Growth performance and nutrient utilisation as influenced in pigs by microbial phytase and vitamin E supplementation to a diet of high oxidative capacity

Abstract

In the first of two experiments carried out with growing-finishing pigs, 40 barrows were kept from 25 to 104 kg body weight (BW). In the second experiment, 24 pigs were kept from 75 to 104 kg BW. The pigs were fed either a barley-maize-based diet (C), or the same diet supplemented with either 1 200 PTU phytase (Ph) or 200 mg α-tocopheryl acetate·kg-1 (E), or both (PhE) in order to assess the effect of microbial phytase and vitamin E on growth performance (experiment 1) and the precaecal digestibility of P, Ca, Mg, Fe, Cu, Zn, crude fat and fatty acids (experiment 2). Ph supplementation improved mean daily weight gain (P < 0.05) and reduced the feed conversion ratio (kg feed·kg-1 weight gain, P < 0.01). Supplementation with α-tocopherol (vitamin E) did not affect growth performance. Ph inclusion improved precaecal digestibility of P (P < 0.001) and reduced that of Zn (P < 0.05). The α-tocopherol addition improved (P < 0.01) the digestibility of Zn, whereas the α-tocopherol digestibility was not affected. The precaecal digestibility of total lipids and the saturated, monounsaturated and polyunsaturated fatty acids were reduced (P < 0.05 to 0.001) by Ph supplementation. The combined addition of Ph and E improved the digestibility of dietary fatty acids. We concluded that dietary phytase in pig diets susceptible to lipid oxidation demands an additional vitamin E supplementation in order to avoid detrimental effects on fat digestibility. (© Elsevier / Inra).