Study On The Effectiveness Of Leg Bone CT For Discriminating Wild From Farmed Ring-Necked Pheasant

China is a major country in the commercial breeding of wild animals and hundreds of special livestock and poultry derived from wild animals and non-edible wild animals can be farmed,managed and used according to law.At the same time,the Chinese government continuously strengthens the protection of wild resources and strictly regulates their use.However,there are often criminals who mix illegally hunted animals in the wild into the legal market under the guise of breeding to make huge profits.The ring-necked pheasant belongs to such a species,which was listed as a special poultry in 2020.Beneficial animals with important economic value and important scientific research value（such as wild animals）are protected by law,while illegal acts of poaching and illegal use occur from time to time.Therefore,the accurate identification of wild and farmed ring-necked pheasant has become a key requirement to protect law enforcement and maintain the normal order of the breeding industry.However,there are no available identification techniques.In this study,CT technology was used to analyze the differences of leg bone morphology and density between wild and farmed ring-necked pheasants,and to explore the possibility of establishing a non-injury identification method.The tibia and tarsus of wild（n=55）and farmed（n=50）ring-necked pheasant were scanned and 3D reconstructed by 16-slice spiral CT in this study.Length(L_tibia、L_tarsus),middle cross-section area（S₁）,area of the upper middle section hollow area（S₂）,bone density index（CT value,HU）and tibial actual volume(V_actual)were determined.Then,the ratio of tibia(L_tibia/L),bone dense area ratio（S₁/S）,relative volume（V/L）were constructed,and the difference between the two groups was tested by independent sample T-test.The results showed that these indices of tibia and tarsus were significantly different between the wild group and the farmed group（P<0.01）.Using these indices,15 index combinations were constructed which were not affected by body shape.Then the index combinations with a discrimination power higher than 80%were screened.Among them,“S_1tibia/S_tibia”、“HU_tibia+HU_tarsus”、“L_tibia/L+S_1tibia/S_tibia+S_1tarsus/S_tarsus”、“L_tibia/L+HU_tibia+HU_tarsus”、“S_1tibia/S_tibia+S_1tarsus/S_tarsus+HU_tibia+HU_tarsus”、“HU_tibia+HU_tarsus+V/L”、“Ltibia/L+S1tibia/Stibia+S1tarsus/Starsus+HUtibia+HUtarsus”are better.When gender was ignored,the combination of three indices“Ltibia/L+S1 tibia/Stibia+S1tarsus/Starsus+HUtarsus+HUtarsus”had the highest discrimination.The discrimination can reach 97.1%.These results indicate that the length,cross-sectional area,bone density,volume and other indexes based on leg bone CT can be sensitive to reflect the difference of leg bone between wild and farmed ring-necked pheasant,and which can be used to identify the origin of ring-necked pheasant.CT is an effective technology to excavate the information of bone differences between wild and farmed animals and a non-invasive source identification method can be established based on CT technology.