Research/PIC Project 177
From Poultry Hub
Project title: Osteoclast inhibition in laying hens by yeast beta glucan to reduce osteoporosis. (Canadian Poultry Magazine February 2009)
Project Leader: Dr. Bruce Rathgeber
Organisation: Nova Scotia Agricultural College, Canada.
Project Status Complete
Contents |
Project overview
Each year, the North American poultry industries suffer enormous economic losses due to poor eggshell quality. As a hen ages, the mobilization of calcium from medullary bone decreases and less calcium carbonate is produced, creating a calcium deficiency which adversely affects eggshell quality. Recently, in vitro studies have shown that partially purified soluble beta-glucan was a potent inhibitor of bone resorption through the inhibition of osteoclast activity. Therefore, these yeast beta-glucans have the potential to slow bone turnover which may allow for better utilization of dietary calcium. Read full report
Research Project objectives
In this experiment 240, 18-week old White Leghorn hens of the Babcock variety were randomly assigned to four diets supplemented with 0, 25, 50 or 250 g/tonne of refined yeast beta-glucan (YBG). Increasing dietary inclusion of YBG had no effect on egg weight, specific gravity or albumen height. The specific gravity for the 25g/tonne treatment was higher than the other dietary treatments for the time period 22 to 50 weeks of age. However, when the data for beyond 50 weeks of age was included in the analysis there was no longer a statistical difference between treatment groups. A Whipping volume and albumen pH was analyzed up to 66 weeks of age. The highest inclusion level(250g/tonne) of yeast beta glucan reduced albumen pH (P<0.05) compared to the control and the 50g/tonne treatment. When results for all three weeks (including week 69) were analyzed there was a significant interaction (P<0.05) between the age of the birds and the level of dietary inclusion of YBG for the birds offered YBG from week 22 . The pH of albumen increased with age of the bird but this was not as obvious for the control birds. For the group fed YBG from week 50 (second group) it was clear that the pH increased with age for all treatment groups and there was no significant interaction with age and YBG. As hens age the shell becomes thinner and carbon dioxide is lost more readily which results in a reduced rate of reduction of pH with egg storage time. Whipping volume would be related to albumen pH and was not influenced by dietary treatment. Although there was no effect of dietary YBG inclusion on bone breaking strength, there was a significant (P<0.05) effect on ulna density, with trabecular density increasing and cortical density decreasing at the 50 g ton-1 level. Dietary supplementation of a soluble YBG extract appears to increase bone density, and may thereby reduce the incidence of bone breakage during the laying hen production cycle. Read full report
Results
These results indicate that presence of YBG in the diet does influence bone metabolism but this was not reflected in bone strength or in egg production and shell quality. The level of inclusion seems to be very important and unfortunately only a small number of treatment levels were evaluated in this situation. Read full report
Source
Poultry Industry Council
- 483 Arkell Road, Guelph, Ontario, N1H 6H8.
- pic@poultryindustrycouncil.ca
- http://www.poultryindustrycouncil.ca
