Serum leptin (LEP), a satiety-regulating adipokine often elevated in HFD-induced obesity, was significantly decreased by 28.80% in the L-SLN group (p < 0.05) and 36.39% in the D-SLN group (p < 0.05). The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.