Low-protein diets supplemented with essential amino acids (EAA) can improve growth and performance. However, the dietary amount of non-essential amino acids (NEAA) may be a limiting factor in these diets. This may ultimately affect the efficient utilization of the dietary EAA for maximum nitrogen (N) retention and growth. Appropriate quantities of EAA and total N may be provided using the EAA-N to total N ratio (E:T). The present study showed that, generally, N retention increased linearly with increasing dietary lysine (Lys), but N retention was higher in the low E:T group. A higher Lys requirement was observed in the low E:T group compared to the high E:T fed group, contrary to the study hypothesis. The results from the present study indicate that NEAA or N becomes limiting in high E:T diets but not in low E:T diets, and more EAA are required in low E:T diets to maximize N retention. In conclusion, the E:T ratio should be an important consideration in formulating low-protein diets for pigs to ensure optimal and efficient utilization of the EAA provided in the diet.
Non-essential amino acids affect nitrogen retention in pigs (full article)
