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Day-old Chickens (day-old + chicken)
Selected AbstractsEffect of L-carnitine on proliferative response and mRNA expression of some of its associated factors in splenic mononuclear cells of male broiler chicksANIMAL SCIENCE JOURNAL, Issue 2 2010Kazuaki TAKAHASHI ABSTRACT The effect of L-carnitine supplementation on mitogen (concanavalin A, Con A) induced proliferation of mononuclear cells (MNC) in the spleen was investigated in broiler chickens at different ages. Day-old chickens were fed a diet supplemented with or without L-carnitine (100 ppm) for 24 days. The carnitine-supplemented group showed greater proliferation of MNC in the spleen in response to Con A than that of the control group at 24 days of age. In addition, at 24 days of age the carnitine-supplemented group showed higher expression of interleukin (IL)-2 and interferon (IFN)-, mRNA, but lower expression of inducible nitric oxide synthase (iNOS) in the Con A-stimulated splenic MNC than the control group. The enhancement effect of L-carnitine on MNC proliferation and IL-2 mRNA expression was not found in chicks at 14 days of age. Addition of L-carnitine (50 nmol/mL) to the culture medium enhanced proliferation and IL-2 mRNA expression of splenic MNC obtained from 24-day-old but not from 14-day-old broiler chickens. The results suggest that L-carnitine is capable of enhancing MNC proliferation in broiler chickens at 24 days of age partly through increasing IL-2 and IFN-, production and decreasing NO production. [source] Selecting for development of fluoroquinolone resistance in a Campylobacter jejuni strain 81116 in chickens using various enrofloxacin treatment protocolsJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2010K. Stapleton Abstract Aims:, To determine the effect of various enrofloxacin dose regimes on the colonization and selection of resistance in Campylobacter jejuni strain 81116P in experimentally colonized chickens. Methods and Results:, Two experiments were undertaken, in which 14-day-old chickens were colonized with 1 × 107,1 × 109 CFU g,1Camp. jejuni strain 81116P and then treated with enrofloxacin at 12,500 ppm in drinking water for various times. Caecal colonization levels were determined at various time-points after start-of-treatment, and the susceptibility of recovered isolates to ciprofloxacin was monitored. Resistance was indicated by growth on agar containing 4 ,g ml,1 ciprofloxacin, MICs of 16 ,g ml,1 and the Thr86Ile mutation in gyrA. Enrofloxacin at doses of 12,250 ppm reduced Camp. jejuni colonization over the first 48,72 h after start-of-treatment. The degree of reduction in colonization was dose, but not treatment time, dependent. In all cases, maximal colonization was re-established within 4,6 days. Fluoroquinolone-resistant organisms were recoverable within 48 h of start-of-treatment; after a further 24 h all recovered isolates were resistant. In contrast, a dose of 500 ppm enrofloxacin reduced colonization to undetectable levels within 48 h, and the treated birds remained Campylobacter negative throughout the remaining experimental period. By high pressure liquid chromatography, for all doses, the maximum concentrations of enrofloxacin and ciprofloxacin in the caecal contents were detected at the point of treatment completion. Thereafter, levels declined to undetectable by 7 days post-treatment withdrawal. Conclusions:, In a model using chickens maximally colonized with Camp. jejuni 81116P, treatment with enrofloxacin, at doses of 12,250 ppm in drinking water, enables the selection, and clonal expansion, of fluoroquinolone-resistant organisms. However, this is preventable by treatment with 500 ppm of enrofloxacin. Significance and impact of the study:, Treatment of chickens with enrofloxacin selects for resistance in Camp. jejuni in highly pre-colonized birds. However, a dose of 500 ppm enrofloxacin prevented the selection of resistant campylobacters. [source] Hypoxia-Induced Apoptotic Cell Death is Prevented by Oestradiol Via Oestrogen Receptors in the Developing Central Nervous SystemJOURNAL OF NEUROENDOCRINOLOGY, Issue 3 2008V. M. Pozo Devoto The neuroprotective effects of oestrogens have been demonstrated against a variety of insults, including excitotoxicity, oxidative stress and cerebral ischemia under certain conditions. However, the molecular mechanisms underlying oestrogen neuroprotection are still unclear. We aimed to determine whether 17,-oestradiol (E2) administration post-hypoxia (p-hx) was neuroprotective and whether these actions were mediated through oestrogen receptors (ER). For this purpose, 12-embyonic day-old chickens were subjected to acute hypoxia [8% (O2), 60 min], followed by different reoxygenation periods. To test the neuroprotective effect of E2 and its mechanism, embryos were injected 30 min after the end of hypoxia with E2 alone or with ICI 182 780, a competitive antagonist of ER. Cytochrome c (cyt c) release, an indicator of mitochondrial apoptotic pathway, was measured by western blot in optic lobe cytosolic extracts. DNA fragmentation by TUNEL fluorescence and caspase-3 fragmentation by immunofluorescence were detected on optic lobe sections. Acute hypoxia produces a significant increase in cyt c release from mitochondria at 4 h p-hx, followed by an increase in TUNEL positive cells 2 h later (6 h p-hx). Administration of E2 (0.5 mg/egg) produced a significant decrease in cytosolic cyt c levels at 4 h p-hx, in casapse-3 activation and in TUNEL positive cells at 6 h p-hx compared to vehicle treated embryos. In the E2 -ICI 182 780 treated embryos, cyt c release, caspase-3 fragmentation and TUNEL positive cells were similar to the hypoxic embryos, thus suggesting the requirement of an E2,ER interaction for E2 mediated neuroprotective effects. In conclusion, E2 prevents hypoxia-induced cyt c release and posterior cell death and these effects are mediated by oestrogen receptors. [source] Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibersBIOPOLYMERS, Issue 3 2005B. C. Vidal Abstract The optical anisotropies (linear dichroism or LD and birefringence) of crystalline aggregates of the sulfonic azo-dye Ponceau SS and of dye complexed with chicken tendon collagen fibers were investigated in order to assess their polarizing properties and similarity to liquid crystals. In some experiments, the staining was preceded by treatment with picric acid. Crystalline fibrous aggregates of the dye had a negative LD, and their electronic transitions were oriented perpendicular to the filamentary structures. The binding of Ponceau SS molecules to the collagen fibers altered the LD signal, with variations in the fiber orientation affecting the resulting dichroic ratios. The long axis of the rod-like dye molecule was assumed to be bound in register, parallel to the collagen fiber. Picric acid did not affect the oriented binding of the azo dye to collagen fibers. There were differences in the optical anisotropy of Ponceau SS-stained tendons from 21-day-old and 41-day-old chickens, indicating that Ponceau SS was able to distinguish between different ordered states of macromolecular aggregation in chicken tendon collagen fibers. In the presence of dichroic rod-like azo-dye molecules such as Ponceau SS, collagen also formed structures with a much higher degree of orientation. The presence of LD in the Ponceau SS-collagen complex even in unpolarized light indicated that this complex can act as a polarizer. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 121,128, 2005 This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | ||||||||||