Dietary supplementation with inosine-5'-monophosphate improves the functional, energetic, and antioxidant status of liver and muscle growth in pigs.

Inosine 5'-monophosphate (5'-IMP) is an essential nucleotide for de novo nucleotide biosynthesis and metabolism of energy, proteins, and antioxidants. Nucleotides are conditionally essential, as they cannot be produced sufficiently rapidly to meet the needs of the body in situations of oxidative stress or rapid muscle growth. A deficient intake of nucleotides can result in decreased ATP and GTP synthesis and impaired metabolism. We demonstrated that supplementation of finishing pig diets with 5'-IMP reduces the relative weight of the liver, and increases oxygen consumption during mitochondrial respiration without changing the ADP/O ratio, indicating an increase in the respiratory efficiency of liver mitochondria. We also observed a reduction in liver lipid peroxidation and an increase in muscle creatine. Moreover, 5'IMP supplementation increases slaughter weight, lean meat yield, sarcomere length, and backfat thickness in finishing barrows, demonstrating influence on protein metabolism. We suggest that 5'-IMP supplementation increase the mitochondrial respiratory capacity when the liver metabolic activity is stimulated, enhances antioxidant defense, and promotes muscle growth in finishing barrows.

Antinociceptive effects of interleukin-4, -10, and -13 on the writhing response in mice and zymosan-induced knee joint incapacitation in rats.

The antinociceptive effects of interleukin (IL)-4, -10, and -13 were investigated in two different experimental pain models. Our results showed that pretreatment (30 min) with IL-4 (1-5 ng/animal), IL-10 (0.4-10 ng/animal), or IL-13 (0.4-2.5 ng/animal) inhibited the writhing response induced by the i.p. administration of acetic acid (53-89%) or zymosan (63-74%) in mice, and the knee joint incapacitation induced by i.a. injection of zymosan (49-66%) in rats. Neither of the cytokines affected the pain elicited in mice using the hot-plate test. This analgesic effect of IL-4, -10, and -13 was not reversed by the combined pretreatment with the opioid receptor antagonist naloxone. IL-4, -10, or -13 significantly inhibited the release of both tumor necrosis factor (TNF)-alpha (60, 53, and 100%, respectively) and IL-1beta (80, 100, and 100%, respectively) by mice peritoneal macrophages obtained after local (i.p.) injection of zymosan. Antisera against IL-4, -10, and -13 potentiated both the zymosan-induced writhing response and the articular incapacitation. Our results demonstrate that IL-4, -10, and -13 display analgesic activity that is probably not due to endogenous opioid release. This analgesic effect could be related to a peripheral mechanism, probably via the inhibition of the release of the pro-inflammatory cytokines TNF-alpha and IL-1beta by resident peritoneal macrophages.