According to the Renewable Fuels Association, U.S. production of distiller’s grains with solubles (DDGS) attained 14,6 million metric tons in 2007. This ingredient is typically included in diets for laying hens in the range of 5% to 15%.
The purpose of this article is to briefly review the use of DDGS in feed for laying hens in order to reduce cost of production. A secondary objective is to quantify the benefits from a commercially available complex enzyme supplement to improve the nutritional value of layer feeds containing DDGS.
Characteristics of corn-derived DDGS
During the past five years a number of Land Grant Colleges have conducted assays and feeding trials on DDGS with specific reference to poultry.
The major conclusions are:
- There is a potential for contamination with mycotoxins derived from affected corn feedstock. Assessing mycotoxin levels is difficult due to the inherent difficulty in obtaining a representative sample from a bulk shipment with uneven distribution of toxins.
- Inter- and intra-plant variation in quality and inconsistent nutrient composition is commonly encountered.
- Variation in metabolizable energy, available lysine and phosphorus, crude protein and fat is common.
Theoretically DDGS may be contaminated with virginiamycin which is added to reactors as Lactrol to suppress Lactobacillus spp. which produce undesirable lactic acid reducing ethanol yield. Currently, virginiamycin is not approved as a dietary additive for laying hens. There will be no detectable level of virginiamycin in DDGS applying the FDA-approved microbiological assay which has a detection threshold of 0.5 to 1 ppm of active antibiotic. The European ELISA procedure may yield a false positive result as this antigen capture assay will detect biologically inactive heat-degradation products of virginiamycin. Studies in the U.S. failed to detect residues in either abdominal fat or in eggs when virginiamycin was fed to laying hens at a dietary level of 20 ppm over a prolonged period.
Problems are frequently encountered in unloading rail cars and the texture of some consignments reduces flow rate in mills.
Based on assays of 30 commercial samples of corn-derived DDGS, investigators at the University of Illinois determined that the total non-starch polysaccharide content to be 23.1% of which 88.4% was insoluble in water. Cellulose, xylose, arabinose, galactose, and mannose were main components of the insoluble fraction. Glucose, mannose, arabinose and galactose comprised the soluble fraction. Arabinoxylan (arabinose + xylose), and cellulose contributed 50% and 35% respectively to the total non-starch polysaccharide of DDGS.
Effects of DDGS on performance
Studies at the University of Georgia evaluated DDGS at dietary increments of 0% to 15% in conventional commercial diets (18.5% protein, 1,302 kcal TME/lb) and in low-nutrient density (17.0% protein, 1,272 kcal TME/lb) diets during 25 to 43 weeks of age. There was a significant reduction in hen-day egg production during the 25 to 35 week period when a low-nutrient density diet containing 15% of DDGS was fed. There was no statistically significant reduction in egg production when the same level of DDGS was incorporated in the diet with commercial specifications.
A range of 10% to 12% inclusion of DDGS was suggested for standard laying hen diets. A subsequent UGA experiment showed that up to 15% inclusion of DDGS did not adversely affect egg production from 48 to 67 weeks of age. It was suggested that a lower level of DDGS should be fed when the ingredient is initially added to diets. Increments of DDGS produced a linear increase in the intensity of color in egg yolks. Yolk color scores were elevated within 1 month when a lightly colored DDGS was fed at 10% or higher and at 2 months with an inclusion level of 5% DDGS.
A range of DDGS inclusion (0% to 20% DDGS) was evaluated in the diets of Hy-Line Brown layers fed from 24 to 34 weeks of age during hot weather in Korea. Performance parameters were not affected at any of the levels of inclusion. Color of egg yolks was intensified, linoleic acid content of yolks increased and oleic acid content decreased with increments of dietary DDGS. Addition of DDGS to the formulas resulted in proportional decreases in feed cost.
In a definitive series of evaluations at the University of Nebraska using Bovans strain White hens, increments of DDGS (0%, 5%, 10%, 15%, 20% or 25%) were fed from 22 to 46 weeks of age. There were no negative effects on egg production, feed intake, hen body weight, Haugh units or specific gravity. Feeding DDGS at 20% or 25% levels reduced egg weight compared to lower inclusion rates. Yolk color increased when feeding DDGS at 25% of the diet compared to lower levels of inclusion. During Phase 2 (47 to 76 weeks of age), there were no significant differences among treatments except for yolk color which increased at the 25% level of DDGS compared to lower levels of inclusion.
A second trial in the series conducted at the University of Nebraska using Hy-Line W-36 laying hens evaluated diets with 5 levels of DDGS (0%, 10%, 20%, 30% or 40%) with or without 0.02% supplementation with Allzyme¹ SSF at 0.02% in a factorial arrangement. To attain standardization BPXTM² (Poet) DDGS was used in this evaluation. The basal diet comprised corn, soybean meal, fat and limestone.
The series of diets with or without DDGS and containing the SSF enzyme product were formulated with decreased specifications for metabolizable energy (ME; -75 kcal/kg), calcium (-0.1%) and available phosphorus (-0.1%) to reduce feed cost, since the availability of these nutrients is enhanced by enzymatic action. The Allzyme SSF enzyme complex includes phytase, protease, pentosanase, pectinase, cellulase, beta-glucanase, and amylase activity.
Diets modified to contain reduced ME, calcium, and available phosphorus levels incorporating Allzyme SSF enzyme additive gave excellent results up to an inclusion of 15% DDGS. Performance declined numerically at inclusion levels of 20% to 40% DDGS.
Feed cost/ton was lowered with increments of DDGS with or without reduction of dietary specifications when supplemented with SSF enzyme product. Treatment means were not significantly different for hen-day egg production, egg weight, feed intake or feed/dozen eggs, but feed cost, egg production cost (cents/dozen eggs) approached significance (P = 0.159) and tended to decrease with incremental levels of DDGS. Feed cost/dozen eggs was numerically lower in each case for the modified diets containing SSF enzyme compared to the regular diet with a similar level of DDGS.
The overall means for regular versus modified formulas containing SSF enzyme and for diets with incremental levels of DDGS are presented in Table 1. Feed cost/ton was significantly lower (P<0.001) by $8.24 for modified formulas (decreased nutrient specifications) with SSF enzyme compared to regular diets. Feed cost/dozen eggs was 0.5 cent lower for modified formulas containing SSF enzyme compared to regular diets although this difference was not statistically significant. Increasing levels of DDGS in the diets increased feed/dozen eggs (P=0.008), with some variability, and decreased feed cost/ton (P<0.001) and feed cost/dozen eggs (P<0.001).
DDGS of consistent quality, derived from a reputable supplier, can be incorporated into the diets of hens producing table eggs at levels of up to 15% without affecting commercial performance parameters.
Reducing nutrient specifications for metabolizable energy and critical amino acids may reduce the cost of diets and cost per egg produced if an enzyme complex with broad action against non-starch polysaccharides is included in the diet.
¹ Allzyme SSF, Alltech, Inc., Nicholasville, KY.
² Dakota Gold Brand by Poet Nutrition, Sioux Falls SD.