大豆蛋白对犊牛胃肠形态结构和功能的影响及其机理

随着犊牛代乳料研究的不断深入，大豆蛋白作为优质的蛋白原料在犊牛代乳料中的应用成为人们研究的焦点。但是由于犊牛独特的消化生理特征，其消化吸收机能尚不完善。对非乳源性营养物质消化吸收较差：并且由于大豆本身的营养缺陷，其含有的多种抗营养因子对犊牛胃肠道形态和功能产生广泛的不良影响．这些因素限制了大豆蛋白在犊牛代乳料中推广应用。     

犊牛代乳料的现状

乳用后备犊牛和肉用犊牛的现代化、集约化生产常用更经济实用的代乳料来代替母乳。传统的代乳料———包括脱脂奶、乳蛋白浓缩物、脱乳糖乳清粉和乳清粉。但现在由于许多国家减少了奶品生产补贴 ,造成乳制品价格持续上涨 ,所以 ,在代乳料中使用价格低廉的大豆产品越来越多。尽管现在大豆产品品种繁多 ,但还没有一种能彻解决犊牛优质代乳料的原料问题。代乳料供应商ＭｉｌｋＳｐｅｃｉａｉｔｉｅｓ公司的研究主任ＴｒｅｖｏｒＴｏｍｋｉｎｓ指出 ,许多因素仍限制大豆蛋白产品的使用。诸如“抗营养因子”、物理形状和氨基酸水平等 ,试验一直证…     

大豆蛋白在犊牛代乳料中的应用研究进展

随着人们生活水平的不断提高 ,乳制品加工业的不断兴起 ,对牛奶的需求量越来越大。如果能用营养全面、犊牛能消化吸收、成本又低的代乳料代替部分或全部牛奶 ,就能大大减少犊牛用奶 ,为乳制品加工提供更多的奶源。因此 ,研制成本低又能满足犊牛营养需要的与牛奶近似的饲用代乳料 ,已成为研究者们关注的课题。大豆蛋白以其价廉及蛋白质含量高而成为犊牛代乳料研究的主要蛋白来源。1　代乳料的发展2 0世纪 60年代 ,欧美一些国家开始使用代乳料 ,由于当时脱脂乳蛋白过剩 ,价格较低 ,因而在代乳料中几乎全部使用脱脂乳蛋白作蛋白源。到 80年代 ,…     

犊牛代乳料中添加氨基酸的研究进展

现代犊牛代乳料应用广泛,但由于某些替代蛋白中含有抗营养因子,导致犊牛对代乳料中的部分营养物质无法正常吸收,国内外的众多学者在这方面做了细致的研究.     

大豆蛋白在特牛代乳料中的应用

1大豆蛋白的营养缺陷 尽管大豆制品在代乳料的生产中功不可没,但由于生产技术上的原因,其抗营养因子、物理性状和氨基酸水平等影响蛋白质的回肠氨基酸真消化率,故其蛋白质消化率低于其他乳蛋白.同时,大豆球蛋白和β-聚球蛋白难于被降解,这对消化酶系尚未发育完全的幼龄动物来说是不适宜的.但是随着脱脂乳、乳清蛋白浓缩物、脱糖乳清和乳清等代乳料的主要蛋白源价格升高,大豆蛋白等代乳料原料的进一步开发利用具有广阔前景.     

大豆蛋白在犊牛代乳料中的应用

1　大豆蛋白的营养缺陷尽管大豆制品在代乳料的生产中功不可没 ,但由于生产技术上的原因 ,其抗营养因子、物理性状和氨基酸水平等影响蛋白质的回肠氨基酸真消化率 ,故其蛋白质消化率低于其他乳蛋白。同时 ,大豆球蛋白和 β -聚球蛋白难于被降解 ,这对消化酶系尚未发育完全的幼龄动物来说是不适宜的。但是随着脱脂乳、乳清蛋白浓缩物、脱糖乳清和乳清等代乳料的主要蛋白源价格升高 ,大豆蛋白等代乳料原料的进一步开发利用具有广阔前景。研究表明 ,大豆蛋白中的胰蛋白酶抑制因子对很多酶的活性都有抑制作用 ,造成日粮中含硫氨基酸 (蛋氨酸和半…     

浅析犊牛代乳料

应用犊牛代乳料能降低饲养成本，代乳料能够促进犊牛前胃和消化道的发育增强机体对营养物质的吸收，有利于犊牛后期生长发育。犊代乳料的使用可减少犊牛在消化道方面疾病的发生率，并能根据不同的生产目的和用途，供给犊牛不同的营养水平的代乳料以获得最佳的经济效益     

大豆抗原蛋白的应用研究进展

大豆作为一种优质低价的植物性蛋白原料被广泛应用于各种畜禽饲料中,但大豆蛋白中存在多种抗营养因子,使其在断奶仔猪和犊牛饲料中的应用受到影响。本文就大豆抗原蛋白的组成、作用以及对断奶仔猪、犊牛产生的影响做一概述。     

代乳料-犊牛料不同哺育方案对0～2月龄断奶公犊生长发育的影响

试验旨在为中国荷斯坦犊牛的早期断奶人工培育提供参考。选择品种来源一致、体重(38.00±2.83)kg、平均出生时间1.83 d的健康中国荷斯坦奶公犊36头,采用L9(34)正交试验设计,研究代乳料中添加以甘露寡糖为主的非抗生素营养调控剂、补充以消化酶为主的外源复合酶制剂、以大豆浓缩蛋白为主的非乳源性蛋白不同替代比例以及代乳料-犊牛料不同哺育方案对早期断奶犊牛初生~2月龄生长发育的影响。结果显示,4因子对犊牛初生~2月龄平均日增重(ADG)调控效果的最佳优化组合为:非抗生素营养调控剂0.36%、非乳源性蛋白85%、复合酶制剂0.20%以及哺育方案代乳料7周+犊牛料1周过渡,对ADG的影响分别为802、779、754和770 g。初生~1月龄以非乳源性蛋白为主效因子,1~2月龄以非抗生素营养调控剂为主效因子。中国荷斯坦公犊初生~2月龄体尺与体重的回归公式为:体重(kg)=胸围(m2)×体斜长(m)×96.08-10.80。结果表明,在合理添加以甘露寡糖为主的非抗生素营养调控剂与补充外源复合酶制剂的条件下,代乳料中使用85%的非乳源性蛋白对初生~2月龄中国荷斯坦公犊可取得良好的增重效果。     

不同蛋白源代乳料对肉用犊牛生长性能、营养物质消化率及血清生化指标的影响

试验旨在研究不同蛋白源代乳料对肉用犊牛生长性能、营养物质表观消化率及血清生化指标的影响。试验采用随机试验设计,将20头新生黑安格斯犊牛按体重和生长状况相近的原则随机分成CK组(对照组)、A组(发酵豆粕组)、B组(膨化大豆粉组)和C组(大豆蛋白粉组),每组5头,试验期45d。结果表明:在30~45日龄期间,试验组犊牛日增重均显著低于CK组(P0.05),营养物质消化率低,犊牛腹泻率处于整个试验期的最高水平,在血清生化指标方面,45日龄时不同蛋白源代乳料对犊牛血清中尿素氮、总蛋白、白蛋白、甘油三脂和钙含量均有显著影响(P0.05);在45~60日龄期间,试验组犊牛日增重明显增加,各组犊牛腹泻率开始降低,60日龄时试验组犊牛血清生化指标受不同蛋白源代乳料的影响减小;在60~75日龄期间,试验B组和C组犊牛日增重与CK组相比差异不显著(P0.05),各试验组犊牛营养物质消化率明显提高,腹泻率大幅降低,甚至无腹泻情况发生,75日龄时各组犊牛血清生化指标之间无显著差异(P0.05)。综上,不同蛋白源代乳料的饲喂效果差于母乳,但随着犊牛日龄增加有所改善,其中膨化大豆粉为最佳代乳料蛋白源。     

Intestinal digestion of dietary and endogenous proteins along the small intestine of calves fed soybean or potato.

This study was conducted to investigate the quantitative and qualitative changes in dietary and endogenous protein components along the small intestine of calves. They were fed milk replacers in which protein was provided either by skim milk powder alone, as control diet, or by skim milk powder and a soy concentrate, a partially hydrolyzed soy protein isolate, or a potato protein concentrate (1:1 on a CP basis). The calves were continuously infused with the liquid milk substitute diets into the abomasum. Duodenal, jejunal, and ileal digesta were collected through T-piece cannulas. Digestibility (corrected for total endogenous protein) of dietary protein and the concentration of dietary, host endogenous, and bacterial proteins were estimated from the AA composition of digesta using multiple linear regression. The apparent digestibility of feed components increased linearly between the duodenum and the ileum. It was lower with the diets containing plant protein than with the control, especially at the ileum (85% for CP with soy concentrate, 73% with soy isolate, and 81% with potato concentrate vs 91% with skim milk powder). The real digestibility of dietary protein at the ileum was estimated to be 96, 95, 94, and 99%, respectively, for each of the dietary components. The partition of protein components in digesta between dietary, nonspecific endogenous, specific host endogenous, and(or) specific bacterial proteins varied along the small intestine and between diets at a given site. Intestinal apparent reabsorption of host endogenous protein was estimated to be equivalent to at least 86% of the jejunum flow. To conclude, the lower apparent digestibility of the plant protein sources studied resulted more from an enhanced loss of host and bacterial endogenous proteins than from decreased hydrolysis of dietary protein and absorption of their AA.     

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.     

不同处理大豆蛋白粉对犊牛消化酶活性及小肠发育的影响

本试验旨在研究饲喂含有不同加工处理大豆蛋白的代乳粉对犊牛消化道结构和消化酶活性的影响。试验选用新生公犊牛18只,随机分为3组,每组6只,分别饲喂含有全脂大豆粉(A组)、脱脂大豆粉(B组)或膨化大豆粉(C组)的代乳粉, 预饲期7 d, 试验期42 d。结果表明,代乳粉中不同加工处理的大豆蛋白对犊牛肠道消化酶活性和小肠形态结构具有显著的影响。与膨化大豆粉组和全脂大豆粉犊牛相比,B组犊牛小肠食糜中胰蛋白酶活性和糜蛋白酶活性最低。各组绒毛高度在空肠近端无显著差异,在小肠其它各段,A组和C组都显著高于B组(P<0.05)。各组犊牛十二指肠和空肠近端隐窝深度无显著差异(P>0.05)。A组和C组的小肠绒毛高度与隐窝深度比值均显著高于B组(P<0.05)。十二指肠和空肠近端、中部的黏膜厚度接近(P>0.05),但在空肠远端A组与C组无显著差异(P>0.05),显著高于B组(P<0.05)。综上所述,加热全脂大豆蛋白粉和膨化大豆蛋白粉能够作为蛋白质来源在代乳粉中添加。     

Effects of Phyto-Oestrogens on Veal Calf Prostate Histology

In veal calf production plant-based proteins are frequently included in milk replacer fed to the animals. Since soy products, which are mostly used, are known for their high levels of phyto-oestrogens, the effects of these feeds on the veal calf prostate were examined. Goal was to determine whether these compounds could interfere with histological screening for oestrogenic growth promoters. In a feeding experiment, four groups of veal calves fed plant-based protein-supplemented milk replacer (PBM), containing 5% soy concentrate, 5% soy isolate, 5% wheat gluten and 2% potato protein, for 4 weeks were compared to animals fed dairy-based control feed (DBM); animals treated with estradiol benzoate, diethylstilbestrol and ethinylestradiol served as positive controls. Daidzein and genistein levels measured in feed and urine showed high levels of genistein and daidzein in the soy isolate and soy concentrate supplemented feeds. Genistein and daidzein were also found in the urine of the animals that were fed these feeds. Haematoxylin–eosin-stained prostate sections of PBM-fed animals showed slight hyperplasia and some dilated tubules as compared to the DBM-fed group, but no metaplasia, which is used for screening for oestrogenic hormones. The positive controls showed extensive squamous metaplasia. Immunohistochemical staining for cytokeratin 5 (using RCK 103 monoclonal antibody) in basal cells showed a normal staining pattern of basal cells in the DBM-fed calves and extensive basal cell proliferation and squamous metaplasia in the oestrogen-treated positive control animals. PBM-fed calves showed no increase of basal cell staining but showed elongations of the basal cells in most animals, sometimes resulting in circular figures. It is concluded that the feeds examined in this study did not interfere with histological screening for oestrogens in male veal calves.     

饲喂不同营养水平代乳粉对犊牛生长性能的影响

选择体重和出生日期相近、健康状况良好的荷斯坦公犊牛30头,随机分为3组（试验I组、Ⅱ组和Ⅲ组）,每组10头,研究了饲喂不同脂肪和蛋白质水平代乳粉对犊牛生长性能的影响。不同处理代乳粉的营养水平分别为：试验I组,EE13％、CP22％;Ⅱ组,EE16％、CP24％;Ⅲ组,EE19％、CP26％。研究结果表明．犊牛的日增重随着代乳粉营养水平的升高逐渐提高,试验Ⅱ组和Ⅲ组的日增重分别比试验I组提高了35．45％和37．63％（P〈（1．05）．试验Ⅱ组和Ⅲ组的平均日增重差异不显著;饲喂高营养水平代乳粉具有降低犊牛腹泻的趋势;不同试验处理对犊牛开食料采食量无显著差异。综合分析饲喂不同营养水平代乳粉对犊牛生长和经济效益的影响,代乳粉的适宜营养水平为EE16％、CP24％。     

Effects of wheat protein in milk replacers on abomasal emptying rate in calves

Diarrhoea is a condition with tremendous impact on calf health. Infectious agents play a dominant role; however, non‐infective factors may also contribute to pathogenesis of diarrhoea. One factor, the abomasal emptying rate, is mainly influenced by the composition of feed. The aim of the study was to assess the influence of different protein sources in milk replacers on abomasal emptying rate and clinical parameters. The effect of increasing age of the calves on abomasal emptying was also evaluated. The study compared abomasal emptying rates and clinical parameters in calves, which were fed either milk replacer containing only whey protein or one which partially contained wheat protein. Abomasal emptying rate was estimated by ultrasonography. Ten calves were used in the study over 18 days, and each calf was fed 3 periods of 3 days length using different milk replacers in an alternating crossover design. The abomasum was emptied significantly faster when the wheat protein containing milk replacer was fed (half‐emptying time wheat protein 49.1 ± 4.1 min, half‐emptying time milk protein 59.1 ± 7.4 min); however, clinical parameters and weight gain did not differ between the feeding regimes. Age did not significantly influence abomasal emptying rate. As milk replacers containing wheat proteins increased abomasal emptying rate, they may have a higher potential to initiate diarrhoea, especially if high volumes are fed. Thus, the feeding regimes are likely to be even more important when such milk replacers are used.     

Transport and hindlimb exchange of peptide and serum protein amino acids in calves fed soy- or urea-based purified diets

Holstein steer calves (130 kg) were used to monitor venoarterial concentration differences of plasma peptide and serum protein amino acids across the hindlimbs. Calves were fed purified diets containing soy protein or urea as the sole source of dietary N. Twenty-four hourly feedings per day were imposed to promote "steady-state" metabolism. Negative venoarterial differences of glutamic acid (P less than .10), valine (P less than .10), lysine (P less than .05) and histidine (P less than .01) were observed in soy-fed calves and isoleucine (P less than .10) in urea-fed calves from the peptide fraction. Negative venoarterial differences of amino acids from the peptide fraction were generally similar for the two dietary treatments, except for glutamic acid (P less than .01). A large negative venoarterial difference of glutamic acid was observed when soy protein was fed and, conversely, a large positive venoarterial difference was observed when urea was fed. Two groups of serum proteins were evaluated: fraction I (primarily globulins) and fraction II (primarily albumin). Hindlimb amino acid venoarterial concentration differences for soy-fed calves were inconsistent and nonsignificant for both fractions I and II. Conversely, hindlimb negative venoarterial concentration differences in urea-fed calves for both fractions I and II were large and statistically significant for many amino acids. Fraction II venoarterial differences were much greater than differences observed in fraction I. Soy and urea treatment differences were also much more pronounced in fraction II, being statistically significant for 8 of 17 amino acids. These data indicate venoarterial concentration differences of serum protein amino acids that react differently to varied nutritional regimens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Feeding dairy calves and replacement heifers in South-western Sweden: a survey

Daily feed rations, their nutrient contents and live weight gains were recorded for calves and replacement heifers from birth to calving in 122 Swedish dairy herds. Preweaned calves were fed whole milk (45% of the herds), milk replacer alone or milk replacer combined with whole milk. Calf starters were the most frequently used concentrates for preweaned calves, whereas grain dominated for weaned calves and heifers. Grain was supplemented with protein concentrates until 6 months of age and at calving. Grass/clover hay was the dominant forage for preweaned calves, whereas grass/clover silage alone or in combination with hay was the most common forage for calves and replacement heifers from 6 months of age. Heifers grazed semi-natural grasslands, leys or a combination of semi-natural grasslands and leys in 33, 15 and 52% of the herds, respectively. According to Swedish recommendations, calves in a majority of the herds were fed too low concentrations of crude protein from weaning to 6 months of age and calves were fed too low a metabolizable energy content inadequate for a daily weight gain of 700 g at weaning. Median live weight gain from birth to calving was only 567 g per day. Correct feed ration formulations and strategic grazing management could be means to increase weight gain and hence to decrease rearing costs of calves and replacement heifers in Swedish dairy herds.     

Effect of short-chain fatty acids on pancreatic exocrine secretion in calves aged 2 weeks and 13 weeks

Effects of short-chain fatty acids on pancreatic exocrine secretion were studied under anesthesia in calves within 2 weeks of age (2-wks calves) given only whole milk and milk replacement and in which rumen fermentation has not begun yet, and in calves at 13 weeks of age (13-wks calves) weaned at 40 days of age and in which rumen fermentation has already begun. Basal rate of juice flow and protein concentration and amylase activity in pancreatic juice under basal condition were significantly lower in the 2-wks calves than those in the 13-wks calves. Intravenous administrations of acetate, propionate and butyrate stimulated pancreatic juice secretion and protein and amylase output in both groups of calves. Those responses were increased with increasing carbon number in the molecule of fatty acids. Although the response of amylase output (/kg of body weight) in the 2-wks calves was significantly less than that in the 13-wks calves, the response of juice flow and protein output (/kg of body weight) in the 2-wks calves were equivalent to or greater than those in the 13-wks calves. These results indicate that the characteristic of pancreas, being stimulated by short-chain fatty acids, in calves and probably in other ruminants is not generated on the process of postnatal development, but has been already acquired before rumen fermentation begins.     

Effect of restricted suckling on milk yield,composition and flow,udder health,and postpartum anoestrus in grazing Holstein cows

The effect of restricted suckling on milk yield and composition, udder health, and postpartum anoestrus in dairy cows in pasture-based systems, was studied in 32 Holstein multiparous cows and their calves. At calving, each cow–calf pair was randomly assigned to one of two treatments: restricted suckling (RS) of the cows by her own or another calf, twice daily for 30 min or artificial rearing (AR) of the calves with milk obtained from the bulk tank, offered twice a day in buckets. Treatments were applied until week 8 after calving. The diet of the cows consisted of direct grazing in improved pastures, corn silage and a commercial concentrate which was offered at milking. Milk production and composition, udder health, body condition score of the cows, body weight and milk intake of the calves were measured weekly, and the first postpartum ovulation was determined three times a week by ovarian ultrasonography. Cows with RS management had a lower machine-milked milk yield (17.9 vs. 24.8 kg/d), a lower fat percentage (3.21 vs. 4.11%) and 4% fat-corrected milk yield (16.2 vs. 25.7 kg/d), and also a lower average milk flow (1.35 vs. 1.76 kg/min) than cows in the AR treatment. There was no effect of treatment on milk protein percentage or udder health as measured by milk electrical conductivity. The interval from calving to first postpartum ovulation was shorter in the AR cows than in the RS cows (18.5 vs. 21.8 days). The RS calves consumed more milk (7.2 vs. 5.4 kg/d), gained more body weight (0.813 vs. 0.656 kg/d), and had a higher body weight at weaning (84.3 vs. 73.3 kg) than AR calves. Restricted suckling of grazing dairy cows had a negative effect on machine-milked milk yield, fat percentage and 4% fat-corrected milk yield, but had no effect on udder health or on improved weight gain and body weight at weaning of the calves.