Low sanitary conditions increase energy expenditure for maintenance and decrease incremental protein efficiency in...

Area of Science:

• Animal Nutrition
• Immunology
• Metabolic Physiology

Background:

• Immune system stimulation affects energy and amino acid requirements.
• Existing research often uses models mimicking clinical conditions, limiting extrapolation to chronic, low-grade immune stimulation.
• Understanding these effects in practical farming conditions is crucial for optimizing animal growth and health.

Purpose of the Study:

• To quantify differences in energy requirements and energy/protein utilization efficiencies in pigs under low (LSC) versus high (HSC) sanitary conditions.
• To assess the impact of chronic, low-grade immune stimulation on pig metabolism.
• To evaluate the effect of supplemental amino acids on these parameters.

Main Methods:

• Pigs were housed in either LSC or HSC environments for two weeks.
• Diets were either basal or supplemented with methionine, threonine, and tryptophan.
• Feed intake was ad libitum in week 1 and restricted in week 2.
• Fasting heat production (FHP), energy balance, and incremental energy/protein efficiencies were measured.

Main Results:

• LSC significantly increased pig FHP by 55 kJ/(kg BW)0.6 per day, irrespective of diet.
• LSC reduced incremental metabolizable energy intake, heat production, and energy retained as protein in response to gross energy intake.
• Incremental protein efficiency was reduced by 20% units in LSC pigs; energy retention as fat was unaffected.
• Dietary amino acid supplementation did not impact incremental energy or protein efficiencies.

Conclusions:

• Chronic, low-grade immune stimulation in pigs, simulated by LSC, elevates FHP.
• Under LSC, the efficiency of nitrogen utilization for protein deposition is decreased.
• The efficiency of absorbed energy for fat deposition remains unaffected by LSC, and dietary amino acid supplementation does not mitigate these effects.