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 本试验旨在探究添加不同水平羽毛粉且添加/不添加含脂肪酶和蛋白酶活性的复合酶制剂的日粮中，营养物质与总能（GE）的全肠道表观消化率（CTTAD）、代谢能（ME）、总能代谢率（CM of GE）以及试验犬的粪便特性。选取10只1~2岁、体重为10.2±1.4 kg的成年比格犬，采用5×3不完全拉丁方设计，设置5个处理组与3个试验周期。所有试验犬每日饲喂等量膨化基础日粮（220 g/只·天），并于饲喂前在基础日粮表面添加7.5%和15%的未添加酶制剂的水解羽毛粉（HFM），或添加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质（CP）、GE及ME的CTTAD，而复合酶处理未产生明显影响。但当对两类羽毛粉样品进行评估时，HFM EB组的GE全肠道表观消化率及总能代谢率分别为0.774和0.666，均优于未添加酶制剂的HFM组（分别为0.670和0.567）。两类水解羽毛粉的添加均未对粪便评分产生显著影响。回归分析结果表明，在消化过程中添加于羽毛的复合酶可使添加HFM EB的日粮以干物质计的消化能提升600 kcal/kg。高效液相色谱法（HPLC）检测结果显示，水解羽毛粉的分子量较低，约95%的分子质量低于10000 Da。在羽毛水解过程中添加复合酶，可提升用于成年犬日粮的水解羽毛粉的能值水平。