R. Bras. Zootec.21/Feb/2019;48:e20180039.
Increased urinary losses in piglets fed diets containing high levels of glycerin
This study evaluated the nutritional value of glycerin added to diets of weaned piglets and its effects on animal performance and urinary losses. Weaned piglets were individually housed in metabolic cages and fed diets in which a basal diet containing lactose (Gly0) was replaced by 50 (Gly50), 100 (Gly100), or 150 g kg−1 (Gly150) of glycerin; or a diet in which 100 g kg−1 of the lactose in the basal diet was replaced by glycerin (Gly100Lac0). Diets were offered for two periods of 12 days (phase I and phase II). Performance, nutrient digestibility, nitrogen retention (NR), and urinary production were measured. Digestible (DE) and metabolizable energy (ME) of glycerin were calculated using substitution method and compared to iso-nutritional diets formulated with or without glycerin. No significant differences on average daily gain, average daily feed intake, and feed conversion ratio were found. Glycerin inclusion caused a linear increase in urinary production. Piglets fed Gly100Lac0 diet had higher urinary production, compared with piglets fed Gly0. Glycerin had no significant effects on total tract apparent digestibility (TTAD) coefficients of dry matter (DM), crude protein, and gross energy (GE). Also, no significant effects were found in total tract apparent metabolizability (TTAM) coefficient of GE, NR coefficient, DE, ME, and fecal GE losses. Urinary production and GE in urine increased linearly and quadratically, respectively, with increased levels of glycerin in diets. The Gly100Lac0 diet resulted in lower DM TTAD and GE TTAM and higher GE losses in urine and feces compared with Gly0. The nutritional value of glycerin allows its inclusion at up to 100 g kg−1 in diets of weaned piglets without impairing animal performance and metabolism. Also, glycerin can replace 100 g kg−1 of lactose without impairing performance.