2008 年 33 巻 4 号 p. 1169-1172
The bad smell pollution from livestock farms becomes the social problem. As the experiment was done for the reduction of bad smell in a poultry production, the effects of dietary added 1% rice husk charcoal to 372-day-old laying hen were found that the ammonia gas densities on their feces as bad smell in the poultry farm was reduced almost by a half and the eggshell strength was slightly improved. This rice husk charcoal (RHC) was expensive at the price of 208 yen per kg as a manufactured product. It is ecologically necessary to investigate the effects of farmer made rice husk charcoal (FRHC), being a low cost. In this experiment, 1% and 3% of RHC and FRHC were added into the formula feed at inner percents. Effects of both 1% and 3% RHC and FRHC dietaries to each 22 laying hens (451-day-old) were investigated in comparison with Non RHC dietary. The egg production rate during the test was indicated that 1% FRHC and 1% RHC dietaries increased but 3% FRHC and 3% RHC dietaries decreased than Non RHC dietary. However, the ammonia gas densities on their feces was significantly reduced 21-44% in 1% and 3% RHC dietaries and also 21-25% in 1% and 3% FRHC dietaries at 5-6 weeks in comparison with Non RHC dietary, and was also significantly reduced in 1% RHC dietary at 2-6 weeks continuously.