Circulating Metabolic Hormones During the Peripubertal Period and Their Association with Testicular Development in Bulls     

LFC Brito  AD Barth  NC Rawlings  RE Wilde  DH Crews Jr    PS Mir  JP Kastelic 《Reproduction in domestic animals》2007,42(5):502-508

The objective of the present study was to characterize changes in serum metabolic hormones concentrations from 20 weeks before to 20 weeks post-puberty in bulls and to investigate the associations of metabolic hormones concentrations with testicular development. Leptin concentrations increased from 16 weeks before puberty to 8 weeks post-puberty and insulin concentrations increased from puberty to 8 weeks post-puberty. Growth hormone concentrations decreased after 4 weeks post-puberty, whereas IGF-I concentrations increased from 8 weeks before puberty to 8 weeks post-puberty. During this period, testicular growth was accelerated and testosterone secretion increased substantially, without any significant changes in gonadotropin secretion. Monthly circulating concentrations of leptin, IGF-I and insulin accounted for 63% of the variation in scrotal circumference and 59% of the variation in paired testes volume. In conclusion, the secretion of metabolic hormones was not associated with changes in gonadotropins concentrations. Furthermore, the associations of leptin, IGF-I and insulin concentrations with testes size indicated that these hormones might be involved in a gonadotropin-independent mechanism regulating the testicular development in peripubertal bulls.  相似文献   

Thiabendazole--an anthelmintic for cattle.          下载免费PDF全文

L Michaud 《The Canadian veterinary journal. La revue veterinaire canadienne》1967,8(4):85-87

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Fucoidans of Moroccan Brown Seaweed as Elicitors of Natural Defenses in Date Palm Roots     

Soukaina Bouissil  Zainab El Alaoui-Talibi  Guillaume Pierre  Halima Rchid  Philippe Michaud  Cdric Delattre  Cherkaoui El Modafar 《Marine drugs》2020,18(12)

Fucoidans from Moroccan brown seaweed Bifurcaria bifurcata and Fucus spiralis were tested for their elicitor activity after their purification and complete characterization. The fucoidans of B. bifurcata (BBF) and of F. spiralis (FSF) were extracted and purified then characterized by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and size exclusion chromatography. The results show that BBF and FSF are mainly sulfated with 45.49 and 49.53% (w/w) sulfate, respectively. Analysis of neutral sugars determined by gas chromatography–mass spectrometry showed that FSF and BBF were mainly composed of 64% and 91% fucose and 20% and 6% galactose, respectively, with a few other sugars such as glucose (8% in FSF), rhamnose (1% in BBF) and mannose (8% in FSF and, 2% in BBF). The eliciting activity of these sulfated polysaccharides in stimulating the natural defenses of the date palm was evaluated through the activity of phenylalanine ammonia-lyase (PAL), and the increase in phenols and lignin content in the roots. The results obtained clearly show that the two fucoidans early and intensely stimulate the natural defenses of the date palm after 24 h of treatments. This remarkable elicitor effect seems to be linked to the sulfated groups compared to non-sulfate alginates extracted from the same algae. These results open promising perspectives for a biological control approach against date palm diseases.  相似文献   

Non-target effects of chlorantraniliprole and thiamethoxam on Chrysoperla carnea when employed as sunflower seed treatments     

Pablo C. Gontijo  Valéria F. Moscardini  J. P. Michaud  Geraldo A. Carvalho 《Journal of pest science》2014,87(4):711-719

The use of systemic insecticides as seed treatments has raised concern about the possible impacts of these products on natural enemies. This study assessed the effects of sunflower seed treatments with chlorantraniliprole and thiamethoxam on Chrysoperla carnea by exposing larvae and adults to sunflower stem segments grown from treated seeds and the nectar secreted by their extrafloral nectaries. Confinement of larvae with stem segments for their entire developmental period had no effect on their survival or any life history parameter, except that the sex ratio of resulting adults was lower in the thiamethoxam treatment than in chlorantraniliprole. However, when adult pairs of C. carnea were exposed to treated stem segments during their maturation period, their subsequent survival and fecundity was significantly reduced by both materials, with thiamethoxam reducing median survival (LT₅₀) and fecundity to a greater degree than chlorantraniliprole. Insufficient offspring were obtained from adults exposed to thiamethoxam to permit assessment of their fitness, but the offspring in the chlorantraniliprole-exposed adults had reduced larval survival relative to controls. The greater impact of seed treatments on adult lacewings may be partly attributable to their greater consumption of extra-floral nectar. Our results indicate that seed treatment with systemic insecticides can cause negative effects on beneficial insects, potentially disrupting their population dynamics, and should not be assumed compatible with biological control and IPM simply because this mode of application limits direct exposure.  相似文献   

Molecular and physiological characterisation of psychrotrophic hydrocarbon-degrading bacteria isolated from Terra Nova Bay (Antarctica)     

Francesco Pini  Cristina Grossi  Sabrina Nereo  Luigi Michaud  Angelina Lo Giudice  Vivia Bruni  Franco Baldi  Renato Fani   《European Journal of Soil Biology》2007,43(5-6):368

A set of 21 Antarctic marine bacteria isolated from the Ross Sea and able to utilise diesel fuel as the sole carbon and energy source was characterised. Isolates were analysed by amplified 16S rDNA restriction analysis using the enzyme AluI, resulting in two different groups corresponding to different bacterial species. These species were assigned to the genera Rhodococcus and Alcaligenes, on the basis of 16S rDNA sequencing. This low degree of inter-specific biodiversity was parallel to a low intra-specific biodiversity, as shown by Random Amplified Polymorphic DNA analysis. Then, a 550-bp DNA fragment coding for the inner region of alkane mono-oxygenase was PCR-amplified from the genome of each strain. The phylogenetic analysis of the sequence of the putative AlkB protein coded for by the amplified DNA fragment revealed that these alkB genes were very likely inherited by horizontal gene transfer. Lastly, the analysis of the biodegradation ability of four strains revealed two different strategies of hydrocarbon uptake, mediated either by bio-surfactants and peculiar of Rhodococcus isolates, or by membrane modifications and shown by Alcaligenes isolates. In order to understand the interrelationships between hydrocarbon-degrading isolates, the dynamics of two strains, belonging to Rhodococcus and Alcaligenes, grown together in a co-culture was also followed over a seventeen days period.  相似文献   

沧州市滨海盐碱区耕层土壤盐分特征     

王伟  赵月  钮力亚  王伟伟  王连鹏  陆莉  王奉芝  于亮 《陕西农业科学》2021,(7):62-66

为了解沧州市滨海盐碱区耕层土壤的盐渍化特征,采集三个时期沧州不同地区耕层土壤（0~20 cm）样品,结合样品实验分析,探究土壤盐分特征。结果表明：①沧州滨海盐碱区耕层土壤离子类型多样,检测的八大离子中氯离子、钠离子、硫酸根、碳酸根+碳酸氢根离子为主要盐分离子,土壤类型为硫酸盐-氯化物型。②相关分析表明,耕层土样中总含盐量与氯离子和钠离子均存在显著或极显著相关关系,沧州市滨海盐碱地耕层土壤的总含盐量一定程上取决于土壤中氯化钠的含量;氯化钠、氯化镁和氯化钙为氯化物的主要组成部分;主要硫酸盐类为硫酸钠、硫酸镁和硫酸钙。③方差分析表明,三个不同采样时期和不同地区均对沧州市滨海区盐碱地的盐渍化的影响存在显著或极显著差异。④主成分分析表明,钠离子、氯离子、镁离子、钙离子和硫酸根与第1主成分相关性较高;钾离子和碳酸根+碳酸氢根与第2主成分相关性较高;第3主成分主要反映硅酸盐类对土壤离子成分的影响。由于钠离子、氯离子、钙离子和硫酸根在土壤中含量相对较高,是表征沧州滨海盐碱区土壤盐渍化的主要特征因子。  相似文献   

Catabolism of L-ascorbate by Lactobacillus rhamnosus GG     

Linares D  Michaud P  Delort AM  Traïkia M  Warrand J 《Journal of agricultural and food chemistry》2011,59(8):4140-4147

Catabolism of L-ascorbate by enteric bacteria is well documented, but no study has formally proved that bacteria of the Lactobacillus genus ferment this compound. However, some genes analogous to those of yiaK-S operon and ula regulon, which encoded proteins leading to L-ascorbate degradation by Escherichia coli and Klebsiella pneumoniae , have been identified in the recently sequenced Lactobacillus rhamnosus GG genome. Investigations by HPLC and in vivo (13)C NMR using L-[1,6-(13)C]-ascorbate showed that L. rhamnosus GG, a common probiotic strain, has the ability to catabolize L-ascorbate under anaerobiosis. The main products of the ascorbate degradation have been identified as CO(2), acetate, and lactate. These results are in accordance with the metabolic pathway proposed for the fermentation of L-ascorbate by E. coli.  相似文献   

Fungal arthritis due to infection by Candida famata in a horse     

CB RILEY  JV YOVICH  JP ROBERTSON  FL O''HARA 《Australian veterinary journal》1992,69(3):65-66

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Pathology of experimentally-induced, acute toxoplasmosis in macropods   总被引：1，自引：0，他引：1  

GL REDDACLIFF  WJ HARTLEY  JP DUBEY  DW COOPER 《Australian veterinary journal》1993,70(1):4-6

SUMMARY Thirteen Tammar wallabies (Macropus eugenii) were dosed orally with 500, 1000 or 10 000 oocysts of Toxoplasma gondii, as part of a vaccination trial. Eleven animals died of acute toxoplasmosis 9 to 15 days after challenge. The lesions were similar in all animals, consisting of foci of necrosis and inflammation in the intestines, lymphoid tissue, adrenal cortex, heart, skeletal muscle and brain, and severe generalised pulmonary congestion and oedema. Free and intracellular tachyzoites of Toxoplasma were associated with the lesions. The remaining 2 animals had shown no signs of disease when euthanased four months after challenge. Small, focal, non-suppurative inflammatory lesions were seen in brain, heart and skeletal muscle of these animals and chronic Toxoplasma infection was confirmed by mouse inoculation.  相似文献   

Effect of oxidation–reduction potential on performance of European sea bass (Dicentrarchus labrax) in recirculating aquaculture systems     

Xian Li  Jean-Paul Blancheton  Ying Liu  Sebastien Triplet  Luigi Michaud 《Aquaculture International》2014,22(4):1263-1282

The direct impact of oxidation–reduction potential (ORP) on fish welfare and water quality in marine recirculating aquaculture systems (RAS) is poorly documented. In this study, the effects of the fish size (S₁, S₂, S₃) and ORP level (normal, four successive levels) on the performance of European sea bass (Dicentrarchus labrax) were investigated. Three size fish were distributed into two RAS (RAS and RAS O₃). Ozone was injected into RAS O₃ to increase the ORP level. The ORP was stabilized to four successive levels: 260–300, 300–320, 320–350, and 300–320 mV in fish tanks during four periods (P_1–4). At the last day of each period, the hematological parameters, plasma protein and mortality of sea bass were analyzed. Two-way ANOVA revealed that several hematological parameters, including pH, hematocrit, concentrations of oxygen, carbon dioxide, glucose (Glu), ionized calcium, kalium, and hemoglobin, were significantly influenced by the increased ORP levels over the experimental period. The alteration in blood Glu and plasma protein concentration showed that ORP around 300–320 mV started to stress sea bass. Once the ORP exceeded 320 mV in the tanks during the P₃ period, mortality occurred even when total residual oxidants/ozone-produced oxidants was only 0.03–0.05 mg L^?1 in the fish tanks. At the same time, plasma protein decreased notably due to appetite depression. After the decrease in ORP during the P₄ period, mortality continued. In conclusion, the results strongly suggest that for European sea bass in RAS, the ORP should not exceed 320 mV in the tanks. Once ozonation damaged fish, the effect seemed to be irreversible. However, how ORP affected related hematological parameters still need the further investigations.  相似文献