Dietary oils and fats; as most concentrated energy source in poultry diets have an opportunity to explore beyond rancidity and free fatty acids for ascertaining the quality. In order to understand the nutritional quality of oils and fats, Kemin introduced Lipid Evaluation Test (LET) to check 200+ oil/fat samples across India and Bangladesh to understand the nutritional quality which helps the poultry feed producers with accurate information for feed formulation. Surprisingly, most of them did not meet the expectations of the energy value used in the feed formulation. The energy variation is up to 35% downward than the energy considered for various fats and oils. This not only leads to energy variation in the feed but also alters the energy/lysine ratio and digestible amino acid ratio which further impacts feed conversion and economics.
The higher net worth of oils and fats beyond energy value makes them as an essential component in poultry feed. With the varying sources of industrial by-products, it is critical for the feed producers and nutritionists to understand the nutritional quality of lipids. Various industrial processes altering the chemical structure thus induces changes in metabolizable energy and sensitivity towards oxidation. In addition to processing and storage; energy diluting factors such as moisture, impurities and unsaponifiable (MIU) (e.g. waxes and complex lipids) also influences the nutritional value of lipids.
The study by Wiseman J (1999) established the relationship between the degree of saturation, the level of free fatty acids and MIU on the energy value of the lipids. The oxidative quality of the lipids is much important in the aspects of palatability and health related issues. The nutritional quality is not only influenced by oxidation but also primarily by fatty acid levels, free fatty acids and MIU in correlation with bird age, health and mineral levels.
LIPID EVALUATION TEST (LET)
In order to understand the dietary oils, during early 2016 Lipid Evaluation Test (LET) has been introduced for South Asian customers. LET provides nutritionist and feeds formulators with the accurate nutritional profile to minimise the variations in the quality and animal performance.
LET analyses the saturated and unsaturated fatty acid levels, free fatty acids and MIU which are the critical information required for the Wiseman equation to assess the metabolizable energy value of lipids.
200 plus oil/fat samples commonly used in poultry diets across India, Bangladesh and South East Asia (Tallow) has been analysed to profile the fatty acid composition and to determine the metabolizable energy. The following are the observations on FFA, U/S ratio, MIU and AME (wise man equation).
“The free fatty acids levels of commonly used oils like crude rice bran oil and blended vegetable oils were relatively higher than the assumed levels for purchasing criteria”. In a case of consistency crude soybean oil, crude rice bran oil and tallow showed a higher degree of variation, thus leading a great concern on the level of ME delivered for the formulation.
“This part really needs a better attention from the point of purchasing to ration formulation. This part of the oil or fat directly reduced the energy in relation to their level of the lipid”. The MIU of crude soybean oil was within the limits of commonly acceptable one (<3%), whereas the other predominantly used oils such as crude rice bran oil and blended oil had a higher MIU.
The average value of U/S ratio are much closer to the common levels of respective oils. Lesser the ratio makes the digestibility challenging for the bird, especially emulsification and hydrolysis and so delivers relatively lesser energy. But a wider variation like in crude soybean oil is probably due to undeclared components in the oil. “However, a final U/S ratio of 2.25 -2.50 in the complete feed for young birds and 2.0-2.25 for older birds could be ideal”.
Based on the analysed data crude soybean oil showed highest average value as well as highest absolute energy value, followed by crude rice bran oil, blended oils and tallow among the commonly used oils. Blended oils and soybean oils showed a relatively high variation whereas crude rice bran oil and tallow were relatively consistent.
“Surprisingly, most of them did not meet the expectations of the energy value used in the feed formulation. This not only leads to energy variation in the feed but also alters the energy/lysine ratio and digestible amino acid ratio which further impacts feed conversion and economics”.
The outcome of this preliminary study on the nutritional quality of oils and fats provides critical insights which can be useful for the feed producer /Nutritionist. The initial data shows that the clear variation among different types of oil which is obvious. Whereas the variation within the same type of oil is a concern for the feed formulator on applying a specific reference energy value for ration formulation. The variation is relatively high in FFA particularly crude rice bran oil and blended oils and the levels of MIU which has the direct dilution effect on AME. In terms of MIU, which is relatively a less focused parameter, all oils except crude soybean oil had a high level. Unfortunately, most of the oils tested showed the practical levels used in the feed formulation which often affects the nutritional quality of the feed.
The Lipid Evaluation Test (LET) can be a helpful tool to estimate the nutritional quality of the oils and fats, thus helping in improvement in precision feed formulation and achieving the modern genetic potential of poultry.
Lately, a technology is developed that can be applied directly to the oil or to the feed based on the LET profile, thereby improving the nutritional profile of the lipids, enhancing the animal performance and better economics.
To know more about technology, please contact at email@example.com
by Dr. S. Chandrasekar, Kemin Industries South Asia