Use Of Bone And Muscle For Segragating Wild From Farmed Animals:as Exampled In The Mink

The great demands for wildlife commodities stimulated the booming of wildlife farming. However, populations of wildlife are still declining or maintaining at small endangered level. Utilization of wild populations of endangered species is usually strictly prohibited or restricted by laws, but utilization of farmed raised commodities are legal. This raises a widespread concern that illegally acquired commodities from wild populations might enter legal market in the name of farm origins. Thus discriminating the origin of wildlife commodities are essential for supervision of wildlife farming and ensuring the security of wild populations. However, there have been very limited effective method to achieve this goal. We here propose two novel strategies for origin discrimination of bones and muscles based on the hypothesis that wild animals perform more activity than the farmed ones, resulting in different morphology and density in skeleton, and copy number of mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA) in skeletal muscles. The hypothesis was tested on farmed and wild American minks (Mustela vison).Ten measurements were performed on the femur, tibia and fibula of farmed and wild minks and the effectiveness of15relative indexes for origin discrimination were tested. Results showed all measurements, including femur length (L0), femur volume (Vf), femoral condyle width (Wk), femoral head width (Wt), femoral condyle height (Hk), femoral head height(Hi), femur diaphysis width (Bh,), femur diaphysis height (Bz), tibia length (Lj) and fibula length (Lf) were significantly different between the farmed and wild groups (0<p<0.005). Correct discriminatory rate ranged from87.9%to100%when each of the measurements was used. However, they could be influenced by level of nutrition and sex and are not appropriate to practice discrimination. Femur linear density (T) and femur volume density (D) eliminated the influence of level of nutrition and were highly effective with correct discriminatory rate of86.1%and97.2%. The classification correctness of volume density even reached100%when sex is known.Using real-time quantitative PCR approach, the copy number of mtDNA and nuDNA in five muscles namely namely masseter, head rhomboid muscle, abdominal muscle, vastus lateralis and gastrocnemius were analyzed. The ratio of copy number of mtDNA to nuDNA (Rmt:nu) was significantly higher in farm group than in wild group for the five skeletal muscles (0<P<0.052). Sexual difference of Rmt:nu was only seen in vastus lateralis (p=0.047). Correctness of discrimination ranged from62.9%to79.0%when single muscle was used. This figure reached80.6%when four unrelated muscles were combined, either for masseter-head rhomboid muscle-abdominal muscle-vastus lateralis, or for masseter-head rhomboid muscle-abdominal muscle-gastrocnemius.These results suggest bone volume density and Rmt:nu can be two potential approaches to discriminate the origin of skeleton and muscle. Since these approaches are based on the fact that wild animals performe more and intense activities than farmed ones, these approaches are also potentiall applicable to other species with the same scenario of activity difference.