Study On Instestinal Protein Digestibility Of Feed Ingredients For Shaanbei White Cashmere Goat

Intestinal degradability of14kinds of feedstuffs (8kinds of concentrate feeds and6kinds of roughage forages) were used to determine intestinal protein degradation by mobile nylon bag technique (MNBT) and three-step in vitro procedure in this study.Trail1:Study on the intestinal degradability of rumen undegradable protein (RUP) by MNBTIn the current study, seven Shaanbei White Cashmere Goats were separately fitted with a rumen fistula (3goats) and with T-type proximal duodenal fistula (4goats). The samples were dried at65℃for48h and then ground using a domestic mill to pass through a40mesh screen for chemical analysis and in situ rumen incubation. Samples were incubated in rumen for16h and then placed in the mobile nylon bag (1cm×2cm). After subjected to pepsin incubation, the samples were inserted in the duodenal. The next day, the mobile bag was collected from feces to measure the degradability of RUP in small intestine.Results showed that the digestion of concentrate feeds were higher than roughage forages after16h incubation in rumen. The degradability of dry matter and crude protein had linear correlation and the linear regression equation was y=0.8344x+13.976(R2=0.4675, n=14). The degradability of RUP in intestine of soybean meal (SBM), cottonseed meal (CSM), rapeseed meal (RSM), distillers dried grains with solubles (DDGS), Wheat bran (WB), corn gluten meal (CGM), corn, yeast, mulberry leaf (ML), alfalfa, astragalus adsurgens (AD), amorpha fruticosa (AF), reed, caragana microphylla (CM) were86.33%,77.24%,60.08%,76.78%,77.56%,96.36%,61.60%,18.49%,42.05%,31.97%,33.95%,30.36%,49.62, and52.21%, respectively.Trail2:Study on the intestinal degradability of rumen undegradable protein (RUP) by three-step in vitroSamples of residue were placed in small nylon bag (2.5cm×4cm) and incubated at40℃for1h with pepsin-HCl solution (0.01%, pH=1.9). After removal from pepsin, the bags were washed in tap water. Subsequently, samples were incubated at40℃for24h with trypsin solution (pH=7.75). The bags were then dried at65℃for48h and then measured the CP concentration to calculate the degradability of RUP in small intestine. Results showed that the degradability of RUP in the intestine of SBM, CSM, RSM, DDGS, WB, CGM, Corn, Yeast, ML, Alfalfa, AD, AF, Reed, CM, were91.70%,80.19%,72.25%,75.43%,61.47%,95.08%,71.03%,18.65%,41.92%,46.51%,45.75%,11.35%,37.98%, and46.25%, respectively. The results of the three-step in vitro procedure with those of the MNBT had a good linear correlation and the linear regression equation was y=0.8465x+0.0868(R2=0.8328, n=14)In this study, it could be concluded that the intestinal digestibility of the feedstuff of all kinds were dissimilar, and the potential that could provide for animal with intestinal protein was different. Three-step in vitro might be a simple, cheap, convenient and reliable method for feed evaluation in ruminants without T-type proximal duodenal fistula.