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61.
M Steinhardt S Reimer U Bünger J Kutschke 《Archiv fuer experimentelle veterinaermedizin》1989,43(2):309-314
Comprehensive studies into domestic pigs and wild boars together with literature data provided a basis for an assessment of aerobic metabolic capacity (VO2max) of swine. The values quoted, from 20 to 94 ml/min-1/kg, had been due to several factors of methodological approach, growth, training, and nutrition as well as to pathophysiological aspects. For full capacity utilisation of VO2max, untrained pigs can be challenged at belt velocities between 0.8 and 1.8 m/s-1 and trained animals at 5 m/s-1. 相似文献
62.
The effect of heat stress on the components of grain weight was analysed in wheat ( Triticum aestivum L.) varieties differing in grain weight stability. The wheat varieties PBW154, Sonalika and Hindi62 were raised in the field (New Delhi, India; 77°12' E, 28°40' N, 228.6 m a.s.l.) at three dates of sowing: 19 November 1992 (DOS I), 14 December 1992 (DOS II) and 18 January 1993 (DOS III). The late-sown crop (DOS III) experienced 6–8 °C warmer temperatures during grain development than the crop sown at the normal time (DOS I). The heat susceptibility index (S) revealed that grain weight was less susceptible to heat in Sonalika and PBW154 than in Hindi62. Heat stress reduced both the grain growth duration (GGD) and the grain growth rate (GGR). The grain weight reduction in PBW154 and Sonalika was mainly due to a reduction in GGR, while that of Hindi62 was due to a reduction in GGD. In vivo studies on starch and protein synthesis in excised endosperm at 15, 25 and 35 °C revealed that both processes were more thermotolerant in Hindi62 than in PBW154. The grain starch content was stable in Hindi62 while that in PBW154 was significantly reduced under heat stress. The grain nitrogen content at maturity increased in both varieties under heat stress. It was concluded that the heat susceptibility of grain weight in Hindi62 was mainly due to a reduction in GGD, although GGR, starch and protein synthesis were more thermotolerant in developing grains of Hindi62 than in those of PBW154. 相似文献
63.
64.
本文以黑龙江省三江平原耕地白浆土为主要研究对象,并以复区内存在的草甸土和暗棕壤作比较,研究了土壤各种理化性质与不同形态氮素之间的相关关系:白浆土中 HA 和 FA 的主要差别,在于前者含有较多的碱性氨基酸,而后者则含有较多的酸性氨基酸;各种不同形状 N素与土壤 pH 值,质地等相关性不显著,而与土壤有机质、全 N 和 C/N 比值等的相关性极为显著。 相似文献
65.
有机微量元素具有多种优点,本文阐述了有关外源微量元素生物学利用率,回顾了微量元素不同添加方法的研究成果并进行比较。1影响动物对微量元素吸收的因素微量元素的吸收水平直接影响动物机体对微量元素的利用。如果饲喂量超过机体的代谢量,微量元素的吸收下降;如果饲喂量不足,机体则会提高对微量元素的吸收,这就说明机体自我平衡作用可以调节营养素的吸收。日粮总体消化率及各营养素间的相互作用均会影响矿物质吸收,这种相互作用包括协同作用(如铁和维生素C)和拮抗作用(如钙和锌,铜和钼、硫)。动物种类、品种、年龄、性别等也会影响微量元… 相似文献
66.
Legumes contain a range of non‐nutritional phytochemicals that may have health‐promoting effects in humans. In this study, we determined the concentrations of four phytoestrogens (coumestrol, apigenin, luteolin and quercetin) in field‐grown alfalfa (Medicago sativa L.). Differences between plants of different stages of maturity, between plant parts, and different canopy segments were assessed. The concentration of individual phytoestrogen in whole herbage varied between 15 and 225 μg g?1 dry matter (DM) and was strongly affected by stage of maturity. Coumestrol and apigenin concentrations were highest at early vegetative stages, luteolin and quercetin at early vegetative and late flowering stages. All phytoestrogens were found in lowest concentrations at the early flowering stage (average 68 μg g?1 DM); stage at which alfalfa is usually harvested when used as a forage source for animals. At vegetative stages, apigenin was the predominant phytoestrogen in herbage followed by coumestrol, the reverse being observed upon initiation of flowering; luteolin and quercetin were found at all stages in similarly lower concentrations. Concentrations of luteolin, quercetin and apigenin were 225, 410 and 690 % greater, respectively, in flowers than in leaves or stems; coumestrol concentration was similar between plant parts. In flowers and stems the predominant phytoestrogens were apigenin and quercetin, followed by coumestrol and luteolin. Similar concentrations (average 26 μg g?1 DM) of each of the four phytoestrogens were found in leaves. Concentrations through the herbage canopy varied and were greatest at >60 cm from the soil surface for apigenin and coumestrol, but greatest at >60 and 0–20 cm for quercetin and at 0–20 cm for luteolin. The results suggest that if alfalfa is to be used as a source of phytoestrogens and is harvested for the production of herbal supplements or nutraceuticals, management will need to be adapted. 相似文献
67.
腐蚀管道剩余寿命的性能衰减模型研究 总被引:4,自引:0,他引:4
管道在长期的运行过程中,由于介质和土壤的腐蚀性,管材的微塑性变形、结构转变和渗氢等。不仅会使管道出现各种腐蚀损伤,而且还存在着老化效应和氢化作用,导致管材的脆变并改变材料的塑性,使机械性质参数发生衰退,从管材性能衰减和腐蚀损伤角度研究了管道的剩余寿命,提出了根据结构承载能力的极限值确定塑性变形时工作寿命的方法,为了确定剩余使用寿命,对剪切损伤率和屈服性能比等概念进行定义,在掌握管材金属剪切损害率和屈服性能比的时间特性基础上,建立了剩余寿命计算模型。并给出了算例。 相似文献
68.
A 7-year-old male Giant Schnauzer was referred with a history of severe vomiting, lethargy, weight loss, polydipsia and polyuria. Detailed investigations revealed leucocytosis with a marked lymphocytosis, mild non-regenerative anaemia, thrombocytopenia, hypercalcaemia and azotaemia. Circulating lymphocytes were small and well-differentiated, and the same lymphoid population was present in bone marrow. Chronic lymphocyctic leukaemia with associated paraneoplastic hypercalcaemia was diagnosed. Immunohistochemical staining of a bone marrow biopsy revealed a neoplastic B-cell line expressing CD79. The dog responded to therapy with prednisolone and chlorambucil for a period of 8 months. 相似文献
69.
1. The effect of supplementing grower diets with bicarbonate or chloride on haematological variables, pulmonary hypertension syndrome and ascites in broilers exposed to cold temperature was investigated. 2. High concentrations of dietary chloride had no effect on the pH of the venous blood but a low chloride/high bicarbonate diet significantly increased blood pH. There was no consistent effect of dietary chloride or bicarbonate concentrations on growth performance, although in 1 experiment birds given a low chloride/high bicarbonate diet consumed less food and gained less weight than controls. 3. Birds fed on high-chloride diets tended to have a higher incidence of ascites and pulmonary hypertension than controls. Birds fed on low-chloride and high-bicarbonate diets had significantly lower pulmonary hypertension and lower heart weights, which may have indicated a decrease in pulmonary and systemic blood pressure. 4. We conclude that increasing dietary bicarbonate and reducing dietary chloride has potential as a low cost and effective method to reduce the pulmonary hypertension which leads to ascites in broiler chickens. 相似文献
70.