Ongoing high feed prices have meant that the search for new ways to decrease poultry feed costs has become more important than ever. According to the Poultry Science Association, researchers at the University of Nebraska have identified one possible approach that may be effective for laying hens – increasing the percentage of dried distiller’s grains with solubles, DDGS, used in hens diets.
While there have long been concerns about the variability and quality of DDGS, it can be a valuable source of energy, protein and amino acids in poultry diets and the number of producers turning to this feed source is growing. There are lingering concerns about the volume of DDGS that be used in poultry diets, however, recent research has sought to address this.
The Nebraska research was carried out by Drs. Mahmoud Masa’deh, Sheila Purdum, and Katharine Hanford.
Commenting on their findings, Dr Purdum said: “Dried distillers grains with soluble have previously been shown to be a valuable and, especially given current prices of corn and soybean meal, affordable ingredient in poultry diets. Current usage levels of DDGS in poultry diets typically range from 5% up to 10%.
“What our recent study has shown is that growers can safely explore levels of DDGS in their diets for laying hens up to 15%, and perhaps as high as 25%, with no negative effects on feed intake, egg production, or other key metrics, and with improved yolk colour at the higher levels.”
She continued that more studies are planned, particularly on the impact of replacement rations containing DDGS for pullets.
The study comprised two egg production phases, during which diets were formulated to include 0, 5, 10, 15, 20 or 25% corn DDGS. The only difference between the diets in Phase 1 (weeks 24-46) and Phase 2 (weeks 47-76) was that in Phase 1, the diets were formulated on fixed lysine and TSAA (total sulfur amino acids) level. During the second phase, the diets were designed to keep lysine and methionine at a fixed level, but the TSAA levels were allowed to increase due to higher cystine levels in DDGS.
The researchers found that neither feed intake nor egg production were affected by dietary DDGS concentration in either phase of the study. In Phase 1, however, they observed that increases in DDGS levels correlated with a roughly linear decrease in egg weight. However, the negative correlation between DDGS and egg weight loss was not seen in Phase 2 of the study.
The authors note that differences in amino acid levels and potential bioavailability, as well as changing amino acid balance in Phases 1 and 2 could have been the reason for the reduction in egg weight only during Phase 1.
No differences in Haugh units due to DDGS levels were found in either production phase. In addition, the researchers observed a linear increase in the retention of nitrogen and phosphorous with increasing levels of DDGS; the output per kilogram (as measured in the hens’ excreta) of these elements, however, decreased linearly as DDGS increased. This result is the opposite of what was reported by other researchers, whose work focused on broiler chicks.
One difference the researchers consistently found throughout the study was that egg yolk colour increased linearly with increased dietary levels of DDGS, reaching its greatest Roche colour fan score of 7.2 in eggs from hens fed the diet containing 25% DDGS.
According to the authors, this indicates that xanthophylls in the DDGS were “highly available”. They also point out that the xanthophylls content of DDGS is approximately three times that of corn by weight (34 mg/kg vs. 10.62 mg/kg, respectively). This finding may be useful for producers selling eggs in markets where there is a consumer preference for increased yolk pigmentation.