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True mineral digestibility in C57Bl/6J mice
No full textData on mineral digestibility is key to understand mineral homeostasis and refine the recommendations for the dietary intake of these nutrients. In farm animals and pets, there is plenty of data on mineral digestibility and influencing factors. In laboratory mice, however, there is a lack of information on mineral digestibility under maintenance conditions, although this should be the basis for studies on mineral homeostasis under experimental conditions. The aim of the present study was to analyse data on intake, faecal excretion, and apparent digestibility of calcium, phosphorus, sodium, potassium, and magnesium in C57BL/6J mice fed different maintenance diets with varying voluntary dry matter intake. Lucas-tests were used to quantify true digestibility and describe correlations between dietary intake and excretion/absorption of the nutrients. Calcium, phosphorus, and magnesium showed a linear correlation between intake and faecal excretion (R2: 0.77, 0.93 and 0.91, respectively). Intake and apparently digested amounts of sodium and potassium were correlated linearly (R2: 0.86 and 0.98, respectively). These data show that intake is the major determinant of absorption in the minerals listed above. Faecal calcium and phosphorus excretion were correlated as well (R2 = 0.75)
Genetische und serologische Charakterisierung glatter und rauer Salmonellen und Bestimmung ihrer phänotypischen Stabilität unter variablen abiotischen Stressbedingungen
No full textDer Einfluss des Stärkeaufschlussgrads kommerzieller Versuchstierfutter auf das gastrointestinale Mikrobiom von Labormäusen
Full text linkDas Mikrobiom und dessen Zusammensetzung ist abhängig von der Ernährung des Wirtes. Kommerzielle Labormausfutter sind in verschiedenen Verarbeitungs-formen (Pellet, Extrudat, Mehl, Hybridpellet) erhältlich und werden dabei iden-tisch deklariert und als gleichwertig vermarktet. Bei Analysen verschiedener Fut-termittel für Labormäuse konnte festgestellt werden, dass sich die verschiedenen Verarbeitungsformen in ihrem Stärkeaufschlussgrad voneinander unterschieden (BÖSWALD & KIENZLE, 2019). Bei Tierversuchen ist eine Reproduzierbarkeit im Sinne der 3R eines der obersten Ziele. Diese Reproduzierbarkeit erreicht man nur durch eine konsequente Standardisierung der Tierversuche.
Ziel unserer Studie war es zu untersuchen, inwiefern sich diese Abweichungen in Nährstoffzusammensetzung und Stärkeaufschlussgrad auf die Verdaulichkeit des Futters und dementsprechend auf das Mikrobiom der Mäuse auswirken. Analysen des Futters zeigten, dass sich verschiedene Verarbeitungsformen in ihrer Nähr-stoffzusammensetzung und ihrem Stärkeaufschlussgrad voneinander unterschie-den. Zudem war festzustellen, dass sich sogar zwei Chargen derselben Verarbei-tungsform (Pellet) voneinander unterschieden und in ihrer Nährstoffzusammenset-zung und insbesondere dem Stärkegehalt voneinander abwichen. Es zeigte sich des Weiteren, dass die extrudierte Verarbeitungsform besser verdaulich ist als die pelletierte, in Versuch zwei war die pelletierte Diät auf Grund des hohen Stärke-gehalts besser verdaulich. Das extrudierte Futter zeigte ähnliche Ergebnisse wie im ersten Versuch.
In Versuchsteil 1 unterschied sich das Mikrobiom in der α-Diversität signifikant im Magen und Caecum. Die β-Diversität zeigte lediglich geringe Unterschiede zwischen den beiden Gruppen. Die Analyse der molekularen Spezies auf dem Ni-veau der zOTU zeigte eine signifikant erhöhte Anzahl an Muribaculaceae in E1 in allen Lokalisationen außer dem Kot. Lachnospiraceae waren insbesondere im Cae-cum im Mikrobiom der pelletierten Gruppe signifikant vermehrt vorhanden. Limo-silactobacillus reuteri war im Mikrobiom der pelletierten Gruppe im Magen und Dünndarm signifikant häufiger zu finden. Ligilactobacillus animalis war im Kolon der Gruppe E1 signifikant vermehrt. In Versuchsteil 2 unterschied sich die β-Diversität in allen Regionen außer dem Kolon signifikant zwischen P2 und E2. Interessanterweise waren diese Unterscheide jedoch nicht in der α-Diversität er-kennbar. Auf zOTU Level waren verschiedene molekularen Spezies der Familie Muribaculaceae im Magen und Kot in der pelletierten Gruppe signifikant stärker vertreten, im Dünndarm und Kolon in der extrudierten Gruppe, im Caecum war das Verhältnis eher ausgewogen. Die molekularen Spezies des Genus Duncaniella waren in Dünndarm, Caecum und Kolon in der extrudierten Gruppe signifikant vermehrt zu finden, in den Faeces zeigte sich ein signifikant häufigeres Auftreten in der pelletierten Gruppe. Die molekularen Spezies der Familie Lachnospiraceae waren in der extrudierten Gruppe in allen Regionen vermehrt vorhanden, einzelne zOTUs waren jedoch in der pelletierten Gruppe signifikant erhöht. Limosilactoba-cillus reuteri und Ligilactobacillus animalis waren in diesem Versuch in Gruppe P2 signifikant stärker im Dünndarm vertreten.
Die Ergebnisse dieses Versuchs zeigen, dass die Verarbeitung von Futtermitteln zu einer Veränderung der Nährstoffzusammensetzung und des Stärkeaufschluss-grads führte. Es konnte gezeigt werden, dass es in der Fütterung von Labormäu-sen noch einen Mangel an Standardisierung gibt. Die hier beobachteten Verände-rungen der Futter hatten Einfluss auf die Verdaulichkeit der Futtermittel und auf Entwicklung des Mikrobioms im Gastrointestinaltrakt der Maus. Forscher sollten daher beachten, dass unterschiedliche Chargen und verschiedene Verarbeitungs-formen einer Labormausdiät das Mikrobiom beeinflussen können. Ebenso sollten daraus resultierende metabolische Veränderungen in Betracht gezogen werden. Im Moment ist die biologische Reproduktion und ein Vergleich von Mausversuchen bezüglich des Mikrobioms nicht gewährleistet.The microbiome and its composition are subject to the host’s diet. Commercial laboratory mouse diet is available in different physical forms (pelleted, extruded, powdered, semipelleted) and is declared to contain identical ingredients and nu-trient composition and are marketed as equal products. After the analysis of dif-ferent laboratory mouse feeds, it could be shown, that product processing leads to variation in starch gelatinization (BÖSWALD & KIENZLE, 2019). In animal ex-periments a reproduction according to the goals of the 3R is of utmost importance. This reproduction will only be achieved following a consistent standardization.
The aim of this study was to investigate, how far this divergence in nutrient con-tent and starch gelatinization influences the digestibility of this diet and thus the microbiome of the mice used in this experiment. Analysis of the diets used in this experiment showed, that different product processing leads to a change in nutri-ent’s composition and starch gelatinization. Furthermore, two batches of the same product processing (pelleted) differed in their nutrient’s composition and in their starch content. It could be seen that the extruded form had a higher digestibility than the pelleted form. In trial two the pelleted diet was more digestible due to its high starch content, the extruded diet showed results similar to those in trial 1.
The samples were analyzed using the 16S rRNA gene amplicon sequencing. In trial 1 the microbiome significantly differed in the α-diversity in the stomach and caecum. β-diversity displayed only minor differences between the groups. An analysis of molecular species showed a significantly higher richness of Muribacu-laceae in E1 in all regions beside the feces. Lachnospiraceae were especially in the caecal content of the pelleted fed group significantly stronger than in the extruded fed group. Limosilactobacillus reuteri was in the microbiome of stomach and small intestine in group P1 significantly higher than in group E1. Ligilactobacillus ani-malis was significantly more abundant in the colon of E1. In trial 2 β-diversity differed significantly in almost all sampled regions between P2 and E2, except for the colon. Interestingly, these differences were not noticeable in the α-diversity. At zOTU level the molecular species of the family Muribaculaceae were signifi-cantly stronger in the stomach and feces of P2 than E2, however in the small intes-tine and colon species of this family were significantly more abundant in E2 than P2, in the caecum the relative abundance was similar in both groups. Molecular species of the genus Duncaniella were significantly more abundant in the small intestine, caecum and colon in the extruded group. In the feces this genus was significantly more abundant in the pelleted group. The family Lachnospiraceae was more abundant in the extruded group in all regions sampled, however some zOTUs were significantly stronger in the pelleted group. Limosilactobacillus reu-teri and Ligilactobacillus animalis were significantly more abundant in the small intestine of P2.
The results of this study show, that the processing of feed leads to changes in nu-trient’s content and starch gelatinization. These results reveal that standardization in the feeding of laboratory mice may lack. The changes observed in this study influenced the digestibility of the diets and the development of the microbiome in the gastrointestinal tract of mice. Researchers should keep in mind, that different batches and different product processing of laboratory mouse diet could influence the mouse microbiome. Likewise, possible metabolic changes due to changes in the microbiome should be considered. At the moment biological reproducibility and comparison of mouse experiments is not given, and future research will be helpful here
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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