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21.
Vikingstad E Andersson E Norberg B Mayer I Klenke U Zohar Y Stefansson SO Taranger GL 《Fish physiology and biochemistry》2008,34(3):289-298
Atlantic salmon (Salmo salar L.) females (2 SW), maturing for the first time, were reared under one of three temperature regimes (high: 14.3 ± 0.5°C;
natural: 10.6 ± 1.0°C; and cold: 6.9 ± 1.0°C) in combination with one of two experimental treatments; an injection of GnRH
analogue (GnRHa) contained in biodegradable microspheres, or a sham injection (microspheres only). The six experimental groups
were then reared under simulated natural photoperiod for 4 weeks. Blood samples were drawn for analysis of plasma steroid
levels and the fish were inspected for ovulation weekly. Batches of stripped eggs were incubated in triplicate incubators
in raceways until the eyed stage. Treatment with GnRHa resulted in a substantial advancement and synchronization of ovulation
at all temperatures, while exposure to cold water also appeared to advance ovulation slightly. While 75% (warm and cold) to
90% (natural) of GnRHa fish ovulated during the 4-week trial, only 30% of sham-treated females exposed to cold water, and
none of the sham-treated fish held at higher temperatures, ovulated during this period. Survival rates of embryos to the eyed-stage
were significantly higher for broodstock exposed to cold water. Plasma levels of testosterone (T), 17β-oestradiol (E2), and 17α,20β-dihydroxy-4-pregnen-3-one (17,20βP) were all significantly affected by treatment with GnRHa and, to a lesser
extent, temperature. The efficiency of GnRHa in counteracting the negative effects of high temperature on ovulation and the
associated changes in circulating sex steroids suggest that temperature inhibition operates at least in part at the brain
or pituitary. 相似文献
22.
Effect of mineral nitrogen fertilizer forms on N2O emissions from arable soils in winter wheat production 下载免费PDF全文
Nitrogen fertilizers are supposed to be a major source of nitrous oxide (N2O) emissions from arable soils. The objective of this study was to compare the effect of N forms on N2O emissions from arable fields cropped with winter wheat (Triticum aestivum L.). In three field trials in North‐West Germany (two trials in 2011/2012, one trial in 2012/2013), direct N2O emissions during a one‐year measurement period, starting after application of either urea, ammonium sulfate (AS) or calcium ammonium nitrate (CAN), were compared at an application rate of 220 kg N ha?1. During the growth season (March to August) of winter wheat, N2O emission rates were significantly higher in all three field experiments and in all treatments receiving N fertilizer than from the non‐fertilized treatments (control). At two of the three sites, cumulative N2O emissions from N fertilizer decreased in the order of urea > AS > CAN, with emissions ranging from 522–617 g N ha?1 (0.24–0.28% of applied fertilizer) for urea, 368–554 g N ha?1 (0.17–0.25%) for AS, and 242–264 g N ha?1 (0.11–0.12%) for CAN during March to August. These results suggest that mineral nitrogen forms can differ in N2O emissions during the growth period of winter wheat. Strong variations in the seasonal dynamics of N2O emissions between sites were observed which could partly be related to weather events (e.g., precipitation). Between harvest and the following spring (post‐harvest period) no significant differences in N2O emissions between fertilized and non‐fertilized treatments were detected on two of three fields. Only on one site post‐harvest emissions from the AS treatment were significantly higher than all other fertilizer forms as well as compared to the control treatment. The cumulative one‐year emissions varied depending on fertilizer form across the three field sites from 0.05% to 0.51% with one exception at one field site (AS: 0.94%). The calculated overall fertilizer induced emission averaged for the three fields was 0.38% which was only about 1/3 of the IPCC default value of 1.0%. 相似文献
23.
Panagiotis G. Xenoulis Jörg M. Steiner 《Veterinary journal (London, England : 1997)》2010,183(1):12-21
Lipid metabolism in dogs can be divided into exogenous and endogenous pathways and exhibits some unique characteristics compared to other species. Hyperlipidemia is common in dogs, and can be either primary or secondary to other diseases. Secondary hyperlipidemia is the most common form and can be a result of endocrine disorders, pancreatitis, cholestasis, protein-losing nephropathy, obesity, and high fat diets. Primary hyperlipidemia is less common and usually associated with certain breeds. Hypertriglyceridemia of Miniature Schnauzers is the most common type of primary hyperlipidemia in dogs in the United States, and appears to have a genetic basis although its etiology remains unknown. Possible complications of canine hyperlipidemia include pancreatitis, liver disease, atherosclerosis, ocular disease, and seizures. Management is achieved by administration of low fat diets with or without the administration of lipid-lowering agents such as omega-3 fatty acids, gemfibrozil, and niacin. 相似文献
24.
Steiner JM Williams DA Twedt DC 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(5):605; author reply 605-605; author reply 606
25.
Steiner JM Williams DA Bunch SE 《Journal of the American Veterinary Medical Association》2003,223(4):429; author reply 429-429; author reply 430
26.
Suchodolski JS Steiner JM Ruaux CG Williams DA 《American journal of veterinary research》2003,64(9):1146-1150
OBJECTIVE: To develop and validate an ELISA for measurement of serum canine pepsinogen A (cPG A) as a diagnostic marker of gastric disorders in dogs and to measure serum cPG A in healthy dogs after food deprivation and after feeding. SAMPLE POPULATION: Sera from 72 healthy dogs. PROCEDURE: A sandwich ELISA was developed and validated. The reference range for serum concentrations of cPG A was determined in 64 healthy dogs. Postprandial changes in serum concentrations of cPG A were evaluated in 8 healthy dogs. RESULTS: Assay sensitivity was 18 microg/L, and the maximum detectable concentration was 1,080 microg/L. The observed-to-expected ratio (O:E) for 3 serial dilutions of 3 serum samples ranged from 69.3 to 104.1%. The O:E for 3 serum samples spiked with 8 concentrations of cPG A ranged from 58.8 to 120.4%. Coefficients of variation for intra- and interassay variability of 3 serum samples ranged from 7.6 to 11.9% and from 10.1 to 13.1%, respectively. Mean +/- SD serum concentration of cPG A in healthy dogs was 63.8 +/- 31.0 microg/L and the reference range was 18 to 129 microg/L. Significant increases in serum concentrations of cPG A were observed between 1 and 7 hours after feeding. CONCLUSIONS AND CLINICAL RELEVANCE: The ELISA for measuring cPG A was sufficiently sensitive, linear, accurate, precise, and reproducible for clinical use. Serum concentrations of cPG A increase substantially after feeding, which should be taken into account when conducting clinical studies. 相似文献
27.
Spring C Mevissen M Reist M Zulauf M Steiner A 《Journal of veterinary pharmacology and therapeutics》2003,26(5):377-385
The effects of serotonin (5-hydroxytryptamine, 5-HT), a 5-HT2-receptor agonist, alpha-methyl-5-hydroxytryptamine (alpha-M-5-HT) and RS-67506, a 5-HT4 receptor partial agonist, on spontaneous contractility of bovine abomasal smooth muscle preparations were investigated in vitro. Preparations from the abomasal antrum of freshly slaughtered healthy dairy cows were cut parallel to the longitudinal fibres, suspended in isolated organ baths, and concentration-response curves were performed by cumulative application of the 5-HT receptor agonists. Blockade of 5-HT2-induced response was tested with atropine and hexamethonium. Serotonin evoked a significant increase in the area under curve (AUC), whilst the 5-HT2 receptor agonist alpha-M-5-HT significantly increased the AUC and resting tone (RT). RS-67506 induced a significant increase in AUC and RT and a significant decrease in the maximum force. The effect of alpha-M-5-HT was mediated by a muscarinic cholinergic pathway, as the effect of alpha-M-5-HT was inhibited in the presence of atropine but not hexamethonium. It is concluded that 5-HT2 and 5-HT4 receptors are present in the bovine abomasal antrum. Muscarinic receptors are involved in the increase in RT seen after 5-HT2 receptor stimulation. 相似文献
28.
Zulauf M Spring C Eicher R Meylan M Hirsbrunner G Scholtysik G Steiner A 《American journal of veterinary research》2002,63(12):1687-1694
OBJECTIVE: To characterize and compare in vitro contractility patterns of sections of abomasal wall harvested from cattle of 3 dairy breeds. SAMPLE POPULATION: Longitudinal and circular smooth muscle preparations harvested from the antrum and body of the abomasum of 30 recently slaughtered Holstein-Friesian, Brown Swiss, and Simmental X Red Holstein cows. PROCEDURE: Spontaneous isometric contractions of specimens in tissue baths of modified Krebs solution were recorded during a 4-hour period. Maximal amplitude, frequency of contractions, and change of basal tension were used to characterize contractility. Statistical analyses were used to test for differences among time periods, among breeds, between specimen locations, and between fiber orientations. RESULTS: Myoactivity patterns of abomasal smooth muscle preparations are highly variable and differ on the basis of location and fiber orientation. Frequency of contractions differed significantly among time periods for longitudinally oriented specimens with decreasing frequencies of contractions over time. Maximal amplitude of the longitudinally oriented specimens from the antrum increased significantly, whereas maximal amplitude of the circularly oriented specimens from the antrum decreased significantly. Values did not differ significantly among breeds. CONCLUSIONS AND CLINICAL RELEVANCE: Patterns of spontaneous contractility of abomasal wall specimens are not homogeneous. During a 4-hour recording period, maximal amplitude and frequency of contractions of specimens varied significantly with respect to orientation and location; however, spontaneous contractile myoactivity did not differ significantly among breeds. Therefore, breed predisposition for displaced abomasum is not correlated with spontaneous activity of smooth muscle specimens. 相似文献
29.
Meylan M Eicher R Röthlisberger J Steiner A 《American journal of veterinary research》2002,63(1):78-85
OBJECTIVE: To describe myoelectric activity of the spiral colon in healthy cows. ANIMALS: 7 lactating Simmental X Red-Holstein crossbred cows. PROCEDURE: Cows were implanted with 7 pairs of bipolar silver electrodes (4 in the spiral colon and 1 each in the cecum, distal part of the ileum, and proximal loop of the ascending colon [PLAC]). Myo-electric activity was recorded during 4 days for each cow. Patterns were analyzed, using computer-based methods. RESULTS: Myoelectric activity of the spiral colon was closely associated with motility of the ileum and PLAC and showed the typical organization of migrating myoelectric complexes (MMC). The MMC in the bovine spiral colon (bcMMC) had a mean +/- SD duration of 188.6 +/- 30.8 minutes and was divided into 4 phases. Phases I and II lasted 11.3 +/- 1.4 and 159.4 +/- 33.3 minutes, respectively. Phase III (duration, 5.4 +/- 1.2 minutes) was characterized by 5.2 +/- 0.9 regular spindles (35.4 +/- 5.4 seconds) and 1 final elongated spindle (137.2 +/- 56.4 seconds). Phase III most commonly (73.8 +/- 16.1%) was followed by phase IV (duration, 173 +/- 3.6 minutes). Propagation velocity of phase III was 4.4 +/- 0.5 cm/min, and 13.6% of bcMMC were incompletely propagated through the spiral colon. CONCLUSIONS: Myoelectric activity of the bovine spiral colon is composed of a recurring cyclic pattern similar to MMC of the small intestine. Data of colonic myoelectric activity in healthy cows will serve as a basis for studies on cecal dilatation and dislocation in cattle. 相似文献
30.
Cryptorchism is an inherited congenital abnormality characterized by the failure of one or both testes to descend into the scrotum. Diagnosis can be difficult if the retained testicular tissue cannot be localized during clinical examination and the history of the animal is unknown, or if the animal shows persistent male behaviour despite the history of successful previous castration. The present case report describes the history of a cryptorchid Lama and the techniques of general anesthesia and laparoscopic cryptorchidectomy advocated. 相似文献