禁食对蛋鸡肝脏腺苷-磷酸激活的蛋白激酶活性的影响

腺苷 -磷酸 (AMP)激活的蛋白激酶 (AMP- acti-vated protein kinase,AMPK)是丝氨酸激酶家族的一员 ,由 AMP和其上游激酶 AMPK激酶所活化 ,对细胞内 AMP/ATP的变化非常敏感 [1] ,被称为真核细胞的“代谢感受器”[2 ]。研究发现在跑步 [3 ,4 ]、电刺激肌肉 [5,6]或禁食应激后 [7] ,大鼠肝脏和肌肉中的AMPK活性升高数倍 ,乙酰辅酶 A羧化酶 (ACC)活性显著下降甚至丧失 ,丙二酸单酰辅酶 A产量降低甚至为零 ,脂肪酸合成受抑。同时 ,AMPK活化后 ,脂肪酸的氧化率显著提高 ,CO2 和酮体生成量明显增加[4 ,8] 。这些均表明 ,AMPK活化…     

含碘血浆对动物的毒性作用研究

目的 观察经交联淀粉碘及紫外处理的血浆静脉输入后对动物的毒性作用。方法 将鸡作为实验动物,采用自动生化分析仪、酶联等技术,观察输用消毒血浆后鸡的肝、肾及甲状腺功能变化。结果 连续５ｄ,每日给鸡静脉输入血浆１０ｍｌ后,试验组动物与对照组相比其肝、肾及甲状腺功能指标变化差异不显著。结论 适量消毒血浆的输入对试验动物无毒性作用。     

Egg size and yolk steroids vary across the laying order in cockatiel clutches: A strategy for reinforcing brood hierarchies?

When a female bird begins incubation before clutch completion, the nestlings hatch sequentially, and a size hierarchy forms within the brood. This size hierarchy may be minimized or exacerbated through differential allocation of resources to eggs across the laying order. In this study, we characterize intra-clutch variation in cockatiel clutches by measuring egg mass, yolk mass, and concentrations of yolk testosterone, androstenedione, and corticosterone. Cockatiels are a long-lived member of the Psittaciformes. Because asynchronous hatching may reduce sibling competition and allow for extended development periods in long-lived birds, we predicted that female cockatiels would allocate maternal resources in a way that would reinforce the brood size hierarchy. Significant within-clutch differences in egg size and steroid concentrations were observed. Eggs at the end of the laying sequence were smaller and had significantly smaller yolks than eggs early in the laying order. Fifth-laid eggs, as well as first-laid eggs, contained significantly lower concentrations of testosterone than eggs in other positions of the laying sequence. No differences in yolk androstenedione concentration were observed. Yolk corticosterone concentrations increased linearly with laying order. Together, these patterns might reinforce the brood size hierarchy created by asynchronous hatching.     

Differential roles of hypothalamic serotonin receptor subtypes in the regulation of prolactin secretion in the turkey hen

In the turkey, exogenous serotonin (5-hydroxytryptamine, 5-HT) increases prolactin (PRL) secretion by acting through the dopaminergic (DAergic) system. In the present study, infusion of the 5-HT_2C receptor agonist, (R)(−)-DOI hydrochloride (DOI), into the third ventricle stimulates PRL secretion, whereas the 5-HT_1A receptor agonist, (+/−)-8-OH-DPAT hydrobromide (DPAT), inhibits PRL secretion. Using the immediate-early gene, c-fos, as an indicator of neuronal activity, in situ hybridization histochemistry showed preferential c-fos co-localization within tyrosine hydroxylase immunoreactive neurons (the rate limiting enzyme in DA synthesis) in the areas of the nucleus preopticus medialis (POM) and the nucleus premammillaris (PMM), in response to DPAT and DOI, respectively. To clarify the involvement of 5-HT_1A and 5-HT_2C receptors in PRL regulation, their mRNA expression was determined on hypothalamic tissue sections from birds in different reproductive stages. A significant difference in 5-HT_1A receptor was observed, with the POM of hypoprolactinemic short day and photorefractory birds showing the highest expression. 5-HT_2C receptors mRNA did not change during the reproductive cycle. The data presented support the notion that DA neurons in the PMM and POM mediate the stimulatory and inhibitory effects of 5-HT, respectively, on PRL secretion and the 5-HTergic system can both stimulate and inhibit PRL secretion.     

New PA/1220/98-like variant of infectious bronchitis virus in Poland

ABSTRACT

The aim of the present study was to report the first detection of a new infectious bronchitis virus (IBV) variant in Polish commercial flocks which is completely different to any previously known in this region. In 2018, samples from Ross 308 breeding hens aged 35 weeks were delivered for IBV diagnosis. IBV presence was detected, but all attempts to amplify the S gene fragment were negative. The field material was analysed using the Illumina MiSeq platform and a 1073-nt fragment of the S1 coding region was obtained. The gCoV/ck/Poland/516/2018 strain shared only 52.7–58.1% nucleotide identity to any known genotype of IBV and shared the highest identity of 81.4% to the unique North American PA/1220/98 variant. Based on the obtained sequence, a specific molecular test was constructed and used for screening of chicken samples from 35 field cases delivered to our laboratory between 2018 and 2019 for IBV diagnosis. Application of this test enabled detection of another three chicken flocks as positive for this new strain. All positives were identified in commercial layers with egg production problems. To date, the virus has not been detected in broiler chickens. Taking into account the proposed criteria for the definition of a new IBV genotype or lineage, it seems that the detected viruses in Poland, together with the unique North American PA/1220/98 variant, may be classified as separate lineages/genotype in the new IBV classification.

RESEARCH HIGHLIGHTS

• The new IBV variant is distantly related to other known GI–GVII IBV genotypes/lineages.

• It affects long-lived birds causing egg production problems.

• The detected IBV and the unique North American PA/1220/98 variant are candidates for separate lineages in the new GVIII genotype.

     

富硒蛋鸡硒水平的研究

在蛋鸡饲料中添加有机硒 ,通过生物转化可以提高鸡体的硒含量 ,从而生产富硒鸡肉和鸡蛋。用新极谱法分别测定了富硒和对照蛋鸡的血、肉、蛋、毛及粪中的硒含量 ,测得富硒蛋鸡的硒含量分别为 4 5 1 9±4 2 1μg/L、0 2 0 6± 0 0 0 6mg/kg、0 4 15± 0 0 5 2mg/kg、1 6 6 3± 0 199mg/kg及 1 349± 0 2 39mg/kg ,分别为对照蛋鸡的 4 8、1 6、3 8、5 0及 31倍。     

Toxic Effects of Cadmium on Reproduction, Development, and Hatching in the Freshwater SnailLymnaea stagnalisfor Water Quality Monitoring

The freshwater snailLymnaea stagnaliswas exposed to cadmium concentrations of 0, 25, 50, 100, 200, and 400 μg liter⁻¹. The influence of this highly toxic metal on various stages of reproduction (number of egg masses, number of eggs, embryo development, and hatching) was studied. Egg production ceased at 400 μg Cd²⁺liter⁻¹and hatching was reduced to 0.4% with 200 μg liter⁻¹at 20°C. The study revealed that embryo development was the most sensitive stage, the main anomalies observed depending on the Cd²⁺concentration. At the highest concentration studied (400 μg liter⁻¹) the eggs were blocked in the first cleavage stage. At 100 and 200 μg Cd²⁺liter⁻¹, development of the eggs was halted at various stages of embryogenesis (cleavage, gastrula, veliger, and prehatching) depending on their position in the egg masses. At concentrations of 25 to 100 μg Cd²⁺liter⁻¹, development was slowed down and hatching occurred 5 to 15 days later than in the controls (controls hatched 12 to 13 days after laying). The results obtained demonstrate the effects of Cd²⁺on reproduction and development inL. stagnalisand provide information on the targets affected (neuroendocrine control of laying or cell multiplication and organogenesis of the embryos). It is thus possible to predict the probability of survival of the species in an environment polluted with cadmium and to compare it with the effects of other pollutants in the same or other species.     

Detection of Ovarian Tumors in Chicken by Sonography

OBJECTIVE: Animal models of spontaneous ovarian cancer are important for understanding early tumor development. Ovarian imaging may play an important role in following changes in tumor development. Laying hens are the only animals that develop spontaneous ovarian cancer similar to humans. The aim of this study was to determine the feasibility of detecting ovarian tumors in laying hens using sonography. METHODS: Ovaries of commercial strains of White Leghorn laying hens (n = 29, 2.5-3.0 years old) were examined by transvaginal 2-dimensional gray scale and color Doppler sonography. Sonographic evaluations were compared with ovarian anatomy and histologic features. RESULTS: Results of in vivo sonography and ovarian anatomic and histologic examinations were consistent. The presence of gross ovarian tumors was correctly detected in all hens by sonography. The resistive and pulsatility index values associated with ovarian tumors were lower than for normal ovaries (P < .001) suggesting that blood flow velocity was increased in ovarian tumors. Values associated with abnormal ovarian histologic findings but no gross tumors were intermediate. CONCLUSIONS: Transvaginal sonography can be used to determine ovarian status in hens. It offers the ability to make repeated examinations on the same hen to monitor early changes in the ovary associated with ovarian cancer.