LEP and obesity due to melanocortin 4 receptor deficiency: MC5R is a functional candidate for fatness in domestic animals and obesity in humans (Switonski et al., 2013) because it regulates interleukin 6 (IL6) (Jun et al., 2010) and downregulates leptin secretion (Hoggard et al., 2004) respectively resulting in increased fat deposition and increased feed intake.