Effects of varying levels of β-mannanase on growth performance, nutrient digestibility, blood metabolites and diarrhea incidence in weaning pigs

This study was carried out to examine the effects of varying levels of β-mannanase supplementation in corn-soybean meal (SBM)-based diet on growth performance, nutrient digestibility, blood metabolites, and diarrhea incidence of weaning pigs. A total of 160 pigs with an initial body weight (BW) of 8.66 ± 0.060 kg were used in the experiment. Using a randomized complete block (RCB) design, they were assigned to 4 treatments with 5 replicates and 8 pigs per pen, considering sex and initial BW. Treatments for early (0-2 weeks) and late weaning phases (2-5 weeks) were as follows: β-Man0: corn-SBM-based basal diet + β-mannanase 0%; β-Man0.05: basal diet + β-mannanase 0.05%; β-Man0.1: basal diet + β-mannanase 0.1%; and β-Man0.15: basal diet + β-mannanase 0.15%. During the early weaning phase, average daily gain tended to increase when β-mannanase level increased (linear, <i>p</i> = 0.07). When β-mannanase level increased in the late weaning phase, the average daily feed intake tended to decrease (linear, <i>p</i> = 0.08), and gain to feed ratio (G:F ratio) increased (linear, <i>p</i> = 0.02). Throughout the whole experimental period, G:F ratio tended to increase as β-mannanase level increased (linear, <i>p</i> = 0.06). According to nutrient digestibility, crude fat digestibility increased when the β-mannanase level increased (linear, <i>p</i> = 0.04). Accordingly, the total protein and triglyceride concentration increased as β-mannanase level increased in the early weaning phase (linear, <i>p</i> = 0.01; <i>p</i> = 0.01). During the entire experimental period, the total cholesterol concentration increased significantly (linear, <i>p</i> < 0.01), whereas the high-density lipoprotein cholesterol and low-density lipoprotein cholesterol concentration increased with higher levels of β-mannanase (linear, <i>p</i> = 0.02; <i>p</i> = 0.02). Lastly, diarrhea incidence showed no significant variation during the early and late weaning phases according to β-mannanase levels. As the level of β-mannanase supplementation in the weaning pig diet increased, growth performance, nutrient digestibility, and blood metabolites showed some positive trends. Therefore, supplementing β-mannanase up to 0.15% in the diet of weaning pigs could enhance their productivity.