Effects of copra meal inclusion level in growing‐ finishing pig diets containing β‐mannanase on growth performance, apparent total tract digestibility, blood urea nitrogen concentrations and pork quality

Abstract

This experiment was conducted to evaluate the effects of copra meal (CM) inclusion level on the growth performance, apparent total tract digestibility (ATTD), blood urea nitrogen (BUN) concentrations, and pork quality of growing‐finishing pigs fed diets containing β‐mannanase. Eighty crossbred pigs with average body weight (BW) of 27.22 ± 0.09 kg were allotted to five dietary treatments with four pigs per pen and four replicates per treatment based on sex and BW. The dietary treatments were: (1) NC: negative control, corn‐soybean meal (SBM) based basal diet, (2) PC: positive control, basal diet + 0.10% β‐mannanase (800 IU/ kg diet), (3) CM6: PC diet with 6% CM inclusion, (4) CM12: PC diet with 12% CM inclusion, and (5) CM18: PC diet with 18% CM inclusion in a three‐phase feeding program (growing: 0–6 weeks, finishing I: 7–9 weeks, and finishing II: 10– 12 weeks). The quadratic responses were observed in the BW at six weeks (p < 0.05), ADG in the growing phase (0–6 weeks; p < 0.05), and ADFI in the finishing phase with a tendency (7–12 weeks; p = 0.06) as the inclusion level of CM increased. However, the BW at 12 weeks (linear, p < 0.05 and quadratic, p = 0.06), the overall ADG (0–12 weeks; linear and quadratic, p < 0.05), and the G:F ratio in the finishing (7–12 weeks; linear, p < 0.05) and overall (0–12 weeks; linear, p < 0.05) phases decreased with increasing levels of CM in the diets. The ATTD of crude protein (linear, p < 0.05), crude fiber (linear, p < 0.05), and ash (linear, p < 0.05) decreased linearly as the inclusion level of CM increased. The BUN concentrations increased linearly with increasing levels of CM in the diets at 12 weeks of the experiment (p < 0.05). As the inclusion level of CM increased, TBARS value at d 3 post-mortem (linear, p = 0.07) tended to increase, whereas initial loin pH at 1 h post‐mortem decreased (linear and quadratic, p < 0.05) with no difference in ultimate loin pH at 24 h post‐mortem. These results indicated that CM inclusion up to 12% in the growing‐finishing pig diets with β‐mannanase did not affect growth performance, nutrient utilization, and pork quality whereas 18% CM inclusion to the diets could negatively impact nutrient digestibility, BUN concentrations, and thereby growth performance.