Performance and Metabolism of Calves Fed Starter Feed Containing Sugarcane Molasses or Glucose Syrup as a Replacement for Corn.

The aim of this study was to evaluate the effect of replacing corn grain for sugar cane molasses (MO) or glucose syrup (GS) in the starter concentrate on performance and metabolism of dairy calves. Thirty-six individually housed Holstein male calves were blocked according to weight and date of birth and assigned to one of the starter feed treatments, during an 8 week study: i) starter containing 65% corn with no MO or GS (0MO); ii) starter containing 60% corn and 5% MO (5MO); iii) starter containing 55% corn and 10% MO (10MO); and iv) starter containing 60% corn and 5% GS (5GS). Animals received 4 L of milk replacer daily (20 crude protein, 16 ether extract, 12.5% solids), divided in two meals (0700 and 1700 h). Starter and water were provided ad libitum. Starter intake and fecal score were monitored daily until animals were eight weeks old. Body weight and measurements (withers height, hip width and heart girth) were measured weekly before the morning feeding. From the second week of age, blood samples were collected weekly, 2 h after the morning feeding, for glucose, ß-hydroxybutyrate and lactate determination. Ruminal fluid was collected at 4, 6, and 8 weeks of age using an oro-ruminal probe and a suction pump for determination of pH and short-chain fatty acids (SCFA). At the end of the eighth week, animals were harvested to evaluate development of the proximal digestive tract. The composition of the starter did not affect (p>0.05) concentrate intake, weight gain, fecal score, blood parameters, and rumen development. However, treatment 5MO showed higher (p<0.05) total concentration of SCFAs, acetate and propionate than 0MO, and these treatments did not differ from 10MO and 5GS (p>0.05). Thus, it can be concluded that the replacement of corn by 5% or 10% sugar cane molasses or 5% GS on starter concentrate did not impact performance, however it has some positive effects on rumen fermentation which may be beneficial for calves with a developing rumen.

Structure and protective capacity of tetanus and diphtheria antibodies produced during human pregnancy and transferred to new-born.

PROBLEM: The structure and protective activity of antibodies against tetanus (anti-T) and diphtheria (anti-D), produced during human pregnancy and transferred to new-born, was studied. METHOD: Antibody levels were measured by ELISA in non-pregnant women (control group), primiparae, and multiparae, and in their children. The proportion of symmetric and asymmetric IgG molecules was determined and their respective protective capacity evaluated. RESULTS: The quantity of asymmetric anti-T and anti-D antibodies in mothers at the time of delivery was roughly four- and three-fold that of the control group, respectively, dropping significantly 1 month later. A similar proportion of these antibodies was observed in the new-born. The lower neutralizing capacity of asymmetric molecules was demonstrated in vivo. CONCLUSION: Results show that during pregnancy there is a modulation of the immune response with an increase in the production of asymmetric molecules of lower protective capacity.

Serum antibodies to diphtheria-tetanus-pertussis vaccine components in Argentine children.

The Argentine vaccination schedule against diphtheria, tetanus and pertussis (DTP) recommends three doses of DTP vaccine at 2, 4 and 6 months of age, two boosters at 18 months and 6 years, a booster dose of tetanus vaccine every 10 years and two doses during pregnancy. To evaluate the effect of this schedule, antibodies against pertussis toxin (PT) and filamentous hemagglutinin (FHA) and against tetanus and diphtheria toxoids were determined by ELISA in serum samples from children (1 month to 6 years) who received different doses of DPT vaccine: 0 dose (n = 50), 1 dose (n = 25), 2 doses (n = 25), 3 doses (n = 55), first and second booster (n = 25); 25 pregnant women and their offspring, and 45 adults. High antibody levels against PT (> 140 EU/ml) and FHA (> 80 EU/ml) were recorded in mothers and in the newborn. Antibody titers against PT increased with the number of doses given and decreased with time. Full protection against tetanus (titers > 0.1 IU/ml) was observed in the group of adults (0.37 IU/ml), in mothers (4.4 IU/ml) and their newborn offspring (5.5 IU/ml), and in children after receiving the second dose of DTP vaccine (1.86 IU/ml). The immune status for diphtheria was far lower, as most of the groups lacked adequate protection. After the third dose of DTP vaccine, only 78% of the children had antibody titers above the protective level (0.1 IU/ml). Since antibody levels considered to provide full protection were only achieved after the first booster dose of DTP vaccine, the primary three-dose schedule seems to be insufficient to confer adequate immunity in all vaccinees. Because of the high proportion of non-protected adults, a booster dose of Td vaccine should be considered for this group.

Development of an alternative method for testing the immunogenicity of diphtheria vaccines.

The immunogenicity of the diphtheria component of 73 commercial vaccines from five different manufacturers was tested by the toxin neutralization test (TNT) and the enzyme-linked immunosorbent assay (ELISA) developed in our laboratory. A comparison of the antibody levels measured by both assays showed a very good correlation (r = 0.95, p < 0.001). The results suggest that the proposed ELISA is a reliable, simple and economical alternative to the TNT in guinea pigs. Also, the ELISA was found to measure IgG antibody levels as low as 5.5 x 10(-5) IU ml-1. To evaluate the possibility of accelerating the active immunization during the activity test of vaccines, an alternative schedule using one single human dose was assayed. A very good correlation was observed between the IgG antibody response obtained with this schedule and with the traditional programme. Therefore, the cost and the time required to perform the activity test may be considerably reduced when both the rapid immunization schedule and the ELISA are used.

Inhibition enzyme-linked immunosorbent assay for detection of Pseudomonas fluorescens on meat surfaces.

An inhibition enzyme-linked immunosorbent assay was developed for Pseudomonas fluorescens enumeration of meat surfaces. The assay detected contamination levels as low as 3 x 10(5) bacteria per ml and could be completed within 4 h. It could be used as a framework for a test system for quantifying P. fluorescens spoilage in meat products.

Development of an ELISA for measuring the activity of tetanus toxoid in vaccines and comparison with the toxin neutralization test in mice.

An enzyme-linked immunosorbent assay (ELISA) has been developed to measure anti-tetanus toxoid antibody levels in immunized guinea-pig sera as a useful alternative to the currently used toxin neutralization test (TNT) in determining the activity of the tetanus toxoid in vaccines. The ELISA was found to measure antibody levels as low as 5.8 x 10(-5) IU/ml. Furthermore, a comparison of the results from ELISA and TNT involving 132 different commercial vaccines showed a very good correlation (r = 0.94, p < 0.001) between antibody levels measured by both methods. The results suggest that the proposed ELISA is a reliable, simple and economical alternative to the TNT in mice for assessing the activity of tetanus toxoids in vaccines.