Comparison ofin vitro techniques for predicting digestibility of mixed cereal straw and citrus by-product diets in goats
✍ Scribed by Madrid, Josefa; Hern�ndez, Fuensanta; Meg�as, M Dolores
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 127 KB
- Volume
- 79
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Prediction of in vivo digestibility of diþ erent übrous feedstuþ s using üve in vitro techniques (rumen ýuid-pepsin, pepsin-cellulase, NDF-cellulase, amylase-NDF-cellulase and rumen ýuid-NDF) was assessed using 13 diþ erent diets. Samples were grouped into four batches : (1) barley straw ; (2) barley straw supplemented with urea ; (3) barley straw treated with urea ; and (4) barley straw treated with urea + NaOH. Batches 2, 3 and 4 were also supplemented with citrus by-product at four diþ erent levels. The predictive power of the in vitro techniques was assessed using a simple linear regression analysis (Y = a + bX) between the coefficients of in vivo digestibility (Y) and the diþ erent in vitro methods (X). Rumen inoculum was signiücantly associated with in vivo organic matter digestibility (OMD) (r = 0.778, P AE 0.01 and r = 0.901, P AE 0.001 for rumen ýuid-acid pepsin and rumen ýuid-NDF, respectively). Pepsin-cellulase, NDF-cellulase and amylase-NDF-cellulase were also related with in vivo OMD (r = 0.969, P AE 0.001 ; r = 0.917, P AE 0.001 and r = 0.920, P AE 0.001, respectively). These results suggest that using pepsin-cellulase provides the better predictive value (RSD 1.2). Bifactorial analysis demonstrated that all techniques were suitable for predicting the eþ ect of the level of supplementation (P AE 0.001) and straw type (P AE 0.001) on in vivo OMD.