| 【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 100-200 μm （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/m2
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. |
