INTRODUCTION of Rice Polish
Rice is one of the most important cereal crops in Pakistan, ranking third in importance. Production of rice was 5.547 million tons during 2005-2006, almost 10.4 percent higher than the last year (Economic Survey of Pakistan, 2005-2006). Rice polishing is a byproduct of rice milling and is the cheapest source of energy and protein for poultry feeding.
It constitutes about 10% of paddy and is available in large quantities in major rice-growing areas of the world (Houston and Kohler, 1970). Rice polishing has great potential as an ingredient in poultry feed, with inclusion levels varying from 25 to 40% (Singh and Panda, 1988).
It is a good source of proteins, energy, vitamins, and minerals (Saunders, 1990). It also contains a better assortment of amino acids, particularly lysine and methionine, compared to other cereal grains, including corn and wheat (Khalique et al., 2004). Rice polishing supplies as much total digestible nutrients as maize (Singh and Panda, 1988
Local name: Tamil: Thavidu
Rice polish is a by-product of rice obtained in the milling operation of brushing the grain to polish the kernel.
The oil content of rice polish varies from 13-19%. The crude protein ranges from 13-16% and TDN from 70-90% depending on the oil content. Rice polish supplies as much TDN as maize. It is a good source of proteins, energy, vitamins, and minerals. It also contains a better assortment of amino acids, particularly lysine and methionine, compared to other cereal grains, including maize and wheat. The phosphorus content is high (1.30%) and calcium content is low. Though much of the phosphorus exists as phytate phosphorus, rumen microorganisms can digest phytate phosphorus.
Rice polish contains factors that promote rancidity, especially under the warm humid climatic conditions that favor auto-oxidation. These include lipoxidase, which are enzymes that promote the oxidation of unsaturated fatty acids. Rancid feeds are unpalatable and potentially toxic. Heat treatment may improve its utilization, especially in nonruminants by inactivating lipoxidase and trypsin inhibitors.