Resumo

PEREZ ALVARADO, María Alejandra; CALDERON MONTANEZ, Diego Alfredo; BRANA VARELA, Diego  e  CUARON IBARGUENGOYTIA, José Antonio. A study of the strategies of amino acid value assignment to phytases. Rev. mex. de cienc. pecuarias [online]. 2015, vol.6, n.3, pp.305-314. ISSN 2448-6698.

The objective of this study was to evaluate the productive performance of growing pigs fed reduced amino acids diets by the use of phytase. During 63 d (three 21 d feeding phases), a total of 96 pigs in two blocks (consecutive farrowing groups), of an average initial weight of 42.7 ± 4.58 kg, were randomized to six treatments which consisted of a 2 × 3 factorial arrangement (conventional diet, a positive control= CP or reduced in amino acids by the addition of phytase, a negative control= CN) and (3 leads of phytase: 0, Phytase A or Phytase B). Weekly feed intake was recorded. At start and the end of each feeding-phase pigs were weighed and fat and muscle depths were measured using real time ultrasound. At the end of each feeding phase, blood samples were drawn to determine plasma urea nitrogen. Aside for final feed efficiency, which was slightly improved by phytase (P<0.08), there were no significant effects on any of the dependent variables during the 63 d trial (P>0.15). On the efficiency of utilization of nutrients, there was an obvious effect by level of digestible lysine (P<0.03), better in the lower lysine diets, although plasma urea nitrogen levels were the same for all treatments (P<0.18). In conclusion, a slight reduction in the concentration of amino acids, nor the addition of phytase to diets for pigs from 40 kg of body weight affect productive performance due to the inherent variation of the apportion and of the requirements.

Palavras-chave : Pigs; Growth; Productive performance; Phytase; Amino acids.

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