消化酶、消化吸收与饲料加工

Digestive enzymes,digestion and absorption and feed processing

动物对饲料的消化吸收是通过消化酶将蛋白质、淀粉和脂肪等物质分解成小分子低肽及氨基酸、麦芽糖、葡萄糖和短链脂肪酸等才被小肠吸收。消化酶对饲料的消化,不仅取决于酶的活性、浓度和添加量;还与温度、pH值、饲料颗粒大小、颗粒表面积大小和饲料熟化度有关,同时应考虑金属离子对消化酶活性抑制和激活的影响。对不同食性和不同生长期的动物消化酶的添加,应根据此动物的特性来选择工艺,对动物本身具有高消化吸收率的组分,不必参与膨化处理,对消化吸收率不高的组分则反之,以获得经济的加工成本。幼小动物因体内消化酶不足,应适当增加体内短缺的消化酶用量;对幼苗期变温动物饲料,宜对蛋白质和淀粉类物料先粉碎、膨化、配料和混合、体外消化酶预处理及湿法超微粉碎到(1~2)μm,再制成(50~100)μm的全价微粒。

Animal digestion and absorption of feed is a process in which substances such as protein,starch and fat are broken down into small molecules of low peptide,amino acids,maltose,glucose and short-chain fatty acids,etc.,and then absorbed by small intestinal mucosa by digestive enzymes.Activity of digestive enzymes of feed depends not only on the activity,concentration and amount of enzymes added,it is also related to temperature,pH,size and surface area of feed grain,and degree of feed maturation,etc.Meanwhile,different metal ions also inhibit or activate the activity of digestive enzymes.For the addition of digestive enzymes to animals of different diets and different growth periods,the process should be selected according to the characteristics of the animal.The components with high digestion and absorption rate for the animal itself do not need to participate in the expansion process,and the components with low digestion and absorption rate are on the contrary to obtain economic processing cost.The amount of digestive enzymes in young animals should be increased due to the deficiency of digestive enzymes in the body.For fish feed at seedling stage and the beginning of winter and spring of poikilothermic animal,it is better to crush protein and starch material to 1-2μm by grinding,expanding,mixing,pretreatment of digestive enzyme in vitro and ultrafine grinding by wet method,and then to make 50-100μm full valent particle.