The Gut Microbiome: It’s Role in Health
In the mid-2000s, Dr. Sokol, a gastroenterologist for humans at St. Antoine hospital in Paris, did a comparative DNA analysis for patients with chronic inflammatory bowel disease. He found that in the diseased section of bowel, there was a relative depletion of a common bacterium, Faecali bacterium. Instead of thinking that this disease was a consequence of bad microbes, he suggested that maybe it represented the loss of good microbes. He, like others, has since found that these good bacteria stimulate receptors along the gut lining to enhance the immune system.
It appears that there are a select group of microbes that are important for gut health and hence a balanced immune system. These microbes belong to a group of what are termed clostridial clusters. While they are distantly related to Clostrium difficile, they appear to be responsible for keeping the gut lining healthy and the barriers of the GI tract tight. Clostridum difficile, on the other hand, causes inflammation of the gut wall and can result in bleeding and loss of fluids to the point of death.
But good microbes appear to occupy a particular ecological niche in the gut lining. They are thought to interact with the immune system, keep bad microbes in check, provide nutrients for cells of the gut, and digest or ferment fiber to help to keep the mucus layer functioning correctly.
The Role of Antibiotics
One of the interesting talks at the meeting focused on the use of antibiotics. In the study presented, the microbiome of healthy dogs was compared with dogs that had inflammatory bowel disease; as you might guess, they were dramatically different. What was most striking was that the standard antibiotic therapy that was used caused further changes in the microbiome. The microbiome only slowly got closer to normal over time, and even then with the use of a microbiome product designed to shift the organisms to the “good” microbes and to healthy immune function in the gut. Studies suggest that the proper mix of microbes contributes to health and reduces inflammation, while the relative absence of good bacteria or an overrepresentation of bad bacteria work against health. The ecology of the gut appears to influence obesity, overall immune response, and even mood.
Gut Check: Companion Birds Vs. Wild Birds
So what about our companion birds? We know very little about the microbiomes compared with humans and small mammals. We know that the microbiome of a particular species tends to be different from another species. Gram staining of fecal samples over the past 30 years has shown that the bacteria of our parrots when they are normal consists of large numbers of gram-positive rods and cocci with limited to no gram-negative or anaerobic bacteria. However, parrots are not very far removed from their wild relatives, so the question is, do wild parrots have similar microbiota as those in our homes?
The studies from Dr. Jan Suchodolski’s lab at Texas A&M showed that there was less biodiversity of the microbiome of the wild parrots compared with the companion parrots. For this study, researchers used cloacal samples, not fresh feces. In mammal studies, they have used fresh feces for their microbiome studies so the results may be different. In this study, they used four mealy parrots (Amazona farinosa), three blue-and-yellow macaws (Ara ararauna), and one red-and-green macaw (Ara chloropterus) with one group from a breeding facility in Texas or the Schubot Center at Texas A&M and the other from the wild near the Tambopata clay lick in Peru. Interestingly, in the wild bird group, sequences belonging to three phyla were identified: Firmicutes (84.5%), Proteobacteria (5.5%), and Actinobateria (10.0%); these same species of bacteria were found in different proportions along with Bacteroides (0.2%) in the companion group. While Lactobacillus organisms were common in the companion bird group, they were not found in the wild parrots. While Staphylococcus species were found in the wild birds, they were not found in the companion parrot group. Enterobacteriaceae, which are gram-negative bacteria, however, were found in the companion bird group, but none were found in the wild parrots. There were also some trends as to the microbiome of the species and to the place of housing with the companion birds. These data help us to better understand which species of the microbiome are normal for our birds. It also gives us some clues for future work on enhancing their immune system.
In an ongoing study with researchers in Italy, they have tried the use of a special probiotic called Sivoy on growing chickens and then on young, hand-raised parrots. The Sivoy is a blend of eight different species of bacteria at high levels that are designed to support the immune system. In groups that had the Sivoy, their body weights and body condition were improved compared with the age-matched controls as they grew to weaning. Researchers are looking at components of the immune system to further understand how this product works in birds. Additionally they are finishing the studies on how the microbiome of these groups were affected over time. These data may help with understanding how to treat various disease conditions on our pet birds. By understanding the microbiome and how it is affected with growth and diseases that are difficult to treat, we may improve responses with new ways of looking at these conditions.