With the price and availability of soybean and corn fluctuating, the poultry and animal nutrition industries are opting for alternatives that can compensate for the price without compromising nutrition. Dr Badal Singh, a freelance consultant from North India, and Dr Pradeep Mahajan, a renowned nutritionist working with feed mills and feed additive companies in India and abroad, shared their experiences with using various alternatives and suggestions for improvements.
Dr Badal Singh
Alternate raw material – Not just a substitute
In 2009, maize and soya were the main ingredients for feed formulation. Nowadays, along with variable costs, there are multiple challenges in the feed raw materials. Hence, the industry started using alternatives which today are rather essential ingredients for cost savings.
Energy sources other than maize such as pearl millet, broken rice, wheat, and ragi can be used considering their anti-nutritional factors. By using enzymes and quality alternates, the quantity of maize can be reduced in feed formulations.
- Pearl millet (Bajra) is one of the best energy sources with a lesser risk of aflatoxin. It does not have any xanthophyll content. While using alternatives like pearl millet, wheat, or rice, pigment is to be added.
- Vegetable oil is another important energy source for both broilers and layers, and it also contains a lot of fatty acids that protect the birds from different diseases and improve gut health. However, rancidity is the main issue with vegetable oil if not stored properly.
- Ground nut cake (GNC) contains aflatoxin, so it should be avoided. If GNC has aflatoxin levels of <20 ppb, then it can be used up to 12-15% in layer diet and up to 5% in broiler diet.
- Rapeseed meal usually contains glucosinolates, which is an anti-nutritional factor, and with solvent extraction, the meal contains less than 0.1% oil and a lesser anti-nutritional factor.
- Sesame (Til) cake contains 30% protein and more than 2000 kcal of energy, which can be used in both layer and broiler diets without any side effects.
- Cotton seed cake contains gossypol, an anti-nutritional factor, which can affect the immune system and the liver. Hence, using dehulled cotton seed cake is recommended.
- Guar meal is another protein alternative with anti-nutritional factors like guar gum, and carcinogenic hydroxide, which can harm the liver of birds. Hence, it is recommended to use roasted guar meal with some amino acids; this contains >45% protein, which is almost the same as that of soya.
DDGS – 2nd most important protein ingredient after soymeal
DDGS with some amino acids, if stored properly, can be an excellent source of protein and energy (~ 2600 kcal) with good digestibility.
Insect Meal – the future ingredient
It is one of the best sources of protein which is anticipated to be used as a regular ingredient.
Role of grain cleaning
Many Indian companies are investing in upgraded technology, though it is not widely publicized. Feed quality control is well taken care of, and even grain cleaning is adopted in a few places. There is a big feed mill facility in North India using some of the best equipment where 3-4% of the dust is cleaned and small particles of the grain are removed before using maize and broken rice.
Dr Pradeep Mahajan
DDGS – Yet to be standardized
When ethanol production from grains started in India, most plants were selling the residual grain in wet form without drying. But slowly, the ethanol production economics changed and the ethanol producers were forced to realize some value from the distiller’s grain to keep the venture profitable. So, nearly all of those plants installed dryers and started selling Distiller’s Dried Grain Solubles (DDGS). The nutrient content of DDGS available in India used to vary a lot mainly due to the type of grains being used. Most plants were using a variable mixture of corn, rice, and sorghum.
Six years ago, an informal survey of ethanol producers showed high variation in the mix of grains being used. In any given plant, the mix of grain varied wildly from day to day. They were using any combination, for e.g. 80% corn and 20% rice to 20% corn and 80% rice and anything in between. This posed a big challenge for the users. For effective use of any protein source, one must know the amino acid content which changes depending on the grain type used. With the given wide variation in the combination of grains being used, there is simply no way to know the amino acid content unless one actually analyses it.
Over time, the scenario has changed slowly. The economics of producing grain-based ethanol has ensured that most plants at least in the North and East must use mostly rice as the source grain. Producing ethanol from corn is mostly not economically viable due to the higher price of corn. Along with installing dryers, centrifuges to recover soluble protein were also installed and therefore, DDGS from rice consistently shows 45-48% protein. Corn DDGS has much less protein content.
For corn, most plants use steeping with sulfur addition. This is not required for rice. For both grains, during the fermentation stage, sulfuric acid may be used for achieving the required pH. This also adds sulfur. Whatever sulfur is added, whether in steeping or in pH adjustment will all come to the DDGS and does not go to ethanol, thus increasing the sulfur content of the product. As steeping is not required in the case of rice, the sulfur content is not very high. With given higher protein and lower sulfur, rice DDGS can be considered more consistent on these two criteria.
Mycotoxins and color variation
As ethanol is of prime interest for the plants, physical quality especially fungal or mold damage to the grain is less of a concern and incoming grains are not tested for mycotoxins content. During the process, all the mycotoxins present in starting grains will come to DDGS and hence, by definition, will get concentrated three to four times.
A big variation in color is observed in DDGS. It can range from very light to brown, dark brown color, and sometimes, black burnt particles are also visible. This happens due to a variable amount of heat or variation in residence time in the dryer. Due to higher heat, the protein digestibility may go down, especially, lysine digestibility can be poorer. To remove the subjectivity, color measurement criteria may be introduced. In addition, Acid Detergent Insoluble Nitrogen (ADIN) or Acid Detergent Insoluble Crude Protein (ADICP) is a good measure of heat-damaged protein. It is a good idea to agree on a maximum limit on ADICP or ADIN while buying DDGS.
The current economics of ethanol production dictates higher value realization from DDGS. If the ethanol plants want to achieve this, they will have to invest in testing grains for mycotoxins and limiting mycotoxins coming into DDGS. They will also have to ensure consistent drying which gives uniform color and ensure that the ADIN / ADICP content of the product remains low. Besides this, transparency on the grains and their combination used will go a long way in earning the confidence of the users of DDGS.