline content from the small intestine might result in short-time elevations in caecal pH that complicates data processing. We used two caecal-cannulated horses fed two different rations in a cross-over design experiment. We compared frequent in situ measurements of caecal pH measured with an unweighted and a weighted pH electrode. Based on our results, we recommend to use a weighted pH electrode situated in the deeper layers of the caecum compared to an unweighted. If an unweighted electrode is used, we present a peak-detecting algorithm to eliminate short-time elevation peaks caused by the ileal influx.     

L-色氨酸5L罐发酵条件的研究

在摇瓶发酵实验的基础上,对L-色氨酸生产菌TQ2223的5L罐发酵条件进行了优化。在最优的条件下,L-色氨酸的产量达到10.3g/L。     

Digestion coefficients achieved by the black rhinoceros (Diceros bicornis), a large browsing hindgut fermenter

In contrast to the grazing white (C. simum) and Indian (R. unicornis) rhinoceros, the black rhinoceros (D. bicornis) is an exclusive browser. Due to the particular fermentation characteristics of browse, one would expect browsers to display both shorter ingesta retention times and lower digestion coefficients on comparable diets than grazers. In order to generate a database to test this hypothesis, we performed digestibility studies in eight black rhinoceroses (D. bicornis) from three zoological institutions, using total faecal collection for the quantification of faecal output. One to three regularly fed zoo rations of roughage, concentrates and varying proportions of browse material were used per animal. Additional data was taken from three hitherto unpublished studies as well as several published sources. When compared with horses on similar rations, black rhinoceroses achieved lower digestion coefficients for organic matter and CF. In general, an increase in dietary CF content led to a steeper decrease in organic matter and GE digestibility in black rhinoceroses than in horses. When comparing available data for rhinoceroses, browsing species showed a steeper decrease in organic matter digestibility than grazing species with increasing dietary cell wall content. Endogenous losses as determined by linear regression analysis were within the range reported for horses and Indian rhinoceroses. The results suggest that the horse is not a useful model animal for evaluating diets for black rhinoceroses energetically. In general, diets fed to captive black rhinoceroses seem to include higher proportions of concentrates than diets for other rhinoceros species, and an increase in browse or roughage would reduce digestion coefficients to levels observed in animals fed natural forage.     

病死动物腐败过程中优势菌种的筛选与分离鉴定

本研究旨在筛选出病死动物无害化处理罐中参与动物尸体腐败的优势菌种,为研发加速动物尸体腐败的微生物制剂提供理论依据。收集病死动物无害化处理罐中动物尸体腐败液,按照10倍递增稀释方法,在参与动物尸体腐败的微生物菌群中成功筛选出一株优势菌种,采用传统分离鉴定方法和分子生物学鉴定方法对优势菌种进行鉴定。结果表明,优势腐败菌种为芽孢杆菌属的枯草芽孢杆菌,其16S rRNA基因序列与Bacillus subtilis strain 22（FJ435215.1）的同源性为99.53%。     

柑橘提取物对肥育猪后肠食糜蛋白质代谢产物的影响

【目的】通过研究柑橘提取物对肥育猪后肠食糜蛋白质代谢产物的影响,旨在为柑橘提取物从源头调控臭气的产生提供依据。【方法】选取108头56日龄(19.73±0.39)kg杜×长×大猪,公母各半,随机分为3组,每组分6栏,每栏6头猪。对照组饲喂基础饲粮,抗生素组在基础饲粮中添加75 g/t金霉素,柑橘提取物组在基础饲粮中添加柑橘提取物(56～112日龄添加250 mL/t柑橘提取物,113～194日龄添加200 mL/t柑橘提取物)。194日龄时收集肥育猪盲肠和结肠食糜,测定食糜中游离氨基酸、酚和吲哚类物质、生物胺的含量。【结果】(1)在盲肠食糜中,与对照组相比,柑橘提取物组和抗生素组牛磺酸、天冬氨酸、丙氨酸、缬氨酸、亮氨酸、赖氨酸、组氨酸、精氨酸、吲哚和甲胺含量均显著降低(P<0.05)。与对照组相比,柑橘提取物有降低苏氨酸、丝氨酸、谷氨酸、甘氨酸、瓜氨酸、异亮氨酸、脯氨酸和粪臭素含量的趋势(0.05≤P<0.10),苯酚、腐胺、酪胺和精胺含量均显著降低(P<0.05)。与抗生素组相比,柑橘提取物组腐胺和酪胺含量均显著减少(P<0.05)。(2)在结肠食糜中,与对照...