comparison of nanosilver and in-feed disinfectants on layer performance and intestinal microflora and yolk cholesterol

this study was conducted to compare the effect of various commercial in-feed disinfectants on layer performance, intestinal microflora, and egg cholesterol. one hundred and eight layer hens (lsl, 24 wks of age) were divided into six groups consisting: control, formaycin-200 ppm, formalin-200 ppm, and nanosilver in feed-15 ppm or drinking water-7.5 ppm. there were no differences between experimental groups for egg production and egg weight. formycin fed birds produce the highest egg mass (p< 0.05). in comparison of the two methods of nanosilver administration, no significant differences were observed for egg production, egg weight and egg mass. lactic acid bacteria counts in caecal contents were significantly increased in comparison to control and formycin fed groups (p< 0.01). gram negative counts in ileum contents were reduced by all additives, in comparison to control (p< 0.01). cholesterol content of egg was increased in response to formycin and nanosilver (in drinking water) (p< 0.01). in conclusion, in-feed supplementation of formalin and nanosilver in laying hens’ feed resulted in efficient control of intestinal microbial counts and simultaneously improved the egg yield.