Effects of the Plane of Nutrition on Physicochemical Characteristics and Sensory Quality Traits of the Muscle in Finishing Pigs

This study was performed to examine the feasibility of using the low plane of nutrition (LPN) as a means of improving the meat quality of crossbred finishing pigs with a medium weight gain potential. Twenty-four barrows and 24 gilts weighing approximately 48 kg were placed on LPN [a finisher (2.86 Mcal ME/kg and 0.67% lysine) for 91 d] or on a high plane of nutrition [HPN; a commercial grower for 38 d and a finisher (3.35 Mcal ME/kg and 0.9% lysine) for 46 d]. Five barrows and five gilts per treatment weighing approximately 125 kg were slaughtered after the indicated days on the respective diets, followed by physicochemical analysis and sensory evaluation on their muscles. Overall average daily gain was 12.6% less in the LPN group vs. the HPN group (p<0.05). The redness ($a^*$) of fresh longissimus muscle (LM) from the loin as well as from Boston butt was greater in the LPN group vs. HPN whereas the shear force for fresh LM from these primals and semimembranosus muscle was lower in the former. In sensory evaluation for cooked LM, no treatment effect was detected in any of the quality traits examined, except for a lower color score in the LPN vs. HPN group. Results suggest that meat quality of the finishing pigs can be improved to some extent by using LPN. However, the present pigs, whose backfat thickness was 24 mm at 125 kg, are thought not to be lean enough to be fattened over 120 kg.