241 Increased Inflammatory Tone and Impaired Skeletal Muscle Growth in Intrauterine Growth-Restricted Neonatal Lambs Is Improved By Daily Supplementation of -3 Polyunsaturated Fatty Acid Ca2+Salts

Abstract Low birthweight due to fetal intrauterine growth restriction (IUGR) often results from maternofetal heat stress. IUGR fetuses exhibit enhanced inflammatory tone, which persists after birth and impacts body composition, skeletal muscle growth, and metabolic function. Therefore, our objective was to determine whether daily oral supplementation of Ca2+ salts of ω-3 polyunsaturated fatty acids (ω-3 PUFA) to IUGR-born neonatal lambs improved inflammatory tone, body composition, and growth metrics. Pregnant ewes were exposed to heat stress (40°C, 35% humidity, THI = 85) from d 40 to 95 of gestation to induce IUGR. Lambs were weaned at birth and hand-reared on milk replacer. Daily oral boluses of 0.5 mL molasses containing 0 or 0.42 g/kg bodyweight of ω-3 PUFA (Virtus Nutrition) were administered. Femoral catheters were placed at d 24 and lambs were necropsied at d 30. At birth, IUGR lambs (n = 8; 3.12 ± 0.34 kg) and IUGR+ω-3 lambs (n = 7; 3.67 ± 0.32 kg) were lighter (P < 0.05) than controls (n = 12; 4.28 ± 0.15 kg). Plasma TNFα concentrations were greater (P < 0.05) at birth for IUGR (557 ± 121 pg/mL) and IUGR+ω-3 lambs (437 ± 82 pg/mL) than for controls (213 ± 78 pg/mL). Plasma TNFα concentrations remained increased (P < 0.05) for IUGR lambs but not for IUGR+ω-3 compared with controls at 2, 3, and 4 wk of age. Adjusted 30-d bodyweights were lighter (P < 0.05) for IUGR lambs (9.83 ± 0.6 kg) but not for IUGR+ω-3 lambs (11.59 ± 0.4 kg) than for controls (12.35 ± 0.2 kg). Heart and brain weights were 17% and 6% lighter (P < 0.05), respectively, for IUGR lambs than for controls. Brain weight deficits were resolved in IUGR+ω3 lambs, but heart weights did not differ between IUGR and IUGR+ω-3 IUGR lambs. Crown circumference/ bodyweight, abdominal circumference/ bodyweight, and cannon bone length/ bodyweight (indicators of asymmetric body composition) were 11% to 15% greater (P < 0.05) for IUGR lambs than for IUGR+ω-3 lambs or controls. At necropsy, IUGR lambs had lighter (P < 0.05) whole hindlimbs (29%) and flexor digitorum superficialis (24%), soleus (36%), biceps femoris (25%), semitendinosus (24%), gastrocnemius (29%), and longissimus dorsi (26%) muscles compared with controls. Weight deficits were partially or fully resolved in IUGR+ω-3 lambs for whole hindlimbs and for all muscles but the soleus, which did not differ from IUGR lambs. These findings demonstrate that daily oral supplementation of Ca2+ salts of ω-3 PUFA reduced the enhanced inflammatory tone observed in IUGR-born offspring, which coincided with improved skeletal muscle growth and indicators of symmetrical body composition.