Intestinal health is essential to maintain efficient and sustainable functioning of the gastrointestinal(GI) tract within its physiological parameters. Preserving the digestive, absorptive, metabolic, immunological and endocrinological functions of the GI tract. Therefore, any alteration regarding intestinal health can seriously affect one or several systemic functions. Hampering overall animal health and negatively impacting productive yields.
This topic has gained great interest in poultry production within the past two decades due to increasing demands related to: economic efficiency, animal welfare levels, food safety, and the reduction of environmental impacts associated with animal production. There is no doubt that healthy avian guts are essential for the development of sustainable and efficient poultry production systems.
Nutrinews International had the opportunity to speak with Dr. Edgar Oviedo about intestinal health in poultry and how to approach it from a holistic view. Dr Oviedo is a professor at the Prestage Department of Poultry Science at North Carolina State University, as well as being one of the technical directors of NutriNews International magazine.
The following publication contains the second part of our interview with Dr. Oviedo.
NutriNews International: You spoke about feed quality and the importance of quality ingredients. Could you tell us a little bit about why water quality must be considered as important factor when talking about gut health and what aspects must be taken into account to assure water quality? Why is water deprivation something that must be looked after, and completely avoided when trying to preserve intestinal health?
Dr. Oviedo: As we know water is the nutrient that passes through the intestine even more frequently than feed. Animals and humans consume almost 3 to 4 times more water than feed. Therefore, water volume really impacts many intestinal functions, as well as impacting: microbiota, enzyme concentrations, and acids found within the GI tract. It is known that some of the physical properties of water like pH, and salt concentrations have a buffering effect in the crop and even in the gizzard at the proventricular level, affecting the animal’s digestion. We can actually buffer and reduce acidity in the foregut within these sections which will hamper enzyme function. Therefore. it is important to maintain pH levels, and reduce the amount of salts that can cause this buffering effect, or the calcium carbonate found in water. Other water contaminants like magnesium sulfate can affect intestinal motility acting as a laxative and modifying the intestinal passage rate. This will have negative impacts on digestibility, as well as causing dysbiosis and creating gut health problems.
Lack of water can cause the most negative effects that we can see on performance. Hence maintaining water pressure in the lines is critical according to the age of the animals. Due to the fact that when nipple systems are used, these require adequate pressure in order for animals to obtain the necessary amounts of water to fulfill their requirements. Otherwise, this will affect their feed intake, and this imbalance between water intake and feed intake can affect nutrient concentrations and their solubility. Which can also result in dysbiosis and intestinal health issues.
On the other hand, excess water supply can also cause issues. It is something you did not ask, but it is worth mentioning. In general, we need to think that animals must be efficient regarding water utilization. Sometimes the changes in pressure in water lines can cause excessive dripping on the litter, which will increase its humidity. Leading to ammonia and housing issues related to air and litter quality. This can also favor the proliferation of certain bacteria, or protozoa like coccidia and others which can be harmful for the animals. Therefore, water management is critical to maintain good environmental conditions and to preserve animals’ intestinal health.
Nutrinews International: That’s perfect. Could you briefly tell us about what types of health programs allow us to establish preventive actions and what biosecurity measures contribute to maintaining high levels of gut health in modern flocks? What tools are there available to measure gut health, and overall gut health status right now? Is it feasible to implement these tools in different productive scales?
Dr. Oviedo: Yes. Let’s start by parts. In regards to the health programs, in general it could be stated that the disease that can have a greater impact on intestinal health is coccidiosis. Thus, the programs to control coccidiosis, include different feed additives like ionophores or other chemical products. There are also other tools like vaccination. Lately, we also have some phytochemicals that can also be used to reduce coccidiosis, or its negative effects. Allowing the bird to obtain immunity against these pathogens without having major health impacts associated with infection. All of these are helpful, and sometimes we require the inclusion of all of them in a program that rotates and helps to maintain a healthier environment. Due to the fact that it is also important to prevent coccidial reproduction in the environment through the management of ventilation and avoiding wet litters like we previously mentioned. Coccidiosis ad Clostridial infection could considered some of the most important intestinal issues. Nowadays we have bacterines which are applied to the breeders and this can help with that control. This type of tool can also help to control Salmonella. In general, the prevention against these pathogens require good biosecurity measures as you mentioned before. The main factor to take into account is to avoid the entry of new strains into the environment were animals are housed. Therefore, having a closed system that limits the entry of people, rodents or other animals that may act as vectors, and reduce the entry of equipment contaminated with fomites, is essential to preventing any health issues. The quality of the feed ingredients is also very important. Making sure that these ingredients are not contaminated with levels of Clostridium for example. There will always be a certain bacterial load, as well as fungi, but it is expected that their levels are within acceptable limits. Mycotoxin levels must be low and within the acceptable limits. All of this will contribute to preserving the intestinal health of animals.
However, when we talk about health, we must consider all the potential diseases that can affect the flock. Therefore, we must also assure control for Newcastle disease, bronchitis, and even Mycoplasma. Due to the fact that although the animal may be sick with a respiratory infection, this will affect its feed intake, and eventually lead to intestinal health issues also.
You asked about markers for intestinal health right? For many years the industry, scientists and veterinarians have looked at specific ways to evaluate the health status of birds and of the flock. Making assessments in relation to specific diseases, as well as evaluating intestinal health as a whole. Some indexes have been developed in this regard, and as you may know companies have created scoring systems where they check different parts of the gastrointestinal tract through necropsies. So, there are scores for: crop status, gizzard status, and for all the GI tract. There are also scores for coccidia, as well as cecum scores and fecal scores. These scores are useful, and many people have this data. This helps to track what is going on when we see a lot of health issues, and we are able to detect the diseases that are responsible for such health problem sin the flock. So, this is one of the available tools and it has been used since quite a while, but its main disadvantage is that it requires constant surveys through necropsies, which makes it impractical, and it cannot be carried out as frequently as it should in order to have an updated picture of what is going on. For such reasons many scientists have tried to develop analytical tools that correlate blood values, samples from the intestinal tract, as well as histological findings to evaluate intestinal health. Some have also developed methods to analyze metabolites found within the intestine and in feces. However, these analytical methods may not always be the most suitable as they might not be fast enough. Therefore, nowadays the trend is to try and use metabolic sensors that can identify certain metabolites that can be correlated with adequate intestinal fermentation processes. This occurs when there is a good digestibility, and microorganisms produce certain metabolites that can be associated with a healthy gut. The more we can run these methods on excreta, or through cloacal swabs, instead of on necropsy samples will be much better. Right now we are still using the same technologies we used 30 years ago, but we need to advance soon in order to have sustainable and faster methods to evaluate intestinal health.
Nutrinews International: That is very interesting. For our final questions. Could you briefly tell us why is it important to maintain adequate breeder and hatchery conditions, and how is this associated with higher intestinal health levels?
Dr.Oviedo: Well the microorganisms of a newborn or a new hatch in this case depend on the maternal microbiome, that the hen will pass to the chick or poult in the case of turkeys or ducks through the reproductive tract. As we now know that vertical transmission does not only occur with pathogenic bacteria like Salmonella. There is also vertical transmission of beneficial or commensal bacteria that colonize the reproductive tract, and transfer on to some parts of the egg. Contributing to the colonization of microorganisms within the embryo that will help develop immunity against future microbial challenges. There are some bacteria that remain within the pores of the eggshell, and upon hatching the embryo will come in contact with them. If these are pathogenic bacteria, they can create intestinal health issues directly from the hatch. Quite often, if eggs remain in the hatcher for prolonged periods they can become contaminated with pathogenic bacteria like Enterococcus or E.Coli. On the other hand, if we have a beneficial microbiome that is transferred from the hen, this will translate into healthy progeny. If we use too many disinfectants that modify the microflora, this can have negative impact on the progeny. A hatchery with adequate environmental conditions: clean, well ventilated, with the proper humidity to allow a proper development of embryos while avoiding the proliferation of fungi and other pathogenic bacteria, can also benefit the embryo. All of these management practices carried out through the process help the bird to be colonized by healthy microorganisms. The proper nutrition of hens, and their adequate management to reduce stress will also contribute to good gastrointestinal development in chicks and assure a good transfer of immunity. Proper incubation condition will also help the embryo develop a good intestine as well as a whole system of immune and endocrine regulation that will allow it to cope with the challenges that it will face in the farm and in its life post hatch. Therefore, all of these factors, definitely play a significant role in maintaining high levels of intestinal health within the farm.
NutriNews International: That is perfect. Could you just give us your final thoughts regarding the importance of gut health in poultry nutrition and production in general? Why is it important to look at it from a holistic approach? Do you think intestinal health will continue to be a subject of interest within the poultry industry within the coming years, and will continue to strengthen its position as driver of research and innovation?
Dr. Oviedo: As we have discussed through this interview, we have explored many factors involving management, health, nutrition which we mentioned a little bit although this is the main focus of this magazine. There are many aspects to successful nutrition that depend on a holistic management of intestinal health. Including management, good sanitary conditions, adequate biosecurity measures, amongst others. Intestinal health depends on a holistic view of the whole production system, and even considers the previous generations, in order to achieve high intestinal efficiency at the lowest possible cost. Which will also be a success from a nutritional standpoint.
Therefore, this is an area in which we will continue to see greater development and where we will continue advancing because we depend on good intestinal health management to achieve productive efficiency, animal welfare and food safety. Hence, all of these aspects that we have reviewed will end up affecting the sustainability of poultry production. Consequently. Today gut health is considered a central part of One Health. A one Health approach that also includes the environment, and the environmental impacts that we are generating through animal production and how we use nutrients in their feeding. Thus, optimizing the utilization of such nutrients at the intestinal level. Allowing us to move forwards, and that is probably the main focus driving the research that we will see in the coming years.
NutriNews International: Thank your Dr. Oviedo it has been quite an interesting chat. On behalf of NutriNews International we want to thank you, and we hope t: have you back for future webinars and podcasts.