本试验旨在研究β-葡聚糖酶、木聚糖酶、纤维素酶和植酸酶用于肉鸡小麦型饲粮的最佳复合酶谱.采用单因素完全随机试验设计,将不同水平的β-葡聚糖酶(30、60、90、120、150和180 U/g)、木聚糖酶(200、400、600、800、1 000和1 200 U/g)、纤维素酶(200、400、600、800、1 000和1 200 U/g)和植酸酶(500、1 000、1 500、2 000、2 500和3 000 U/kg)分别添加于肉鸡小麦型饲粮中,采用模拟胃肠液体外消化试验,研究单酶的最佳添加水平;据此,采用4因子3水平L₉(3⁴)正交设计和体外法研究4种单酶复配效应,每种酶各设计3个添加水平:β-葡聚糖酶为100、150和200 U/g,木聚糖酶为900、950和1 000 U/g,纤维素酶为900、950和1 000 U/g,植酸酶为1 500、2 000和2 500 U/kg,以还原糖生成量、植酸磷降解率、饲料残渣总能为判定指标,确定4种单酶的最佳复合酶谱.结果表明:1~3周龄肉鸡小麦型饲粮中,当β-葡聚糖酶、木聚糖酶、纤维素酶添加水平分别为150、960、950 U/g时,分别获得最大还原糖生成量0.918、1.161、0.927 mg/g,当植酸酶添加水平为2 010 U/kg时,获得最大植酸磷降解率92.35%;4~6周龄肉鸡小麦型饲粮中,当β-葡聚糖酶、木聚糖酶、纤维素酶添加水平分别为150、950、960 U/g时,分别获得最大还原糖生成量0.920、1.160、0.929 mg/g,当植酸酶添加水平为1 940 U/kg时,获得最大植酸磷降解率92.23%;当4种酶的复合酶谱为β-葡聚糖酶150 U/g、木聚糖酶950 U/g、纤维素酶900 U/g、植酸酶2 500 U/kg时,还原糖生成量、植酸磷降解率、饲料残渣总能均获得较优值.综上,肉鸡小麦型饲粮中β-葡聚糖酶、木聚糖酶、纤维素酶和植酸酶的最佳添加水平,1~3周龄分别为150、960、950 U/g和2 010 U/kg,4~6周龄分别为150、950、960 U/g和1 940 U/kg,且2个阶段肉鸡小麦型饲粮中4种酶的最佳复合酶谱为β-葡聚糖酶150 U/g、木聚糖酶950 U/g、纤维素酶900 U/g、植酸酶2 500 U/kg.

The aim of this experiment was to study the optimal compound enzyme preparation containing β-glucanase, xylanase, cellulase and phytase added into broiler wheat meal diets. The in vitro digestion tests of broiler wheat meal diets added with different levels of β-glucanase (30, 60, 90, 120, 150 and 180 U/g), xylanase (200, 400, 600, 800, 1 000 and 1 200 U/g), cellulose (200, 400, 600, 800, 1 000 and 1 200 U/g) and phytase (500, 1 000, 1 500, 2 000, 2 500 and 3 000 U/kg) were conducted by one factor complete randomized experiment design to determine the optimal supplemental levels. Then the combination effects of the above four enzymes added in broiler wheat meal diets were evaluated by L₉(3⁴) orthogonal design and the in vitro digestion tests, and the supplemental levels were set according to the optimal levels in the first test by β-glucanase (100, 150 and 200 U/g), xylanase (900, 950 and 1 000 U/g), cellulase (900, 950 and 1 000 U/g) and phytase (1 500, 2 000 and 2 500 U/kg). The optimal complex formula of the four enzymes were determined by reducing sugar content, phytate phosphorus degradation rate and the feed residue gross energy. The results showed as follows: when the supplemental levels of β-glucanase, xylanase, cellulase were 150, 960 and 950 U/g, respectively, the maximum reducing sugar contents were 0.918, 1.161 and 0.927 mg/g, respectively; when the supplemental level of phytase was 2 010 U/kg, the maximum phytate phosphorus degradation rate was 92.35% in 1 to 3-week-old broiler wheat meal diets. When the supplemental levels of β-glucanase, xylanase, cellulase were 150, 950, 960 U/g, the maximum reducing sugar content were 0.920, 1.160, 0.929 mg/g, respectively; when the supplemental level of phytase was 1 940 U/kg, the maximum phytate phosphorus degradation rate was 92.23% in 4 to 6-week-old broiler wheat meal diets. When the compound enzyme preparation containing the above four enzymes was 150 U/g β-glucanase, 950 U/g xylanase, 900 U/g cellulase and 2 500 U/kg phytase in diets, the reducing sugar content, phytate phosphorus degradation rate and feed residue gross energy could all obtain better values. In summary, the optimal supplemental levels of β-glucanase, xylanase, cellulase and phytase are 150, 960, 950 U/g and 2 010 U/kg in 1 to 3-week-old broiler wheat meal diets, respectively, and 150, 950, 960 U/g and 1 940 U/kg in 4 to 6-week-old broiler wheat meal diets, respectively. The optimal compound enzyme preparation containing the above four enzymes is 150 U/g β-glucanase, 950 U/g xylanase, 900 U/g cellulase and 2 500 U/kg phytase in diets.