Background <p>This study investigated the effects of dietary graviola (<i>Annona muricata</i> L.) oil extract (GOE) (supplemented at 200, 400, and 600&#xa0;mg/kg) on the growth performance and circadian rhythm profiles of adipokine, cardiac, and mitochondrial function biomarkers in 48 male Anatolian Merino lambs (2.5 months old).</p> Methods <p>Lambs were assigned to a control group (G0) or supplementation groups (G200, G400, G600 mg/kg) for a 60-day trial (70 days total). The study was conducted under a 12-h light/12-h dark cycle to ensure controlled environmental conditions. To analyze circadian profiles, blood samples were collected on days 0, 15, 30, 45, and 60 at four time points (07:00, 13:00, 19:00, and 01:00). Serum levels of Apelin, cTnI, BMAL1, MOTS-c, and BMCP1 were measured by ELISA. Data were analyzed using GLM Multivariate analysis (<i>p</i> &lt; 0.05).</p> Results <p>Key findings showed the G400 dose resulted in the most effective linear increase in live weight and live weight gain by day 60, and had a significant overall effect on live weight (<i>p</i> &lt; 0.05). The G200 dose significantly improved the feed conversion ratio (<i>p</i> &lt; 0.05), while feed consumption was unaffected (<i>p</i> &gt; 0.05). Regarding biomarkers on day 60, the G400 dose effectively modulated BMAL1, MOTS-c, and BMCP1 (peak at 19:00). The G600 dose yielded the best results for Apelin (peak at 19:00) and cTnI (peaks at 13:00 and 07:00).</p> Conclusions <p>In conclusion, GOE at a dose of 400&#xa0;mg/kg (G400) not only optimizes fattening performance in Anatolian Merino lambs but also supports metabolic homeostasis by modulating adipokine levels, cardiac function, and mitochondrial biogenesis processes in a manner consistent with the circadian rhythm. These findings demonstrate that the G400 dose is a safe and effective phytogenic strategy for improving animal health and production efficiency.</p>