BACKGROUNDVarium (Amlan International, Chicago, IL) has demonstrated consistent Clostridium perfringens toxin neutralization both in vitro and in vivo.1 In order to identify the most efficient and cost-effective dosage scheme to prevent C. perfringens induced necrotic enteritis, a study was conducted to evaluate the performance of Varium at 0.1% and 0.25% inclusion, with and without supplemental bacitracin methylene disalicylate (BMD).

The 28-Day study was performed at Southern Poultry Research, Inc., Athens, Georgia, USA, to compare the efficacy of Varium at two dose levels. Each treatment group included eight pens containing eight male Cobb X Cobb broilers (Cobb-Vantress, Cleveland, GA). Routine vaccinations were given on the day of hatch. On day 14, all birds were orally inoculated with Eimeria maxima, a known risk factor for C. perfringens proliferation. Birds in the challenged treatment group were given C. perfringens on days 19, 20, and 21. Necrotic enteritis lesion scores, weight gain, feed conversion, and mortality were compared among the treatment groups. Three birds from each pen challenged with C. perfringens were euthanized for the purposes of intestinal examination. Necrotic enteritis damage was scored by a veterinarian based on a 0 (normal) to 3 (severe damage) ranking.

All groups treated with Varium and/or BMD demonstrated significantly less severe lesion scores compared with the challenged control group. Interestingly, of all the C. perfringens challenged groups the 0.1% Varium concentration, with or without BMD, resulted in the most favorable results. Inclusion of Varium at either concentration (0.1 or 0.25), both with and without BMD, showed significantly improved feed conversion compared with the challenge control group and numerically improved conversion compared with BMD alone. Here again, the lower Varium concentration (0.1%) demonstrated numerically favorable conversion rates.

Total weight gain for Varium and/or BMD supplemented groups was equivalent to the gain realized by the Control group. Once again, feeding broilers 0.1% Varium resulted in higher total weight gain. Feeding the combination of Varium with BMD or 0.25% Varium reduced necrotic enteritis induced mortality compared to the challenged control group. Feeding 0.1% Varium or BMD gave equal performance showing a numerical decrease in mortality compared with the challenge control group and similar mortality rates compared with the combination or 0.25 Varium groups.

1 See Amlan International Technical Bulletins: USDA-ARS In-Vitro Analysis of Varium Biotoxin Neutralization and Necrotic Enteritis, a growing concern amidst reduced antibiotic use

SOUTHERN POULTRYRESEARCH CENTER, INC.Athens, Georgia, United States

VARIUMTM DOSAGE ANALYSIS Guidance for Optimal Effectiveness

Technical Bulletin

Volume 700

PATENT PENDING

DISCUSSION The inclusion of Varium at 0.1% and 0.25% demonstrated consistent and significant improvement in intestinal health, feed conversion, and mortality compared with C. perfringens challenged birds with no supplementation. Because there was no statistical benefit to including a higher Varium concentration, a 0.1% (1 kg/metric ton of feed) Varium dosage is recommended for optimally cost-effective necrotic enteritis protection.

TRIAL FINDINGS

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0.96

0.54

0.38

0.75

0.50

0.58

NotChallenged Challenged

Control Control BMD BMD BMD

LESION SCORES

0.1% 0.1%

+ +

0.25% 0.25%

FEED CONVERSION

1.77

2.10

1.91

1.81

1.85

1.79

1.83

Control Control BMD

0.1% 0.1%0.25% 0.25%

BMD BMD+ +

NotChallenged Challenged

WEIGHT GAIN (g)

678

582

631

658

634 633 633

Control Control BMD

0.1% 0.1%0.25% 0.25%

BMD BMD+ +

NotChallenged Challenged

MORTALITY (%)

20.3

12.5 12.5

10.9

6.37.8

Control Control BMD

0.1% 0.1%0.25% 0.25%

BMD BMD+ +

NotChallenged Challenged

Varium at 0.1% improved feed conversion of birds challenged to induce necrotic enteritis as much or more than BMD, Varium at 0.25%, or the combinations of the two products.

Adding Varium at 0.1% inclusion decreased necrotic enteritis lesion scores. With scores that were lower than those of BMD, Varium at 0.25%, or the combination of the two products.

Feeding Varium at 0.1% reduced mortality to equal that of those given BMD.

Weight gain of C. perfringens challenged broilers improved when Varium was fed at 0.1%.

©2015, Amlan International 10-2015