Effects of Sapindus saponaria fruits on ruminal fermentation and duodenal nitrogen flow of sheep fed a tropical grass diet with and without legume.
Six adult African-type hair sheep (BW = 40.3 +/- 6.3 kg) fitted with ruminal and duodenal cannulas were subjected to four treatments. Sheep were offered basal diets at a rate of 80 g of DM/kg of metabolic BW (equivalent to ad libitum access) consisting either of a low-quality grass hay (Brachiaria dictyoneura, 3.7% CP, DM basis) alone or in combination with a forage legume (Cratylia argentea, 18.6% CP, DM basis) in a 3:1 ratio (DM basis). In addition, 0 or 8 g of DM of Sapindus saponaria fruits (12.0% crude saponins, DM basis) per kilogram of metabolic BW was administered intraruminally. Supplementation of C. argentea increased intakes of OM (+21%; P < 0.01) and CP (+130%; P < 0.001), as well as ruminal fluid ammonia N concentrations (from 2.40 to 8.43 mg/dL; P < 0.001). Apparent OM and N digestibilities were not affected by legume addition, but ADF digestibility decreased by 10% (P < 0.01). Total ruminal VFA concentration was unchanged, but acetate:propionate was lower (P < 0.01) and isobutyrate proportion was greater (P < 0.001) with the legume addition. Legume supplementation increased duodenal flows of total N (+56%; P < 0.001), nonammonia N (+52%; P < 0.001), ruminal escape N (+80%; P < 0.001), and microbial N (+28%; P < 0.05). Microbial efficiency was not affected by legume addition. Supplementation of S. saponaria increased (P < 0.05) dietary OM intake by 14%, but had no effect on CP intake and ruminal fluid ammonia concentration or on OM and N digestion. Digestibility of ADF was decreased (P < 0.01) by 10% with S. saponaria as was acetate:propionate (P < 0.001) and the isobutyrate proportion (P < 0.001). Ruminal protozoa counts increased (P < 0.01) by 67% with S. saponaria. Duodenal N flows were not significantly affected by S. saponaria supplementation, except for microbial N flow (+34%; P < 0.01). Microbial efficiency was greater (P < 0.05) by 63% with the addition of S. saponaria. Few interactions between legume and S. saponaria supplementation were observed. The NDF digestibility was decreased with S. saponaria in the grass-alone diet, but not in the legume-supplemented diet (interaction; P < 0.05). Interactions were absent in ruminal fermentation measures and duodenal N flow, indicating that effects were additive. Results suggest that, even when not decreasing ruminal protozoa count, supplementation of S. saponaria fruits is a beneficial way to improve ruminal VFA profile, microbial efficiency, and duodenal flow of microbial protein in sheep fed tropical grass-alone or grass-legume diets.
Abreu
A
A
Department of Animal Production, National University of Colombia, Bogotá, Colombia.
Carulla
J E
JE
Lascano
C E
CE
Díaz
T E
TE
Kreuzer
M
M
Hess
H D
HD
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D004043:Dietary Fiber / Q000032:analysis; D019587:Dietary Supplements; D004063:Digestion; D004386:Duodenum / Q000378:metabolism*; D056890:Eukaryota / Q000254:growth & development; D007887:Fabaceae; D005232:Fatty Acids, Volatile / Q000032:analysis; D005285:Fermentation; D009584:Nitrogen / Q000378:metabolism; D006109:Poaceae; D011897:Random Allocation; D012417:Rumen / Q000378:metabolism* / Q000469:parasitology; D032127:Sapindus; D012756:Sheep / Q000378:metabolism*
D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D009584:Nitrogen