ReduÃÃo de nutrientes em raÃÃo com fitase para suÃnos em crescimento / Reduction of nutrients in diets with phytase for growing pigs

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Two experiments were conducted in the Animal Science Department at the Federal University of Lavras to evaluate different formulations of diets containing levels of nutrients and energy reduced in accordance to a nutritional plan of phytase, in order to establish the contribution of the enzyme through performance, energy and nitrogen balance, availability of calcium and phosphorus and economic viability of diets formulated for growing pigs. In Experiment I, 50 barrows pigs and 50 gilts pigs of the Topigs genetics with initial weight of 25 Â 1.72 kg and final weight of 50 Â 2.86 kg were housed in a randomized block design (RBD), with five treatments and ten replicates, namely, two animals per experimental unit (one male and one female) during a 30-day period. The experimental diets were formulated on the basis of corn and soybean meal, supplemented with vitamins, minerals and aminoacids in order to meet the minimum recommendations of genetics. The treatments were distributed as follows: T1-nutrient recommendations of genetics (positive control), T2- reduced nutrient levels according to a nutritional plan and without phytase (negative control) and T3- reduced nutrient levels according to a nutritional plan and with the phytase supplementation. The diets (except the positive control) had their levels of nutrients and energy reduced according to a nutritional plan of phytase. The variables analyzed were final weight (FW), daily gain (DG), daily feed intake (DFI) and feed conversion (FC). DFI did not differ (P>0.05) among the treatments. With regard to FW, DFI and FC, there was difference (P <0.05). It was found that animals fed diets with reduced nutritional levels and supplemented with phytase had better performance since they did not differ from the positive control treatment. In Exp II, 45 barrows pigs of the Topigs genetics, with initial weight of 49 Â 3.67 kg, were housed in (RBD), in three consecutive times, amounting to nine treatments and five replicates, the experimental plot being represented by one animal (metabolism cage) and nine-day duration. The analyzed variables were; digestibility dry matter (DDM), digestibility of gross energy (DCE), digestible energy (DE), metabolizable energy (ME), absorbed nitrogen (%NABS), nitrogen retention (%NRET), retained and absorbed nitrogen (%NRETABS), digestibility of calcium (CaD), digestibility of phosphorus (DP) and economic viability of the diets. No difference was found (P>0.05) for DDM, DCE, DE and ME. Likewise, the %NABS, %NRET, %NRET ABS showed no differences (P>0.05) among the treatments. With relation to both CaD and DP there was effect (P <0.05) and phytase supplementation in the diet improved (P <0.05) phosphorus utilization. As for DCA, the diet containing enzyme showed higher values than the positive control and similar to the negative control. With respect to the economic viability analysis of the diets, there was difference (P <0.05). The diet containing reduced nutrient levels and supplemented with phytase presented a lower total cost (P <0.05), not differing from the negative control diet, in addition, it showed a higher net income when compared to other diets. Thus, it follows that phytase supplementation in diets with reduced levels of energy and nutrients according to the nutritional plan, presents itself as an economically viable alternative to growing pigs, since that the animals show the same performance when compared to pigs fed diets containing the recommended nutritional levels.

ASSUNTO(S)

metabolism metabolismo formulaÃÃo de raÃÃo performance diet formulation nutriÃÃo desempenho zootecnia enzima nutrition enzyme

ACESSO AO ARTIGO

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