ExoticsCon — Building Better Birds!
Veterinarians and vet techs who are deeply involved with birds, small mammals and reptiles flocked to Portland, Oregon, in the summer of 2016 for the ExoticsCon Veterinary Conference. There is an excitement to learn new things and new thinking that I would like to share. The first area that I think is important is that we vets are seeing a large increase in our pet birds with metabolic bone disease. Now you say: “But I feed my bird all kinds of great foods.” And that has certainly helped our companion birds lead longer lives and is very important. But one thing that is sitting out there quietly — and that is literal in this case as well — is metabolic bone disease. And what it is and why is that becoming a problem, you ask?
Metabolic bone disease is a general term for any noninfectious problem of the bone that causes a reduction in bone mass. Bone is composed of cells and an extracellular matrix that is firm, which produces the rigidity of bone. Extracellular material (ground substance) contains glycosaminoglycans (GAG), fibers and structural glycoproteins. But bone is under stressors and those stressors influence the cells and the matrix that they produce. Bone is a strong, flexible and semi-rigid supporting tissue. It can withstand compression forces, and yet it can bend. Bone is not static but ever changing due to these stressors and for our discussion — lack of stressors. And in addition to the cells and the matrix with fibers, bone has a very good supply of blood to bring calcium and other nutrients that can be stored — such as calcium for making egg shells in birds.
One form of metabolic bone disease is osteoporosis. Osteoporosis is a loss of structural bone that leads to bone fragility and susceptibility to fractures. Spinal degeneration and/or transient irregularities in intracellular calcium metabolism may lead to the abnormal muscle activity and paralysis seen with this disease. In chickens, this was described as cage layer paralysis due to chickens being cage-bound and not walking or flying to build bone strength. Common boney abnormalities of chickens with cage layer paralysis include an S-shaped keel, rib deformities (swollen vertebral-sternal junctions) and thin and easily broken bones. Vertebral fractures and damage directly to the spinal cord are likely what results in the paralysis that derives it term cage layer paralysis.
According to Dr. Scott Echols in his paper on Metabolic Bone Disease, he says that “Birds that tend to not fly much have generally poor bone density along the thoracic girdle (coracoid, furcula and proximal humerus) and distal neck/proximal notarium vertebrae. Birds that tend to not walk or climb much generally have poor bone density along the synsacrum, proximal femurs and sometimes extending down the legs. Birds that tend to not walk or fly much have the aforementioned deficits plus a more generalized radiolucency along the entire spine. That means the vertebral column and the bones of the wings and legs lose their mass and are very fragile.”
There are several factors that may help with this problem of osteoporosis. One factor is diet. Deficiencies of phosphorus, calcium and cholecalciferol have been shown to result in osteomalacia or softened bones. All-seed diets are deficient in calcium and cholecalciferol. But avoiding osteomalacia has not been shown in chickens at least to reduce the incidence of osteoporosis. Particulate forms of calcium in chickens appears to improve their bone density. It is thought that particulate calcium remains in the gut longer (than do powders) and is more consistently available through the day and/or night for egg shell production.
According to Scott Echols, DVM, Dipl. ABVP (Avian), seed-based diets “… are generally considered to be nutritionally inadequate for long-term health. How exactly seed-based, pellet-based, fruit- and vegetable-based, combination and more diets relate to bone development and, more interestingly, long-term bone maintenance for captive birds is not exactly clear. Unfortunately, the general recommendation of feeding an appropriate diet (often consisting of a species-formulated pellet-based diet plus added vegetables and some fruits) for captive parrots (and other species) is currently the most common advice avian veterinarians give concerning captive parrots. The appropriate diet must be considered not only for the species in question, but also that animal’s lifestyle, health status and more. There is no one magic diet.”
One recommendation that Dr. Echols made was to make sure that the diet has balanced omega fatty acids. He pointed out that most commercial bird foods are made from corn and soybean components, and these diets are typically high in omega-6 fatty acids (O-6 FA). On the other hand, balanced diets with the omega 3 fatty acids (O-3FA) are important for bone health. The O-3 FAs reduce the concentration of arachidonic acid and subsequent production of PGE2, which is pro-inflammatory for the body, including bone. However, the opposite is true with O-6 FA as that increases the PGE2s, resulting in a stimulation of bone resorption. That is not what we want to happen! The Lafeber foods, including Nutri-Berries, Avi-Cakes and Senior Nutri-Berries, are balanced nutritionally, and the O-3 and O-6 fatty acids are balanced as well.
Dr. Echols said that “for granivores, seed-based diets are typically high in phosphorus and/or low in calcium and are likely the most common dietary cause of low grade MBD. Additionally, research supports that diets either high in O-6 fatty acids and/or low in O-3 fatty acids may be another risk factor for osteoporosis and other forms of MBD.”
So it appears that we need to pay attention to not only the balance of various components of the diet including the minerals but also the balance of omega fatty acids. And according to Dr. Echols — another big factor is EXERCISE! His work using “radiographs and CT shows that in our companion birds inactivity does seem to play a role in avian bone density.” Dr. Echols pointed out that “The obvious remedy is to increase bone-loading activities such as flying, climbing and walking for pet birds. This can be accomplished by providing larger space, creating an environment that encourages movement (e.g., foraging, outside play time, flight training) and even forced exercise (e.g., moving the food and water bowls away from the bird, training the bird to flap or perform various activities). What is not clear is just how much activity (and for how long) is needed to improve structural bone formation.”
My next column will take a look at Dr. Ken Welle’s approach to flying his birds, as well as other information from the conference. Stay tuned!