61 Trainee Award: Daily supplementation of ω-3 polyunsaturated fatty acids to IUGR-born neonatal lambs improved skeletal muscle growth and body composition

Abstract Abstract: Introduction Muscle growth is impaired in intrauterine growth-restricted (IUGR) offspring by programming that includes elevated inflammatory tone. The resulting body composition changes reduce production efficiency in livestock and compromise long-term health in humans. Objective Evaluate whether anti-inflammatory ω-3 polyunsaturated fatty acid (PUFA) supplements improve body composition in IUGR-born lambs. Methods Pregnant ewes were housed under thermoneutral or hyperthermic conditions to produce control (n = 12) or IUGR lambs. From birth, IUGR lambs were supplemented (oral bolus) 0.42 g/kg ω-3 PUFA Ca2+ salts (IUGR+ω-3; n = 12) or placebo (IUGR; n = 11). Biometrics were assessed weekly. Loin ultrasounds were conducted on day 23. Muscle weights were determined at necropsy on day 28. Results Crown circumference/BW, abdominal circumference/BW, and cannon bone length/BW were greater (P<0.05) for IUGR lambs than for controls or IUGR+ω-3 lambs. Body length/BW was greater (P<0.05) for IUGR lambs than for controls and was intermediate for IUGR+ω-3 lambs. IUGR lambs had 14% less (P<0.05) ultrasound-estimated subcutaneous fat and 22% smaller (P<0.05) loin cross-sectional areas. Both were recovered in IUGR+ω-3 lambs. Ultrasound-estimated loin depth was less (P<0.05) for IUGR lambs (16.5±0.4 mm) than for controls (14.6±0.5 mm) and was intermediate for IUGR+ω-3 lambs (15.6±0.6 mm). At necropsy, IUGR lambs had 20 – 23% lighter (P<0.05) biceps femoris, semitendinosus, gastrocnemius, flexor digitorum superficialis, and longissimus dorsi muscles than controls. These deficits were partially or completely recovered in IUGR+ω-3 lambs. Conclusions Supplementing ω-3 PUFA improved muscle growth and body composition of IUGR-born lambs, demonstrating the role of inflammatory programming in IUGR growth outcomes. (Supported by USDA 2019-67015-29448, 2020-67015-30825)