| Recent years the development of low erucic acid, low glucosinolate cultivars of rapeseed (double-low rapeseed) in China has led to the availability of a feed ingredient with considerable potential to replace or partially replace soybean meal in diets for mono-gastric animals. Double-low rapeseed meal is a high quality product with high protein content and well-balanced amino acids. It is the prerequisite and foundation to analyze and assess the content and component of the chemical composition in the meal, to study how the processing affected the composition and the nutritive quality, and also to study the utility of the nutrients in the meal by the animal so that the nutritive quality of the double-low rapeseed meal could be improved and the meal could be fully utilized as a ingredient in pig and poultry diet. The purpose of this research was to evaluate the quality characteristics of Chinese double-low rapeseed meals, and also to explore the potential for improved utilization of meal by pigs. The results are as follows:1. A comprehensive evaluation of the nutritive profiles of the meals and de-fatted seed samples derived from 3 Chinese double-low rapeseed varieties and 1 Canola were undertaken. The evaluation involved the analysis of crude protein (CP), amino acids, sucrose, oligosaccharides, dietary fiber (DF), ash, calcium, phosphorous and phytate. DF components determined includes non-starch polysaccharides, lignin and ploy-phenols, cell wall protein, and minerals. From the viewpoint of nutritional value, Chinese double-low rapeseed defatted seed samples contained similar or more amounts of sucrose, CP and lysine (lys) than that of Canadian canola defatted seed sample; lys, the first limited amino acid in pig diet, were more than 2% in the 3 defatted seedsamples. However, in comparison to the corresponding meal samples, the nutritional value changed considerably. The lys and sucrose contents decreased markly. On the other hand, the amounts of DF increased substantially in those 2 over-heat treated meal samples. In particularly, the increases of cell wall protein content in the 2 samples were responsible for the large increase of DF in terms of processing technology.2. The study was conducted to determine the digestible protein content by using a two step pepsin-pancreatin system in vitro. 4 defatted seed samples were moist heat at 2 temperature conditions, ie, 105 1 or 109 1 so 8 defatted seed samples in total were obtained; 4 corresponding meal samples processed in different commercial plants either in China or in Canada. For the defatted seed samples, dry mailer (DM) and protein digestibilities were significantly higher in the samples heat treated at 109 PC than those treated at 105 1. In the cases of commercial meal samples, the digestibility values of protein depended on the processing conditions. The highest values were obtained in canola meal; on the other hand, either over-heated (>110 ) or under-heated(< 105 ) in the commercial processing, the protein digestibilities in vitro decreased considerably. The reduction in digestible protein content for meal samples heat treated at temperatures above 110 was associated with the increased neutral detergent fiber (NDF) content as measured in Chapter 2, and also the extent of protein damage was reflected by high protein content in the NDF residue. The results suggested temperature during the processing be critical for the quality of double-low rapeseed meal.3. Available energy and amino acid determinations were carried out with adult SCWL cockerels using the improved precision-feeding technique described by Sibbald (1986) with modifications according to Zhang et al. (1994). The results showed that all four rapeseed/canola defatted seed samples had similar TME values whereas the three samples of Chinese meal had lower TME values than that of the Canadian commercial canola meal. These data indicate that the processing conditions used for the preparation of the meals may have influenced energy digestibility. This result is in agreem...
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