Short communication: Absorption of protein and immunoglobulin g in calves fed a colostrum replacer

A well-managed colostrum program on farms is the most important step in reducing disease in neonatal calves. In the last few years, colostrum replacers have increased in popularity and are designed to be an alternative to colostrum on farms that have poor colostrum quality, limited colostrum reserves, or to break the cycle of transmission for certain infectious diseases. However, it is important to make sure these products are effective and are capable of providing adequate serum immunoglobulin concentrations. The objective of this study was to evaluate the efficacy of a commercially available colostrum replacer product in dairy calves. Holstein calves from a single dairy were randomly assigned to 1 of 3 groups at birth. Group 1 (n = 21) calves were given 4 quarts of colostrum via esophageal feeder within 3 h of birth and served as the control group for this study. Group 2 (n = 21) received 2 packages of a colostrum replacer product, and group 3 (n = 21) received 3 packages of the colostrum replacer product within 3 h of birth. Blood samples from all calves were collected 24 h after colostrum administration and analyzed for serum total protein and IgG concentrations. Calves fed fresh colostrum had significantly higher serum total protein levels and IgG concentrations compared with calves fed the colostrum replacer product. Calves fed the colostrum replacer also had a significantly higher percentage of calves with failure of passive transfer (serum IgG <1,000 mg/dL). The colostrum replacer product evaluated in this study failed to routinely provide adequate IgG concentrations when fed according to label directions.     

牛初乳中IgA的分离纯化及其产品免疫学检测方法的建立

用离子交换及分子筛的方法提纯牛ＩｇＡ，并制备抗血清。以此为基础，建立了测定牛初乳制品中ＩｇＡ含量的方法。该方法稍加改变后适用于各种产品中ＩｇＡ的免疫学测定及效用评价。     

Agar-Gel Immunodiffusion Test for Rapid Identification of Pollock Surimi in Raw Meat Products

A test for the rapid identification of raw pollock surimi (TRIPS) was developed. This was an adaptation of previously developed field screening agar-gel immunodiffusion tests for speciation of meat products. It was specific for Alaska pollock surimi at 2% concentration and other surimis at higher concentrations, showed detectable sensitivity to surimi in meat at 2–4%, and was 100% accurate in detection in laboratory trials.     

Use of immunological techniques for detecting species substitution in raw and smoked fish

 Immunological techniques based on double immunodiffusion and immunodotting have been designed to detect the substitution of halibut (Hippoglossus hippoglossus) for sole (Solea solea) fillets. An immunodotting technique has been also developed to differentiate between smoked cod (Gadus morhua) and smoked eel (Anguilla anguilla) fillets. Antisera raised against water-soluble extracts of raw halibut and smoked cod were employed. Antiserum to cod proteins did not show cross-reaction with eel proteins, whereas antiserum to halibut proteins cross-reacted with sole proteins. Species-specific antiserum to halibut proteins was achieved by adsorption on a polymer of sole proteins. These methods are very easy to perform and provide the basis for the development of rapid tests for detecting species substitution in fish products. Received: 18 April 1996/Revised version: 5 July 1996     

Invited review: The importance of colostrum in the newborn dairy calf

It is critical that bovine maternal colostrum is fed to newborn calves during their first hours of life. Colostrum is the secretion a cow produces after mammary involution that is rich in various nutrients. In addition to the nutritive value for newborn calves, immunoglobulins are of interest due to their role in developing the naïve immune system of calves at birth. The process by which a calf acquires immunity via absorption of immunoglobulins is defined as passive immunity. When calves consume an adequate amount of immunoglobulins, they are classified as having successful passive immunity (SPI). In contrast, if they are deprived of adequate colostrum, they are considered to have had a failure of transfer of passive immunity (FPI). Transfer of passive immunity is assessed by measuring serum IgG concentrations at 24 to 48 h of age. The major factors that influence whether a calf has SPI or FPI are colostrum IgG concentration, quantity fed, and age of calf at colostrum feeding. Monitoring apparent efficiency of immunoglobulin absorption in calves is often recommended to evaluate overall colostrum management practices. Serum IgG analyses can be determined with direct (radial immunodiffusion) or indirect (refractometry) methods and used to assess SPI or FPI prevalence.     

二步超离心法分离纯化人血浆ApoB100及兔抗人ApoB100抗血清制备

建立一种从人血浆中分离纯化ApoBl00的方法,并制备兔抗人ApoBl00抗血清。将血浆用溴化钾调成1．019g／mL的密度液进行差分超速离心,将分离产物在溴化钾不连续密度梯度液（1．006-1．210g／mI。）中进行等密度超速离心。用G-100葡聚糖凝胶柱纯化ApoB100,以ELISA双抗体夹心法检测浓度,真空冷冻干燥。取冻干粉与弗氏佐剂混合后免疫新西兰白兔,制备兔抗人ApoB100抗血清,利用双向免疫扩散检测抗原纯度与抗血清效价。结果是一步超离法分离的ApoB100最高浓度为0．91μg／mL;二步超离法分离的ApoB100最高浓度为1．40μg／mL,对应的抗血清效价为1：64。结果表明二步超离心法提高了人血浆ApoB100的分离效果。     

Rapid assessment of bovine colostrum quality: How reliable are transmission infrared spectroscopy and digital and optical refractometers?

The objectives of this study were to evaluate the performance of the transmission infrared (IR) spectroscopic method and digital and optical Brix refractometers for measurement of colostral IgG concentration and assessment of colostrum quality of dairy cows. Colostrum samples (n = 258) were collected from Holstein cows on 30 commercial dairy farms in Nova Scotia and Newfoundland, Canada. Colostral IgG concentrations of 255 samples were measured by the reference radial immunodiffusion (RID) assay and IR spectroscopy. The Brix scores were determined on 240 of these samples using both the digital and optical Brix refractometers. Approximately half (48%) of the colostrum samples had RID IgG concentrations <50 g/L, which was the cut-point for poor quality. The correlation between RID and IR IgG concentrations was 0.88. The correlations between RID IgG concentration and Brix scores, as determined by the digital and optical refractometers, were 0.72 and 0.71, respectively. The optimal cutoff levels for distinguishing good- and poor-quality colostrum using IR spectroscopy, and digital and optical Brix refractometers were at 35 g/L and 23% Brix, respectively. The IR spectroscopy showed higher sensitivity (90%) and specificity (86%) than the digital (74 and 80%, respectively) and optical (73 and 80%, respectively) Brix refractometers for assessment of colostrum quality, as compared with RID. In conclusion, the transmission-IR spectroscopy is a rapid and accurate method for assessing colostrum quality, but is a laboratory-based method, whereas Brix refractometers were less accurate but could be used on-farm.     

Evaluation of the capillary electrophoresis method for measurement of immunoglobulin concentration in ewe colostrum

Capillary electrophoresis (CE) is a technique routinely used in clinical laboratories that allows the separation and quantification of blood serum proteins in a rapid, precise, accurate, and inexpensive manner. Recently, CE has been proposed to separate and measure colostral proteins, but an evaluation of the agreement between CE and radial immunodiffusion (RID) method, currently used to quantify IgG in colostrum, is still lacking. The purpose of this study was to test the ability of a CE instrument, normally used in blood serum protein analysis, to realize the correct quantification of total Ig concentration in ewe colostrum, using RID assay as reference. Colostrum samples (n = 68) were collected from 35 multiparous Sarda ewes at first milking (n = 33) and at 24 h postpartum (n = 35). The mean ± standard deviation of IgG concentration measured by RID and whey colostrum total Ig concentration measured by CE were 54.76 ± 41.82 g/L and 54.70 ± 41.43 g/L, respectively. Lin's concordance correlation coefficient (r = 0.993; 95% confidence interval = 0.989 to 0.996) and linear regression analysis results (RID = 1.0022CE ? 0.063; R² = 0.986) showed an excellent agreement between these 2 methods. Bland-Altman analysis confirmed that CE method can be a suitable alternative to RID: the mean of the differences between CE and RID was ?0.055 ± 4.95 g/L (95% confidence interval = ?1.25 to 1.14 g/L) and the agreement limits were ?9.75 to 9.60 g/L (low limit 95% confidence interval = ?11.82 to ?7.68 g/L; high limit 95% confidence interval = 7.57 to 11.72 g/L). In conclusion, the current study indicates that CE method may be a reliable tool for the quantification of the total Ig concentration in ewe colostrum.     

抗金黄色葡萄球菌IgY酶解稳定性及体外抑菌研究

金黄色葡萄球菌(Staphylococcus aureus)是引起细菌性食物中毒的重要病原菌之一,近年来由金黄色葡萄球菌污染引起的食品安全问题,越来越受到人们的关注。抗金黄色葡萄球菌IgY热稳定性能优良,同时IgY具有较强的耐酸碱能力;IgY虽然对胃蛋白酶有较好的抵抗力,但在胰蛋白酶作用下会失去活性;体外抑菌实验表明IgY对金黄色葡萄球菌具有抑制生长活性,抑菌率达到93.5%;双向琼脂扩散实验检测IgY效价为64。因此,抗金黄色葡萄球菌IgY有望代替抗生素用于细菌感染性疾病的治疗。      

Colostrum immunoglobulin G concentration of multiparous Jersey cows at first and second milking is associated with parity,colostrum yield,and time of first milking,and can be estimated with Brix refractometry

The objective of this study was to evaluate colostrum IgG concentration harvested at first and second milking from multiparous Jersey cows, the dam's lactation number, colostrum yield, and time of first milking. In addition, we validated the use of a Brix refractometer to estimate IgG concentration in colostrum from multiparous Jersey cows using radial immunodiffusion as the reference method. Colostrum samples and total weight of colostrum harvested at first (n = 134) and second (n = 68) milking were collected from 134 multiparous Jersey cows housed in a California herd. Fresh colostrum samples were analyzed for IgG concentration with Brix refractometry and frozen samples by radial immunodiffusion. A total of 90.4 and 42.7% of the samples from first and second milking met industry standards of quality for IgG concentration (>50 g/L). Second and third lactation cows had similar colostrum IgG concentration but lower than cows on their fourth and greater lactation. At second milking, 56.4% of cows on their fourth or greater lactation had colostrum IgG concentrations >50 g/L. When colostrum yield increased from low (<3 kg), medium (3 to 6 kg), to high (>6 kg), IgG concentration decreased. Higher IgG concentration was observed on colostrum harvested at <6 h (short) versus 6 to 11 h (medium) after calving. However, IgG concentration in colostrum harvested after 11 h (long) was similar to that harvested at short and medium time. Readings of %Brix were highly correlated with IgG at first (r = 0.81) and second (r = 0.77) milking. The best Brix threshold to identify colostrum from first milking with >50 IgG g/L was 20.9% based on logit equations with Youden's index criterion and 18.0% based on accuracy criterion. For colostrum harvested at second milking, similar Brix thresholds were obtained, 19.2 and 19.0%, regardless of whether Youden's index or accuracy was used as the selection criterion. Our results indicate that the dam's lactation number, colostrum yield, and time of first milking relative to calving are associated with IgG concentration in colostrum from multiparous Jersey cows. Second milking colostrum from mature Jersey cows should be evaluated to extend colostrum supply on dairies especially during times of shortage. Readings of %Brix can be used to rapidly estimate IgG concentration in Jersey colostrum harvested at first and second milking.