Determination of the digestible energy and prediction of the net energy content of toasted and non-toasted canola meals from Brassica junceae and Brassica napus in growing pigs by the total faecal collection and the indigestible marker method

Abstract

The study aimed to compare the digestible and net energy (DE and NE) contents of three canola meals (CM) toasted (95°C) or not after desolventization from yellow Brassica junceae (YBJ) and yellow and black Brassica napus (YBN and BBN) in growing pigs. A basal diet and six CM-based diets (2/3 basal diet and 1/3 CM) supplemented with acid-insoluble ash (indigestible marker) were prepared. The growing pigs (28 kg; six per treatment) were kept in metabolic cages for 18 d and their faeces were collected for the last 10 d. The digestibilities and DE content of the CM were determined based on the total faecal excretion and the indigestible marker method. NE was estimated with a prediction equation. The DE and NE contents of the YBN meal (3.98 and 2.73 Mcal kg-1 DM) were higher (P = 0.007) than that of the YBJ (3.76 and 2.59 Mcal kg-1 DM) and BBN (3.64 and 2.43 Mcal kg-1 DM) meals. Toasting had no effect (P > 0.05) on the DE and NE contents. Inconsistent values were obtained with the indigestible marker, as compared with the total faecal collection method. In conclusion, YBN canola presents the highest energy content, and toasting of CM does not affect its energy values in growing pigs.Key words: Canola meal, growing pigs, toasting, digestible energy, net energy