Inclusion of exogenous enzymes to feathers during processing on the digestible energy content of feather meal for adult dogs

ABSTRACT This study was conducted to determine the coefficient of total tract apparent digestibility (CTTAD) of nutrients and gross energy (GE), metabolizable energy (ME), coefficient of metabolizability of gross energy (CM of GE), and fecal characteristics of dogs fed diets with two levels of feather meal, with or without addition of an enzyme blend containing lipase and protease activity. Ten adult Beagle dogs (aged between 1 and 2 years and weighing 10.2±1.4 kg) were arranged in a 5 × 3 incomplete Latin square design with five treatments and three periods. The extruded basal diet was provided in equal amounts to all dogs (220 g/d), and 7.5 and 15% of hydrolyzed feather meal without enzymes (HFM) or HFM processed with addition of the enzyme blend (HFM EB) was added on top of the basal diet just before feeding. The contrast analysis showed that inclusion of 7.5 or 15% feather meal negatively affected CTTAD of crude protein (CP), GE, and ME of the diets with no apparent effect of the enzyme treatment. However, when both feather meal samples were evaluated, the HFM EB resulted in better CTTAD of GE and CM of GE (0.774 vs. 0.666) than HFM without enzymes (0.670 vs. 0.567), respectively. There was no effect of either feather meal on fecal score. Regression analysis showed that the enzymes added to the feathers during the digestion process increased digestible energy by 600 kcal/kg of dry matter in the diet containing HFM EB. High-performance liquid chromatography (HPLC) analysis demonstrated that feather meal had a low molecular weight, with about 95% of the molecules below 10,000 Da. Addition of enzymes during the feather hydrolysis process may improve the energy content of the feather meal when included in diets for adult dogs.

摘要 本试验旨在探究饲喂含两种水平羽毛粉、添加或不添加含脂肪酶与蛋白酶活性的复合酶制剂的日粮时，犬的养分与总能（gross energy, GE）总肠道表观消化系数（coefficient of total tract apparent digestibility, CTTAD）、代谢能（metabolizable energy, ME）、总能代谢率（coefficient of metabolizability of gross energy, CM of GE）以及粪便性状。选取10只1~2岁龄、体重为10.2±1.4 kg的成年比格犬，采用5处理3期不完全拉丁方设计开展试验。所有受试犬均饲喂等量的挤压型基础日粮（220 g/d），并于饲喂前在基础日粮表面添加7.5%与15%的未酶解水解羽毛粉（hydrolyzed feather meal, HFM），或经复合酶制剂处理的水解羽毛粉（HFM EB）。对比分析结果显示：添加7.5%或15%的羽毛粉会显著降低日粮粗蛋白（crude protein, CP）、GE及ME的CTTAD，但复合酶制剂处理未产生明显影响。然而，当对两种羽毛粉样品进行评估时，经复合酶制剂处理的HFM EB组的GE与CM of GE的CTTAD分别为0.774和0.666，显著高于未酶解HFM组的0.670与0.567。两类羽毛粉均未对粪便评分产生影响。回归分析表明，在含HFM EB的日粮中，于消化过程中添加至羽毛粉的酶制剂可使日粮干物质的可消化能提升600 kcal/kg。高效液相色谱（high-performance liquid chromatography, HPLC）分析显示，羽毛粉的分子量较低，约95%的组分分子质量低于10,000 Da。在羽毛水解过程中添加酶制剂，可提升用于成年犬日粮的羽毛粉的能量含量。