In view of the interest in non-antibiotic dietary supplements to enhance production and immune function, a meta-analysis was carried out on available reports on the benefits on mannanoligosaccharide (MOS) for laying hens.

Eight controlled feeding trials conducted from 2004 through 2006 were reviewed from six nations comparing hens receiving diets supplemented with MOS (BioMos, Alltech Inc.) compared to non supplemented controls. One trial from Greece was conducted using non-confined hens on a wooden slat floor and the remaining seven trials were conducted in caged hens in the U.S., Turkey, Spain, Romania and Hungary.

The results of the trials which were published in proceedings of national and international scientific meetings, abstracts and a peer reviewed journal were reviewed with respect to egg production, egg mass, feed conversion and livability. These parameters are all of financial significance. Differences between mean values reported by the authors were analyzed for significance using a paired t-Test.

The results of trials are shown in the table below. Feed conversion efficiency and hen day egg production were significantly improved by supplementation with MOS at an average dietary inclusion of 0.1% (2 lbs per tons of diet). The beneficial effect on feed conversion efficiency was noted in all 6 trials where specific results were provided and hen-day egg production was enhanced in 7 out of 8 trials. Although there were numerical advantages with respect to egg mass, daily feed intake and livability, there were no significant differences between treatments which could be attributed to MOS.

The mode of action of MOS in enhancing production parameters of hens producing table eggs has not been defined but it is apparent that advantages maybe attributed to a combination of effects. These include:

  • MOS inhibits colonization of potentially pathogenic bacteria bearing Type-1 fimbriae thereby blocking adhesion to the receptor sites of enterocytes lining the intestinal tract.
  • MOS modifies the microflora of the distal intestinal tract production of ammonia is suppressed
  • MOS functions as an immune regulator
  • MOS increases the mucus barrier coating the brush boarder of enterocytes
  • MOS improving the integrity of the intestinal mucosa, reducing the rate of cell turnover as confirmed by increased villus height in relation to the depth of crypts.

Given the ever increasing cost of feed and the competitive situation in U.S. egg industry, feed supplements which provide positive benefits to cost ratios should be considered based on a known mode of action and supported by scientific data. 


 Parameter   Control   MOS2    % Difference    Number of Trials with a Numerical Improvement  
 Hen day egg production (%)





 Egg Mass lbs/doz





 Feed Intake (lb/100/day)3 





 Feed Conversion (lbs/doz)





 Mortality (%)






a,b Mean values with a common superscript are mot significantly different (P<0.05)
applying a paired t-Test
2 MOS = mannanoligosaccharide supplementation at 0.1% diet (2 lb/ton)
3 Brown-feathered hens in EU Trials