273 Effects of Xylanase Supplementation in Diets with Reduced Metabolizable Energy and Supplemental Fat on Intestinal Health, Mucosa Associated Microbiota and Growth Performance of Nursery Pigs

Abstract

Abstract This study aimed to investigate the effects of reducing metabolizable energy (ME) below the requirement by reducing supplemental fat on intestinal health and growth performance of nursery pigs. One hundred and ninety-two newly weaned pigs at 7.3 ± 0.6 kg BW were allotted in a RCBD with sex and initial BW as blocks. Pigs were assigned to one of 8 dietary treatments with varying ME levels (3,400, 3,375, 3,350, 3,325, and 3,300 kcal/kg ME) by reducing supplemental fat and increasing xylanase (X0: 0, X40: 1,200, X80: 2,400 and X120: 3,600 XU/kg of feed) in ME deficient diets by 100 kcals/kg. Pigs were fed diets for 35 d in 2 phases (14 d and 21 d, respectively) and growth performance was measured at the end of each phase. Phase 2 diet had titanium dioxide (0.4%) as indigestible external marker to measure ileal digestibility of nutrients. At d 35, a pig representing the median BW within each pen from 3 dietary treatments (ME at 3,400 and 3,300 kcal/kg ME with or without xylanase) were euthanized for sampling jejunal mucosa, jejunal tissue, and ileal digesta to analyze intestinal health parameters, mucosa associated microbiota, and apparent ileal digestibility (AID) of nutrients. Data were analyzed using Mixed procedure of SAS 9.4. Overall, reducing ME level had no effect on growth performance of nursery pigs. However, reducing ME by 100 kcal/kg ME below the requirement increased (P < 0.05) digesta viscosity (1.7 to 2.2 cP) and protein carbonyl (0.18 to 0.40 nmol/mg), tended to change the relative abundance of Prevotellaceae (P = 0.062, 49 to 23%) and Lactobacillaceae (P = 0.086, 7 to 19%), reduced (P < 0.05) villus height (467 to 433 µm) and villus height to crypt depth ratio (1.80 to 1.64) in the jejunum, and reduced (P < 0.05) AID of DM (59.5 to 47.3%), gross energy (59.1 to 43.0%), crude protein (63.4 to 44.6%), and ether extract (67.7 to 55.2%). Xylanase supplementation decreased (P < 0.05) digesta viscosity (2.2 to 1.82 cP) and protein carbonyl (0.40 to 0.17 nmol/mg), increased the relative abundance of Prevotellaceae (20.22 to 61.56%), increased villus height (433 to 462 µm) and villus height to crypt depth ratio (1.64 to 1.99) in the jejunum, and increased (P < 0.05) AID of DM (47.3 to 58.7%), and gross energy (42.9 to 56.0%). In conclusion, reducing ME (100 kcal/kg below the requirement) by reducing supplemental fat (by 2% unit) impaired intestinal health, reducing ability of the pigs to digest feeds whereas xylanase supplementation appeared to mediate some of the negative effects seen by energy reduction by improving intestinal morphology, reducing oxidative damage products, and diversity of the mucosa-associated microbiota.