Dairy cows are customarily given grains and highly digestible byproduct ingredients as additions to forage to support milk production. In many parts of the world growing seasons are short, and the grain crops that can...Dairy cows are customarily given grains and highly digestible byproduct ingredients as additions to forage to support milk production. In many parts of the world growing seasons are short, and the grain crops that can be grown may not provide adequate yields. Sugar beets, on the other hand are relatively hardy, and dry matter yields surpass the yields of most grain crops. There are however, perceptions that beets may not be suitable as a feed ingredient due to the fact that the storage form of carbohydrate is sugar rather than starch. With little analytical support, sugar has been rejected in many feeding programs with the view that sugar reduces rumen pH, fiber digestion and microbial yield. This review explores available facts revolving around these concerns. Information regarding the feeding of sugar beets is provided and the use of sugar beets as a partial replacement for grain is proposed.展开更多
Background： During processing in a desolventizer/toaster（DT）, rapeseed meal（RSM） is heated to evaporate the hexane and to reduce the level of heat-labile anti-nutritional factors such as glucosinolates（GSL）. Ho...Background： During processing in a desolventizer/toaster（DT）, rapeseed meal（RSM） is heated to evaporate the hexane and to reduce the level of heat-labile anti-nutritional factors such as glucosinolates（GSL）. However, excessive heat treatment may reduce amino acid（AA） content in addition to lower AA digestibility and availability in RSM. The objective of the present study was to produce from one batch of a 00-rapeseed variety（17 μmol GSL/g dry matter（DM）, seed grade quality） five differently processed RSM under standardized and defined conditions in a pilot plant,and to determine the impact of these different treatments on protein solubility and chemical composition, in particular with regard to contents of AA including reactive Lys（rL ys） and levels of total and individual GSL.Methods： Four RSM were exposed to wet toasting conditions（WetT C） with increasing residence time in the DT of 48,64, 76, and 93 min. A blend of these four RSM was further processed, starting with saturated steam processing（〈 100 °C）and followed by exposure to dry toasting conditions（DryT C） to further reduce the GSL content in this RSM.Results： The contents of neutral detergent fiber and neutral detergent fiber bound crude protein（CP） increased linearly（P 〈 0.05）, as residence time of RSM in the DT increased from 48 to 93 min, whereas contents of total and most individual GSL and those of Lys, rL ys, Cys, and the calculated ratio of Lys：CP and r Lys：CP decreased linearly（P ≤ 0.05）.The combination of wet heating and DryT C resulted in the lowest GSL content compared to RSM produced under WetT C, but was associated with lowest protein solubility.Conclusions： It can be concluded that by increasing residence time in the DT or using alternative processing conditions such as wet heating combined with DryT C, contents of total and individual GSL in RSM can be substantially reduced.Further in vivo studies are warranted to elucidate if and to which extent the observed differences in protein quality and GSL content between RSM may affect digestibility and bioavailability of AA in monogastric animals.展开更多
文摘Dairy cows are customarily given grains and highly digestible byproduct ingredients as additions to forage to support milk production. In many parts of the world growing seasons are short, and the grain crops that can be grown may not provide adequate yields. Sugar beets, on the other hand are relatively hardy, and dry matter yields surpass the yields of most grain crops. There are however, perceptions that beets may not be suitable as a feed ingredient due to the fact that the storage form of carbohydrate is sugar rather than starch. With little analytical support, sugar has been rejected in many feeding programs with the view that sugar reduces rumen pH, fiber digestion and microbial yield. This review explores available facts revolving around these concerns. Information regarding the feeding of sugar beets is provided and the use of sugar beets as a partial replacement for grain is proposed.
文摘Background： During processing in a desolventizer/toaster（DT）, rapeseed meal（RSM） is heated to evaporate the hexane and to reduce the level of heat-labile anti-nutritional factors such as glucosinolates（GSL）. However, excessive heat treatment may reduce amino acid（AA） content in addition to lower AA digestibility and availability in RSM. The objective of the present study was to produce from one batch of a 00-rapeseed variety（17 μmol GSL/g dry matter（DM）, seed grade quality） five differently processed RSM under standardized and defined conditions in a pilot plant,and to determine the impact of these different treatments on protein solubility and chemical composition, in particular with regard to contents of AA including reactive Lys（rL ys） and levels of total and individual GSL.Methods： Four RSM were exposed to wet toasting conditions（WetT C） with increasing residence time in the DT of 48,64, 76, and 93 min. A blend of these four RSM was further processed, starting with saturated steam processing（〈 100 °C）and followed by exposure to dry toasting conditions（DryT C） to further reduce the GSL content in this RSM.Results： The contents of neutral detergent fiber and neutral detergent fiber bound crude protein（CP） increased linearly（P 〈 0.05）, as residence time of RSM in the DT increased from 48 to 93 min, whereas contents of total and most individual GSL and those of Lys, rL ys, Cys, and the calculated ratio of Lys：CP and r Lys：CP decreased linearly（P ≤ 0.05）.The combination of wet heating and DryT C resulted in the lowest GSL content compared to RSM produced under WetT C, but was associated with lowest protein solubility.Conclusions： It can be concluded that by increasing residence time in the DT or using alternative processing conditions such as wet heating combined with DryT C, contents of total and individual GSL in RSM can be substantially reduced.Further in vivo studies are warranted to elucidate if and to which extent the observed differences in protein quality and GSL content between RSM may affect digestibility and bioavailability of AA in monogastric animals.
