硒的分子生物学研究及在猪上的应用

自1950年发现硒是动物机体的必须矿物元素后,对硒的分子生物学、营养性及毒理性进行了研究。研究发现,硒在动物体内以蛋白或酶的形式存在;硒是GSH-PX的重要组成成分,它可以激活GSH-Px,保护机体免除自由基所造成的损伤;硒还可以调节甲状腺激素代谢与细胞生长。硒作为一种必需微量矿物元素,在畜禽组织硒沉积、肉质改善、免疫力提高等方面具有重要作用。综合前人的研究结果,本文从分子学水平阐述了硒蛋白的合成与分解及硒对猪生产性能、组织硒沉积及免疫功能的影响。     

硒及其在鱼类营养上的应用

硒（Se)是动物必需微量元素，它与动物的生长、发育和疾病发生有着密切的联系。近年来发现的一些结构和功能与硒密切相关的生物大分子，丰富了对硒生物功能的认识，现对硒在动物体内的分布、存在形式、代谢、生物学功能以及其在鱼类营养中的应用作以简述。     

植物硒蛋白提取研究(英文)

硒(Se)是生物必需的一种微量元素,其生物学功能主要是以硒蛋白的形式表现的,植物硒蛋白具有抗氧化、抗癌、提高免疫力等功能。综述了硒在植物中的存在形态、硒蛋白的分类及提取方法,并提出今后的研究方向。     

硒添加剂在畜牧业中的应用

硒与人类和动物的生长、发育和繁殖以及抵抗疾病有着密切联系。我国在硒与克山病关系的研究上取得了举世瞩目的成果。从最近的报道可知，体内有２８种硒蛋白，已经克隆并测定哺乳动物９种硒蛋白的ＤＮＡ顺序，其它硒蛋白的结构和生物学功能将是今后研究的课题。１硒的生物...     

硒的营养生物学研究进展

硒是生物生长发育所需的一种微量营养元素,适量补充硒对生物生长有益.文章从硒与植物、昆虫、禽畜和哺乳动物、人体健康的关系及硒的解毒功能等方面进行了全面综述,阐述了国内外有关硒对生物营养的研究现状及作用机制,指出硒在植物、昆虫、动物和人类的生长发育、能量代谢、抗逆能力等方面均发挥着重要作用,同时也指出了丽的营养生物学特性研究方面仍存在许多问题和难点,今后应深入了解硒蛋白的调控与表达,探析不同形式和不同浓度硒对不同生物的作用效果差异,明确硒缓解重金属毒性的作用机制,争取开发硒的新生物学特性等,为合理利用硒提供更多的可能性途径.     

硒在畜牧业生产中的应用与开发

硒是动物体必需的微量元素,在动物体的新陈代谢中起着极其重要的作用。论述了硒在动物体内的分布、代谢与生物学功能,分析了缺硒或硒过量对动物机体的影响和危害,指出了如何进行科学补硒。     

微量元素硒的研究进展

在综述硒的生物化学功能基础上,介绍了动物对硒的缺乏与中毒,硒与人和动物在免疫、肿瘤方面的关系,列举了硒在畜禽生产中的应用,特别指出有机硒的生物学效价、营养功能等方面要明显优于无机硒.     

微量元素硒的研究进展

在综述硒的生物化学功能基础上，介绍了动物对硒的缺乏与中毒，硒与人和动物在免疫、肿瘤方面的关系，列举了硒在畜禽生产中的应用，特别指出有机硒的生物学效价、营养功能等方面要明显优于无机硒。     

硒对动物健康的影响及缺硒病的防治

微量元素对动物具有特殊的功能,是动物体内进行正常生理生化过程所不可缺少的。动物缺乏这些元素将会引起生理功能和组织结构的异常,进而导致各种疾病的发生。硒是动物体内必需的微量元素。近年来大量资料证明,许多疾病与硒缺乏有关。本文综述了硒的生物学作用以及动物因缺硒而导致的微量元素硒缺乏症的防治。     

肌肉生成抑制素(MSTN)基因及其在畜牧业上的应用

肌肉生成抑制素(Myostatin,MSTN)是控制肌肉生长的负调控因子,属于TGF-β超家族成员,是影响畜禽瘦肉率、改善肉质性状的重要营养基因。文章主要对MSTN基因的结构、基因表达、生物学功能及其在畜禽生产中的应用进行综述。     

L-肉碱在猪生产中的应用

L-肉碱是一种类维生素制品,主要功能是参与动物体内脂肪酸代谢,作为载体将长链脂肪酸从线粒体膜外输送到膜内促进脂肪酸的β-氧化,将脂肪酸氧化并释放能量。L-肉碱也可以作为饲料添加剂,可提高动物的生产性能和瘦肉率,并降低脂肪含量,改善肉质,其应用前景十分广阔。文章就L-肉碱的特性、生理功能及其在猪生产中的研究作以综述。     

遗传、环境和营养因素对猪肉品质的影响*

 影响肉品质的因素主要有遗传因素、环境因素和营养因素,因此改善肉品质需要从其影响因素入手。通过遗传途径改善肉品质是将主效基因作为分子遗传标记,经过遗传育种的选育改善肉质;环境应激是导致肉质下降的主要因素,这些因素包括饲养方式、环境温度、屠宰前应激等;营养则通过干预机体代谢促进肉质改善。综合考虑营养、环境和品种对肉品质的影响,是提高肉品质的关键所在。     

不同硒源对肉鸡生长性能、胴体特性和肉质的影响

在基础日粮中分别添加亚硒酸钠、蛋氨酸硒、酵母硒0.15 mg/kg(以硒计),研究不同硒源对岭南黄肉鸡生长性能、胴体特性和肉质的影响.结果表明,与对照组相比,蛋氨酸硒组和酵母硒组的日增重分别提高16.08%(P＜0.01)和17.86%(P＜0.01),饲料转化率分别提高15.26%(P＜0.01)和16.19%(P＜0.01),亚硒酸钠组与蛋氨酸硒组和酵母硒组相比日增重及饲料转化率差异显著(P＜0.05),表明有机硒具有显著的提高肉鸡日增重和改善饲料利用率的作用;蛋氨酸硒组和酵母硒组肌肉红色色度分别比对照组提高20.84%(P＜0.01)和10.76%(P＜0.05),滴水损失率分别降低21.32%(P＜0.01)和14.23%(P＜0.05),且与亚硒酸钠组差异显著(P＜0.05).不同硒源对肉鸡胴体特性无显著影响(P＞0.05).     

脂蛋白脂酶基因及其多态性研究进展

脂蛋白脂酶主要催化乳糜微粒和极低密度脂蛋白中的甘油三酯水解产生不饱和脂肪酸和单酰甘油,影响脂肪代谢,是动物肉质候选基因。综述了脂蛋白脂酶的生物学功能、基因结构,以及多态性与动物肉质关联的研究进展。     

Selenium distribution and nitrate metabolism in hydroponic lettuce(Lactuca sativa L.): Effects of selenium forms and light spectra

A deficiency in selenium(Se) in the human diet is a worldwide problem. The intake of Se-rich vegetables can be a safe way to combat Se deficiency for humans. However, most leafy vegetables can accumulate a high content of nitrates, which poses a potential threat to human health. Light is an important environmental factor that regulates the uptake and distribution of mineral elements and nitrogen metabolism in plants. However, the effects of Se forms and light conditions, especially light spectra, on the uptake and translocation of Se and on nitrate reduction are poorly understood. In this study, lettuce(Lactuca sativa L.) was treated with exogenous Se applied as selenate(10 mmol L~(-1)) and selenite(0.5 mmol L~(-1)) and grown under five different light spectra: fluorescent light(FL), monochromatic red LED light(R), monochromatic blue LED light(B), and mixed red and blue LED light with a red to blue light ratio at 4(R/B=4), 8(R/B=8), and 12(R/B=12), respectively. The effects of light spectra and Se forms on plant growth, photosynthetic performance, Se accumulation and nitrate reduction were investigated. The results showed that the light spectra and Se forms had significant interactions for plant growth, foliar Se accumulation and nitrate reduction. The Se concentration and nitrate content in the leaves were negatively correlated with the percentage of red light from the light sources. Compared to Se applied as selenite, exogenous Se applied as selenate was more effective in reducing nitrate via promoting nitrate reductase and glutamate synthase activities. The lowest nitrate content and highest plant biomass were observed under R/B=8 for both the selenate and selenite treatments. The significant effect of the light spectra on the root concentration factor and translocation factor of Se resulted in marked variations in the Se concentrations in the roots and leaves. Compared with FL, red and blue LED light led to significant decreases in the foliar Se concentration. The results from this study suggest that the light spectra can contribute to Se distribution and accumulation to produce vegetables with better food quality.     

Effects of selenium source and level on growth performance,antioxidative ability and meat quality of broilers

This experiment was conducted to investigate the effects of selenium(Se) source and level on growth performance, carcass traits, antioxidative ability and meat quality of broilers. A total of 320 one-d-old Arbor Acres commercial broilers were randomly assigned to 1 of 5 treatments with 8 replicates in a completely randomized design involving a 2×2 factorial arrangement of treatments plus one Se-unsupplemented basal diet control for 42 d. The two Se sources were sodium selenite and Se yeast, and the two supplemental Se levels were 0.20 and 0.40 mg Se kg–1. The results showed that broilers fed the Se-supplemented diets had higher(P0.05) average daily gain and average daily feed intake from 22 to 42 d of age, eviscerated yield and abdominal fat percentages, Se concentrations and glutathione peroxidase(GSH-Px) activities in breast and thigh muscles on d 42, and lower(P0.05) feed/gain from 1 to 21 and 22 to 42 d of age, mortality from 22 to 42 d of age and malondialdehyde(MDA) concentration in thigh muscle on d 42 than those fed the control diet. Broilers fed the diets supplemented with Se yeast had higher(P0.05) p H value and lower(P0.05) shear force in thigh muscle than those fed the diets supplemented with sodium selenite. Additionally, broilers fed the diets supplemented with 0.40 mg Se kg–1 had lower(P0.05) shear force in thigh muscle and higher(P0.05) GSH-Px activities in breast and thigh muscles than those fed the diets supplemented with 0.20 mg Se kg–1. Furthermore, broilers fed the diet supplemented with Se yeast at 0.40 mg Se kg–1 had higher(P0.05) Se concentrations in breast and thigh muscles than those fed the diet supplemented with Se yeast at 0.20 mg Se kg–1, but no differences(P0.05) were observed in these indices of broilers fed the diets supplemented with sodium selenite between 0.20 and 0.40 mg Se kg–1. The results from the present study indicated that supplemental Se could increase the growth performance, muscle Se concentration and antioxidative ability of broilers; and the Se from Se yeast was more effective than the Se from sodium selenite in improving meat quality of broilers.     

维生素D对家禽的营养研究进展

维生素D(VD)是一种脂溶性维生素,是动物体内不可缺少的,其在促进骨骼发育和钙磷吸收、改善动物肉品质及免疫细胞的形成等方面都起到重要的作用,虽然VD在动物体内可以合成,但其需要量较大,仍需要从食物中获得,饲料中添加的VD量过多或过少都会影响动物的生产性能、钙和磷的代谢和骨代谢等。因此,适宜的VD添加量具有重要的生物学意义。文章综述了家禽VD的需要量、影响因素及其生理功能。