Exogenous leptin advances puberty in domestic hen

The present study was undertaken to examine the effect of recombinant chicken leptin administered to fed ad libitum and feed-restricted immature chickens of a layer strain on ovarian development and the timing of sexual maturity. In the first experiment 11-week-old pullets (77 days of age) fed ad libitum were injected daily with leptin at four dose levels (4, 16, 64 and 256 microg/kg body weight) until sexual maturity (lay of the first egg). Leptin treatment at the highest dose significantly (P<0.05) advanced the onset of puberty (day 116.3+/-1.0) in comparison to controls (day 121.3+/-1.2). The rises of luteinizing hormone, estradiol and progesterone in blood plasma were also advanced by leptin treatment. In the second experiment, both full-fed and feed-restricted pullets (79 days of age) were injected daily with leptin (256 microg/kg body weight). In birds fed ad libitum, exogenous leptin again significantly (P<0.05) advanced first ovipostion (day 118.4+/-1.4 versus day 124.4+/-1.7), while abolishing the significant (P<0.05) delay caused by feed restriction (day 131.5+/-1.6) and restoring the normal onset of sexual maturity (day 125.7+/-1.6). Analysis of the ovaries in 106-day-old pullets revealed that leptin injections advanced follicular development, particularly in birds fed ad libitum, and significantly (P<0.01) reduced follicular apoptosis both in full-fed and feed-restricted birds. In conclusion, we have shown that in female chickens exogenous leptin advances the onset of puberty by attenuation of ovarian apoptosis and enhancement of folliculogenesis.     

Existence of different physiological forms within genetically diverse strains of <Emphasis Type="Italic">Ampelomyces quisqualis</Emphasis>

Powdery mildew fungi are parasitized by strains of the genetically distinct Ampelomyces quisqualis. To investigate whether differences in the phylogeny and other cultural, morphological and physiological characteristics of these different strains are related to differences in their geographic origins or the host species from which they were isolated, several A. quisqualis strains isolated from different species of Erysiphaceae collected in different countries and possessing different ITS rDNA sequences were selected and characterized. The results revealed some significant variation among the selected strains, which provides evidence for the existence of different physiological forms within the A. quisqualis species. Two groups that display differential growth on artificial media were identified. These groups also differ in the morphology of their mycelium, but not in the morphology of their pycnidia and conidia. Temperature greatly affected the in vitro growth of the A. quisqualis strains and growth rate was closely correlated to colony color. Differences in the conidial germination of distinct strains were observed during the recognition phase of the parasitic relationship. The germination of each of the investigated strains was greatly stimulated by all of the examined powdery mildew species and not only by the conidia of their original hosts. An Italian strain isolated from grapevine in the Trentino Alto-Adige region was identified as the strain that germinates the most quickly in the presence of powdery mildew conidia. Phylogenetic analysis revealed that these A. quisqualis strains can be classified into five different genetic groups, which generally correlate with the fungal host of origin and morphological and growth characteristics.     

Comparative spatiotemporal analysis of the intrathecal immune response in natural listeric rhombencephalitis of cattle and small ruminants

This study examined the spatiotemporal immune response in listeric rhombencephalitis of ruminants in situ. Our data support the view that astrocytes facilitate the containment of infectious lesions. Results on the natural disease recapitulate observations in experimental rodent models and suggest that the mounted adaptive lymphocytic response of ruminants is effective in eliminating Listeria monocytogenes (LM). However, our data indicate earlier participation of the adaptive immune response, a stronger B lymphocyte contribution and a more protracted macrophage infiltration in the natural disease than it has been deduced from experimental models. Therefore, such models should be complemented by studies in natural host systems. Various macrophage and microglia subsets are involved in listeric rhombencephalitis and their differential contribution may account for species differences in clinical course and outcome of infection as might species differences in the B-cell response. Future functional ex vivo and in vitro studies are necessary to further investigate the findings obtained in the present study.     

Establishment of diagnostic criteria for feline nonflea-induced hypersensitivity dermatitis

Hypersensitivity dermatitides (HD) are commonly seen in cats, and they are usually caused by environmental, food and/or flea allergens. Affected cats normally present with one of the following clinical reaction patterns: head and neck excoriations, usually symmetrical self-induced alopecia, eosinophilic skin lesions or miliary dermatitis. Importantly, none of these clinical presentations is considered to be pathognomonic for HD skin diseases, and the diagnosis of HD is usually based on the exclusion of other pruritic diseases and on a positive response to therapy. The objectives of this study were to propose sets of criteria for the diagnosis of nonflea-induced HD (NFHD). We recruited 501 cats with pruritus and skin lesions and compared clinical parameters between cats with NFHD (encompassing those with nonflea, nonfood HD and those with food HD), flea HD and other pruritic conditions. Using simulated annealing techniques, we established two sets of proposed criteria for the following two different clinical situations: (i) the diagnosis of NFHD in a population of pruritic cats; and (ii) the diagnosis of NFHD after exclusion of cats with flea HD. These criteria sets were associated with good sensitivity and specificity and may be useful for homogeneity of enrolment in clinical trials and to evaluate the probability of diagnosis of NFHD in clinical practice. Finally, these criteria were not useful to differentiate cats with NFHD from those with food HD.     

Risk factors for death from canine parvoviral-related disease in Australia

Canine parvovirus (CPV) is a highly contagious cause of serious and often fatal disease in dogs worldwide despite the availability of safe and efficacious vaccines. Although a number of studies have focussed on identifying risk factors in disease development, risk factors associated with death from CPV are largely unknown. In this study we analysed a total of 1451 CPV cases reported from an Australian surveillance system - using univariate and multivariate techniques - to determine significant risk factors associated with death and euthanasia. A crude case fatality rate of 42.3% was estimated - higher than has been reported previously. We found that 3.3% of CPV cases had a history of vaccination in the previous 12 months, despite having completed the primary puppy vaccination course. The majority (89.5%) of these cases occurred in dogs <12 months of age, indicating failure of the primary vaccination course to provide protective immunity (most likely due to interference of the vaccine antigen with maternal antibodies but other reasons are discussed). Extending the age at which the final puppy vaccination is administered might be one of several strategies to consider. The final multivariate model showed that in non-litter CPV cases, risk of death was significantly associated with season of diagnosis (summer) and pedigree type (hounds and non-sporting dogs). Euthanasia in non-litter CPV cases was significantly associated with season of diagnosis (summer), state of residence (Northern Territory/South Australia/Tasmania combined), age (相似文献   

Structural changes in femoral bone tissue of rats after subchronic peroral exposure to selenium

Background

The role of selenium (Se) on bone microarchitecture is still poorly understood. The present study aims to investigate the macroscopic and microscopic structures of femoral bone tissue in adult male rats after subchronic peroral administration of Se.

Methods

Twenty one-month-old male Wistar rats were randomly divided into two experimental groups. In the first group (Se group) young males were exposed to 5 mg Na₂SeO₃/L in drinking water, for 90 days. Ten one-month-old males without Se administration served as a control group. At the end of the experiment, macroscopic and microscopic structures of the femurs were analysed using analytical scales, sliding instrument, and polarized light microscopy.

Results

The body weight, femoral length and cortical bone thickness were significantly decreased in Se group rats. These rats also displayed different microstructure in the middle part of the femur, both in medial and lateral views, where vascular canals expanded into the central area of the bone while, in control rats, these canals occurred only near the endosteal surfaces. Additionally, a smaller number of primary and secondary osteons was identified in Se group rats. Histomorphometric analyses revealed significant increases for area, perimeter, maximum and minimum diameters of primary osteons’ vascular canals but significant reductions for all measured variables of Haversian canals and secondary osteons.

Conclusions

Se negatively affected the macroscopic and microscopic structures of femoral bone tissue in adult male rats. The results contribute to the knowledge on damaging impact of Se on bone.     

Effect of Incorporating White,Red or Black Quinoa Flours on Free and Bound Polyphenol Content,Antioxidant Activity and Colour of Bread

Plant Foods for Human Nutrition - Interest in quinoa as a functional food ingredient is currently emerging. The flours from white, red and black quinoa seeds were analysed in terms of total...