Revista Brasileira de Zootecnia
versão On-line ISSN 1806-9290
AROUCA, Cláudio Luiz Corrêa et al. Available phosphorus levels in diets for barrows at 60 to 95 kg. R. Bras. Zootec. [online]. 2010, vol.39, n.12, pp. 2646-2655. ISSN 1806-9290. http://dx.doi.org/10.1590/S1516-35982010001200013.
The effects of available phosphorus levels on performance and carcass composition of barrows with high genetic potential for meat deposition were evaluated. Sixty swine with initial body weight of 59.84 ± 1.64 kg were assigned to a randomized block experimental design, with five diets (0.097; 0.190; 0.280; 0.370 and 0.460% aP), six replicates and two animals per experimental unit. Experimental diets and water were supplied ad libitum until the end of the experimental period, when animals reached 96.64 ± 3.68 kg. Weight gain and feed conversion improved in a quadratic way until the estimate levels 0.35 and 0.33% aP in the diets, respectively. There was no effect of the diets on daily feed intake. Consumption of available phosphorus linearly increased as levels of this mineral increased in the diet. The diets did not change activity of alkaline phosphatase enzym. However, values of serum inorganic phosphorus at 21 days of age and in the end of the experimental period increased in a quadratic way until the estimate level 0.35 and 0.38% in the diet, respectively. Levels of available phosphorus affected in a quadratic way loin depth, daily fat-free lean deposition rate, and the amount of fat-free lean which improved until the estimated level of 0.35; 0.31 and 0.33% of aP in the diet, respectively. In the phase from 60 to 95 kg, the level of 0.33% of aP in the diet, which corresponds to a 9.38 aP/day intake provided better feed conversion and a greater amount of fat-free lean meat in hybrid commercial barrows genetically selected for meat deposition on the carcass.
Palavras-chave : carcass; finishing; minerals; nutrition; performance.