Effects of bromelain supplementation on growth performance, nutrient digestibility, blood profiles, faecal microbial shedding, faecal score and faecal noxious gas emission in weanling pigs

A total of 140 weanling pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (b.w.) of 6.75 ± 1.48 kg were used in a six-week trial. Pigs were randomly allotted to one of four experimental treatments according to their initial b.w. (seven pens per treatment with five pigs per pen). Dietary treatments were: CON = control diet, T1 = CON + 0.05% bromelain, T2 = CON + 0.10% bromelain, T3 = CON + 0.20% bromelain. The experiment was divided into two phases (Days 1 to 14 and Days 15 to 42). All diets, in mash form, were formulated to meet or exceed the nutrient requirements (NRC, 2012) for weanling pigs. Feed intake and b.w. were monitored at the end of each phase. T3 treatment had greater (342 vs. 305 g; 409 vs. 387 g; P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) than CON treatment in Phase 1. In Phase 2, the ADG was improved (from T1 to T3: 612, 616, 637 vs. 583 g; P < 0.05) in all bromelain treatments compared with CON treatment, ADFI and growth efficiency (G : F) ratio of T3 treatment were higher (833 vs. 803 g; 0.765 vs. 0.726 g; P < 0.05) compared with CON treatment. Overall, T3 treatment showed greater (539 vs. 490 g; 691 vs. 664 g; P < 0.05) ADG and ADFI than CON. Moreover, pigs fed bromelain diets exhibited increased (0.769, 0.770, 0.780 vs. 0.738; P < 0.05) G : F ratios compared with those fed CON diet. Pigs fed bromelain diets exhibited increased (two weeks: 79.06, 79.97, 79.42 vs. 77.98%; 78.51, 78.86, 78.43 vs. 75.69%; six weeks: 74.49, 74.67, 75.02 vs. 72.70 %; 69.43, 70.78, 71.32 vs. 73.39%; P < 0.05) apparent total tract digestibility (ATTD) of dry matter and nitrogen compared with those fed CON diet at Week 2 and Week 6. On Day 42, the blood creatinine in the CON group was higher (1.30 vs. 1.04, 0.97, 0.88 mg/dl; P < 0.05) compared with the bromelain treatment groups. Faecal E. coli counts were decreased (6.22 vs. 6.41 log10 cfu/g; P < 0.05) in T2 treatment compared with CON treatment. The faecal ammonia (NH3) gas emission in T2 and T3 treatments decreased (17.72, 17.33 vs. 22.95 ppm; P < 0.05) compared with CON. In conclusion, dietary supplementation with 0.2% bromelain has here been shown to improve the growth performance, apparent total tract digestibility of dry matter and N and to decrease E. coli and faecal NH3 gas emission in weanling pigs.