Mortality in organic free-range chickens and molecular characterization of the involved pathogens

Longitudinal investigations on causes of mortality were carried out at one organic layer farm with four flocks of Lohman Brown and Lohman White chickens producing table eggs. All flocks were housed separately. One flock of each breed were followed from September 2001 to August 2002. Post mortem examinations were performed on a total of 16% of the dead chickens over the entire period. Of these 346 (96%) of the Lohmann Brown and 315 (91%) of the Lohmann White chickens were subjected for bacteriology. High mortality rates, 91% and 63% were observed in Lohman Brown and Lohman White chickens, respectively and were found to be due to infections with mainly Pasteurella multocida, Erysipelothix rhusiopathia and Escherichia coli. E. rhusiopathia, P. multocida and E. coli were isolated from 46%, 19% and 17%, respectively of the Lohmann Brown chickens. In the flock of Lohmann White chickens P. multocida and E. coli were isolated from 46% and 15%, respectively while E. rhusiopathia was not recorded. P. multocida and E. rhusiopathia isolates were characterized by Restriction Endonuclease Analysis (REA), Restriction Fragment Length Polymorphism (RFLP) and Pulse Field Gel Electrophoresis (PFGE). It was demonstrated that all the P. multocida isolates were genotypic identical over time. The E. rhusiopathia isolates obtained were also identical. It was concluded that the outbreaks caused by P. multocida and E. rhusiopathia were clonal and these two pathogens may cause severe losses in free-range chickens

Consequences of concurrent Ascaridia galli and Escherichia coli infections in chickens

Three experiments were carried out to examine the consequences of concurrent infections with Ascaridia galli and Escherichia coli in chickens raised for table egg production. Characteristic pathological lesions including airsacculitis, peritonitis and/or polyserositis were seen in all groups infected with E. coli. Furthermore, a trend for increased mortality rates was observed in groups infected with both organisms which, however, could not be confirmed statistically. The mean worm burden was significantly lower in combined infection groups compared to groups infected only with A. galli. It was also shown that combined infections of E. coli and A. galli had an added significant negative impact on weight gain

Sygdomme og velfærd

Siden anden verdenskrig er der sket store ændringer i fjerkræproduktionen. Indførslen af nye produktionssystemer, robuste og højtydende dyr, forbedret management og indførslen af biosecurity har medført en stor produktionsfremgang med lav mortalitet. I de senere år har forbrugerønsker medført at udvikling af udendørs produktionssystemer, hvor de klassiske fjerkræsygdomme nu er på fremmarch med en forhøjet mortalitet til følge. Forfatterne diskuterer, om de udendørs produktionssystemer reelt har betydet en forbedret velfærd for hønerne

The effect of concurrent infections with Pasteurella multocida and Ascaridia galli on free range chickens

Pasteurella multocida and Ascaridia galli are observed with high prevalences in free range chickens in Denmark, but the impact is unknown. A study was carried out to examine the interaction between A. galli and P. multocida in chickens and the impact on production. Five groups, each with 20 18-week-old Lohmann Brown chickens were infected. Group I was orally infected with 1000 +/- 50 embryonated A. galli eggs. Group 2 received 10(4) cfu p. multocida intratracheally. Group 3 was infected with A. galli and subsequently with P. multocida. Group 4 was infected with P. multocida followed by A. galli. Group 5 was the control. The study ran for I I weeks where clinical manifestations, weight gain and egg production were recorded. Excretion of P. multocida was determined on individual basis and blood smears were made for differential counts. At the end of the study pathological lesions and the number of adult worms, larvae and eggs in the faeces were recorded. The birds were more severely affected when infected with both pathogens compared to single infections with A. galli or P. multocida, respectively. A lower weight gain and egg production was observed with dual infections. A. galli infection followed by a secondary P. multocida infection resulted in more birds with pathological lesions and continued P. multocida excretion. In conclusion a negative interaction between A. galli and R multocida was observed and it is postulated that free range chickens are at higher risk of being subjected to outbreaks of fowl cholera when they are infected with A. galli

A novel derivative of thioridazine shows low toxicity and efficient activity against gram‐positive pathogens

Thioridazine hydrochloride (HCl) has been suggested as a promising antimicrobial helper compound for the treatment of infections with antimicrobial-resistant bacteria. Unfortunately, the therapeutic concentration of thioridazine HCl is generally higher than what can be tolerated clinically, in part due to its toxic side effects on the central nervous system. Therefore, we aimed to synthesize a less toxic thioridazine derivative that would still retain its properties as a helper compound. This resulted in a compound designated 1-methyl-2-(2-(2-(methylthio)-10H-phenothiazin-10-yl)ethyl)-1-pentylpiperidin-1-ium bromide (abbreviated T5), which exhibited low blood–brain barrier permeability. The lowest minimal inhibitory concentration (MIC) against Staphylococcus aureus exposed to the novel compound was reduced 32-fold compared to thioridazine HCl (from 32 µg/mL to 1 µg/mL). The MIC values for T5 against five Gram-positive pathogens ranged from 1 µg/mL to 8 µg/mL. In contrast to thioridazine HCl, T5 does not act synergistically with oxacillin. In silico predictive structure analysis of T5 suggests that an acceptably low toxicity and lack of induced cytotoxicity was demonstrated by a lactate dehydrogenase assay. Conclusively, T5 is suggested as a novel antimicrobial agent against Gram-positive bacteria. However, future pharmacokinetic and pharmacodynamic studies are needed to clarify the clinical potential of this novel discovery

Forskning og udvikling i økologisk ægproduktion

Nærværende rapport er en beskrivelse og diskussion af forskningsprojekter gennemført under FØJO i årene 1996-1999. I korthed vidste forskningen følgende: Opdrætning og belægning Det har vist sig at konventionel opdræt giver en del problemer og der er anvendt en del kræfter på at belyse konsekvensen af forskellige opdrætningsmetoder, herunder lysintensitet, adgang til udeareal, opdræt på blivende sted eller flytning. Konklusionen fra disse undersøgelser er, at: Tidlig adgang til udearealet giver øget brug af udearealet senere, tendens til færre gulvæg og signifikant færre snavsede æg Opdrætning i hytte giver større kropsvægt, større ægvægt, færre gulvæg, færre snavsede æg og bedre fjerdragt end opdrætning under konventionelle forhold. Lav belægning i æglægningsperioden med 3.5 høner pr. m2 giver højere læggeprocent, bedre fodereffektivitet, tendens til færre gulvæg og signifikant færre snavsede æg samt bedre fjerdragt, dog kun hos de høner, der var opdrættet i stald Avl og selektion Avlsmaterialets kvalitet har været en vigtig del af forskningsarbejdet, dels fordi der kun er få avlsvirksomheder tilbage, der sælger afstamninger med en vis æglægningskapacitet, dels fordi disse afstamninger primært er fremavlet med sigte på burægsproduktion. Den konklusion, der kan drages af de genetiske studier er, at såfremt fjerpilningsadfærd inddrages i et passende selektionsprogram, vil et af de største velfærdsproblemer inden for ægproduktion blive løst. Parasitter Et problem, som møder den økologiske høne, er indvoldsorme. Mulighederne for at forebygge på dette område er i projektet blevet undersøgt i forskellige sammenhænge. Konklusionen er, at man må regne med, at indvoldorme altid vil være til stede i en vis udstrækning, når besætningen har adgang til udendørs arealer. Fuldstændig udryddelse er ikke mulig. I dag findes der kun konventionelle antiparasitære midler til behandling og kontrol af parasitære infektioner. Disse midler anses ikke for at være anvendelige, da tilbageholdelsestiderne er lange. På sigt bør man avlsmæssigt arbejde mod at etablere specielle racer til udendørsproduktion som er resistente mod parasitære og andre infektioner. Grovfoder Forsøg med tildeling af grovfoder har haft en positiv effekt på ægproduktion, forbrug af fuldfoder og der var en markant lavere dødelighed. Der kan iagttages mindre fjerpilning og en forbedring af fjerdragtens kvalitet, når der gives grovfoder. Endelig kunne der hvad angår tarmsundhed konstateres en øget kråseaktivitet og øget fermentering i blindtarmene samt lavere antal af coliforme bakterier, laktose negative bakterier og enterokokker. På temamødet på Forskningscenter Foulum, berettede flere landmænd om græsrodsprojekterne, og deres resultater og erfaringer er beskrevet i denne rapport. I sit afsnit vurderer Arne Bæk Jensen bl.a., at det økologiske opdræt og anvendelsen af kyllingemødre har været en succes idet: Kyllingerne har levet under forhold, som har givet en forøgelse af dyrevelfærden. Indeklimaet i opdrætsstalden har været godt som følge af et tørt gulv Energiforbruget er blevet reduceret Den tidlige prægning har haft sin virkning I æglægningsstalden sidder ca. 90 pct. af hønerne på siddepindene om natten efter ca. 14 dage Noget tyder på, at de høner, som ikke kommer på pindene om natten, også lægger deres æg på gulvet, hvor de overnatter. Hønerne på siddepindene har en bedre redesøgningsadfærd Ved indsætning ligger hønerne et pænt stykke over normen for væg

Hot Pressing of Ho2O3 and Dy2O3 Based Magneto-Optical Ceramics

The paper presents results of a research on fabrication of magneto-optical ceramics based on Ho2O3 and Dy2O3 sesquioxides. The ceramics were made by hot pressing of powders prepared by self-propagating high-temperature synthesis. The methods and modes of the powder treatment developed made it possible to significantly increase the thickness of the ceramics without deterioration in optical quality in comparison with the samples obtained by vacuum sintering. The characteristics of the ceramics, such as transmission spectrum, thermal conductivity, linear thermal expansion coefficient, microhardness, elastic modulus, and crack resistance have been investigated. © 2021 The Author(s).The study was funded by the Russian Science Foundation, research project No. 18-13-00355, https://rscf.ru/en/project/18-13-00355