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甜菜碱是一种天然化合物,它无毒、无害、性质稳定,又在动物蛋白质和脂肪代谢中起看非常重要的作用。甜菜碱通过影响生长代谢调控轴激素和氨基酸、脂肪代谢对猪生长性能、胴体组成、肉质等产生一定的影响,并达到降低动物脂肪沉积的目的。 相似文献
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Stillborn and mummified swine fetuses from swine farms experiencing reproductive problems were investigated for evidence of infection with encephalomyocarditis (EMC) virus by fetal serology, virus isolation, and histopathologic examination. Fetal sera or thoracic fluids of 478 abnormal fetuses collected during January through December 1987 were tested for the presence of antibody specific to EMC virus. Of 478 samples tested, 175 (36.6%) had EMC virus serum neutralizing antibody titers of 1:64 or greater. The samples positive for EMC virus antibody were obtained from 38 swine farms located in 9 states in the United States. In addition to serologic observations, tissue samples of some abnormal fetuses were examined for the presence of virus and histopathologic lesions. The EMC virus was isolated in 1 case from the fetuses of an aborted litter. The isolate was serologically identical to a reference EMC virus. Nonsuppurative encephalitis and myocarditis were observed in the fetal samples collected from 2 different herds. Thoracic fluid of 1 stillborn pig with lesions was positive for EMC virus antibody at a titer of 1:512. We suggest that a widespread reproductive problem recently experienced in several major swine-producing areas of the United States may have been caused by EMC virus infection. 相似文献
939.
G H Wentink S van Dijk S A Goedegebuure J Vos T Wensing 《The Veterinary quarterly》1992,14(4):159-160
A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period. After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases. 相似文献
940.
Selective muscarinic receptor antagonists were used to identify muscarinic receptor subtypes in equine trachealis strips. The M1 receptor antagonist pirenzepine (10–7 mol/L to 3 × 10–5 mol/L) and the M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine (4-DAMP, 10–9 mol/L to 3 × 10–7 mol/L3) dose dependently inhibited the contractile responses to electrical field stimulation (EFS) and exogenous acetylcholine (ACh). Schild plots yielded a pA2 value for pirenzepine vs ACh of 6.75 ± 0.09, which is consistent with the affinity for M2 or M3 receptors, and a pA2 value for 4-DAMP vs ACh of 8.47 ± 0.09, which is in agreement with the affinity for M3 receptors. The M2 receptor antagonist gallamine (10–5 mol/L and 10–4 mol/L) did not affect the response of trachealis to exogenous ACh and low-frequency EFS (0.1–2 Hz) but decreased the responses to high-frequency EFS (4–16 Hz). These results suggest that the muscarinic receptors mediating contractions induced by ACh in equine tracheal smooth muscle are of the M3 subtype. The lack of an increase in the response to EFS following gallamine suggests that functional prejunctional inhibitory M2 receptors are not present on the cholinergic nerves innervating equine tracheal smooth muscle. 相似文献