Effects of the immune system on metabolism: implications for production and disease resistance in livestock

Author: Colditz, I.G.

Description: The immune system provides host defence by sensing non-self molecules that herald a threat from foreign organisms. A level of stimulation of this sense organ is necessary for health of the host. Following excessive stimulation, as may occur during disease challenge or exposure to a high microbial burden in an unhygienic environment, outputs of the immune system affect homeostatic pathways that regulate metabolism, nutrient partitioning, behaviour, thermoregulation and hypothalamic-pituitary-adrenocortical (HPA) activity. Important consequences of excessive immune activation include production of the pro-inflammatory cytokines IL-1B, IL-6, TNFa, and IFNa/B, activation of the acute phase response, fever, inappetence, amino acid resorption from muscle, redirection of nutrients from accretion in meat, milk and wool towards liver anabolism of acute phase proteins, and stimulation of leptin production. Thus immunological resistance to disease in livestock may incur a production cost due to redirection of nutrients away from production tissues. Counter-balancing the cost of resistance is the metabolic cost of disease. The metabolic costs of resistance to internal parasites in sheep are considered. Genetic variation in the cost of disease resistance could occur due to (1) variation in sensitivity to input stimuli that trigger immune responses or (2) variation in the quantity or type of output signals generated following immune stimulation. Downstream sensitivity of tissues to outputs of the immune system could also differ. The ideal product to monitor the burden imposed on metabolic pathways by activity of the immune system would be unique to innate and acquired immune responses. Acute phase proteins and pro-inflammatory cytokines have attracted attention in this respect; however, non-immunological stimuli such as tissue injury and psychosocial stressors can also induce these products that are usually associated with the immune system. Immunonutritional and therapeutic strategies to limit the production costs of excessive activation of the immune system are considered.

Subject headings: Acute phase response; Metabolic cost; Immunonutrition; Cytokines; Disease resistance

Publication year: 2002

Journal or book title: Livestock Production Science

Volume: 75

Issue: 3

Pages: 257-268

Find the full text : https://www.sciencedirect.com/science/article/abs/pii/S0301622601003207

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Type: Journal Article

Serial number: 3022