No abstract

In the European Union (EU) millions of laboratory mice are used and killed for experimental and other scientific purposes each year. Although controversially discussed, the use of carbon dioxide (CO2) is still permitted for killing rodents according to the Directive 2010/63/EU. Within the scope of refinement, our aim was to investigate if isoflurane and sevoflurane are an appropriate alternative killing method to CO2 in mice. Different concentrations of CO2 (filling rates of 20%, 60%, 100%; CO2 20, 60, 100), isoflurane (Iso 2%, 5%) and sevoflurane (Sevo 4.8%, 8%) were compared in two mouse strains (NMRI, C57Bl/6J) using a broad spectrum of behavioral parameters, including the approach-avoidance test, and analyzing blood for stress parameters (glucose, adrenaline, noradrenaline). We focused in our study on the period from the beginning of the gas inlet to loss of consciousness, as during this period animals are able to perceive pain and distress. Our results show that only higher concentrations of CO2 (CO2 60, 100) and isoflurane (5%) induced surgical tolerance within 300 s in both strains, with CO2 100 being the fastest acting inhalant anesthetic. The potency of halogenated ethers depended on the mouse strain, with C57Bl/6J being more susceptible than NMRI mice. Behavioral analysis revealed no specific signs of distress, e. g. stress-induced grooming, and pain, i. e. audible vocalizations, for all inhalant gases. However, adrenaline and noradrenaline plasma concentrations were increased, especially in NMRI mice exposed to CO2 in high concentrations, whereas we did not observe such increase in animals exposed to isoflurane or sevoflurane. Escape latencies in the approach-avoidance test using C57Bl/6J mice did not differ between the three inhalant gases, however, some animals became recumbent during isoflurane and sevoflurane but not during CO2 exposure. The rise in catecholamine concentrations suggests that CO2 exposure might be linked to a higher stress response compared to isoflurane and sevoflurane exposure, although we did not observe a behavioral correlate for that. Follow-up studies investigating other fast-acting stress hormones and central anxiety circuits are needed to confirm our findings.

The transition to using dual-purpose chickens is an alternative to killing male hatchlings of high performance egg-laying chickens. This study aimed to compare the gastrointestinal tract of a recently developed genetic line of dual purpose male chicken, Lohmann Dual (LD), with that of a broiler line, Ross 308. Eighty birds from each line were grown until they reached an average body weight 2000 g (5 weeks for Ross and 9 for LD birds). Six birds of each line were sampled weekly. Body weight (BW), normalized mass of gastrointestinal segments and relative length of intestine were determined. Histologically the villus height, epithelium height, crypt depth, mucosal enlargement factor and the tunica muscularis thickness were measured in jejunum and ileum. Data were regressed against body weight and genetic line. Jejunal enterocyte microvilli and junctional complexes length were measured. Normalized mass and relative length of the gastrointestinal segments were greater in LD birds than in Ross birds at all ages. After day 7 these decreased steadily over the lifetime of the birds in both genetic lines. The growth curves of the gastrointestinal segments of the LD birds were similar to those of the Ross birds. In birds of the same BW, LD birds had a significantly heavier gizzard, shorter intestine, higher jejunal villi, thicker ileal tunica muscularis and smaller ileal mucosal enlargement factor than were found in Ross birds. The large gizzard in LD chickens presumably increases the degree of food processing and enhances availability of nutrients in the orad part of the intestine leading to a lower nutrient concentration and a smaller absorption surface area in the ileum of the LD compared to the Ross chickens. The anatomical differences between the two lines are important criteria for further selection and should be considered in their feeding management.

VSOP-C91 significantly improves visualization of the coronary arteries at MR angiography from immediately to 35 minutes after injection.

Salmonellae are among the most widespread sources of foodborne infections and Salmonella Typhimurium, in particular, is correlated with human disease caused by the consumption of contaminated pork. Intraepithelial lymphocytes (IEL) have early contact with intestinal antigens and play an important role in the detection of pathogenic bacteria. The objective of this study was to determine whether a presumed probiotic Enterococcus faecium strain could improve histomorphological and immune system-related parameters of gut function after a Salmonella challenge in weaned pigs. In particular the morphological parameters villus length and width, crypt depth and width as well as the actual enlargement of the intestinal epithelial surface were calculated and the number of IEL was evaluated in sections of the porcine gut. Weaned piglets were challenged with Salmonella enterica serovar Typhimurium DT 104, and half of them also received Enterococcus faecium NCIMB 10415 in the diet. Animals were sacrificed at days post infection (DPI) 2 and 28. The effect of the factors "time post-infection/age" and "probiotic treatment" on jejunal morphology and IEL numbers and distribution was evaluated by light microscopy. The time post-infection had significant effects in both feeding groups. Animals sacrificed at DPI 28 had longer and wider villi, deeper and wider crypts, a higher villus enlargement factor, a higher ratio between villus and crypt enlargement factors as well as more IEL. Probiotic treatment resulted in longer villi, a higher ratio of villus surface/crypt circumference enlargement factors and significantly more IEL. The larger total number of IEL displayed by the probiotic group resulted from significantly higher numbers of IEL at the nuclear and apical levels of the intraepithelial compartment but not from the number of IEL situated at the basement membrane. The probiotic effects were only measurable 28 DPI. It is proposed that Enterococcus faecium NCIMB 10415 exerts an immune modulatory effect by increasing the numbers of intraepithelial lymphocytes.