| Elephant grass has been spread in southern province of China, as its high yield and nutritional value. Guimu-l was cultivated by Guangxi Institute of Animal for many years. The quality and forage yield are higher than their parents. Many years of application promotion, find that the result of feeding ruminant are not satisfactory. In order to find out the factors that influence the Guimu-l and make better use of Guimu-l's feeding value, this research is to assess Guimu-l by using gas production method and static fermentation-nylon bag method in vitro. The present research included three experiments listed as follow:1. Evaluation of Guimu-l's gas characteristics of different rumen fluid by gas production method in vitro of within 48h fermented. The sources of rumen fluid, the goat feed Guimu-l (goat rumen fluid ?), goat the goat feed conventional concentrate and roughage (rumen fluid ?), the cow feed conventional concentrate and roughage (cow rumen fluid ?), respectively. The gas production after 3h,6h,12h,24h,48h in vitro digestion, the results were showed as follows:Along with the extending cultivation time, the gas production has increasing tendency. Guimu-1 has the highest volume production in rumen fluid ? (28ml). The gas production were goat rumen fluid II>goat rumen fluid ?>rumen fluid ?after 3h,6h,12h; goat rumen fluid I>goat rumen fluid ?>rumen fluid ?after 24h,48h. The total gas production were goat rumen fluid ? (28.00mL)> goat rumen fluid ? (24.97mL)> cows rumen fluid ?(22.71 mL),which ? and ? were significantly different (P <0.05).The gas production curve of Guimu-1 Pennisetum purpureum in vitro, showing "S" shape.2. Studying of nutrient digestibility of Guimu-1 by using static fermentation method in vitro. We evaluated the degradability of dry matter (DM), crude protein (CP), true Protein (TP), soluble crude protein (SCP), crude fiber (CF), neutral detergent fiber (NDF) and acid detergent fiber (ADF) by the static fermentation-nylon bag method. The results showed that the dry matter degradation rates were 23.39%,33.95%,45.74% in vitro fermentation 12h,24h, 48h, respectively. The degradation of crude protein and true protein had been gradually increased with the extension of time in the protein group. But the degradation rate of soluble crude protein was gradually increased during 0-12h, then it declined during 12-24h, showing "S" curve. The digestive characteristic of proteins that the early (0-12h) had high digestibility and the late (12-48h) had low digestibility was not consistent with the law of gas production. It turned that the protein and carbohydrate digestion in the rumen was different. In the fiber group, the degradation rate of each component was gradually increased with the extension of digestion time. The crude fiber degradation rate was low in the 48h, the rate was 26.78%. Its law was consistent with the gas production rule.3. The study of amino acid digestibility of Guimu-1, showing that the concentration of amino acid was rose with the extension of time, the proportion of amino acids accounted for the crude protein was increased after rumen fluid digestion. The degradation rates of Arg, Lys, His, Val, Ile and Leu were 9.2%, 4.76%,0.41%,8.07%,9.2% and9.46%, respectively. It's indicated that they can resist the early degradation in the rumen.According to above analysis, we found that Guimu-1 Pennisetum purpureumcv was not easy to be digested during 0-12h in the rumen. Main problems:gas production, fiber and amino acid (Arg, Lys, His, Val, Ile and Leu) degradation rate is low. This may be why the elephant grass feed ruminant not ideal. Different sources of rumen fluid in vitro gas test showed that long-term feeding Guimu-l can improve digestibility and eliminate obstruction. |
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