Effects of increasing levels of palm kernel meal containing β-mannanase to growing-finishing pig diets on growth performance, nutrient digestibility, and pork quality

In this study, we investigated the effects of increasing levels of palm kernel meal (PKM) in diets containing beta-mannanase on growth performance, nutrient digestibility, and pork quality in growing-finishing pigs. One hundred twenty pigs [(Yorkshire x Landrace) x Duroc] with 29.68 +/- 0.17 kg BW] were allotted to 5 dietary treatments with 4 pigs per pen and 6 replicates per treatment on the basis of sex and BW. These dietary treatments were: NC (negative control; corn-soybean meal-based diet), PC (positive control; basal diet + 0.10% beta-mannanase), PKM6 (diet containing 6% PKM + 0.10% beta-mannanase), PKM12 (diet containing 12% PKM + 0.10% beta-mannanase), and PKM18 (diet containing 18% PKM + 0.10% beta-mannanase). The BW was linearly decreased as the dietary inclusion level of PKM increased in early finishing phase (linear, P < 0.05) and late finishing phase (linear, P < 0.01). Similarly, ADFI was linearly decreased as the dietary inclusion level of PKM increased in late finishing phase (linear, P < 0.03), and during the entire experimental period (linear, P < 0.01). However, no PKM effect was observed on the G/F ratio. Digestibility of crude protein and crude fiber were linearly decreased when dietary levels of PKM increased (linear, P < 0.05). Moreover, increasing level of PKM in the diet linearly increased fecal nitrogen levels (linear, P < 0.03). Dietary treatment had no adverse effects on plasma urea nitrogen (PUN) levels. Pigs fed diets containing 18% PKM tended to have decreased carcass yield (P < 0.08) as well as increased backfat depth (P < 0.10). Consequently, growing-finishing pigs fed increasing levels of PKM had a linear reduction on growth performance and digestibility. Overall, PKM can be added up to 12% in corn-soybean meal diets supplemented with 0.10% beta-mannanase without detrimental effects on growth performance and pork quality of growing-finishing pigs.