Biochemical and Molecular Roles of Nutrients Food Deprivation Changes Peroxisomal b-Oxidation Activity but Not Catalase Activity during Postnatal Development in Pig Tissues

Peroxisomal b-oxidation and catalase activity were investigated in liver, kidney and heart from pigs at the following timepoints: within 0.5 h after birth (0 h, unfed) and at 24 h (suckled or unsuckled), 10 d (suckled or 24-h food-deprived), 21 d (suckled or 24-h food-deprived) and 5 mo (overnight food-deprived). In liver, peroxisomal b-oxidation increased about twofold at 24 h for suckled pigs (P õ 0.001) but did not change for unsuckled pigs. The rate was further increased in 21-d-old pigs compared with 0(P õ 0.001) or 24-h-old (P õ 0.05) pigs, but was lower at 5 mo than at 10 or 21 d (P õ 0.01). The rate was higher for food-deprived pigs than suckled pigs at 10 d (P õ 0.001) of age. In kidney, peroxisomal b-oxidation was unchanged during the first 24 h but was higher (P õ 0.05) at 10 d for suckled pigs and at 21 d than at 0 h. Nutritional state did not influence renal peroxisomal b-oxidation. In heart, peroxisomal b-oxidation did not change with age or nutritional state. The developmental pattern of fatty acyl-CoA oxidase activity was similar to that of peroxisomal b-oxidation in each tissue. Developmental increases of peroxisomal b-oxidation were greater than those for first-cycle peroxisomal b-oxidation reported earlier, suggesting that peroxisomal b-oxidation became more complete in older pigs. Catalase activity did not change during the first 24 h after birth but then increased 10.5-, 2.9-fold and 33% at 10 d in liver, kidney and heart, respectively. The concentration of catalase mRNA was only 1.1and 1.3-fold higher at 10 d than at 24 h in liver and kidney, respectively. Catalase activity was not affected by food deprivation. We concluded the following: 1 ) peroxisomal b-oxidation develops rapidly after birth and may be important for piglets to oxidize milk fatty acids; 2 ) food is required for the initial induction after birth; and 3 ) rapidly increased catalase activity during the first 10 d of life resulted from both pretranslational and post-translational regulation. J. Nutr. 128: 1114–1121, 1998.