Oxidative stress induced by corticosterone administration in broiler chickens (Gallus gallus domesticus) 1. Chronic exposure

Two trials were conducted to evaluate the effects of short-term administration of corticosterone (CORT) on the induction of oxidative injury in broiler chickens (Gallus gallus domesticus). Twelve broiler chickens of 30 and of 40 days of age were respectively employed in Trial 1 and 2. Half of the chickens were administered subcutaneously with CORT (4 mg/kg body weight [BW] in corn oil), while another half served as controls (corn oil) in each trail. In Trial 1, a blood sample was obtained from each chicken immediately before administration and at 1 and 3 h after injection. In Trial 2, the liver and heart were obtained after 3 h of CORT exposure. Short-term administration of CORT resulted in enhanced proteolysis and gluconeogenesis. There were no obvious changes in lipid peroxidation status of the heart and liver, whereas a decrease in lipid peroxidation in the plasma was observed after acute CORT exposure. The significantly increased plasma nonenzymatic antioxidants (uric acid [UA] and total antioxidant capacity) in concert with the enhanced enzymatic antioxidant activity (SOD in heart) during short-term CORT administration indicate preventive changes to counteract the oxidative injury, and these may be tissue specific.     

Bone response of broiler chickens (Gallus gallus domesticus) induced by corticosterone

Experiments were conducted with chickens exposed to corticosterone (CORT), with the aim of determining its effects on bone characteristics. At 7 d of age, the experimental birds were injected daily with CORT (4 mg/kg of body mass) for 1 week. CORT administration significantly decreased the body weight while increasing relative liver weight of the chickens and the bone parameters were also decreased. Histology and immunohistochemistry of type X collagen revealed that CORT reduced the lengths of proliferative and prehypertrophic zone in growth plate and the number of positive chondrocytes in the prehypertrophic zone. In conclusion exposure to CORT depressed the growth performance and retarded the longitudinal growth of the long bones by inhibiting the proliferation and differentiation of chondrocytes in growth plate in broilers.     

Altered development and protein metabolism in skeletal muscles of broiler chickens (Gallus gallus domesticus) by corticosterone

Two trials were conducted to investigate the effect of corticosterone (CORT) on protein metabolism and the amino acid composition in muscle tissues of broiler chickens (Gallus gallus domesticus). In Trial 1, two groups of 30 broiler chickens were subjected to control or CORT treatment (30 mg/kg diet) from 28 to 39 days of age. In Trial 2, three groups of chickens of 28 days of age were randomly subjected to one of the following treatments for 7 days: CORT (30 mg/kg diet), pair-fed (maintaining the same feed intake as CORT treatment) and control treatments. The body mass gain and feed efficiency was significantly decreased by CORT treatment, while the food intake was decreased. The breast and thigh masses (% body mass) were significantly suppressed by CORT treatment, while the abdominal fat and liver masses (%) were obviously increased. The plasma levels of glucose, urate and total amino acid were significantly elevated by CORT treatment. The capacity for protein synthesis, estimated by RNA:protein ratio, were significantly suppressed by CORT in M. pectoralis major and M. biceps femoris. The 3-methylhistidine concentrations were significantly increased in both M. pectoralis major and M. biceps femoris of CORT chickens, compared to control but not the pair-fed chickens. The amino acid composition of M. pectoralis major and M. biceps femoris was not significantly affected by CORT treatment. In conclusion, the arrested growth in skeletal muscles induced by CORT administration has tissue specificity. The CORT treatment retards the growth of skeletal muscle by suppressed protein synthesis and augmented protein catabolism.     

Biological response of chickens (Gallus gallus domesticus) induced by corticosterone and a bacterial endotoxin

Experiments were conducted with chickens exposed to corticosterone and lipopolysaccharide (LPS) from Escherichia coli, with the aim of evaluating and differentiating their effects on endocrine, metabolic and immune response. Both, corticosterone and LPS significantly elevated plasma corticosterone concentrations and increased heterophil to lymphocyte (H/L) ratios 1 h, 3 h and 24 h post-treatments. Repeated exposure to corticosterone caused a prolonged elevation of plasma corticosterone concentration and H/L ratio. Data on blood metabolites demonstrated that corticosterone stimulated hyperglycaemia, hypercholesterolemia and hypertriglyceridemia. In contrast, LPS induced hypocholesterolemia and hypotriglyceridemia at 24 h post-injection. Weight gain and relative weight of the spleen and bursa were reduced in chickens treated with corticosterone. The LPS did not show any significant effect on weekly weight gain, but stimulated an increase in the relative weight of the spleen. Corticosterone initially stimulated antibody responsiveness to infectious bronchitis virus (IBV) vaccination, but thereafter the titres decreased. This was in contrast to LPS which depressed the antibody titre to IBV vaccination. It was concluded that the biological response of chickens induced by corticosterone could be differed from the response to LPS. The major difference occurred in metabolic, growth and immune activities. It appears that, both corticosterone and LPS differently alter physiological, metabolic and immunological responses of chickens through an activation of different molecular components (cytokines and chemokines) and neuroendocrine-immune network systems.     

Ontogeny of magnetoreception in chickens (Gallus gallus domesticus)

Chickens are precocial birds, capable of moving independently from within a few hours of hatching, and thus provide a useful model to investigate the development of magnetoreception in young birds. Chicks show some sharply-timed behavioural changes at around 11 days of age that may be indicative of improvements in navigation ability around this age. We trained Young (<10 days, n = 7) and Old (11 days or older, n = 6) chicks to find a hidden imprinting stimulus behind one of four screens in a square arena. Once criterion was reached, the directional choices of chicks were recorded in unrewarded tests in the geomagnetic field and in an experimental field shifted by 90° clockwise. These tests were separated with rewarded training trials to avoid extinction. In the first, and the first 3 tests, no indication was found that chicks chose the correct unimodal magnetic direction. Instead, in all tests, Old chicks preferred the screens in the same magnetic axis as the training direction in tests in the geomagnetic and shifted experimental fields significantly more than Young chicks (P < 0.05). Choices of Young chicks were no different to chance in tests, whereas choices by Old chicks were significantly different from chance (P < 0.05). Our findings support the hypothesis that magnetoreception appears in the second week of life in the chicken. It is, however, unclear when a truly directional magnetic response (i.e. an unimodal, rather than axial, response in our test) develops that could be used by the chicks for accurate navigation.     

Dietary thyroxine induces molt in chickens (Gallus gallus domesticus)

Thyroxine increases during a molt in wild and captive birds, and thyroidectomy prevents induction of molt. This trial examined the effect of dietary thyroxine on molt induction molt in chickens (laying hens, 59 weeks of age). In a completely randomized design (n=15 hens/replication; 6 replications/treatment), hens were randomly assigned to either a traditional molting program consisting of feed withdrawal (FWD), or to diets containing 40 mg thyroxine/kg diet (HT), 20 mg thyroxine/kg diet (LT), or 40 mg thyroxine from thyroactive iodinated casein/kg diet (TIC). The molting treatment lasted 7-13 d, until egg production reached 0%. After molt induction, birds had ad libitum access to the same diet, until egg production was re-initiated and maximized ( approximately 56 d). All treatments induced molt, based upon cessation of egg laying and regression of ovary and oviduct. Birds on FWD treatment lost more body weight during the molting period, but gained more after molt compared to thyroxine treatments (P<0.01 for each), although all body weights were similar when egg production was maximized. Data demonstrate that oral thyroxine, in purified or non-purified form, induces a molt and may enhance animal well-being by reducing the need for FWD.     

Depolarisation and repolarisation sequences of ventricular epicardium in chickens (Gallus gallus domesticus)

Activation and recovery sequences were mapped by means of 64-channel synchronous recording of extracellular potentials on ventricular epicardium in chickens. Ventricular epicardium was depolarized due to multiple breakthroughs. The recovery of ventricular epicardium occurs from the apex to the base of heart and does not repeat the activation sequence. Gradients of repolarisation exist over the ventricular epicardium in birds. Repolarisation pattern of ventricular epicardium depends primarily on intrinsic spatial heterogeneities of ARIs over epicardium.     

Genome-wide expression analysis of roxarsone-stimulated growth of broiler chickens (Gallus gallus)

Roxarsone is a commonly used additive in chicken (Gallus gallus) industry. However, little is known on the intrinsic molecular mechanism via which the growth performance of birds improves. This study was therefore performed to investigate the expression profiles of genes induced by roxarsone. Fifty-six broiler chickens were divided into two groups, namely treated and untreated with roxarsone. The treated group was provided a diet of 45.4 mg/kg roxarsone medication and the other group acted as control. Data analysis showed that roxarsone consistently and significantly (P < 0.05) increased chicken growth performance. In addition to this a significant (P < 0.05) increase of arsenic residue in liver has been seen. Microarray expression analysis of 8935 genes in liver showed that 22 genes (10 up- and 12 down-regulated) had altered expression throughout the experimental periods. Two novel genes (GenBank accession no. GU724343 and GU724344) were cloned through rapid amplification of cDNA ends (RACE). Gene GU724343 was predicted to encode an unidentified protein and the second gene GU724344 was presumed to encode a new member of immunoglobulin-like receptor (CHIR) family. Our results suggested for the first time that the role of roxarsone could be mainly to modify the expression levels of cell growth, immunity/defense and energy metabolism associated genes, as a result promoting animal growth. Further research on these genes should help to increase the knowledge of improving animal productivity safely and effectively.     

Glucose and cationic amino acid transporter expression in growing chickens (Gallus gallus domesticus)

Tissue glucose transporter (GLUT1-3) and cationic amino acid transporter (CAT1-3) mRNA expression was determined in growing broiler chicks posthatch. In two experiments, tissues were either collected on days 1, 3 and 7 or days 1 and 14 posthatch. Heart and liver were the only tissues expressing a GLUT isoform on day 1. All tissues expressed a GLUT isoform on day 7 except for the thymus. Most tissues expressing a CAT isoform on day 1 decreased mRNA levels through day 7 (P<0.05), except for bursa CAT-1 which tended to increase (P=0.05). The thymus and spleen did not express any CAT isoform mRNA until day 7. The liver was the only tissue expressing GLUT-2 mRNA through day 14. On day 14, GLUT-1, CAT-1 and CAT-2 mRNA were differentially expressed across tissues (P<0.05). High-affinity GLUT and CAT mRNA expression was highest in the heart and bursa, respectively (P<0.05). Total CAT mRNA expression was greatest in the bursa (P<0.05). The thymus had the lowest high affinity GLUT and total CAT mRNA expression on day 14 posthatch. Therefore, T lymphocytes within the thymus may be most susceptible to glucose and cationic amino acid supply.     

Membrane potential and H2O2 production in duodenal mitochondria from broiler chickens (Gallus gallus domesticus) with low and high feed efficiency

Increased hydrogen peroxide (H2O2) production was observed in duodenal mitochondria obtained from broiler chickens with low feed efficiency (FE). As a decrease in mitochondrial membrane potential (Deltapsi(m)) due to mild uncoupling of oxidative phosphorylation reduces reactive oxygen species production, this study was conducted to evaluate the effect of uncoupling on Deltapsi(m) and H2O2 production in duodenal mitochondria isolated from broilers with low (0.48+/-0.02) and high (0.68+/-0.01) FE. Membrane potential and H2O2 production were measured fluorometrically and in the presence of different levels of an uncoupler, carbonylcyanide-p-trifluoromethoxyphenylhydrazone (FCCP). The Deltapsi(m) was higher (P相似文献   

Morphological and phylogenetic analysis of Raillietina spp. in indigenous chickens (Gallus gallus domesticus) in Bangladesh

Raillietina spp. (Cestoda: Davaineidae), the most common cestodes in indigenous chickens, cause a substantial production loss in poultry industry in Bangladesh. Here, we estimated the prevalence, confirmed the species and determined the genetic pattern of species of Raillietina using molecular tools. We collected and examined 375 chickens randomly from household of different villages of Mymensingh sadar and Gouripur upazila, Mymensingh district and adult parasites were isolated and identified. Genomic DNA was extracted from collected parasites, amplified ITS-2 and ND-1 genes, sequenced and analyzed. Out of 375 samples, 270 (72.0%) were found positive with Raillietina species and mean worm burden was 10.46 ± 0.56. Microscopically, three species of Raillietina, such as R. cesticillus (37.9%), R. echinobothrida (41.1%) and R. tetragona (52.8%) were detected on the basis of their morphological features. The total length, length and width of scolex, sucker and rostellum were also measured. Among different factors, age, farming nature and flock size of chickens were significantly (p < 0.05) influenced Raillietina infections. For further validation, the sequences of ITS-2 gene generated in this study were matched with reference sequences of R. cesticillus, R. echinobothrida and R. tetragona and found 99.63% − 100% similarity. The phylogenetic analyses of ITS-2 and ND-1 sequences were clustered together with the reference sequences of R. cesticillus, R. echinobothrida and R. tetragona confirming microscopic identification. This is the first confirmation of species of Raillietina along with the prevalence of the species, which will be helpful for the formulation of a control strategy and provide basic information for further molecular study.     

Ethanol administration fails to produce hypoglycemia in fasted chickens (Gallus domesticus)

Chickens weighing approx. 1500 g were fasted 64 hr and then continuously infused with [6-3H]glucose to determine effects of ethanol on plasma glucose concentrations and on rates of glucose turnover. Ethanol infusions (222 or 444 mumol/min X kg-1 body weight) did not cause hypoglycemia although the high dose infusion slightly decreased the rate of glucose turnover. Metabolite ratios measured in livers of chickens infused with the high dose of ethanol indicated that the hepatic cytosolic redox state was relatively unchanged. Chickens have an unusual resistance to ethanol-induced hypoglycemia.     

Genetic characterization of Bhutanese native chickens based on an analysis of Red Junglefowl (Gallus gallus gallus and Gallus gallus spadecieus), domestic Southeast Asian and commercial chicken lines (Gallus gallus domesticus)

The genetic diversity of Bhutanese chickens needs to be understood in order to develop a suitable conservation strategy for these birds in Bhutan. In this, work, we used microsatellite markers to examine the genetic diversity of Bhutanese chickens. Four Bhutanese chicken varieties (Black plumage, Frizzle, Naked neck and Red Junglefowl-like, corresponding to Yuebjha Narp, Phulom, Khuilay and Seim, respectively), two subspecies of Red Junglefowl (Gallus gallus gallus and Gallus gallus spadecieus), two varieties of Thai native chickens (Pradhu Hang Dam and Chee; Gallus gallus domesticus) representing the Southeast Asian domestic chicken, and two commercial lines (Broiler and Single Comb White Leghorn) were genotyped with 18 microsatellites that included 16 loci recommended by the FAO/ISAG for investigations of genetic variability in chickens. All loci were polymorphic, with the number of alleles ranging from six (MCW0111) to 23 (MCW0183). Substantial genetic variation was observed in all populations, with the Bhutanese native chicken Yuebjha Narp (Black plumage chicken) showing the lowest genetic variability. Despite extensive intrapopulation variation, the genetic differentiation among 10 populations was moderate. A neighbor-joining tree revealed the genetic relationships involved while principal component analysis showed that Bhutanese native chickens should be given priority in conservation efforts because of their genetic distinctiveness. Chee chickens are especially valuable as a reservoir of predomestic diversity, as indicated by their greater genetic variation and their position in the phylogenetic tree.     

The effect of an acute phase response on tissue carotenoid levels of growing chickens (Gallus gallus domesticus)

Plasma, liver and skin carotenoids decrease following infectious disease challenges. Since these challenges often involve substantial host pathology and chronic immune responses, the mechanism underlying altered carotenoid deposition is unclear. Therefore, changes in tissue carotenoid levels were examined during an acute phase response induced by lipopolysaccharide (LPS) or interleukin-1 (IL-1). In two experiments, chicks were hatched from carotenoid-deplete eggs (n=28, n=64, respectively) and fed 0, 8 or 38 mg carotenoids (lutein+canthaxanthin)/kg diet. For chicks fed 38 mg carotenoids, but not those fed 0 or 8 mg, LPS generally reduced plasma lutein, canthaxanthin and total carotenoids (P<0.05), and liver lutein, zeaxanthin, canthaxanthin and total carotenoids (P<0.05). Additionally, LPS reduced thymic total carotenoids (P=0.05) and increased thymocyte lutein (P=0.07), zeaxanthin (P=0.07) and total carotenoids (P=0.07). Finally, LPS increased bursal canthaxanthin (P<0.01), but had no effect on shank carotenoids (P>0.5). In chicks hatched from carotenoid-replete eggs (n=36) and fed dietary lutein (38 mg/kg diet), LPS reduced plasma and liver zeaxanthin and liver total carotenoids (P<0.05); IL-1 reduced plasma and liver lutein, zeaxanthin and total carotenoids (P<0.05). Therefore, an acute phase response plays a role in reduced tissue carotenoids during infectious disease.     

Maternal and dietary carotenoids interactively affect cutaneous basophil responses in growing chickens (Gallus gallus domesticus)

This trial examined effects of lutein supplied from maternal (i.e., in ovo) and dietary routes on cutaneous basophil hypersensitivity responses in chickens. Chicks hatched from one of two in ovo carotenoid levels (n=100/level; carotenoid-replete or carotenoid-deplete eggs) were fed one of two diet lutein levels (0 or 40 mg diet lutein/kg diet). At 14 d post-hatch, phytohemagglutinin (PHA) was injected into the wing web, and thickness and leukocyte populations were measured at 0 to 48 h. PHA increased wing web thickness at 4 to 48 h post-PHA (p<0.05), and the swelling response was most related to macrophage numbers in the wing web. Swelling occurred more rapidly in chicks from carotenoid-deplete eggs (p<0.05), but eventually reached a greater thickness in chicks from carotenoid-replete eggs (p<0.05). Differences in leukocyte infiltration occurred due to diet and in ovo carotenoid exposure, and indicate that pre- and post-hatch carotenoid exposure had additive or synergistic effects on the PHA-induced wing web response. Evaluation of the cellular contents of the injection site is a much better indicator of the immunomodulatory effects of lutein than measurements of the amount of swelling.     

Neurogenic inflammation in the chicken (Gallus gallus var domesticus)

1. Neurogenic inflammation has been studied in the anaesthetized adult hen using a variety of different stimuli.2. Plasma extravasation was produced following antidromic stimulation of the external mandibular ramus of the trigeminal nerve which innervates the skin at the angle of the jaw and the anterior part of the wattle.3. Stimulation of the wattle by external application of mustard oil, thermal and mechanical stimuli, as well as intradermal injection of substance P and bradykinin, all produced plasma extravasation.4. These results demonstrate that, in contrast to previous findings in the pigeon, at least in the trigeminal of the chicken peripheral C-fibre nociceptors have similar physiological characteristics in relation to the neurogenic inflammatory mechanism to those seen in mammals.     

Left ventricular myocardal activation under ventricular paced beats in chickens Gallus gallus domesticus

The aim of the study was to advance our knowledge regarding the activation process of the ventricular myocardium in birds in which Purkinje fibres penetrate into the ventricular wall to reach the epicardium. A depolarization pattern of the left ventricular free wall was studied in chickens (Gallus gallus) during ventricular paced beats. Duration of the activation process of the left ventricular free wall is significantly increased during ventricular ectopic excitation as compared with sinus rhythm. Its lowest increase occurs during subendocardial pacing of the middle part of the left ventricle, but its greatest increase is observed during subepicardial pacing of the left ventricular base. Multifocality and mosaicity of depolarization of the left ventricular free wall myocardium in chicken are expressed in a considerably less degree during ventricular paced beats in comparison with sinus rhythm. During ventricular paced beats, excitation of the left ventricular free wall is mostly due to the successive spreading of the depolarization wave from pacing sites.