大豆浓缩蛋白是乳猪饲料的优质蛋白源

乳猪能否顺利断奶是养猪业成功的关键。乳猪消化系统的发育尚未完善,需要易消化、质量高的蛋白原料。因此,高质量、易消化的乳蛋白和血浆蛋白等常被用作乳猪开食料的蛋白原料。但这些蛋白原料因价格昂贵而增加了乳猪料的原料成本。ADM大豆浓缩蛋白是一种高质量、易消化的植物蛋白原料,可用作为高价蛋白原料像乳蛋白和血浆蛋白的替代品,从而降低乳猪料的原料成本,并维持乳猪良好的生长率。     

大豆浓缩蛋白在动物生产中的应用

大豆浓缩蛋白是一种高质量、易消化的植物蛋白原料,具有比豆粕更高的营养价值。可以作为高价蛋白原料如乳蛋白、血浆蛋白和鱼粉的替代品,降低动物生产饲料的成本,并维持良好的生长率,显示出在动物生产上具有广阔的应用前景。本文综述了大豆浓缩蛋白的营养特点及其在仔猪和水产动物生产上的应用效果。     

家蚕丝素蛋白的氨基酸组成与营养分析及酶消化产物的体外抗氧化活性

对家蚕丝素蛋白的氨基酸组成、食用营养价值,以及经酶处理的消化产物的体外抗氧化活性进行测试分析,为开发高附加值丝素蛋白产品提供理论依据。测定结果表明,甘氨酸和丙氨酸是丝素蛋白的主要组成部分,占总氨基酸质量的62.21%;丝素蛋白富含非极性氨基酸,占总氨基酸质量的69.08%。体外消化试验表明,丝素蛋白不易被胃蛋白酶消化,但易被肠道胰蛋白酶和胰凝乳蛋白酶消化。丝素蛋白的酶消化产物具有良好的体外清除DPPH自由基活性(IC50=151.6μg/m L)、螯合Fe2+能力(IC50=201.4μg/m L)和还原能力。以上结果提示:虽然丝素蛋白的氨基酸组成不均衡,食用营养价值低,但因其有极高的非极性氨基酸含量,是制备药用氨基酸和生物活性肽的理想原料。     

金属硫蛋白对应激猪血液和肌肉中非酯化脂肪酸及肌乳酸含量的影响

采用驱赶法使乳猪产生应激,探讨金属硫蛋白对应激猪血清与肌肉中非酯化脂肪酸及肌乳酸含量的影响.结果表明:在应激状态下,金属硫蛋白可使血清和运动初期肌肉中的非酯化脂肪酸含量升高,肌乳酸的生成降低,因而可增强有氧代谢,改善机体对运动负荷的压力,提高动物的抗应激能力,因此金属硫蛋白对乳猪具有一定的应激保护作用.     

新型生物功能性饲料蛋白源-生物E蛋白对猪的营养价值评定

试验首先对新型生物功能性饲料蛋白源 -生物E蛋白进行了营养成分测定 ,结果干物质、粗蛋白、粗脂肪、粗灰分、无氮浸出物含量分别为 91.5、6 0 .8、4 .5、3.2、6 .4、16 .7% ,总能为19.4MJ/kg ,赖氨酸、蛋氨酸、谷氨酰胺含量分别为 4 .4、1.4、3.1% ,α -淀粉酶、中性蛋白酶、酸性蛋白酶、纤维素酶活性分别为 4 30 0、115、2 5 0、32 0U/g ,有益菌活菌总数 5× 10 9/kg。猪消化试验结果表明 ,粗蛋白、粗脂肪、粗纤维、无氮浸出物、有机物消化率分别为 80 .4、71.2、4 3.0、95 .9、81.5 % ,消化能为 17.2MJ/kg。试验结果表明 :试验所用新型生物功能性饲料蛋白源—生物E蛋白作为一种新的蛋白原料 ,不仅蛋白含量高 ,而且富含多种生物活性物质 ,易于消化吸收。     

乳猪开食料的研制及饲养效果研究

乳猪出生后 ,其机体内消化母乳养分（如蛋白质、乳糖和脂肪等）的酶活性很高 ,而消化饲料养分酶的活性尚未出现或处于很低的水平。一方面随着日龄的增长 ,消化母乳酶的活性不断降低 ,而消化饲料酶的活性则迅速增强。Ｃｒａｎｗｅｌｌ（１９８５）研究表明 ,乳猪在出生后７ｄ或更早便会出现采食行为 ,给出生后的乳猪及早补料 ,能增加小猪胃酸和胃蛋白酶的含量 ,并能改善肠壁的环境条件 ,提高消化性能和吸收能力 ;另一方面 ,母乳虽含有乳猪生长发育的营养物质以及少量抗体 ,但大量研究表明 ,仅靠母乳喂养不能最大限度发挥乳猪生产潜力。Ｐｌｕ…     

利用ELISA双抗体夹心法检测血浆蛋白粉中IgG相对活性的研究

母乳中的免疫球蛋白具有帮助乳猪抵抗,腹泻等疾病的能力。血浆蛋白粉除为乳猪提供均衡的蛋白质营养外,还含有大量的免疫球蛋白以及其他活性成分以提高乳猪的免疫力、提高乳猪的生长能力。免疲球蛋白的活性依赖于其天然结构的保持,结构变性就丧失活性。本研究以3,000头猪新鲜血浆混合样为标准样,利用ELISA双抗体夹心法对血浆蛋白粉中的免疫球蛋白IgG的相对活性进行检测。研究结果表明,该方法可有效评估经喷雾干燥处理以后血浆蛋白粉中IgG的活性保持情况,从而推断出血浆蛋白粉的核心质量。方法稳定、测试结果可靠,可作为血浆蛋白粉的核心成分免疫球蛋白IgG活性检测的手段。     

乳猪饲料蛋白质原料的选择方法

1选择蛋白质原料的要求 乳猪料中蛋白质原料选择以消化率为首要标准,其他指标居次要位置。因为乳猪的消化率很低,尤其对蛋白质的消化能力极低,造成各种常见消化道问题的直接间接原因也是蛋白质消化不良造成的。     

日粮乳清粉含量对乳猪生产性能的影响

1代替仔猪内源性糖、促进消化防止下痢;2给乳猪添加乳清粉能够提高日增重;3给乳猪添加乳清粉能够降低料肉比;4给乳猪添加乳清粉能够降低饲料成本;5通过试验进一步分析在乳猪日粮中添加5%乳清粉效果最佳.     

丝素蛋白在生物医药工程中的应用

丝素蛋白是蚕丝的主要组成部分,具有良好的生物相容性、降解性和力学性能,且安全无毒、原料易获得,早已成为生物医药材料制备和研究的热点.文章综述了丝素蛋白在降血糖、抑菌等方面的医疗保健作用,以及在药物缓释、止血、伤口愈合、组织工程支架等生物医药工程领域及其他生物医学材料中的应用与开发前景.     

Ruminal protein degradation and protein value of feeds

The relationship between dry matter (DM) degradation and crude protein (CP) degradation in the dairy cow's rumen was determined with a view to defining the protein value of feeds for ruminants. The nylon bag technique was applied for these studies. For all the feeds investigate (green fodder and preserves from cocks-foot, ryegrass, alfalfa/grass and meadow grass, as well as alfalfa, extracted soybean meal) a significantly positive relationship was found to exist between the levels of DM and CP degradation (r = 0.73 to 1.0). The regression coefficient b1 (CP degradation as regressor) was found to average 0.87. The positive relationship between DM degradation and CP degradation implies that microbial protein amount and unfermented feed protein at the duodenum are negatively correlated. Model calculations show that, on account of the compensation between microbial protein and feed protein at the duodenum, in feeds with a CP concentration below 200 g/kg DM, the extent of ruminal protein degradation does not exert a marked influence on duodenal protein passage. The partial calculation of the duodenal protein supply on the basis of undegraded feed protein and microbial protein, as practiced in the new models of protein evaluation, leads to systematic errors unless the relationship between DM degradation and CP degradation is considered.     

Hypolipidaemic effects of potato protein and fish protein in pigs

This study was performed to assess the effects of potato protein and fish protein on concentrations of lipids in plasma and lipoproteins and the expression of genes involved in lipid metabolism in pigs used as an animal model. Therefore, 27 young male pigs with an average body weight of 22 kg were fed diets supplemented with protein extracted from potatoes (containing 849 g protein/kg dry matter), Alaska Pollack fillet as a source of fish protein (containing 926 g crude protein/kg dry matter) or casein which was used as control, for 3 weeks. Diets were formulated to supply identical amounts of each protein to the pigs by the three protein sources, namely 116 g/day in first week and 150 g/day in the second and third week. Pigs fed potato protein had lower concentrations of cholesterol in plasma and LDL than pigs fed casein (p < 0.05); no effect was observed on concentrations of HDL cholesterol and triglycerides. Pigs fed fish protein had lower cholesterol concentrations in plasma, LDL and HDL, and lower triglyceride concentrations in triglyceride-rich lipoproteins than pigs fed casein (p < 0.05). mRNA concentrations of genes involved in bile acid synthesis and cholesterol uptake were higher in pigs fed fish protein than in pigs fed casein (p < 0.05); no effect on these genes was observed in pigs fed potato protein. Expression of genes involved in lipogenesis and fatty acid oxidation was not altered by fish protein. In conclusion, this study shows that fish protein and potato protein lower plasma cholesterol concentrations in pigs. The hypocholesterolaemic effect of fish protein might be in part caused by a stimulation of bile acid synthesis; the reason for the hypocholesterolaemic effect of potato protein requires further elucidation.     

Influence of dietary protein intake on whole-body protein turnover in chicks

1. Experiments were conducted to investigate whether or not varying dietary protein intake affects whole-body protein turnover rates in young chicks. 2. Seven-d-old single comb White Leghorn male chicks were fed on diets with protein concentrations of 0, 100, 200 or 400 g/kg diet under conditions of ad libitum or equalised feeding. At the end of the experiments, the rate of protein synthesis and protein degradation in the whole body were measured in vivo. 3. The results showed that both fractional and absolute rates of protein synthesis increased with increasing dietary protein up to 200 g/kg; above this concentration they remained almost constant when feeding was ad libitum. 4. Similar responses were found with equalized feeding except that a significant reduction in protein synthesis was found when dietary protein was increased from 200 to 400 g/kg diet. 5. Less sensitive and almost parallel changes in protein degradation rates were found. 6. It was concluded that adaptation to varied dietary protein intake occurred primarily through changes in protein synthesis, accompanied by parallel alterations in protein degradation in the whole body.     

Adaptation of protein oxidation to protein intake in the domestic cat

It is well-accepted that cats require more dietary protein than omnivores and herbivores. Work on hepatic enzyme activities showed that cats lack the ability to regulate the urea cycle enzymes in response to the dietary supply of protein. It was thus hypothesized that the high protein requirement of cats is due to an inability to regulate these enzymes, limiting adaptation to a low protein diet. We used indirect respiration calorimetry to assess the in vivo ability of cats to adapt substrate oxidation to different levels of dietary protein, including one below their protein requirement. In random order, eight cats consumed each of four semi-purified diets containing 7.7% (LP), 14.6% (AP), 27.3% (MP) and 51.1% (HP) of ME from protein. Cats consumed each diet for at least 14 days and then completed a 5-day nitrogen balance trial and at least 2, 12-hour indirect calorimetry measurements. The data were analyzed by anova using the Mixed procedure of SAS and are expressed as mean ± SEM. There was a significant effect of diet on protein oxidation (p < 0.0001), measuring 9.8 ± 0.5%, 13.4 ± 0.9%, 23.5 ± 0.8% and 49.0 ± 1.8% of total energy expenditure on the LP, AP, MP and HP diets, respectively. The ratio of protein oxidation/protein intake was significantly higher with the LP diet (1.27 ± 0.07) than the other three diets (AP, 0.92 ± 0.06; MP, 0.86 ± 0.03; HP, 0.96 ± 0.04; p < 0.0001), indicating a net loss of protein on the LP diet. Thus, cats adapted to a wide range of dietary protein concentrations, but were unable to fully adapt to the LP diet.     

Substitution of milk protein with isolated soy protein in calf milk replacers

The influence of replacement of milk protein by isolated soy protein on digestion and pancreatic enzyme secretion was determined in nine Holstein male calves. Calves (average weight 47 kg) were fitted with permanent re-entrant pancreatic and a T-type cannula in the distal ileum at 6 to 10 d of age. Following a 2-wk recuperation period, the calves were fed three milk replacers in a triplicated 3 x 3 latin square. Experimental diets consisted of a control, in which 100% of the CP originated from spray-dried skim milk powder (SM), and the test diets, in which 50% (SM/ISP) or 100% (ISP) of the skim milk protein was replaced by isolated soy protein. Each experimental period lasted 2 wk. Replacement of SM protein by ISP decreased (P less than .05) the digestibilities of protein and most amino acids. Ileal digestibilities of total indispensable amino acids for SM, SM/ISP and ISP diets were 82.1, 75.8 and 61.8%, respectively, and total tract digestibilities of total indispensable amino acids were 90.0, 82.6 and 74.0%, respectively. Including ISP did not affect (P greater than .05) the volume of secretion of pancreatic juice, protein or chymotrypsin; however, the secretion of trypsin decreased (P less than .05). Reduction in trypsin secretion may be responsible, in part, for the lower amino acid digestibilities in milk replacers containing isolated soy protein.