Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2010
Publication Date: 5/1/2010
Citation: Park, S.W., Branton, S.L., Gerard, P.D., Womack, S.K., Peebles, E.D. 2010. Influence of Supplemental Dietary Poultry Fat, Phytase, and 25-Hydroxycholecalciferol on the Performance of Commercial Layers Inoculated Before or at the Onset of Lay with F-Strain Mycoplasma gallisepticum. Poultry Science. 89(5):910-916. Interpretive Summary: Although use of live Mycoplasma gallisepticum (MG) vaccines has reduced the loss of approximately 16 eggs/hen, losses still occur. Other efforts to reduce the deleterious effects of MG vaccination on layer performance have included nutritional intervention particularly the use of phytase (PHY) , poultry fat(PF) and vitamin D3 (D3). However, none of the studies that have addressed the usage of these strategies through a complete laying cycle. The objective of this research was to extend the investigation f the interactive effects of age of inoculation with live F strain MG (FMG) vaccine, PF, PHY and D3 on the performance of layers through 58 weeks of age (WOA). The results of this study show that the dietary treatments provided in this study had no influence on the performance of the birds after an FMG inoculation but that the dietary treatments did influence the effects that age of inoculation (12 or 22 WOA) had on body weight and feed conversion. Overall, the results suggest that the use of supplementary PF at the 0.75% level or PHY and D3 in conjunction with PF at the 1.50% level do not provide any additional benefit over that provided by 1.50% PF alone for the performance of layers inoculated with FMG.
Technical Abstract: The effects of 2 levels of supplemental dietary poultry fat (PF) and the combination of PF, phytase (PHY) and 25-hydroxycholecalciferol (D3) on the performance of commercial layers inoculated with F-strain Mycoplasma gallisepticum (FMG) were investigated in 2 trials. Sham and FMG inoculations were administered at 12 (before lay) and 22 (early in lay) wk and dietary treatments [basal control diet (BCD); BCD with 0.75% supplemental PF; BCD with 1.50% supplemental PF; BCD with 1.50% supplemental PF, 0.013% PHY, and 0.025% D3] were initiated at 20 wk of age. Hen BW, egg weight, and egg production (EP) were determined every 4 wk between 24 and 58 wk of age. Feed consumption (FC) and feed conversion were determined in 4 wk intervals beginning on wk 25 and ending on wk 58, and total mortality and mean EP were determined over the entire 24 to 58 wk period. The addition of 0.75 and 1.50% PF increased BW at wk 48 and 58, respectively, and supplemental PF at the 1.50% level increased the BW of hens that had been inoculated (sham or FMG) on wk 22, and reduced the FC of hens inoculated on wk 12. Feed conversion was decreased in the 25-28 and 57-58 and increased in the 45-48 wk age periods by an FMG inoculation. In birds inoculated at 22 wk of age, FMG increased egg weight. Although EP was reduced at wk 24 and was increased at wk 58 by FMG, total EP was not affected. In conclusion, an inoculation of FMG at either 12 or 22 wk of age can result in a relative shift in EP from the early to late stage of lay without affecting total EP, and although the BW and FC responses of hens to added dietary PF was influenced by their age and the age of inoculation, use of the supplemental combination of PHY and D3 had no additional effect on performance when provided in conjunction with 1.50% PF.