2013-06-04 19:19:45
Each year, the adult male deer sheds his antlers and begins to grow new ones. Shedding its antlers requires enormous energy expenditure for the animal because it is equivalent to creating almost a third of the total weight of its skeleton. Antler growth is very rapid, 1 cm/day for the Iberian deer and up to 4 cm/day for the American elk. Maintaining the rhythm requires the continuous supply of calcium and minerals essential for the formation of new bones. Although the diet is abundant, it is not possible for the animal to obtain all the nutrients it needs from the food; an additional supply of calcium is necessary, which it can only obtain by stealing it from the bones of its own skeleton. As a result, the bones weaken and suffer from osteoporosis.
In humans, osteoporosis is a disease that weakens bones, making them brittle and prone to fractures. Little by little, the bone tissue loses calcium salts, becomes less dense and, as a consequence, its entire structure loses solidity and breaks relatively easily when subjected to stress or trauma. Although it can occur in men and women of any age, osteoporosis is more common among women who have lost their menstrual cycle or have entered menopause and in older people.
In deer, however, osteoporosis is a temporary disease. The animal suffers from it while generating a new antler because it extracts the calcium minerals it needs from its own skeleton. When the formation of the new antler is completed, the animal recovers and osteoporosis disappears.
Can the study of osteoporosis in deer help to understand human osteoporosis?
Our guest today on Talking with Scientists, Tomás Landete Castillejos, thinks that the phenomenon of shedding antlers in male deer can be of great help in investigating human osteoporosis. For Tomás Landete, the growth of the antlers is equivalent to the effort that an elite athlete must develop to achieve the goal in his sport. If the athlete is weak or sick, he will not achieve his goal. With this idea in mind, the team of researchers from the UCLM Hunting Resources Institute, to which they belong, together with Tomás Landete, Andrés García and Laureano Gallego, discovered that there are differences in the quality of the bone that forms the antlers of deer. , even when the animals have the same type of diet.
Under normal conditions, the antler is a much stronger bone than any of ours. If our skeleton were made of bones of similar quality, fractures would be very rare and trauma services would not have to go around resetting broken bones so often. We would have a super-resistant skeleton.
However, deer do not always have such high quality antlers. Some years, for unknown reasons, deer’s antlers are so weak that they are relatively common to splinter or break off during battles between males and females during the rutting season. The year 2005 was a very eloquent example of a bad year for deer antlers. In almost all the preserves in Spain, broken or splintered antlers were observed, even though the animals seemed to be in good health and were well fed. What had happened?
Weak and broken antlers.
Analysis of the broken antlers revealed that the bone wall was up to 30 percent thinner than normal among wild deer. On the other hand, the animals raised at the Experimental Deer Farm of the University of Castilla-La Mancha in Albacete did not show any deterioration in the quality of their antlers. The weather that year was particularly severe, with more cold days and abundant frosts during the spring. This led us to think that perhaps the stress caused to the plants could negatively influence the animals that fed on them. On the other hand, those deer that had received a balanced diet on the farm did not present any appreciable deficiencies.
It is known that plants, in response to stress situations (cold, drought or pests), increase the amount of silicon absorbed and modify the concentration of other chemical elements such as manganese. The hypothesis defended by Tomás Landete and his team is that the key is in manganese, due to its role as an intermediary in the fixation of calcium in the bones.
Certain experiments carried out with laboratory rats support this hypothesis. A diet low in manganese causes animals to gain weight but, in turn, their bones are weaker. Research shows that after 12 hours of fasting, a person loses about 12 milligrams of calcium in the blood. The body quickly restores balance by stealing calcium from the bones to balance the concentration in the blood. Osteoporosis sufferers, who have difficulty fixing calcium, literally urinate part of their skeleton.
The hypothesis points to the brain as an organ that, due to its importance, is the recipient of calcium that is stolen from other places in the body. Some studies seem to indicate that the process may have a connection with degenerative diseases such as Alzheimer’s or Parkinson’s. These are, for now, working hypotheses that must be investigated using the scientific method, an investigation that requires economic and material means that, for now, the crisis refuses to provide.
What is clear is that the study of deer antlers can shed light on the understanding of diseases such as human osteoporosis and, perhaps, other degenerative diseases. I invite you to listen to the interview with Tomás Landete Castillejos, ecologist and researcher at the UCLM Hunting Resources Institute.
REFERENCES
Publications by Tomás Landete Castillejos
Federation of European Deer Farmers Associations
EMAD European Meeting on Antlers and Deer
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