外源核苷酸在鱼类饲粮中的应用

核苷酸作为一种新型饲料添加剂,其在水产养殖中的研究还较少。本文就外源核苷酸在鱼体中的消化吸收、营养作用和研究进展进行综述,并对其在鱼类养殖中的应用前景作一展望。     

核苷酸在仔猪营养中的作用

近几年核苷酸在仔猪营养上的试验结果表明：核苷酸在动物健康及在断奶仔猪营养上的应用有着越来越广阔的前景。本文详细探讨了核苷酸对仔猪营养影响的作用机理。     

外源核苷酸在猪营养中的应用

本文对核苷酸的营养功能、消化吸收和代谢及外源核苷酸对猪生长性能、肠道发育和免疫应答的影响进行综述.     

核苷酸在动物营养中的应用

<正>核苷酸是生物体内一类低分子化合物,它具有编码遗传信息、调节能量代谢和传递细胞信号、作为辅酶等重要的生理生化功能(Cosgrove,1998)。由于动物机体能合成各种核苷酸,而且又没有特异性的缺乏症,     

核苷酸营养(一):核苷酸在动物饲料中的使用

从本期起我们将陆续向读者推出核苷酸的营养作用。本期首先介绍核苷酸是怎样促进年轻动物的生长发育的。     

Pigment epithelial function in canine retina

The lateral distribution and temporal changes in the eye standing potential of 15 dogs with normal eyes (as determined by use of an ophthalmoscope and electroretinography) were measured by use of noninvasive methods. The standing potential was converted to an alternating potential by controlled eye movement. The light peak occurred 6 minutes after a stimulus intensity increase of 4 log units. The ratios of the highest measured voltage after the light step divided by the voltage measured immediately before the light step ranged from 1.27 to 2.07 (mean 1.74 +/- SEM, 0.064). The responses typically decayed slowly after the light peak. The potential after the light peak did not return to prelight step values during the observation period. The field potential of the standing potential decreased nonlinearly in temporal direction from the outer canthus.     

Arteriolar nephrosclerosis in the Syrian hamster

Syrian hamsters developed spontaneous renal lesions that resembled those of arteriolar nephrosclerosis in man, and differed from other spontaneously occurring or virus-induced renal diseases in other rodent species. Morphologic changes were mainly degenerative with little cellular exudation and were associated with histologic changes in the intrarenal vasculature. The renal lesions were progressive, often fatal and sometimes were complicated by glomerular amyloidosis with the nephrotic syndrome and uremia. Endstage kidneys often had fibrinoid necrosis of intrarenal arterioles and thus resembled lesions characteristic of the malignant phase of human essential hypertension. Fibrinoid necrosis of small arterioles was common in the uterus, ovaries or testes of affected animals; it was less frequent in mesenteric or coronary vessels. Cardiac thrombosis, often involving the left atrium or left atrioventricular valves, also was common. Changes occurred earlier and often were more severe in females than in males. This disease was a major cause of morbidity and mortality and hampered life-span studies.     

Propofol modulates inner retina function in Beagles

PURPOSE: To further understand a common veterinary anesthetic, propofol (2,6- di-isopropylphenol) and effects of infusion rates on the retinal neurons in Beagle dogs. METHODS: Standard full-field blue xenon-flash stimulation elicited responses of dark-adapted eyes, which were recorded from dogs before and after a propofol infusion rate increase. RESULTS: Electroretinogram b-waves increased significantly after the infusion rate increase and decreased with decline (P < 0.0001). Also, a weak significance (P = 0.041) for a-wave peak amplitude increase was found after infusion rate increase. The initial part (first 18 ms) of the leading edge of the a-wave remained unchanged. No significant differences in times to a- and b-wave peaks were found. CONCLUSION: Enhanced b-wave response and decline is due to sensitivity of postreceptoral cells, possibly interplexiform and amacrine cells, to propofol concentration.     

Malignant fibrous histiocytoma in a Djungarian hamster

A subcutaneous malignant fibrous histiocytoma (MFH) was observed in the region between the right posterior trunk and right hind limb of a 2-year-old male Djungarian hamster weighing 45 g. Histologically, the tumor consisted of bizarre multinucleated giant cells, histiocytic cells, and fibroblastic cells with a storiform pattern, and was considered to be of the storiform-pleomorphic type of MFH. Severe nuclear atypia with prominent nucleoli and many mitotic figures was also observed. Electron microscopy demonstrated fibroblastic cells and histiocytic cells. The fibroblastic cells were spindle-shaped, and sometimes had an invaginated nucleus. The histiocytic cells were polygonal with an oval or kidney-shaped nucleus. The cytoplasm of both cells contained numerous free ribosomes, small amounts of rough endoplasmic reticulum, and round mitochondria. Tumor cells were immunohistochemically positive for vimentin, and were thought to be of undifferentiated mesenchymal cell origin. This is the first report of spontaneous MFH in a hamster.     

Apocrine adenocarcinoma in a golden hamster.

An apocrine adenocarcinoma was observed in the subcutis of the abdomen of golden hamster. Histologically, the tumor cells irregularly formed multiple layers of cysts and some detached cells were presented in the cystic space. PAS stain with alpha-amylase digestion revealed PAS-positive alpha-amylase-resistant granules in the cytoplasm. Immunohistochemically, cytokeratin was demonstrated in the tumor cells. By electron microscopy, the tumor cells had an oval nucleus with invagination, abundant cytoplasmic organelles and microvilli protruding into the intercellular spaces.     

核酸在仔猪营养中的作用

过去2年内,利用核酸型饲料进行的仔猪饲喂试验表明,核酸对仔猪健康和断奶效果可产生众多有益的作用. 目前,低日龄断奶的仔猪在最大限度地提高养猪生产的经济效益上起着至关重要的作用.