19 (kun halve delen) Flashcards
How does the Nutrition influence the Animals ability to resist againt Infectious diseases?
Nutrition may influence the:
- the structure and/or function of the cells of intestine
- size of villi, enzyme activity etc.
- Intestinal microflora
- the effect can be negative or prositive (pre- and probiotics)
- The immune response ability as:
- Colostrum: passive immunity
- Nutrients: energy, amino acids
- Antigens: allergic reactions
- Stimulation: e.g. arginine, glutamine
Feed components:
- Nutrients: values of demand are defined:
- Carbohydrates
- lipids
- amino acids
- macro - and microelements
- vitamins
- Nutraceuticals: Values of demand are not defined:
- antioxidants
- antimicrobial materials
- oligosaccharides
- enzymes, emulgeators
- taste materials
- coloraing agents, etc.
Key players - specific nutrent and dieatry components includes:
- arginine
- glutamine
- selenium
- omega-3 (n-3) fatty acids:
- eicosapentaenoic acid [EPA]
- docosahexaenoic acid [DHA])
• the omega-6
- gamma-linolenic acid [GLA]
• nucleotides
• antioxidants
have been implicated for their potential to modulate the metabolic response to surgery or stress by enhancing immune function.
Glutamine
- primary fuel for enterocytes, lymphocytes and macrophages
- conditionally essential amino acid during metabolic stress
- a substrate for gluconeogenesis, and may be oxidized for fuel for rapidly proliferating cells
- a precursor for renal ammoniagenesis, the process by which ammonia is excreted from the body
Glutamine and the cells of the immune system:
- T-myphocytes:
- proliferate in response to antigenic stimuli
- produce cytokines essential to the propagation of the immune response
- up-regulate specific cytokine receptors on the T-cell surface, which will further enhance rates of proliferation
- concentration of extracellular glutamine appears to regulate T- lymphocyte proliferation, the rate of interleukin (IL)-2 production and IL-2 receptor expression
- Macrophages:
- terminally differentiated cells
- destroy foreign material via exposure to free radicals and hydrolytic enzymes, antigen presentation to T-lymphocytes (in association with MHC II molecules) and activation of lymphocyte subpopulations via cytokine secretion
- macrophage activation [via exposure to lipopolysaccharide (LPS)] leads to a significant increase in glutamine utilization
- enhanced rates of glutamine utilization:
- –> is to satisfy the large demand for arginine by activated macrophages enhancement of cytokine production (IL-6, TNF-α, IL-1β, IL-8)
- Neutrophils:
- respond to glutamine addition by increasing their phagocytic activity and rate of production of superoxide
Arginine
- conditionally essential amino acid during metabolic stress
- precursor for many compounds within body
- required for normal T- and B-lymphocyte and macrophage functions, and can be metabolized and utilized in collagen production by way of proline synthesis
- Arginine stimulates secretion of
- growth hormone,
- insulin, and glucagon
Arginine can be metabolized to
- nitric oxide, thereby altering blood flow, angiogenesis, epithelialization, and tissue granulation
Arginine
- IN safety
- the safety of its use – specifically relating to arginine among septic patients
- Theories:
1. Sepsis results in arginine deficiency and supplementation may improve
septic state
- Sepsis is caused by excess nitric oxide (NO) production. Since NO is the end- product of arginine metabolism that causes vasodilation, arginine supplementation may exacerbate the septic syndrome
- Arginine infusion among septic medical and surgical patients does not cause hemodynamic instability
Omega-3 fatty acids
- immunosupressive by reducing the production of the pro- inflammatory omega-6 fatty acid, arachanonic acid
- EPA and DHA are postulated to reduce macrophage adhesion, alter T- cell proliferation, and stabilize the cytokine response
Arginine and n-3 fatty acids
- arginine and n-3 fatty acids may synergistically improve immune function with:
1. arginine delivery improving cytokine and nitric oxide production
2. n-3 fatty acids reducing proinflammatory eicosanoid production
3. increasing arginine availability by decreasing expression of arginase I, an enzyme responsible for degradation of arginine
Omega-6 fatty acids
• Arachidonic acid: pro-inflammatory eicosanoids, prostaglandins, leukotrienes, and thromboxanes.
Nucleotides
• nucleotides in structural integrity of DNA and RNA, and involvement in the transfer of energy and coordination of hormonal signals, they are often added to IN formulas intended for use during times of stress and/or rapid tissue proliferation
Antioxidants
Antioxidants, including vitamins C and E, beta-carotene, and selenium are often added in an effort to reduce oxidative stress among patients with acute metabolic stress.
Vitamins and microelements
Vitamins:
- Vitamin B-complex
- Vitamin C
- B-carotene and Vitamin A
- Vitamin D
- Vitamin E
Microelements:
- Se
- Cu, Zn, Fe
Vitamin B complex
Vitamin-Bcomplex:
- The B complex supply is necessary for the normal immune functions
Most important is the:
- vitamin B6:
- chronic inflammation will trigger tryptophan degradation and pyridoxal 5’-phosphate (PLP) loss, which increases the requirement of vitamin B6
- Effects both the humoral and the cellular immune response
- Decreased intake causes: limphocytopenia, the antibody and IL-2 production drops
Vitamin C
- Neutralizes the auto reactive and immune suppressive oxidants (disengaged from the phagocytes)
- In absence of vitamin-C:
- the bacteria killing and moving ability of the neutrophyls and macrophages decrease,
- the cell mediated immunity drops
- Vitamin-C requirement increases in case of:
- wound healing
- infectious diseases
- cancerous states
