The aim of this study was to evaluate the effects of a different dietary content of sweet yellow lupine seed meal (YLM) on gastrointestinal tract development and function, the growth performance (13-18 weeks of age) and meat quality of growing-finishing turkeys. Control grower and finisher diets contained soybean meal (SBM), and in experimental diets, SBM was replaced with YLM at 6%, 12% and 18% (Groups L6, L12 and L18, respectively). The diets were formulated to be iso-nitrogenous and iso-energetic. In the first phase of feeding, YLM tended to decrease feed intake (p = 0.087) and body weight gain (BWG, p = 0.078) linearly due to significant deterioration in feed conversion ratio (FCR, p = 0.030). An opposite trend was noted in the second phase of feeding: BWG increased (p = 0.069) and FCR improved significantly (p = 0.004). Over the entire experiment, inclusion of YLM did not affect feed intake, BWG, FCR or excreta dry matter (DM) content. The highest YLM dietary level had no adverse effects on fermentation processes in the caeca. Positive changes, which were observed in turkeys fed YLM-supplemented diets, included an increased gizzard weight, a decreased pH of gizzard contents and a decreased viscosity of small intestinal digesta. The inclusion of YLM at 18% had no effect on carcass quality, the pH and colour intensity of breast meat. The highest inclusion rate of YLM (18%) in turkey diets significantly (p < 0.05) intensified the fatty flavour of meat and increased its hardness, springiness and chewiness, whereas it had no effect on the appearance, aroma and overall acceptability of breast meat. It can be concluded that YLM at the highest dietary rate used in the present experiment (18% of the diet) had no adverse effects on the growth performance or the analysed physiological parameters of turkeys.
Keywords: Lupinus luteus; gastrointestinal tract; growth rate; meat quality; turkeys.