日粮蛋白水平和烟酸对热应激奶牛的影响

为缓解热应激条件下，奶牛蛋白质摄入量和利用效率降低问题，本文研究日粮蛋白水平和烟酸对秸秆型日粮奶牛生产的影响。结果表明，提高日粮蛋白水平、添加烟酸可以显著提高干物质采食量、产奶量和经济效益。     

烟酸在反刍动物营养中的研究进展

烟酸与动物体内脂肪、蛋白质和碳水化合物代谢过程密切相关,对动物生产性能的充分发挥起着重要作用。作者综述了烟酸在反刍动物体内的吸收代谢、影响因素及其烟酸对瘤胃微生物、血液酮体及生产性能等方面的影响,以期为生产实践中科学合理的利用烟酸提供一定的理论依据。     

不同水平烟酸对夏季泌乳水牛饲粮养分消化率和生产性能的影响

本试验旨在研究不同水平烟酸对夏季泌乳水牛饲粮养分消化率和生产性能的影响.选取36头健康广西杂交泌乳水牛(广西水牛×尼里-拉菲水牛×摩拉水牛),按产奶量、泌乳期相近原则随机分为4组.对照组饲喂基础饲粮;试验组分别饲喂在基础饲粮中添加4、8、12 g/d烟酸的试验饲粮.试验期56 d,其中预试期14 d,正试期42 d.结果表明:1)试验泌乳水牛直肠温度和呼吸频率在夏季高温条件下均处于正常生理水平;2)饲粮中添加12 g/d烟酸干物质采食量较对照组提高4.82％ (P＜0.05);3)饲粮中添加烟酸能不同程度提高泌乳水牛对饲粮中总能、粗蛋白质的消化率,其中添加8 g/d烟酸能使粗蛋白质消化率较对照组提高6.36％(P＜0.05);4)与对照组相比,饲粮中添加8、12 g/d烟酸使4％标准乳产量分别提高11.51％、8.09％(P＜0.05),饲粮中添加4、8、12 g/d烟酸使乳蛋白率分别提高9.31％、9.31％、4.41％ (P＜0.05).结果提示,夏季高温条件下,泌乳水牛处于正常生理状态,在饲粮中补饲烟酸有助于改善其养分消化率和生产性能,适宜添加水平为8 g/d.     

Vitamin values ofPleurotus mushrooms

Ascorbic acid, thiamine, niacin, riboflavin, pantothenic acid and folic acid contents were determined in four different species ofPleurotus mushroom grown on wet chopped unfermented rice straw. The estimated values for the respective vitamins ranged from 92–144, 1.36–2.23, 60.6–73.3, 6.66–8.97, 21.1–33.3 mg and 1222–1412 µg per 100g mushrooms on dry weight basis. These vitamin values were comparable with those ofAgaricus bisporus, but were higher than those ofAuricularia, Lentinus andVolvariella.     

烟酸在反刍家畜饲养中的研究进展

本文综述了烟酸的发现过程、结构、性质、代谢途径、特点及来源 ;不同生产阶段、日粮因素及环境条件对烟酸在瘤胃发酵中的影响 ;反刍动物对烟酸的吸收 ;烟酸对反刍动物代谢作用和生产性能的影响等多方面的研究成果,并对有待于继续研究的问题进行了探讨。     

Niacin status of humans as affected by eating decorticated and whole-ground sorghum (Sorghum Gramineae) grain,ready-to-eat breakfast cereals

Niacin utilization to humans from whole grain ground sorghum flour and decorticated grain ground sorghum flour was studied. During two, randomly-arranged experimental periods of 14 days each, the 10 healthy adult subjects ate constant, laboratory controlled diets which included 28 g per day of either a ready-to-eat cereal prepared from whole-ground-sorghum flour or one prepared from decorticated (polished) sorghum flour. All subjects received both experimental treatments, made complete collections of urine and stools, and gave fasting blood samples at the ends of both experimental periods. Although the whole ground cereal contained higher amounts of niacin than did the decorticated cereal, urinary losses of N-methylnicotinamine were higher when the decorticated cereal was fed than when the whole ground cereal was used. Blood serum levels of nicotinamide and N-nicotinamide were higher when the whole ground cereal was fed than the feeding of the decorticated cereal was given. Therefore, it appears that the niacin of whole ground sorghum is absorbed but then the need for niacin is either increased or its urinary excretion is inhibited.Published as University of Nebraska Division of Agriculture Research Journal Series No. 9494. Supported by Nebraska Agriculture Research Division Project 91-031 and U.S.D.A. C.S.R.S. Regional Research Project No. W-143.     

Niacin,thiamin, iron and protein status of humans as affected by the consumption of tea (Camellia sinensis) infusions

The objective of the project was to determine the effects of tea (Camellia sinensis) leaf beverage consumption on the apparent utilization of niacin, thiamin, and protein in human subjects. During two randomly arranged experimental periods of 14 days each, 10 adult female human subjects were fed a constant (same foods each day), measured, laboratory-controlled diet. Tea was fed during one period while no tea was allowed during the other period. A dehydrated black tea infusion product (instant tea, 8 g/subject/day/dry weight basis) was used which subjects were allowed to dilute in water. Subjects made complete collections of urine and stools. Fasting blood samples were drawn at the end of each experimental period. No effects on protein status were demonstrated. Urinary thiamin losses were depressed with the use of tea but niacin losses were increased. Blood serum concentrations of thiamin diphosphate also were depressed during the tea drinking period as compared to values during the non-tea period. No significant effect on blood serum levels of nicotinaminde or N-methylnicotinamine were found but values tended to be lower during the tea than the non-tea period. These results suggest that tea consumption inhibits the utilization of thiamin. However, niacin availability was unaffected by tea drinking. Because of the decreased availability of thiamin, the need for niacin was depressed which caused a greater than expected urinary loss of this vitamin.Published as University of Nebraska Journal Articles Series No. 9496. Supported by University of Nebraska Agricultural Research Division Project 91-031 and U.S.D.A. C.S.R.S. Regional Project W-143.     

烟酸及胆碱对围产期奶牛营养代谢的调控

围产期是奶牛泌乳周期中十分重要的时期,奶牛要经历生理、日粮、环境和管理等一系列变化,因此,采食量下降,机体处于能量和其他营养素的负平衡状态,易诱发多种代谢性疾病,如脂肪肝和酮病等。烟酸和胆碱能够调控脂肪代谢,提高产后泌乳性能,改善奶牛健康。本文总结了烟酸和胆碱的理化性质、生理功能及其对围产期奶牛营养代谢的调控机理,为进一步研究烟酸、胆碱在奶牛围产期合理应用及保障围产期奶牛健康提供参考。     

Effects of energy supply and nicotinic acid supplementation on serum anti‐oxidative capacity and on expression of oxidative stress‐related genes in blood leucocytes of periparturient primi‐ and pluriparous dairy cows

The periparturient period is accompanied by metabolic and oxidative stress. Niacin is known to decrease lipolysis but is also reported to have anti‐oxidative effects. Therefore, we examined the effects of energy supply and a nicotinic acid (NA) supplementation on anti‐oxidative serum parameters and on the expression of oxidative stress‐related genes in blood leucocytes of periparturient dairy cows, differing in parity. Twenty‐nine pluriparous and 18 primiparous cows were allocated to four different feeding groups 42 days before expected parturition until 100 days postpartum and fed a ration with either a low concentrate proportion of 30% (LC) or a high concentrate proportion of 60% (HC). After parturition, all animals received 30% concentrate which was increased to 50% either within 16 (LC group) or 24 days (HC group). Half of the animals per group were supplemented with 24 g NA per day from 42 days prepartum until 24 days postpartum. All investigated parameters varied significantly over time compared to parturition (p < .05). Ferric reducing ability (FRA) exhibited a nadir before parturition, and the antioxidant enzymes glutathione peroxidase (GPX) and superoxide dismutase (SOD) showed peak activities around parturition. Expression levels of GPX1, SOD2, xanthine dehydrogenase (XDH) and nuclear factor (erythroid‐derived 2)‐like 2 (NRF2) peaked before calving. The concentrate level influenced GPX activity and mRNA abundance of SOD2, XDH and poly (ADP‐ribose) polymerase 1 (PARP1). Pluriparous animals exhibited higher serum GPX activities, a more distinct nadir for FRA and higher expression levels for GPX1, SOD2 and XDH. Primiparous cows displayed higher serum SOD activities. NA supplementation increased serum SOD activity antepartum in LC animals. Parturition was characterised by an increased need for antioxidants and an increased expression of oxidative stress‐related genes that clearly differed with parity and was influenced by energy supply while NA exerted only minor effects on the investigated parameters.     

烟酸调节动物肠道黏膜屏障功能的分子机制

作为一种重要的维生素,烟酸在抑制肠道炎症反应及维持肠道健康等方面发挥重要作用。研究表明,烟酸可以直接结合烟酸受体G蛋白偶联受体109A(GPR109A)发挥其生理作用,还能够以辅酶烟酰胺腺嘌呤二核苷酸(NAD^+)的形式参与细胞能量代谢。本文主要阐述了烟酸维护肠道黏膜屏障功能的作用机制,为维护断奶仔猪肠道健康提供科学理论依据。