Supplementation of a β-mannanase enzyme reduces post-weaning diarrhea and antibiotic use in piglets on an alternative diet with additional soybean meal.

Enzyme supplementation with a β-mannanase to degrade β-mannan fibers present in the diet has been shown to restore and improve performance in swine. The current study was conducted on a farm which had historical episodes of post-weaning diarrhea. In total, 896 newly weaned piglets were enrolled in two consecutive trials. Each trial consisted of 32 pens of 14 piglets housed in one large post-weaning compartment. Piglets at the same feeder were randomly assigned to the two treatment groups. The study compared the performance of post-weaned piglets fed either a commercial 3-phase nursery diet (Control) or an adapted diet supplemented with a β-mannanase (Hemicell HT; Elanco) (Enzyme), with some of the more expensive proteins replaced by soy bean meal in phase 1 and 2, and net energy (NE) content reduced by 65 kcal/kg in phase 3. All data analyses were performed using R version 3.6.3 (R Core Team, 2020). All tests were performed at the 5% level of significance. When multiple testing was involved, the nominal 5% Familywise Error Rate (FWER) was used. The study showed similar performance on the alternative diet with β-mannanase and the common commercial diets (P >  0.05). However, the Enzyme treated group had a significantly better general clinical score. Moreover, the number of individual treatments was a factor exp(0.69441) or 2 (CI 95% [1.46; 2.74]) higher (P < 0.001) in the Control group as compared to the Enzyme treated group. The number of treated animals was a factor exp(0.62861) or 1.87 (CI 95% [1.43; 2.53]) higher (P < 0.001) and the number of pigs with a repeated treatment was a factor exp(0.9293) or 2.53 (CI 95% [1.26; 5.09]) higher (P = 0.009) in the Control group as compared to the Enzyme treated group. In total, 7 (1.56%) piglets died in the Control group, whereas only 2 (0.45%) piglets died in the Enzyme treated group. The hazard ratio for mortality in the Control group relative to the Enzyme treated group was and estimated as 1.74 (CI 95% [0.51; 5.96]). Thus, the Control group had a non-significantly (P = 0.375) increased mortality. In conclusion, the results suggest that the use of an exogenous heat-tolerant β-mannanase allowed reduced levels of expensive protein sources to be used in the first two diets fed post-weaning, and 65 kcal/kg lower net energy content to be used in the third diet without adverse effects on intestinal health or overall performance. In fact, the occurrence of PWD and number of individual treatments during the post-weaning period were significantly reduced on the β-mannanase supplemented diets.