Resumen

RIVERA, A. et al. Finishing pigs with low-protein diets supplemented with mannan-oligosaccharides or nucleotides. Arch. zootec. [online]. 2010, vol.59, n.227, pp.357-368. ISSN 1885-4494.

Growth performance, carcass, and plasma urea N concentration of finishing pigs fed low crude protein (PB) diets supplemented with mannan-oligosaccharides or nucleotides were evaluated. In experiment 1, 40 finishing (56.6±5.2 kg of initial body weight) barrows were fed standard (14%) or low (9.5%) protein diets, and four levels of mannan-oligosaccharides (0, 0.25, 0.5 and 0.75%). In experiment 2, 36 finishing (58.4±5.4 kg of initial body weight) barrows were used to evaluate 3 protein levels (14.1, 12.1 and 10.1%) with (0.75%) or without nucleotides addition. The diets were formulated with sorghum-soybean meal basis, supplemented with L-lysine·HCl, L-threonine, DL-methionine and L-triptophan to reach 0.66, 0.43, 0.40 and 0.14% levels; the dietary metabolizable energy was 3.265 Mcal/kg, and each experiment lasted 35 d. When PB was diminished more than 2%, the average daily gain and feed intake, final body weight, and fat free lean gain were reduced, and feed:gain ratio increased. The longissimus muscle area decreased when PB was reduced to 9.5%, and backfat thickness increased when PB was reduced to 12%. The plasma urea N concentration was lowered as PB was reduced. The addition of mannan-oligosaccharides or nucleotides do not improve the analyzed variables in finishing pigs fed low-protein diets, whilst the reduction of the PB affected them.

Palabras clave : Sorghum grain; Soybean; Plasmatic urea.

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