First, unnecessary or overly robust immune responses may diminish the rate and efficiency of production. Although it is understood that parasites may lead to malnutrition, the extent to which malnutrition itself causes increased parasite infestation is not clearly known. Vitamin C is not the only vitamin that should be supplemented during periods of stress. There are, however, plausible explanations that remain undocumented. One of the most serious stressors that can confront poultry is disease. This hormone influences the metabolism of the energy-yielding nutrients. Nutritional deficiencies associated with pregnancy are associated with poor immune response to infection.
Bloom and colleagues 12 — 16 have conducted a number of studies to elucidate the principal mechanisms by which murine mononuclear phagocytes kill M.
Now, Bloom and colleagues take us one major step forward by examining the effects of a low protein diet on anti-mycobacterial immunity Interestingly, these changes were observed in the lungs but not in the liver, and the effects wore off after 2 weeks after challenge.
There was no significant effect on total nitric acid production in vivo. Granulomatous inflammation was studied at the light, immunohistochemical, and electron microscopic levels, and was impaired in the low-protein group, confirming and extending earlier observations The immunologic changes and risk of death could be reversed by reverting to a normal high-protein diet. The seminal work of Bloom and colleagues raises many new questions. Are the findings nutrient-specific? Did body weight and lymphoid organ weight differ in the two animal groups?
It is possible that at least some of the observed effects may be the result of concomitant deficiencies of micronutrients such as zinc. It is recognized that inadequate diets result in poor appetite, malabsorption, and decreased growth.
Thus, the consumption and absorption of nutrients that are critical for optimum immune responses e. This confounding variable can be sorted out by including a pair-fed comparison group.
Would the quality of dietary protein make a difference? In general, animal proteins are superior to vegetable proteins in sustaining growth and maintaining immunity; there are subtle differences in immune responses of animals fed casein-based and whey-based diets.
What is the threshold of nutritional deficiency that results in a significant impairment of anti-mycobacterial defenses? What is the explanation for the marked heterogeneity of survival time in genetically similar mice challenged with the same mycobacterial burden?
What is the basis of tissue specificity of macrophage handling of the microorganisms? It has been shown that CD8 T cells specific for listeriolysin O mediate significant immunity in the liver but not in the spleen Is one cell type essential for antibacterial defense at one site but not at another location, as has been shown for neutrophils and Listeria Would deficiencies of other nutrients result in impaired anti-mycobacterial immunity similar to that observed in mice on low-protein diet?
For instance, deficiencies of vitamin A 1 , 21 , 22 and zinc 1 , 23 — 25 alter a wide range of immune responses. Both in small-for-gestation low-birth-weight infants 26 , 27 and in animal models of intrauterine undernutrition or zinc deficiency 28 , 29 , the immunologic impairment is profound and long lasting. What is the status of other immunologic mechanisms that play an important role in defense against intracellular pathogens, e. Neutralizing antibodies 42 , gene knockout mice 43 , and adoptive transfer assays 19 with bone marrow chimeric or transgenic rodent hosts can be deployed to study the specific role of individual immune processes.
What is the impact of genetic host factors on antigen recognition and immunologic defense 44? Finally, it would be useful to confirm the interesting observations reported in the study by Chan et al. There is exciting new information on another face of host—parasite interaction.
Viruses can mutate and show altered virulence because of nutritional deficiencies in the hosts they infect. Beck and coworkers 45 showed that selenium deficiency enhanced the heart-damaging potential of coxsackievirus. Virus strain recovered from selenium-deficient animals was capable of inducting damage in well-nourished animals.
Most interestingly, there were six nucleotide changes between the avirulent input virus strain and the virulent virus recovered from selenium-deficient animals. This report of a specific nutritional deficiency associated with changes in a viral genome and virulence needs confirmation in other viruses and in other nutritional deficiency states.
Moreover, the magnitude and duration of nutritional insult that has the potential to bring about these changes in the structure and virulence of pathogens needs to be defined.
If confirmed, these exciting data will have far-reaching epidemiologic implications and may explain the emergence of novel infectious diseases in populations with endemic nutritional deficiencies.
Our knowledge in nutrition-immunity interactions has opened up exciting possibilities for nutritional intervention for both primary and secondary prevention of infection in high-risk groups.
Nutritional deficiencies are seen often in hospitalized patients. These individuals are susceptible to develop life-threatening opportunistic infections. Recent animal work 46 has highlighted the value of nutrient-enriched diets in improving immune responses and survival following challenge with organisms such as Listeria Figs.
Similarly, a large proportion of the elderly have reduced dietary intakes and low blood levels of various nutrients They are also prone to respiratory infection. Several investigations have shown a correlation between nutritional status and incidence of infection in old age. The results of a few recent intervention trials indicate that modest supplements of micronutrients improve immune responses and more significantly, reduce the incidence of respiratory infection and antibiotic usage In addition, post-vaccination immune responses are higher in subjects given nutritional supplements than in untreated controls.
These observations have profound clinical and public health implications. One group received a feeding formula that was enriched in those nutrients known to stimulate immune responses; the second group received a control formula. Survival was observed, and the number of bacteria in the liver and the spleen were counted.
Histological examination of the liver showed focal areas of hepatocyte necrosis, mononuclear and neutrophilic infiltrate, and apoptotic liver cells in animals fed control formula Upper Right ; the necrotic liver cells appeared fuzzy. Upper Left In contrast, the normal lobular architecture and hepatocyte appearance was preserved in animals on enriched formula. Lower Left The spleen of animals on the control formula showed subcapsular foci of granulomatous inflammation populated mainly by macrophages and paucity of lymphoid follicles.
There was evidence of cellular necrosis. Lower Right In contrast, the spleen of animals fed the enriched formula showed dense mononuclear cell aggregates and absence of necrotic granuloma. The era of nutritional manipulation of the immune system has finally dawned and it brings with it the promise of using diet and nutrition as innovative powerful tools to reduce illness and death caused by infection. We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail.
We do not capture any email address. Skip to main content. Nutrition, immunity and infection: PNAS December 10, 93 25 ; https: Chandra R K Lancet i: Mechanisms of interactions Plenum , New York.
Sodium, chloride, zinc, methionine, valine, threonine, vitamin A, riboflavin, pantothenic acid, pyridoxine, and selenium will have a negative impact on the immune system if they are deficient in the diet. Thus, these are considered essential to proper immune function. One vitamin that has received a lot of attention with respect to its importance to the immune response in poultry has been vitamin E.
This vitamin appears to be an immune system "booster. These prostaglandins are produced in the cells following the oxidation of cellular membranes and are responsible for inhibiting the inflammation and immune response.
Vitamin E prevents oxidation and thus, the production of prostaglandins. It is well known that deficiencies of vitamin E and selenium will inhibit the immune response in poultry. Selenium works with vitamin E in tissues to protect biological membranes from oxidative damage. Zinc is another element that is important in assisting the bird's immune system to overcome a challenge.
Zinc is especially important in wound healing, thymic function and proliferation of lymphocytes. As discussed by Gershwin et al. The main mechanism of the bioactivity of vitamin E is associated with its antioxidant potential in reducing free radical-induced pathology during normal metabolic stress and immune challenge. By controlling the production of free radicals, vitamin E affects free radical-mediated signal transduction events and ultimately modulates gene expression caused by free radical signaling Packer and Suzuk Vitamin E is also very important in preventing fatty acid peroxidation Benedich Fatty acids can act as immunoregulatory molecules that mediate cellular communication, membrane fluidity and second messenger elaboration Klasing ; Watkins Another potential immunoregulatory mechanism that is associated with vitamin E is the modulation of arachidonic metabolism via cyclooxygenase and lipoxygenase pathways Blumberg which lead to the synthesis of prostaglandins and leukotrienes, respectively.
Tracheal lesion severity scores were evaluated four days post-injection challenge with a Massachusetts Infectious Bronchitis live field virus. Tracheal lesion scores decreased in a dose-related manner as dietary vitamin E levels increased. Thus, these data demonstrated the effectiveness of vitamin E supplementation in limiting the severity of disease after a challenge. Disease challenge is only one of the many factors that will have an effect on the nutrient requirements of poultry.
Insufficient nutrient consumption will reduce the effectiveness of the bird's defense mechanisms. Nutritionists must supply enough dietary nutrients and energy to allow the bird to express the desired growth and feed efficiency.
Since the possibility of disease challenge is always present in today's poultry operations, the nutritionist must realize that the bird's metabolism and immune system are constantly adjusting to the stress of environment or disease and nutrient requirements may need to be increased at certain times. It must not be forgotten that even though immune stimulation is essential for any animal to cope with the continual challenge of antigens, it is not without a cost.
For instance, in broilers, immune stimulation is of extreme importance, but continued genetic selection for growth in broilers results in birds that have inefficient immune systems. Immune stimulation is associated with a catabolic response that results in a growth depression. This fact will continually cause a conflict between geneticists and nutritionists. Geneticists are interested in breeding faster growing birds.
Accelerated growth is accompanied by impaired immune systems. Nutritionists attempt to promote immune stimulation realizing that maximal growth may not be attained if birds get sick. As a result it is not surprising that today commercial meat birds express their extremely high growth potential but seem to be more vulnerable to disease.
Keeping this in mind, it must be realized that the acute phase response associated with immune, neurogenic, or non-specific injury will boost the innate immune response rapidly and is associated with catabolism Berczi et al.
Keeping flocks of poultry in excellent immunological health so that they suffer no immuno-depression from any cause, especially nutrition, should be the goal of the company's veterinarian and nutritionist.
Veterinarians and nutritionists working together with the production manager of the flocks make a very strong team, which will be one of any poultry company's greatest assets. Anyone wishing to understand the interrelation between nutrition and immunity has to also understand that the stress response in the bird has an important influence on the above interrelationship.
A three-way interrelationship exists among stress, nutrition, and immunity, and it is because of this that this paper emphasizes all three of these important factors that influence overall poultry performance. The word stress means different things to different people and because of this, stress has been difficult to define.
Stress is brought about by stress-producing factors, called stressors. It is important to be able to distinguish between a stressor and stress.
Stress is the nonspecific response that the body of an animal has to any demand made upon it. An animal is under stress when it has to make extreme functional, structural, behavioral, or immunological adjustments to cope with adverse aspects of its environment Curtis A natural environment is composed of various potentially hostile stressors.
Animals that are able to cope with the stressors to which they are exposed are those that will perform best in stressful situations. In nature, stress is the rule not the exception—after all, complete freedom from stress is death Selye Survival depends on the severity, duration, and interaction of the environmental stressors and the animal's physiological and behavioral ability to respond and adapt to them Harvey et al.
Once an animal perceives a stressor, its immediate response is usually behavioral Friend an Dellmeier It will tend to move away from the unpleasant stimulus. Depending on the severity and nature of the stressor, the autonomic nervous system responds, followed by a neuroendocrine response.
These biological responses can eliminate or reduce the potential effects of the stressor by changing either the animal's relationship to the stressor or its perception of the stressor. If these responses are not successful, a pathological state may be induced that can result in decreased performance or a disease state. Many of the problems in the poultry industry today are a direct result of the bird having to cope with one or a combination of stressors in the environment.
Poor management is one of the greatest causes of stress in all types of poultry. The exposure to disease agents, poor nutrition, and exposure to immunosuppressive agents also contribute to reduced performance. Poultry must be managed correctly in order to minimize the effects of stress on their performance and health. Successful identification and correction of problems in the poultry house and in the diet will benefit the bird. This paper will review some of the nutritional factors related to stress in poultry.
Whenever poultry are confronted with physiological stress they have to adapt to the situation in order to survive. This process of adaptation is essential and requires energy. The energy for adaptation comes from the three energy-yielding nutrients: These nutrients are only available from the feed and the nutrient reserves in the animal. During the first stages of stress, poultry will eat less initially, and then increase their feed intake Siegel During stress, nutrients in the feed are not digested and absorbed efficiently, and the animal must rely on the nutrient reserves of the body.
These reserves are very important and help to sustain the animal during the stress. The muscle and liver carbohydrate stores glycogen are immediately called upon to furnish energy. Protein is broken down to yield the glucogenic and ketogenic amino acids which, following deamination, will supply the bird with energy.
This energy from carbohydrate and protein allows the bird to maintain its health and survival. During stress the vital functions of the brain, liver, heart, lungs, kidney, etc. Therefore, the less important functions such as egg production, reproduction, growth, and immunity are set aside to promote the vital functions of the body in stressful situations.
Immediate survival has the number one priority in all animals when they are confronted with a severe stressor. The full genetic potential of the bird for growth and egg production is not expressed during stress. The shift in metabolism during stress favors fat deposition. This is contrary to what is happening to protein and glycogen stores in the bird, but carcass data muscle depletion and fat accretion confirm that muscle protein declines and fat deposition increases Nagra and Meyer ; Bartov et al.
During stress the consumption of water increases as a result of the necessity to clear the additional uric acid excretion arising from protein breakdown Siegel and Van Kampen The increased water consumption is also probably necessary to maintain osmolality in the body fluids due to the increased sodium retention concurrent with the effects of corticosterone Holmes and Phillips Corticosterone is the main stress hormone that is produced and released from the cortex of the adrenal gland when an animal is confronted with stress.
This hormone influences the metabolism of the energy-yielding nutrients. Corticosterone is responsible for ensuring that the nutrient stores are allowed to furnish the energy the animal must have in order to cope with the stress. This hormone is responsible for increased use of glucose and amino acids for energy. A high rate of muscle protein synthesis does not occur in the presence of this hormone since the carbon skeletons of the amino acids are used for energy.
Most of the research in Universities and Research Centers conducted to determine the nutritional requirements is done under ideal situations for each species of animal, especially poultry. However, under commercial conditions, ideal environments do not always exist.
Poultry are continually exposed to various stressors that often have a negative effect on their nutritional requirements. Teeter and Wiernusz discussed how new management approaches could be used to allow poultry to cope and adapt to stressful situations. In their review these authors discussed how environmental effects, such as ambient temperature, could have a negative effect on performance and how the bird needed to adapt to high temperatures in order to survive.
Growth rate was sacrificed in order that survival have the top priority. These authors also discussed how the bird was able to respond in growth following a stressful encounter. The daily gain in excess of that observed for non-stressed control animals following a period of stress is commonly known as compensatory gain Teeter and Wiernusz It has been shown that in most stressful situations, the breast muscle of the bird, especially the broiler, is the first muscle to lose protein and the last muscle to rebuild protein to replenish breast mass.
The data presented by Teeter and Wiernusz indicated that the viscera, leg and thigh muscles all have a greater potential for compensatory gain than the breast muscle when a stress-free period follows a period of stress.
Other researchers have shown that the environmental temperature has an influence on the immune response of poultry Beard and Michell ; Donker et al. Siegel and Latimer speculated that the increased activity of the adrenal gland due to heat stress increased the level of serum corticosteroids which resulted in the decreased performance of poultry.
Also, Arjona et al. This adaptation to high temperatures brought about by early exposure has also been reported by Tetter and Wiernusz Thaxton and Siegel reported that the influence of environmental temperature variations on the immune response depends on the degree of adaptation of the animal and the time of immunization. As stated previously, the stress hormone corticosterone is responsible in all physiological stress for the channeling of nutrients and body reserves away from the economically important traits of poultry production to those vital physiological functions necessary for immediate bird survival.
Therefore, any measure of reduction in the release of corticosterone allows nutrients to be used for growth, egg production immune response, etc.
Supplementation of vitamin C in stressful situations has been shown to be of benefit to the animal and has helped to restore some of the performance loss. All poultry are capable of synthesizing vitamin C in the kidney tissue, and because of this, supplementation is often considered by a few nutritionists to be unnecessary. However, the synthesis and use of vitamin C are not constant. The ability of the kidney to synthesize vitamin C in the amount needed changes with age, management, environment, disease, nutrition, and stress.
Some of the highest concentrations of vitamin C in animals can be found in the testicles, ovaries, and adrenal gland. In the adrenal gland, vitamin C functions metabolically to help control the production of the adrenal hormone, corticosterone. Stressors in the environment have a direct influence on plasma and tissue levels of vitamin C. A controlled rate of corticosterone release from the adrenal cortex is preferred in coping with stress. For adrenal cortical depletion of this hormone to occur would result in death of the animal.
Vitamin C plays a central role in the continued synthesis of corticosterone. The proposed mechanism for this effect is through inhibition of the hydroxylase and 11 beta-hydroxylase enzymes in the steroid biosynthetic pathway in the adrenal cortex.
Vitamin C supplementation to the diet and water during periods of stress causes reduced synthesis of corticosterone Brake For best results, the use of vitamin C in the diet or water should begin at least 24 or 48 hours before the onset of stress and should continue throughout the stressful period. The recommended amount of vitamin C to use in the diet is usually between and ppm. Higher levels can be used, but are often cost prohibitive. Vitamin C is not the only vitamin that should be supplemented during periods of stress.
Research has shown that all vitamins should be increased in the diet if the stress level in poultry is high.