Digestible and metabolizable energy of crude glycerin for finishing pigs

The aim of this study was to determine the values of apparent digestible energy (DE) and metabolizable energy (ME) for crude glycerin derived of biodiesel based on pork fat for finishing pigs. The diets consisted of a basal diet and four levels of crude glycerin (0, 5, 10 and 15%). Twelve pigs were housed individually in metabolic cages and after seven days of adaptation, total collections of urine and feces for four consecutive days were performed. Gross energy (GE) of crude glycerin, diets, urine and fecal samples from each animal was determined. The crude glycerin used in this experiment presented 74.74% glycerin and 6,500 kcal kg-1 gross energy. The values of digestible energy (DE) and metabolizable energy (ME) were estimated by difference in the DE, and content of the basal diet was subtracted from the test diets containing the ingredient. The amount of GE, DE and ME for finishing pigs was 6,500, 5,839 and 5,509 kcal kg-1, respectively, with a coefficient of 91.0% of DE and 94.0% of ME. The energy of crude glycerin is based on the levels of fatty acids and GE depends on the concentration of fatty acids and glycerin, ME being a percentage of GE averaging is 84.75%.

本研究旨在测定以猪脂肪为原料制备的生物柴油副产物粗甘油（crude glycerin）用于育肥猪（finishing pigs）时的表观消化能（apparent digestible energy, DE）与代谢能（metabolizable energy, ME）数值。试验日粮包含1种基础日粮（basal diet）及4个梯度的粗甘油添加组，添加比例分别为0、5、10和15%。选取12头育肥猪，单笼饲养于代谢笼（metabolic cages）中，经7天适应期后，连续4天收集全部尿液与粪便样本。分别测定每头受试猪的粗甘油、日粮、尿液及粪便样本的总能（gross energy, GE）。本试验所用粗甘油的甘油含量为74.74%，总能值为6500 kcal·kg⁻¹。本研究通过差减法估算粗甘油的消化能与代谢能：将添加粗甘油的试验日粮的能值减去基础日粮的对应能值，从而得到粗甘油的消化能与代谢能数值。育肥猪对该粗甘油的总能、消化能与代谢能分别为6500、5839和5509 kcal·kg⁻¹，其消化能转化率为91.0%，代谢能转化率为94.0%。粗甘油的能值与其脂肪酸含量相关，总能值取决于脂肪酸与甘油的浓度，代谢能占总能的平均比例为84.75%。