Phytase levels on performance, bone and biochemical parameters of pigs fed with diet of vegetable origin without inclusion of dicalcium phosphate/Niveis de fitase sobre o desempenho, parametros osseos e bioquimicos de suinos alimentados com racao de origem vegetal sem inclusao de fosfato bicalcico

This study was carried out to determine the phytase levels in diets for growing swine selected for meat deposition. Sixty-four crossbred swine (32 barrows and 32 females), with an average initial weight of 23.311 ± 2.254 kg were distributed in a block design with four treatments and eight replications of two animals (one male and one female) each. The treatments consisted of a control diet with vegetables ingredients, without dicalcium phosphate and phytase inclusion, containing 0.100% available phosphorus and three other diets obtained by the inclusion of 300, 600 and 1200 phytase units (FTU [kg.sup.-1]) to the control diet. Levels of phytase influenced linearly the daily weight gain and feed intake, increasing to the level of 293 and 307 FTU [kg.sup.-1] diet, respectively, from which remained on a plateau. Feed conversion ratio decreased to 255 FTU [kg.sup.-1] diet, and remained on a plateau. Levels of phytase did not affect the levels of ash and phosphorus in animal bone. There was decreasing linear effect of treatments on the biochemical results of alkaline phosphatase. The best results in weight gain, feed intake and feed conversion were obtained, respectively, with levels of 293, 307 and 255 FTU [kg.sup.-1] of feed for pigs of high genetic potential for lean deposition during the 55 to 90 days of age. Key words: calcium and phosphorus, development, enzyme, feed, swine production. Este estudo foi conduzido com o objetivo de avaliar os niveis de fitase em racoes para suinos em crescimento selecionados para deposicao de carne. Foram utilizados 64 suinos mesticos (32 machos castrados e 32 femeas), hibridos comerciais, com peso medio inicial de 23,3H ± 2,254 kg, distribuidos em delineamento de blocos casualizados, com quatro tratamentos, oito repeticoes e dois animais (um macho e uma femea) por unidade experimental. Os tratamentos foram constituidos por uma racao controle de origem vegetal, sem inclusao de fosfato bicalcico e fitase, contendo 0,100% de fosforo disponivel; e de outras tres racoes obtidas pela inclusao de 300, 600 e 1200 unidades de fitase (UFT [kg.sup.-1]) a racao controle. Os niveis de fitase influenciaram de forma linear o ganho de peso diario e consumo de racao, aumentando ate o nivel de 293 e 307 UFT [kg.sup.-1] de racao, respectivamente, a partir do qual permaneceram em um plato. A conversao alimentar diminuiu ate 255 UFT [kg.sup.-1] de racao, a qual permaneceu em um plato. Os niveis de fitase nao influenciaram os teores de cinzas e f