International Journal of Advance Research, Ideas and Innovations in Technology © 2021, www.IJARIIT.com All Rights Reserved Page |548 ISSN: 2454-132X Impact Factor: 6.078 (Volume 7, Issue 4 - V7I4-1356) Available online at: https://www.ijariit.com Glycerol – An alternate energy source for livestock feeding Mukesh Sharma drmukesh2004@gmail.com Dau Shree Vasudev Chandrakar Kamdhenu University, Durg, Chhattisgarh Dr. Manoj Gendley drgmanoj.ann@gmail.com Dau Shree Vasudev Chandrakar Kamdhenu University, Durg, Chhattisgarh Dr. Kranti Sharma dr.krantee@gmail.com Dau Shree Vasudev Chandrakar Kamdhenu University, Durg, Chhattisgarh ABSTRACT Glycerol, is being an attractive feed ingredient for cattle, is a by-product of a wide range of industrial applications. Glycerol has potential value in livestock feeding since it improves feed efficiency, metabolism, and can avoid ketosis. Research indicate that glycerol can be a suitable partial grain replacement in the diet of cows during the transition period and at early lactation. The impact on milk yield is not significant, but glycerol mostly decreases milk fat content. The inclusion of glycerol in the dairy ration has an effect on ruminal fermentation patterns. Glycerol is rapidly fermented in the rumen into propionate, and it is metabolized to glucose in the liver through the process of glycogenolysis, additionally, glycerol administration to ruminants can reduce greenhouse gas emissions. The purpose of this review is to highlight the potential benefits and drawbacks related to the use of glycerol in cattle. Glycerol, from biodiesel Industries, must be purified in order to make it useful product for livestock feeding. The use of glycerol in ruminant nutrition can be justified for several reasons: (i) as a source of energy, (ii) as glycogenic precursor, and (iii) it may have an effect on milk composition. The high energy value of glycerol provides the opportunity to use it as a partial substitute of grain in dairy rations. Supplementation of glycerol in dairy animals diet is associated with increased propionate, butyrate, valerate, and isovalerate concentrations in the rumen. Glycerol can be used as 10%–15% of the dietary dry matter (DM) and is well-established tool for treatment for ketosis in cows. Glycerol increases plasma glucose and may reduce non-esterified fatty acids and hydroxybutyrate levels. The dietary supplementation of glycerol does not have a direct effect on DM intake, milk yield, or milk composition. However, some researcher reported an increase in milk yield after glycerol supplementation associated with decreased milk fat concentration. It is also possible that the concentration in the milk of odd- chain fatty acids and cis-9, trans-11 conjugated linoleic acid may increase after glycerol application. Keywords: Dairy Cows, Glycerol, Metabolism, Ketosis, Rumen Microorganism 1. INTRODUCTION Increased concern on greenhouse gas emission, global warming and decreasing fuels have created the importance of an alternative source of energy for the transportation vehicles. Biofuel as an alternative fuel source, which releases less carbon dioxide, carbon monoxide, sulfur and nitrogen oxides upon combustion. These environmental friendly features of biodiesel make it a potential alternative to the conventional fuels. Biodiesel can be derived from the edible or non-edible source of triglycerides. During the biodiesel extraction process, crude glycerol (CG) is obtained at the rate of 10% as a byproduct of trans-esterification process. Crude Glycerol so obtained is chemically composed of catalysts, salts and fatty acids. Purification process of crude Glycerol >95% highly cost involving process (0.28 USD/L production) and time consuming too. Hence, economical management of CG is the need of time, one such alternative way is its utilization in animal food chain as an energy source. Glycerol is a glycogenic intermediate product of fat digestion converted to glucose by the action of key enzyme glycerol kinase. The CG undergo glycolysis and TCA cycle to liberate ATP. The digestible and metabolizable energy content of CG are comparable with the commonly used cereal grains in livestock feeding. So, CG can acts as a bridging gap between the biodiesel industry and livestock production, and can be used as an energy source as a partial replacement of grains in pig, poultry, goat, feedlot cattle and dairy cows. This review provides an overview of utilization of CG and its effect on production performance of different livestock species. Glycerol obtained from biodiesel industry is called crude glycerol (CG) since it is mixed with the impurities like catalysts, salts and fatty acids. Use of vegetable oils as a source of triglycerides for biodiesel production competes with the human food chain. Keeping this in mind many research studies took place to use non-edible oilseeds, waste oils, byproducts of the slaughter house, algae etc., as an alternative source of triglycerides. Many changes and improvements have been adopted in the method of extraction process by using different types of catalysts, enzymes, alcohols, different temperature and pressure combination to decrease the cost involved