Dietary L-carnitine modulates oxidative stress, lipid metabolism, and pulmonary hypertension in chickens raised at high-altitude under cold stress.

Abstract

BACKGROUND: This study evaluated L-carnitine's impact on oxidative stress, lipid metabolism, and pulmonary hypertensive response in broilers under high-altitude and cold stress. METHOD: A total of 225 male broiler chicks (Ross 308, 38.5&#x2009;&#xb1;&#x2009;0.5&#xa0;g) were raised at 2100&#xa0;m altitude and exposed to cold stress. Birds were divided into three groups: control, LC-50 (50&#xa0;mg/kg L-carnitine), and LC-100 (100&#xa0;mg/kg L-carnitine). At 42 days, blood and tissues were collected to measure malondialdehyde (MDA), nitric oxide (NO), hematocrit, and right ventricular to total ventricular weight (RV: TV) ratio (PHS indicator). Gene expression of superoxide dismutase 1 (SOD1), glutathione peroxidase (GPX), catalase (CAT), carnitine palmitoyltransferase 1 (CPT1), carnitine palmitoyltransferase 2 (CPT2), and inducible nitric oxide synthase (iNOS) was analyzed in the heart, lung, and hindbrain using real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: The RV: TV ratio, MDA levels, and hematocrit (%) significantly decreased in the LC-50 and LC-100 groups compared to the control group, while nitric oxide levels increased (For all P&#x2009;<&#x2009;0.05). The expression of SOD1, GPX, CAT, and iNOS genes was significantly increased in the heart, lung, and hindbrain of the LC-100 group compared to the control group (P&#x2009;<&#x2009;0.05), while CPT1 and CPT2 expression increased significantly only in the heart and hindbrain (P&#x2009;<&#x2009;0.05). CONCLUSION: Dietary L-carnitine, especially at 100&#xa0;mg/kg, effectively alleviates oxidative stress, enhances vasodilation, improves lipid metabolism, and mitigates pulmonary hypertensive responses in broilers exposed to high-altitude hypoxia and cold stress.