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.

The present study investigated the effects of varying durations of nursery diets differing in percentages of milk products on growth performance of pigs during the nursery phase (NP) and subsequent grow-finish phase (GFP) to find the feasibility of reducing the use of nursery diets containing costly milk products. A total of 204 21-d-old weanling female and castrated male pigs were subjected to one of three nursery phase feeding programs differing in durations on the NP 1 and 2 and GFP diets containing 20%, 7%, and 0% lacrosse and 35%, 8%, and 0% dried whey, respectively, in 6 pens (experimental units) for 33 d: HIGH (NP 1, 2 and 3 diets for 7, 14, and 12 d), MEDIUM (NP 2 and 3 for 14 and 19 d), and LOW (NP 2 and 3 and GFP 1 for 7, 14, and 12 d). Subsequently, 84 randomly selected pigs [14 pigs (replicates)/pen] were fed the GFP 1, 2 and 3 diets during d 54-96, 96-135, and 135-182 of age, respectively. The final body weight (BW) and average daily gain (ADG) of nursery pigs did not differ among the HIGH, MEDIUM, and LOW groups (14.8, 13.3, and 13.7 kg in BW and 273, 225, and 237 g in ADG, respectively). The average daily feed intake during the nursery phase was greater (p <0.01) in the HIGH group than in the MEDIUM and LOW groups, whereas the gain:feed ratio did not differ across the treatments. The BW on d 182 and ADG during d 54-182 were greater in the HIGH and MEDIUM groups vs. the LOW group (110.0, 107.6, and 99.6 kg in BW, respectively; p <0.01). The backfat thickness and carcass grade at slaughter on d 183 did not differ across the treatments. In conclusion, the MEDIUM program may be inferior to the commonly used HIGH program in supporting nursery pig growth. Nevertheless, the former appears to be more efficient than the latter in production cost per market pig whereas the LOW program is thought to be inefficient because of its negative effect on post-nursery pig growth.