肉仔鸡日粮中不同形态锰源的相对生物学利用率评定

为评价肉仔鸡日粮中不同形态锰源的相对生物学利用率,采用2×5完全随机试验设计,选择玉米—豆粕型基础日粮(锰含量为37.66mg/kg),添加2种锰源(复合氨基酸螯合锰和硫酸锰)和5个锰添加水平(0、45、90、130、180mg/kg),构成10个日粮处理组,将540只1日龄健康艾维茵肉仔鸡随机分为10个处理组,每个处理组3个重复,每个重复18只鸡,公母各半,开展为期42d的肉仔鸡饲养试验。分别于21、42日龄时,取各组试验鸡的肝脏、肾脏及左侧胫骨,采用原子吸收分光光度计测定肝脏、肾脏组织以及胫骨的锰浓度。将各组织锰含量与日粮锰进食量进行多元线性回归方程拟合,采用斜率比法计算复合氨基酸锰相对无机硫酸锰的生物学利用率。结果表明,饲粮中添加锰可显著增加肝脏、肾脏和胫骨锰含量,尤以胫骨锰含量反映最敏感,呈明显的剂量效应(P<0.01);相比肝脏锰和肾脏锰含量,21日龄胫骨锰含量可作为评价锰利用率的有效指标;采用斜率比法估测的复合氨基酸螯合锰的相对生物学利用率要略高于饲料级硫酸锰。研究结果为有机锰添加剂在禽生产上的合理应用提供了基础数据。

Evaluation of Relative Bioavailability of Different Dietary Manganese Sources in Broilers

In an attempt to assess the relative bioavailability of different dietary manganese sources in broilers, an experiment was conducted using a completely randomized design 2×5 factorial arrangements. A total of 540 healthy one-day-old Avian broilers were assigned randomly into one of ten dietary treatments of 3 replicate cages each with 18 chicks per cage, and fed a basal corn-soybean meal diet (containing 37.66 mg/kg of Mn) added with 0, 45, 90, 130, 180 mg of Mn/kg from a compound amino acid chelate manganese preparation or the basal diet supplemented with 0, 45, 90, 130, 180 mg of Mn/kg from MnSO4·H2O. The feeding experiment lasted for 42 days. At 21 and 42 days of age, the liver, kidney and left tibia tissue samples of the experimental broilers were collected and the Mn concentrations in these tissues were determined by using atomic absorption spectrophotometer. The multiple linear regression fitting between Mn content of different tissues and dietary Mn intake was performed, and the relative bioavailability of compound amino acid chelate manganese to inorganic MnSO4 was calculated with slope ratio method. The results showed that dietary supplementation of Mn obviously elevated the Mn concentration in liver, kidney and tibia in broilers, and the most susceptible response was observed in tibia, exhibiting an obvious dosage effect (P<0.01);compared to Mn concentration in liver and kidney, the Mn content in tibia of broilers aged 21 days was considered as an effective evaluating index for bioavailability of Mn;the relative bioavailability of compound amino acid chelate manganese estimated with slope ratio method was found slightly higher than that of feed grade MnSO4. Our results provide basic data for the rational utilization of organic manganese additive in poultry production.