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Virginia Diversified Research Corporation, Harrisonburg, VA USA. Abstract*. Histomonas meleagridis is the etiological agent that causes blackhead disease in ...
Evaluation of Medium Chain Fatty Acids Alone or with a Phytogenic on Tom Turkey Performance and Lesion Development Following Challenge with Histomonas meleagridis. N.P. Evans1, T.P. Karnezos1, R.A. Dvorak1, M. Sims2. 1PMI Nutritional Additives, Arden Hills, MN, USA, 2Virginia Diversified Research Corporation, Harrisonburg, VA USA

Abstract*

Histomonas meleagridis is the etiological agent that causes blackhead disease in turkeys. Histomonas can reside in, and is often transmitted between birds by eggs of the cecal nematode Heterakis gallinarium. Infected birds typically have reduced feed consumption and weight gain. Lesions develop in the ceca and liver and are accompanied by high mortality. With the recent withdrawal of nitarsone approval for use in food animals, few other treatment or prevention options remain. The purpose of this study was to evaluate various levels of medium chain fatty acids, with or without a phytogenic, on performance and lesion development in turkeys. In two separate studies, day-of-hatch turkeys were randomly assigned to floor pens containing fresh pine shavings. Birds were provided diets containing either medium chain fatty acids, medium chain fatty acids + phytogenic, or medium chain fatty acids at a half rate + phytogenic, and compared to control. Birds were challenged by placing infected litter in each pen at 7 days-post-hatch or by a double challenge model. Production parameters (body weights, feed conversion ratio, and mortality) and lesion scores (ceca and liver) were collected through 10 weeks. Overall, birds challenged with Histomonas meleagridis and supplemented with medium chain fatty acids + phytogenic performed similar to birds supplemented with BMD®. *Note: The above abstract has been amended from the original submission.

Study 1 Birds: 30 Nicholas Toms per 4’x8’ pen Reps: 12 pens per treatment Challenge: H. meleagridis infected litter placed in each pen at 7d Performance data: 4, 7, and 10 wk Lesion scores: 5 and 10 wk Treatment

Starter 1 (0-28d) BMD® 50 g/t MCFA 4 lb/t MCFA + Phyto 5 lb/t MCFA ½ + Phyto 3 lb/t

Study 1 Body Weights

FCR

Treatment BMD® MCFA MCFA + Phyto MCFA ½ + Phyto

Week 0-4 1.2002a 1.1758a 1.1468a 1.1810a

Week 0-7 6.2877a 6.0753a 6.0494a 6.1131a

Week 0-10 9.6474a 9.0763b 8.9861b 9.2978ab

Mortality

Starter 2 (29-42d) 50 g/t 3 lb/t 3.75 lb/t 2.5 lb/t

Grower (43-56d) 50 g/t 3 lb/t 3.75 lb/t 2.5 lb/t

Finisher (57-70d) 50 g/t 2 lb/t 2.5 lb/t 1.5 lb/t

Treatment BMD® MCFA MCFA + Phyto MCFA ½ + Phyto

Week 0-4 1.5855a 1.5277a 1.6077a 1.5233a

Week 0-7 2.0353b 2.2249a 2.0884ab 2.0370b

Week 0-10 2.2433b 2.3815a 2.3522ab 2.2703ab

Lesion Scores

Treatment BMD® MCFA MCFA + Phyto MCFA ½ + Phyto

Week 0-4 2.38a 1.19a 2.98a 3.57a

Week 0-7 5.00b 6.00ab 8.33a 8.33a

Week 0-10 7.20a 6.44a 12.50a 12.12a

Treatment BMD® MCFA MCFA + Phyto MCFA ½ + Phyto

Ceca 5wk 0.417b 0.778a 0.472b 0.657ab

Liver 5wk 0.111a 0.167a 0.306a 0.222a

Ceca 10wk 0.417ab 0.472a 0.389ab 0.250b

Liver 10wk 0.806a 0.000c 0.064b 0.369b

Treatments not connected by the same letter are significantly different (P≤0.1)

Study 2 Body Weights

Methods • • • • •

Results

FCR

Treatment Infected Ctrl BMD®

Week 0-4 Week 0-6 Week 0-8 Week 0-10 2.182a 3.378b 5.961b 9.477b 2.105a 3.504ab 6.150b 9.895a

Treatment Infected Ctrl BMD®

Week 0-4 Week 0-6 Week 0-8 Week 0-10 1.530a 2.030a 2.103a 2.395a 1.522a 1.873b 1.980b 2.240b

MCFA ½ + Phyto

2.176a

MCFA ½ + Phyto

1.505a

3.643a

6.355a

10.183a

Mortality

1.848b

1.986b

2.235b

Lesion Scores

Treatment Infected Ctrl BMD®

Week 0-4 Week 0-6 Week 0-8 Week 0-10 4.00a 4.27a 4.80a 6.97a 1.60a 2.13a 2.67a 6.67a

Treatment Infected Ctrl BMD®

Ceca 8wk Liver 8wk Ceca 10wk Liver 10wk 1.467a 1.422a 1.225a 1.225a 1.511a 1.289a 0.500b 0.750b

MCFA ½ + Phyto

1.87a

MCFA ½ + Phyto

1.444a

1.87a

3.20a

6.36a

1.267a

0.725b

0.650b

Treatments not connected by the same letter are significantly different (P≤0.05)

Study 2

• Birds: 25 Nicholas Toms per 4’x8’ pen • Reps: 15 pens per treatment • Challenge: H. meleagridis infected litter placed in each pen at 7d and 5 birds from a communally infected pen swapped into each pen at 4 wk • Performance data: 4, 6, 8, and 10 wk • Lesion scores: 8 and 10 wk Treatment

Starter 1 (0-28d) Infected Ctrl BMD® 50 g/t MCFA ½ + Phyto 3 lb/t

Starter 2 (29-42d) 50 g/t 2.5 lb/t

Grower (43-56d) 50 g/t 2.5 lb/t

Finisher (57-70d) 50 g/t 1.5 lb/t

Conclusion Study 1 • MCFA, MCFA + Phyto, and MCFA ½ + Phyto supplementation resulted in performance and lesion scores similar to BMD® supplementation. • MCFA ½ + Phyto supplementation resulted in a larger numerical improvement in body weight and FCR than MCFA or MCFA + Phyto supplementation.

Study 2 • MCFA ½ + Phyto supplementation resulted in performance and lesion scores that were significantly better than the infected control and often numerically better than BMD® supplementation.