| The seed meal of a tree, Jartropha curcus L., which grows extensively in southern China, has a protein content of as high as 60% with a relatively well balanced amino acid composition. The toxins and anti-nutrient chemicals contained in the meal, however, restrict its use as a feed for animals. This study on Jatropha curcas seed meal involved chemical analysis of its nutritional value, followed by the use of nylon bag method to measure its degradation in the rumen, and finally by in vitro gas production method to estimate the associative effects between Jatropha curcas seed meal and roughages , and its influence on ruminal fermentation The outcome of this study was expected to provide the theoretical foundation for application of Jatropha curcas seed meal in ruminants'feeding. The study included the following four parts.Experiment 1: The nutritional value of Jatropha curcas seed and meal in lab. Jatropha curcas L. seeds were analyzed for their proximate nutrients, trace elements and amino acids, followed by a comparison with the nutritional values of cottonseed meal and soybean meal. The detoxified Jatropha curcas L. seed meal had a crude protein content of 64.47%, indicating its potential use as a high quality protein feed comparative to fish meal. Integrated analyses showed that detoxified Jatropha curcas L. seed meal was a high quality protein feed, and could replace soybean meal and cottonseed meal in ruminants'rations.Experiment 2: The ruminal degradation of Jatropha curcas seed and meal.Three Lirnousin cows fitted permanent rumen fistula were used to estimate the ruminal degradability and effective degradation rate of dry material (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), Ca, P, gross energy (GE) of Jatropha seed meal, detoxified Jatropha seed meal, Jatropha seed kernel, soybean meal and cotton seed meal in the rumen by the nylon bag technique. The results showed that the effective degradation rates of DM and CP of detoxified Jatropha seed meal were similar to soybean meal and were higher than cotton seed meal. Protein degradation of Jatropha seed kernel was higher than 95% after 16 h of incubation in the rumen. Amino acid degradation of detoxified Jatropha seed meal was higher than 90% after 24 h of incubation in the rumen. Protein degradation rates and effective degradation rates of Jatropha seed meal were the lowest in all samples.Experiment 3: Difference of the associative effects of detoxification Jatropha Seed Meal, soybean meal, cotton seed meal and different NDF from roughage feeds .This study was conducted to evaluate the associative effects of different protein levels and roughages on in vitro rumen fermentation and dry matter degradability by using rumen fluids of Simmental×Luxi yellow crossbred cattle. The treatments included eighty four combinations of seven levels (10, 11, 12, 13, 14, 15 and 16%) of each of three protein feeds (Jatropha seed meal, soybean meal and cotton meal), and four types of extracted NDF from roughages (Chinese wildrye, corn silage, wheat straw, maize straw and in a 3×4×7 factorial arrangement. The results showed that the gas production, pH, dry matter degradability, NH3-N concentrations of Jatropha seed meal were lower than those of soybean meal combinations (P < 0.05), but higher than those of cottonseed meal combinations. Dry matter degradation and gas production of corn silage were the highest, and those of Chinese wildrye were the lowest (P < 0.05), but pH and NH3-N concentrations were just the opposite. With the dietary protein level increased, the pH, dry matter degradability and NH3-N concentrations had a tendency to increase (P < 0.1), and gas production increased first but then decreased. The results suggested that fermentation parameters of the detoxified Jatropha seed meal combined with roughages were lower than those of soybean meal combined with roughages. The detoxified Jatropha seed meal combined with maize stalk or corn silage was better than the others. The associative effect of protein feeds and roughages was highly significant for gas production, dry matter degradability and NH3-N concentrations (P < 0.01).
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