A study was conducted to investigate the effects of dietary protease supplementation on growth performance and carcass characteristics of growing-finishing pigs that started with a lower bodyweight than pigs in the control group. A total of 96 growing pigs (initial bodyweight (BW) 31.6 ± 2.97 kg) were allotted to two dietary treatments (48 pigs/treatment, 8 pigs/pen) with different initial BW (34.37 vs. 28.78 kg). The dietary treatments were a control diet (CON), based on maize and soybean meal (grower diets) and wheat (finisher diets), and a protease diet (PRO), which was the CON diet to which 0.02% protease was added. Pigs were fed these dietary treatments (high BW-CON, low BW-PRO) for 12 weeks, comprising six weeks growing and six weeks finishing. In the growing period, PRO had higher average daily gain (ADG) and gain to feed (G:F) ratio than CON. The significant difference in bodyweight that was observed at the beginning of the experiment between the treatment groups was still observed at the end of the growing period. In the finishing period, PRO had reduced feed intake, average daily feed intake (ADFI), and increased G:F ratio compared with CON. At the end of the experiment, there was no significant difference in BW between the treatment groups as a result of lower feed intake and ADFI and higher ADG and G:F ratio. In addition, there were no differences in carcass characteristics between the groups. Therefore, standalone protease supplementation may positively affect the growth performance of growing-finishing pigs through improved feed efficiency without negative effects on carcass characteristics. ______________________________________________________________________________________

Experiment 1 was a feeding trial in which 75 (LandraceⅹYorkshire)ⅹDuroc pigs with average initial bodyweight (BW) of 26 ± 1 kg were used. It was assigned to three pigs/pen and five pens/treatment. Experiment 2 was a metabolic trial in which 25 (LandraceⅹYorkshire)ⅹDuroc pigs with average initial bodyweight (BW) of 36 ± 1 kg were used. The basal diet consisted of maize (57.71 %), soybean meal (32.45 %), and wheat bran (5 %). Treatments consisted of i) CON (control diet); ii) OE (organic acid + essential oils) (Aviplus-S ® ), that is, CON + 0.05 % OE; iii) OC (organic charcoal) (Olga Black ® ), that is, CON + 0.1 % OC; iv) AE (anise extracts) (RESQ ® ), that is, CON + 0.015 % AE; and v) PB (probiotics) (Bonvital ® ), that is, CON + 0.1 % PB. Average daily gain (ADG) and gain/feed ratio (G : F) were significantly higher in the OE and AE groups than in the others. Average daily feed intake (ADFI) for OE, OC, and AE treatments was significantly higher than that for CON and PB treatments. Dry matter (DM) digestibility was significantly higher in AE than CON. Crude protein (CP) was significantly higher in OE, AE, and PB than CON. CON and other treatments did not cause significant differences in blood l-density lipoprotein (LDL), and glucose. NH 3 emissions were significantly lower in all treated groups than in CON. Among the treatments, NH 3 emissions were lowest in OE and AE. H 2 S emissions were significantly lower in OE, AE, and PB than in CON. Among the treatments, OE and AE were most effective at reducing H 2 S emissions. The emissions of volatile fatty acids (VFAs) showed no significant difference between treatments and CON. In conclusion, this experiment was shown to be more effective on growth performance, malodour emission, blood profiles, and nutrient digestibility in OE and AE than other additives.