Effects of a Prelay 6/85-Strain Mycoplasma gallisepticum inoculation alone or in conjunction with subsequent F-strain M. gallisepticum inoculations during lay on the internal egg characteristics of commercial egg-laying hens.

The effects of a prelay 6/85-strain Mycoplasma gallisepticum (6/85 MG) inoculation alone or in conjunction with subsequent F-strain M. gallisepticum (FMG) inoculations during lay on the internal egg characteristics of commercial egg-laying hens were investigated. In the first 2 treatment groups, birds were sham inoculated or were inoculated with 6/85 MG at 10 wk of age. In a third treatment group, birds were inoculated with 6/85 MG at 10 wk in conjunction with a subsequent inoculation of FMG at 22 wk, and in a fourth treatment group, birds were inoculated with 6/85 MG at 10 wk in conjunction with a subsequent inoculation of FMG at 45 wk. Percentage yolk weight, albumen weight, yolk moisture, and yolk lipid were determined at 24, 32, 43, 47, and 58 wk of hen age. The data from wk 24, 32, and 43 were analyzed separately from those at wk 47 and 58. Furthermore, yolk fatty acid profiles were determined at wk 58. The applied treatments affected yolk moisture and fatty acid profiles. Across wk 24, 32, and 43, yolk moisture content was higher in birds inoculated with 6/85 MG at 10 wk and FMG at 22 wk when compared with control birds and those inoculated with 6/85 MG at 10 wk alone. In addition, at wk 58, yolk palmitic, oleic, and linolenic acid concentrations were affected differently by treatment. A 22-wk FMG inoculation in birds previously inoculated with 6/85 MG at 10 wk may increase yolk moisture content, and alterations in yolk palmitic, oleic, and linolenic acid levels with treatment may be manifested by disturbances in fatty acid synthesis.