高饲养密度对山麻鸭饲养环境和生长性能的影响

Effects of High Stocking Density on Rearing Environment and Growth Performance of Shan Partridge Ducks

【目的】饲养密度是影响畜禽规模化生产以及动物福利的关键因素之一。研究饲养密度对山麻鸭饲养环境、体重、血液内毒素、胫骨及胸腿肌肌纤维发育的影响。【方法】选取180只56日龄山麻鸭雌鸭随机分为低密度组(n=30)、中密度组(n=60)和高密度组(n=90)进行水陆-平养。于试验期第0、20、40 d对各组饲养环境水体中的细菌数、内毒素和山麻鸭体重、血液内毒素进行测定,对胫骨和胸腿肌进行组织形态学分析和基因表达检测。【结果】高饲养密度条件下,鸭舍水池水体中沙门氏菌、大肠杆菌和总细菌数增加5倍以上(P<0.05),水体和山麻鸭血液内毒素增加2倍以上(P<0.05),体重平均降低0.1 kg(P<0.01),并且高饲养密度导致山麻鸭胫骨骨质和髓质厚度下降100-200μm(P<0.05),胸肌肌纤维密度显著上升,直径显著减少,腿肌肌纤维密度显著下降,直径显著增加,炎症因子IL-6表达显著升高,并对肌肉生长关键基因(Myod、Myog和Myh1)的表达产生显著影响。【结论】2.5-5只/m^(2)的饲养密度显著减少了山麻鸭养殖环境中细菌和内毒素的含量,有效促进了胸腿肌和胫骨的发育,为后期通过优化饲养密度、提升山麻鸭生长性能提供了借鉴。

【Objective】Stocking density is one of the crucial factors influencing large-scale production of livestock and animal welfare.The study was carried out to explore the effects of different stocking densities on the rearing environment,body weight,blood endotoxin,tibia and pectoral/leg muscle growth of Shan Partridge ducks.【Method】A total of 180 healthy 56-day-old female Shan Partridge ducks were divided into three groups with different densities:low density group(n=30),medium density group(n=60)and high density group(n=90)for land and water rearing.On the 0,20 and 40 days of the test,the number of bacteria,endotoxin in rearing water,body weight and blood endotoxin were measured,and the tibia and pectoral/leg musclewere studied by histomorphological and gene expression analysis.【Result】Under high stocking densities,the number of Escherichia coli and total bacteria in rearing water increased by at least 5 times(P<0.05),endotoxin in water and duck blood increased by more than 2 times(P<0.05),body weight decreased by about 0.1 kg on average(P<0.01).In addition,high stocking densities decreased the thickness of bone and medulla substances of tibia by 100-200μm(P<0.05),increased density and decreased diameter in pectoral muscle myofibers significantly,decreased density and increased diameter in leg muscle myofibers significantly,and increased expression of inflammatory cytokine IL-6 significantly and had significant effects on key muscle growth genes(Myod,Myog and Myh1)in pectoral/l eg muscles of Shan Partridge ducks.【Conclusion】Stocking density of 2.5-5 ducks/m^(2) deceased the number of bacteria and endotoxin content in the rearing environment and promoted the pectoral/leg muscle and tibia development of Shan Partridge ducks,providing references for improving the growth performance of Shan Partridge ducks by optimizing the stocking density.