Effect of phytase dose on productive performance and bone status of layers fed with graded levels of digestible lysine

• Ingrid Y. Martinez Rojas ^[1] ; C. López Coello ^[1] ; E. Ávila González ^[1] ; J. Arce Menocal ^[2] ; GA. Gomes ^[3]
  1. [1] Universidad Nacional Autónoma de México

     Universidad Nacional Autónoma de México

     México

     
  2. [2] Facultad de Medicina Veterinaria y Zootecnia. Universidad Michoacana de San Nicolás Hidalgo. México
  3. [3] AB Vista, Marlborough. UK

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• Localización: Veterinaria México, ISSN 0301-5092, Vol. 5, Nº. 3, 2018, págs. 1-20
• Idioma: inglés
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• Resumen

  • Exogenous phytase could influence dietary protein availability by variation in using dose. The objective of the present study was to determine if incremental dosing of an evolved E.coli 6-phytase would lead to improvements in lysine availability through evaluating performance and bone status in Bovans White layers. A total of 182 layers were placed in individual cages and distributed to 13 treatments: a 3 × 4 factorial arrangement with three levels of digestible lysine (dLys - 0.67, 0.77, and 0.87 %) and four doses of phytase (0, 300, 1 200, and 4 800 FTU/kg) in 0.12 % available P (avP) diets. Additionally, one phytase-free control treatment was included with 0.25 % avP and 0.87 % dLys. Productive parameters were recorded for 25 weeks, from 39 week-old. At the end, abdominal fat deposition and the tibia were sampled; in bone was determined breaking strength and bone ash. Layers fed 1 200 FTU/kg phytase increased egg production percentage (F3,169 = 2.01, p = 0.111), abdominal fat deposition (F3,169 = 2.52, p = 0.059), bone breaking strength (F3,169 = 4.29, p = 0.006) and bone ash weight (F3,169 = 3.62, p = 0.014) compared with non-phytase inclusion.

    Furthermore, 1 200 FTU/kg phytase decreased incidence of broken eggs and soft-shell eggs (F3,169 = 2.9, p = 0.036). Phytase and dLys levels influenced egg mass and bone ash concentration (F12,169 = 1.86, p = 0.043).

    FCR and body weight loss was reduced with phytase inclusion (respectively:

    F12,169 = 2.43, p = 0.006, and F12,169 = 2.24, p = 0.012). Phytase-free control diet increased egg weight (F12,169 = 3.70, p < 0.001), but gave greater BW loss (F12,169 = 17.79, p < 0.001), less abdominal fat content (F12,169 = 5.85, p < 0.001), and no effect on other variables (p > 0.07).

    In conclusion, 1 200 FTU/kg of phytase improved productive performance and preserved body weight and bone status, without equivalence of phytase inclusion for dLys level, even with higher doses.