Levels of dry distiller grains in feedlot diets: performance, carcass traits and beef quality

Abstract

A option that has been highlighted recently are the distillers grains with solubles (DDGS), it has emerged as an option in Brazil as a result of the start of ethanol production from corn. Brazil is a major producer of grains, especially corn, the use of grain for the production of ethanol becomes an interesting opportunity, being very efficient process, it is only less efficient than sugarcane efficiency use to ethanol produce. From one ton of corn is possible to produce 400 liters of ethanol while from a sugar cane ton are produced about 85 liters of ethanol, however sugarcane production in tons per hectare is much higher than that observed with corn. The energy efficiency of conversion of glucose to ethanol is about 51.4%, while 48.6% is attributable to carbon dioxide production. Furthermore, ethanol production from corn has some advantages due to the lack of need for processing soon after harvest, which does not occur with sugarcane, which needs to be processed within 24 hours after harvest. Moreover, the production of ethanol from cereals such as maize is a strategy to drain the excess production of the grain. Thus corn seems to be an interesting option for the off-season of sugarcane. The production of ethanol from corn generates byproduct dry distillers grains with solubles (DDGS), and for each 3.8 liters of ethanol produced 2.4 kg of DDGS are generated. Soybean meal, which is the protein feed commonly used in beef cattle diets can present high cost, therefore, the study of alternative protein sources is of great importance to the beef cattle production. The goals of this project will evaluate the effects of inclusion of dry distillers grains in diets with ground corn, on dry matter intake, performance, carcass traits, beef quality, fatty acid profile, lipid oxidation and expression of genes related to lipid metabolism. Will be used 100 animals, intact males F1 Angus-Nelore with average initial weight of 360 kg. The animals will be kept in concrete floor pens with water dispenser, having a capacity of five animals per pen. The diet will be formulated according to the LRNS software. The animals will be randomly allocated to treatment with different levels of DDG (0, 15%, 30% and 45% of dietary DM) in diets containing 80% concentrate and 20% roughage. The animals will be stunned by cerebral concussion, suspended, and bled through the jugular vein, followed by removal of leather and evisceration. Carcasses will be identified, washed, divided into two halves, which are individually weighed and taken to the cold room for approximately 24 hours at 1 ° C temperature. The measurements in the carcasses will be: hot carcass yield, hot carcass weight, cold carcass weight, ribeye area and backfat thickness, the latter being measured after cooling. At boning on 24h post mortem, Longissimus dorsi muscle samples will be collected from left half of carcass in order to perform the physico-chemical analysis (color, weight loss by cooking and shear force), chemical composition, fatty acid profile and lipid stability. The samples that will be subjected to analysis of shear force, color and cooking weight loss will be packed in plastic bags and frozen at -16 ° C. A sub-sample of LD will be stored under vacuum, also in polyethylene bags in temperature of 3 ° C for 0, 7, 14 and 21 days to determine the color and lipid stability. The samples to be subjected to gene expression analysis will be collected immediately after slaughter and kept at -80 ° C. (AU)