Neutral detergent-soluble fiber improves gut barrier function in twenty-five-day-old weaned rabbits.
The effect of neutral detergent-soluble fiber level on gut barrier function and intestinal microbiota was examined in weaned rabbits. A control diet (AH) containing 103 g of neutral detergent-soluble fiber/ kg of DM included alfalfa hay as main source of fiber. Another diet (B-AP) was formulated by replacing half of the alfalfa hay with a mixture of beet and apple pulp resulting in 131 g of soluble fiber/kg of DM. A third diet (OH) was obtained by substituting half of the alfalfa hay with a mix of oat hulls and a soybean protein concentrate and contained 79 g of soluble fiber/kg of DM. Rabbits weaned at 25 d and slaughtered at 35 d were used to determine ileal digestibility, jejunal morphology, sucrase activity, lamina propria lymphocytes, and intestinal microbiota. Suckling 35-d-old rabbits were used to assess mucosa morphology. Mortality (from weaning to 63 d of age) was also determined. Villous height of the jejunal mucosa increased with soluble fiber (P = 0.001). Rabbits fed with the greatest level of soluble fiber (BA-P diet) showed the highest villous height/ crypt depth ratio (8.14; P = 0.001), sucrase specific activity (8,671 mumol of glucose/g of protein; P = 0.019), and the greatest ileal starch digestibility (96.8%; P = 0.002). The opposite effects were observed in rabbits fed decreased levels of soluble fiber (AH and OH diets; 4.70, 5,848 mumol of glucose/g of protein, as average, respectively). The lowest ileal starch digestibility was detected for animals fed OH diet (93.2%). Suckling rabbits of the same age showed a lower villous height/crypt depth ratio (6.70) compared with the B-AP diet group, but this ratio was higher than the AH or OH diet groups. Lower levels of soluble fiber tended (P = 0.074) to increase the cellular immune response (CD8+ lymphocytes). Diet affected IL-2 production (CD25+, P = 0.029; CD5+CD25+, P = 0.057), with no clear relationship between soluble fiber and IL-2. The intestinal microbiota biodiversity was not affected by diets (P >/= 0.38). Rabbits fed the B-AP and AH diets had a reduced cecal frequency of detection compatible with Campylobacter spp. (20.3 vs. 37.8, P = 0.074), and Clostridium perfringens (4.3 vs. 17.6%, P = 0.047), compared with the OH diet group. Moreover, the mortality rates decreased from 14.4 (OH diet) to 5.1% (B-AP diet) with the increased presence of soluble fiber in the diet. In conclusion, increased levels of dietary soluble fiber improve mucosal integrity and functionality.
Gómez-Conde
M S
MS
Departamento de Producción Animal, Universidad Politécnica de Madrid, E.T.S. Ingenieros Agrónomos, 28040 Madrid, Spain.
García
J
J
Chamorro
S
S
Eiras
P
P
Rebollar
P G
PG
Pérez de Rozas
A
A
Badiola
I
I
de Blas
C
C
Carabaño
R
R
D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D003902:Detergents; D004043:Dietary Fiber / Q000494:pharmacology*; D004063:Digestion; D004305:Dose-Response Relationship, Drug; D007082:Ileum / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology / Q000473:pathology*; D007583:Jejunum / Q000201:enzymology / Q000382:microbiology / Q000473:pathology; D018655:Lymphocyte Count / Q000662:veterinary*; D011817:Rabbits; D011897:Random Allocation; D012995:Solubility; D013393:Sucrase / Q000378:metabolism; D014886:Weaning
D003902:Detergents; D004043:Dietary Fiber; D013393:Sucrase