Studies of high-quality pork production using local agricultural by-product

連合農学研究科博士論文(農学) ; 学位取得日: 平成21年9月18日This study was conducted to establish an effective way to use unqualified potatoes as a feed for pigs. After the preparation of silage using the potatoes below marketing standards, assessment of the silage quality, and the effects of the silage on the perform-ance and carcass quality in finishing pigs were evaluated. Using the obtained data stated above, economical and management prospects of the pig farmer applying this production system was analyzed. Pig production using the silage with outdoor rearing was also investigated to discuss a possibility of sustainable animal production. The re-sults obtained were followed.1. Refused potatoes from the commercial standards were washed, cut, mixed with other ingredients and packed in a flexible container bag. This potato mixed silage was designed to contain potatoes a half of a whole silage and less lysine than the pig re-quirement for their desirable growth. The quality of the silage produced in this way seemed to be favorable, because it had a high lactic acid content and low pH. The nu-tritional loss of the silage through the fermentation was minimal, and the secondary fermentation of the silage after opening was negligible.2. Effects of the potato mixed silage on performance and meat quality in finishing pigs were investigated. The treatment with the silage decreased the growth rate of the pigs, but had no influence on the carcass traits. The silage treated pigs produced a meat with less smell, better flavor and more tenderness than the control pigs fed a commercial diet. According to the physical and chemical analyses, loin meat of the silage treated 117 pigs showed significantly higher percentages in fat, saturated and monounsaturated fatty acids, and lower shear stress value than that of the control pigs. Biochemical analysis of serum and slaughter inspection revealed no problems concerning the health condition of the silage treated pigs. These results suggest that the potato mixed silage has a high potential to produce quality carcasses with highly accumulated fat within a loin muscle.3. Application of this pork production system using potato mixed silage into the practi-cal field (farmer) was examined and the obtained data were used to analyze economi-cal and management prospects of farmers applying this system. Consumer interest in this system was also researched. Consumers highly conscious to environmental prob-lems and food safety had a tendency to support this kind of sustainable animal produc-tion system of using local agricultural by-product as an animal feed. The economical and management analysis prospected that the income of the farmers applying this pig production system with potato mixed silage could be increased by selling the produced quality pork by 10% higher price than that produced by the current conventional sys-tem, and evaluated this system as a valuable sustainable animal production model.4. Effects of different rearing environments (indoor rearing vs. outdoor rearing) and diets (commercial diet vs. potato mixed silage) on behavior, performance, meat quality and muscle fiber characteristics in finishing pigs were investigated. Outdoor rearing and the silage feeding decreased productivity of finishing pigs, but produced different quality meat and muscle fiber characteristics from those of the current conventional rearing management system with a commercial diet fed indoors. Results show that the pig management systems examined in this study could produce acceptable and specific 118 quality pork to meet consumer needs. In conclusion, it was clarified in this study that pigs fed with silage made by un-qualified potatoes produced high-quality pork, farmer income applying this pig pro-duction system could increase, many consumers support this system as sustainable and safety food production agriculture, and the combination of potato mixed silage feeding and outdoor rearing could produce specific types of pork to meet consumer needs. Therefore, this local agricultural by-product feeding and high quality pork production system would be a sustainable animal production model