反刍动物小肽营养的研究进展

本文就小肽在反刍动物的吸收机制、小肽的营养作用和影响小肽吸收的因素以及饲料蛋白源活性肽的开发应用进行综述.     

反刍动物肽营养研究进展

综述了国内外对小肽在反刍动物体内吸收与营养研究的新进展,讨论了小肽在瘤胃内的代谢及其对反刍动物的营养作用,分析了影响小肽吸收,代谢,利用的因素,最后介绍了瘤胃微生物肽营养的体系。     

反刍动物肽营养的研究进展

肽作为蛋白质的主要消化产物,是反刍动物和瘤胃微生物的重要营养来源。文章综述反刍动物对肽的吸收特点及影响因素、肽的吸收代谢机制、肽对瘤胃微生物的调控及对反刍动物生产性能发挥的作用,并阐述饲料蛋白源活性肽的开发应用及肽营养研究与应用前景。     

小肽对反刍动物的营养作用

小肽以其自身的吸收优势和众多的营养功能,受到人们的广泛关注。本文针对小肽在反刍动物中的吸收、营养作用、应用前景和目前存在的问题进行了简要综述。     

反刍动物小肽吸收与利用研究进展

反刍动物是以小肽吸收为主要形式的，这是由于反刍动物存在肽的非肠系膜吸收系统。本文从反刍动物对小肽的吸收途径、吸收机制、反刍动物对小肽的利用以：及影响小肽吸收利用的因素加以论述。     

反刍动物肽的吸收与营养

传统的代谢模型认为 :蛋白质必须水解成氨基酸后才能被吸收利用。但近几十年的研究表明 ,不同来源的饲料在氨基酸利用率上存在差异（Ａｙｄｉｎ,１９７９;Ｅｌｗｅｌｌ,１９８５）。而且当动物采食按理想氨基酸模式配制的纯合日粮或氨基酸平衡的低蛋白日粮时 ,不能达到最佳生产性能（ｐｉｎｃｈａｓｏｕ等 ,１９９０ :Ｋｅｓｈａｖａｒｚ,１９９１）。经过深入研究 ,人们认识到 :动物对蛋白质的需要不能完全由游离氨基酸来满足。动物为了达到最佳生产性能 ,必须需要一定数量的肽特别是小肽（二、三肽）。由于肽对反刍动物具有特殊的调控…     

反刍动物小肽吸收与利用的研究进展

蛋白质在动物消化道内降解成游离氨基酸和肽类后被吸收。试验表明,反刍动物以肽吸收为主要形式。这一点与单胃动物以氨基酸吸收为主不同,原因是反刍动物存在肽的非肠系膜吸收系统。近年来,对寡肽(Oligo-Peptide,OP)特别是小肽(Small—Peptide,SP)在反刍动物蛋白质营养中的作用有了越来越多的研究。本文回顾了国内外的研究进展情况。     

反刍动物肽营养研究进展

本文综述了反刍动物肽的吸收特点及影响因素,肽的吸收代谢机制,肽对瘤胃微生物的调控及对反刍动物生产性能发挥的作用,以及饲料蛋白源活性肽的开发应用。     

反刍动物肽营养研究进展

蛋白质在动物营养中起着重要作用,大量研究已表明蛋白质营养不仅是游离氨基酸营养,肽营养也具有重要作用。本文综述了反刍动物肽的吸收特点及影响因素,肽的吸收代谢机制,肽对瘤胃微生物的调控及对反刍动物生产性能发挥的作用,并阐述饲料蛋白源活性肽的开发应用及肽营养研究与应用前景。     

小肽的吸收机制与营养功能的研究进展

小肽拥有许多特殊的营养生理作用,在蛋白质代谢过程中的地位十分重要,优势也十分明显。就小肽的吸收机制和特殊的营养功能进行了综述。     

Effect of medicinal and aromatic plants on rumen fermentation,protozoa population and methanogenesis in vitro

The potential of tannins from 21 medicinal and aromatic plant leaves as antimethanogenic additives in ruminant feeds was investigated. The effect of tannin from these leaves on rumen fermentation parameters, protozoa population and methanogenesis was studied by incubating the samples [200 mg dry matter (DM)] without and with polyethylene glycol (PEG)‐6000 (400 mg DM) as a tannin binder during 24‐h incubation in the in vitro Hohenheim gas method. Based on the methane percentage estimated in the total gas produced, methane production in millilitre was calculated [methane volume (ml) = methane % × total gas produced (ml) in 24 h]. In the samples, crude protein and neutral detergent fibre (g/kg DM) ranged from 113 to 172 and from 352 to 444 respectively. The total phenol (TP; g/kg DM) content was highest in Terminalia chebula (274) followed by Hemigraphis colorata (71) and Sapindus laurifolia (51) respectively. In the remaining samples, it was <43 g/kg DM. Activity of tannins, as represented by the increase in gas volume on addition of PEG, ranged from 0 to 133%, with the highest being recorded in T. chebula. The per cent increase in methane on PEG addition was 0 for Ammi majus, Aristolochia indica, Cascabela thevetia, Ipomea nil and Lantana camara, illustrating that tannins present in these samples had no effect on methane concentration. The PEG addition increased the total protozoa count by >50% in A. indica and C. thevetica. One of the important findings of our study was that of the 21 samples screened, Entodinia population increased in 12 with PEG as compared to 7 where Holotricha increased, indicating higher susceptibility of Entodinia to tannin. There was no increase in the protozoa population with PEG when incubating Cardiospermum halicacabum, Clerodendrum inerme, Dioscorea floribunda, Nerium oleander and Selastras paniculatus, which strongly suggested that methane suppression recorded in these samples was not because of a defaunating effect of their tannins per se. The fermentation pattern reflected increased total volatile fatty acid (TVFA) concentration from 0 to 28.3% with PEG addition among the leaves. Our results confirmed further observations that methanogenesis in vitro is not essentially related to density of protozoa population. Secondly, medicinal and aromatic plants such as C. inerme, Gymnema sylvestre and Sapindus laurifolia containing tannins appear to have a potential to suppress in vitro methanogenesis.     

Development of an Indirect ELISA for the Detection of Antibodies against Peste-des-petits-ruminants Virus in Small Ruminants

Peste des petits ruminants (PPR) is an acute, febrile, highly contagious and economically important viral disease of small ruminants. A polyclonal antibody based indirect ELISA was developed for detection of antibodies to PPR virus in the serum samples of goats and sheep using purified PPR viral antigen propogated in Vero cell culture. A threshold (cut-off) value was set as twice the mean of the negative population based on the distribution of known negative serum samples in respect of PPR virus antibodies in the test. A total of 1544 serum samples from goats and sheep were screened by indirect ELISA and competitive ELISA. The indirect ELISA compared very well with competitive ELISA, with a high degree of specificity (95.09%) and sensitivity (90.81%). When compared with virus neutralization test, the present assay had 100% specificity and 80% sensitivity. With serum samples, the assay could clearly differentiate animals from the infected population from uninfected ones. These results suggest that the indirect ELISA may be a good alternative tool to competitive ELISA for seroepidemiological surveys.     

不同蛋白质饲料对瘤胃内小肽浓度的影响

选用4只体重30 kg左右,安装永久性瘤胃瘘管的内蒙古苏尼特羊,研究饲料不同蛋白来源对瘤胃内小肽浓度的影响。试验采用4×4拉丁方设计,选取鱼粉、豆粕、酪蛋白、玉米蛋白粉4种蛋白质原料,按14%粗蛋白水平配制单一蛋白源日粮(精粗比3∶7),每只羊每天喂料量1 kg,代谢能供给量为1.2倍维持需要。试验结果表明:不同蛋白源在瘤胃中肽的释放的种类和数量在不同时间点都不尽相同,大多数小肽在2~6 h浓度达到峰值。玉米蛋白组、鱼粉组、豆粕组在瘤胃内6 h的小肽累积量顺序为:Pro-Leu>Val-Val>Pro-Ala>Met-Met;酪蛋白组瘤胃内6 h的小肽累积量顺序为:Pro-Leu>Pro-Ala>Val-Val>Met-Met。进一步证实,从氮端起第一位氨基酸残基是Pro,又有疏水性氨基酸结构的小肽,或者两种结构特点居其一的小肽,有抗瘤胃微生物降解的特性。