Reducing the lysine to energy content in the grower growth phase diet increases intramuscular fat and improves the eating quality of the longissimus thoracis muscle of gilts

Abstract

Sixty-three (Large White × Landrace × Duroc) female finisher pigs were used to determine the effect of nutritional manipulations on growth performance, carcass quality and sensory pork quality. The dietary treatments were: (i) control [pigs fed a commercial grower (73–125 days of age) and finisher diet (126–163 days of age)]; (ii) 15% reduced lysine : energy diet during the grower phase followed by a commercial finisher diet; and (iii) pigs fed the control diet with no supplemented vitamin A in the mineral–vitamin premix during both the grower and finisher phases. Pigs fed the reduced lysine diet had higher (P < 0.05) intramuscular fat levels compared with pigs fed the control and the vitamin A- restricted diets. The pork from pigs fed the reduced lysine diet had a lower ultimate muscle pH, was paler (higher L*) and had a higher b* value (yellowness-blueness) compared with pork from the control pigs (all P < 0.05). Pork from pigs fed the reduced lysine diet was considered to be the most juicy and tender and have the best overall acceptability (all P < 0.05), followed by pork from pigs fed the control and vitamin A-restricted diets. In conclusion, feeding pigs a 15% reduced lysine : energy diet significantly increased intramuscular fat levels and improved the sensory quality of pork.