By C-S, Vasc's inequality and AM-GM we obtain: $$\sum_{cyc}\frac{a^5}{b^3+c}\geq\frac{(a^3+b^3+c^3)^2}{\sum\limits_{cyc}(b^3a+ac)}\geq\frac{(a^3+b^3+c^3)^2}{3+3}\geq\frac{9a^2b^2c^2}{6}=\frac{3a^2b^2c^2}{2}.$$ The Vasc's inequality is the following: $$(a^2+b^2+c^2)^2\geq3(b^3a+c^3b+a^3c).$$ Also I used $a^2+b^2+c^2\geq ab+ac+bc.$