In situ ruminal degradability and intestinal digestion of raw and extruded legume seeds and soya bean meal protein.
An experiment was performed to evaluate the effect of extrusion and carbohydrate addition on rumen degradation and intestinal digestion of raw legume seeds and solvent extracted soya bean meal (SBM) protein. Whole soya beans (WSB) without or with maize added (75:25) (WSB-M), peas, lupins and SBM were extruded at 140 degrees C. Protein rumen degradation and intestinal digestibility of unprocessed and extruded protein sources were measured by in sacco and mobile bag procedures, respectively, in two dairy cows cannulated in rumen and duodenum. Between 12 and 15 polyester bags with 4 g of each protein source were incubated in rumen for 12 h and the residues, pooled by feed, were introduced into the duodenum in small nylon bags after pre-incubation in a pepsin solution, and recovered from faeces the day after. Extrusion significantly (p < 0.001) reduced N degradation of all protein sources, from 98.1%, 91.6%, 90.5% and 64.8% to 53.1%, 73.8%, 70.3% and 44.2% for peas, lupins, WSB and SBM respectively. The addition of maize to WSB strengthened the effect of extrusion on rumen N degradation, from 88.2% to 52.6%. Residues from rumen incubation of extruded feeds showed a higher (p < 0.001) intestinal N digestibility except for SBM (87.0%, 82.9%, 66.3%, 85.0% and 97.2%, and 99.1%, 95.8%, 96.8%, 97.8% and 98.7%, respectively, for non-extruded and extruded, peas, lupins, WSB, WSB-M and SBM). In conclusion, the extrusion of studied legume seeds and SBM promotes a clear and significant increase of their metabolizable protein value, particularly in peas, and the inclusion of a source of carbohydrates before extrusion increase this response.
Solanas
E
E
Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, 50013 Zaragoza, Spain.
Castrillo
C
C
Balcells
J
J
Guada
J A
JA
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004063:Digestion / Q000187:drug effects / Q000502:physiology*; D004386:Duodenum / Q000378:metabolism*; D007887:Fabaceae; D005260:Female; D005285:Fermentation; D005511:Food Handling / Q000379:methods; D009584:Nitrogen / Q000378:metabolism; D012417:Rumen / Q000378:metabolism*; D012639:Seeds / Q000378:metabolism*; D030262:Soybean Proteins / Q000008:administration & dosage / Q000378:metabolism*
D030262:Soybean Proteins; D009584:Nitrogen