Introduction
In poultry nutrition, finding alternative feed ingredients is essential to reduce production costs, with feed accounting for 65-75% of total expenses. Protein sources are the main cost drivers, so substituting expensive proteins with more affordable ingredients is a key strategy for economical broiler production.
Distiller’s dried grains with solubles (DDGS), a by-product of ethanol production from grains like corn and wheat, serve as an alternative plant protein source. Rich in protein, fat, fiber, vitamins, and minerals, DDGS offers benefits for poultry due to its wide availability, suitable protein levels, and balanced amino acid profile.
DDGS enhances phosphorus bioavailability through microbial phytase and supports immunity and gut health with its yeast biomass content. Environmentally, it reduces emissions and pollution from manure. However, DDGS use in poultry is limited due to variability in its physical, chemical, and nutritional properties, which depend on grain source, ethanol production methods, and condensed distillers’ soluble (CDS) levels. In India, rice DDGS is the most widely available type, followed by bajara, barley, corn, wheat, and sorghum.
Physical characteristics
The physical characteristics of DDGS, such as color, smell, particle size, bulk density,
flowability, pH, shelf-life stability, and hygroscopicity, vary by source and affect its feed value and dietary inclusion levels. DDGS color ranges from light yellow to dark brown, influenced by the source grain and the time and temperature of soluble addition, with higher CDS levels leading to a darker color.
The physical characteristics of DDGS, such as color, smell, particle size, bulk density, flowability, pH, shelf-life, and hygroscopicity, influence its feed value and dietary inclusion levels. Color ranges from light yellow to dark brown, affected by source grain and soluble addition levels. Fresh rice DDGS has a sweet, fermented smell, while a charred odor suggests poor quality. Uniform particle size aids mixing, and moisture content should stay below 12% to prevent spoilage. With a pH of 4.1, lower levels reduce bacterial contamination risks. Nutritionally, DDGS is low in starch but rich in concentrated nutrients due to starch use during fermentation.
From January 1 to June 30, 2024, we analyzed 94 samples from various suppliers and regions. Below are the average values for each region, presented in two tables: Table 1 provides the proximate analysis and Table 2 compares amino acid data across different studies.
a) Crude Protein
- Studies report RDDGS crude protein content ranging from 28.55% to 61.41%, with typical values between 44% and 45%. This variability results from differences in raw material composition, fermentation efficiency, and processing methods. Nutritionists should standardize nutrient analysis protocols before using RDDGS in poultry diets, as color score may indicate quality but doesn’t precisely estimate nutrient content.
- b) Crude Fiber and Ether Extract
- Crude fiber ranges from 1.23% to 10.85%, and ether extract content varies between 2.24% and 8.90%.
- c) Energy
- Metabolizable Energy (ME) levels in RDDGS range from 2200 to 2400 kcal/kg.
Mineral Composition
Rice DDGS is a potential source of phosphorus (0.76%), zinc (57.26 ppm), potassium (0.91 ppm), and other minerals. Mineral levels vary with source and ethanol production methods, requiring analysis before feed formulation to avoid impacting poultry performance. Total sulfur should be checked, as levels above 0.6% can cause wet litter, while 1.2% may harm poultry health.
Amino Acid Composition
RDDGS provides concentrated grain nutrients but has lower lysine (0.64–1.23%) than soybean meal (2.99–3.22%), with other amino acids within range. Nutrient variability in RDDGS can result from grain differences, drying methods, and high temperatures affecting protein quality.
Other Nutrients in Rice DDGS
Rice DDGS, though limited in detailed nutrient data, is rich in riboflavin and thiamine, with beneficial compounds like nucleotides, mannan oligosaccharides, β-glucans, inositol, and glutamine, which support immune health. Corn-based DDGS is also expected to contain xanthophyll pigments, though heat may reduce these levels during drying.
Mycotoxins in Rice DDGS
DDGS has a low risk of mycotoxin contamination due to stringent monitoring throughout the ethanol production chain, including rejecting contaminated grains. Strategies like crop rotation, moisture control, and the use of genetically engineered, disease-resistant crops can help further to minimize risks. However, fermentation can concentrate existing mycotoxins like Aflatoxin, Ochratoxin, T2, and Fumonisin up to 3-4 times, with Malathion detected in some samples. Table 3 summarizes mycotoxin data for samples from different Indian regions (January 1 to June 30, 2024).
Production Statistics, Industry Scenario, and Composition of Corn vs. Rice DDGS
Data on the production statistics, industry scenario, and composition of Corn vs. Rice DDGS is provided in Tables 5, 6, and 7.
Optimization of Feed Cost by Including Rice DDGS
Soybean meal (Soya DOC) is rich in lysine but low in methionine, while Rice DDGS offers higher methionine levels and lower lysine. Together, they complement each other when used carefully. Currently, Rice DDGS prices range from 15 to 20, compared to 45 to 49 for Soya DOC, making Rice DDGS a cost-effective alternative without compromising quality.
Steps for Formulating Rice DDGS in Feed
- Storage Conditions
Storage of Rice DDGS depends on initial moisture levels, season, storage area, and packaging type.
- Physical Examination
Assess physical parameters such as pH, moisture, and mycotoxin levels.
- Proximate Analysis
Conduct a detailed analysis of crude protein, crude fiber, moisture, ether extract, and amino acids before formulating the diet.
- Maximum Inclusion Level in Feed
The maximum inclusion level of Rice DDGS is influenced by factors like the age of the birds, daily feed consumption, breed, season, inclusion of other raw materials, pricing, environmental conditions, and disease prevalence. For low-density diets, inclusion should be limited due to nutritional variability. DDGS can be safely included at up to 6-8% in broiler and layer diets.
- Target Organ Protection
Consider risks to target organs such as the liver, kidneys, bursa, and gut health. Ensure adequate levels of biotin, choline, and methyl donors for liver health. Use high-quality toxin binders with multi-toxin binding capabilities to maintain immune status.
To promote gut health, probiotics effective against Clostridium spp., Salmonella spp., and E. coli should be included.
Address nutrient profile variations (crude protein, amino acid levels, digestibility, ME content, and phosphorus bioavailability) by using a combination of enzymes to tackle economic and nutritional challenges.
Employ enzymes like xylanase, amylase, beta-glucanase, cellulase, and multiprotease. This enzyme combination reduces costs and mitigates anti-nutritional factors while enhancing the release of sugars by breaking down non-starch polysaccharides (NSPs) such as beta-glucan, mannan, and oligosaccharides.
Risks of Using ‘Static’ Published Databases
The nutrient composition of feed ingredients can change over time, making reliance on outdated published values from static databases potentially misleading. This issue is particularly significant for DDGS, as its nutrient profile evolves with advancements in ethanol production processes aimed at improving yields, extracting more corn oil, and enhancing protein and amino acid content. Therefore, to accurately determine the nutritional values of DDGS, it is crucial to consider the publication dates and utilize current data to ensure that these databases reflect the latest changes in the ethanol industry’s objectives and practices.
Summary
Biofuel co-products, such as DDGS, provide a cost-effective feed option for animals while helping to mitigate environmental concerns. The Government of India has initiated an ethanol blending program aiming for up to 20% in petroleum, leading to increased ethanol production from sugarcane, maize, rice, sorghum, and wheat. Key factors influencing the suitability of DDGS in feed formulation include amino acid levels, digestibility, metabolizable energy content, and phosphorus bioavailability. Variations in ethanol manufacturing processes, parent grain quality, and other factors must be considered.
The maximum inclusion of DDGS in feed depends on the quality of raw materials and the nutritionist’s understanding of associated risks. Rice DDGS offers several advantages, including improved feed intake and feed conversion ratios, along with positive effects on egg and meat quality due to its high omega-3 fatty acid content. It also enhances phosphorus bioavailability, reducing phosphorus excretion and mitigating environmental pollution. However, the use of DDGS may pose challenges, such as sulfur toxicity from sulfuric acid used in the production process, which can affect nerve tissue, and the persistent risk of mycotoxin contamination.
References available upon request.
by Dr Sudhir Kale & Dr Sushant Labh, Kemin Industries South Asia and Dr Dilip L. Waghmare, JAPFA COMFEED
