Demand for antibiotic-free (ABF) eggs, poultry meat, and pork continues to increase in the United States. This increased demand consequently increases the demand for animals produced in ABF production systems. The most common question related to ABF feed programs is how to effectively replace antibiotics and maintain animal performance and health. Direct-fed microbials, prebiotics, essential oils, and enzymes are just a few of the products available to help producers meet production and profitability goals without antibiotics.

Direct-fed microbials (DFM’s) or probiotics are products containing live, viable microorganisms, including bacteria or yeast. DFM’s improve animal performance by modifying the microorganisms in the intestinal tract. In order to achieve improved performance, the DFM’s must be able to colonize the intestinal tract in sufficient quantities to compete with potential pathogenic or “bad” microorganisms. Since DFM’s are live organisms, they must be protected from steam and pressure when added to feed manufactured as pellets. This is achieved by spraying the DFM product on pellets as a liquid, post-pelleting, or using a DFM product protected with a fat-based coating.

Prebiotics are compounds promoting the growth of gut bacteria but are not living organisms.
Since prebiotics are not live organisms, they are less sensitive to potential destruction by steam and moisture in the pelleting process. There are two common types of prebiotics used in poultry and swine feeds, oligosaccharides and beta-glucans.

Oligosaccharides are carbohydrates with 3 to 10 simple sugars linked together. These carbohydrates are not well digested by the animal as an energy source. However, they can be excellent substrate and energy source for “good” bacteria (i.e. Lactobacillus spp.). Mannan oligosaccharides (MOS) containing products are the most common type of oligosaccharide used in poultry and swine feeds. Beta-glucans are designed to enhance the immune system by binding to and activating macrophages. Macrophages are cells which engulf and the digest pathogens or other cellular debris.

Essential oils are concentrated products containing volatile aromatic compounds derived from plants. Historically, essential oils have been used in human nutrition as flavors and/or preservatives. Essential oils typically have a strong odor and include oregano, cinnamaldehyde (cinnamon), carvacrol (oregano or thyme), thymol (thyme), and limonene (lemon rind or other citrus fruits). Each essential oil has a specific mode of action, but as a whole, essential oil products have been demonstrated to improve animal performance through improved palatability, antimicrobial effects, enzyme stimulation in the digestive tract, and improved nutrient digestibility.

Enzymes are biological molecules that increase the rate of chemical reactions. Enzymes are commonly given the –ase designation at the end of the name to identify the compound the enzyme acts upon. For example, phytase enzymes act on phytate to primarily release phosphorus and proteases act on proteins to release amino acids.

Animal feed, regardless of type, must contain the substrate the enzyme acts upon for the enzyme to be effective. Enzyme additions to ABF feeds can provide a couple of unique benefits. Enzymes can improve the digestibility of nutrients in feed, which in turn reduces the quantity of undigested feed available to pathogenic bacteria in the cecum or large intestine. In addition, enzymes can break down targeted anti-nutritional factors in feed ingredients, which in turn can reduce the negative effects of the anti-nutritional factors on the performance and health of the animal.

The use of DFM’s, prebiotics, essential oils, and enzymes can play a role to help producers meet production goals when producing eggs and meat with ABF feed programs.

Wenger Feeds uses a combination of additive types in ABF feeding programs. A study was recently completed at the Wenger Feeds Broiler Research House to evaluate the effect of additives on the performance of broilers fed an ABF feed program. Birds were housed in a tunnel ventilated building with 37,500 birds (5 pens of 7,500 birds/pen) and fed one of three treatments for 42 days.

Treatment 1 was a control ABF feed program with no additives added for disease prevention. Treatment 2 was an ABF program with a prebiotic + an essential oil in the starter phase (days 0 to 16) and the same prebiotic + a DFM in the grower phase (days 17 to 28). Treatment 3 was an ABF program with an alternative prebiotic + the same essential oil from Treatment 2 in the starter phase and the same prebiotic from Treatment 2 + an alternative essential oil in the grower phase. All diets contained the same multi-enzyme product and a coccidiostat. The results are shown in Table 1.

Table 1. Effect of Feed Additives on Broiler Performance and Carcass
Treatment 1 Treatment 2 Treatment 3
Starter Additives: None Prebiotic 1/Essential Oil 1 Prebiotic 2/Essential Oil 1
Grower Additives: None Prebiotic 1/DFM Prebiotic 1/Essential Oil 2
Average Weight, lb 5.25 5.36 5.36
Daily Gain, lb 0.119 0.122 0.122
Feed Conversion 1.91 1.91 1.88
Livability, % 93.1 91.4 93.3
Feed/Pound Gain, $/lb 0.337 0.340 0.356
Breat Meat Yield, % 20.8 20.7 20.8
(a)Experiment SCAF 1102

Broilers fed either of the ABF feeding programs with additives grew faster and were heavier at slaughter than birds fed no additives. Feed conversion was improved when the prebiotics and essential oils used in Treatment 3 were added to the ABF feed program, but not when the prebiotic, essential oil and DFM combination in Treatment 2 were used. Overall, feed cost per pound of gain of birds fed the additive combination in Treatment 2 was similar to Treatment 1, but increased nearly $0.02/pound of gain when the additives from Treatment 3 were utilized.

The results of this experiment demonstrate the potential benefits of including additives in ABF feed programs. Producers must evaluate the profitability measures important to their operation to determine the best value additive program in ABF production.

The use of DFM’s, prebiotics, essential oils, and enzymes can play a role to help producers meet production goals when producing eggs and meat with ABF feed programs. There are many products available within each of these categories. Wenger Feeds has demonstrated the potential benefits of different combinations of these products in a commercial research house. Operations producing meat and eggs using an ABF production system should use cost effective products with proven efficacy (determined through research) to reach performance and profitability goals.

For more information about Wenger Feeds’ Products and Services, contact us.