Beta-Mannanase Supplementation Effects on Nursery Pig Growth Performance, Feed Efficiency, and Serum Acute Phase Protein Concentrations

Dietary b-mannans can mimic carbohydrate structures on pathogen surfaces which may activate the innate immune system. Beta-mannanase supplementation has been proposed to reduce this immune stimulation and spare energy for growth. The objective of this experiment was to evaluate the effects of dietary mannan level, b-mannanase supplementation, and their interaction on growth performance, feed efficiency, and serum acute phase protein concentrations in nursery pigs. Pigs (n = 480, 10 pigs per pen) were blocked by initial weight and pens (n = 12 per treatment) were randomly assigned to 1 of 4 treatments in a 2x2 factorial arrangement for a 28-d experiment with 4 phases. Two levels of dietary mannan were achieved by replacing 10% of the soybean meal in the low mannan diet (est. 0.36% b-mannan) with copra meal for a high mannan diet (est. 2.79% b-mannan). Each of these diets were fed with and without 0.05% endo-1,4-b-mannanase (Hemicell HT 1.5X, Elanco Animal Health). Serum was collected (1 pig/pen) for haptoglobin and C-reactive protein (CRP) analysis prior to treatment initiation (baseline) and on d 28. Data were analyzed as a 2x2 factorial design with main effects of mannan level and b-mannanase supplementation. There were no significant interactions between mannan level and b-mannanase supplementation overall (d 0 to 28; P = 0.852) or within each phase (P ≥ 0.106). Overall, the high mannan diets decreased ADG (0.37 vs. 0.38 kg/d; P = 0.027) and ADFI (0.52 vs. 0.54 kg/d; P = 0.024) compared to low mannan diets. A similar effect was observed only in phase 3. There were no significant b-mannanase effects on growth performance or feed efficiency (P > 0.10). Serum acute phase protein concentrations were similar among treatments at baseline. At d 28 haptoglobin concentrations were lower (P ≤ 0.0001) and CRP concentrations were greater (P ≤ 0.0001) compared to baseline values, but neither were affected by mannan level or b-mannanase supplementation (P ≥ 0.160). Beta-mannanase supplementation tended to increase serum CRP in the high mannan diet (290.64 mg/ml) compared to the low diet (243.49 mg/ml) with no differences compared to when the enzyme was not supplemented (avg. = 273.91 mg/ml; P = 0.0791). In conclusion, the high mannan diets decreased ADG through decreased ADFI with no apparent effect on haptoglobin or CRP concentrations. Beta-mannanase supplementation had no impact on performance and did not affect haptoglobin or CRP concentrations differently in high compared to low mannan diets.