The aim of this study was to determine the effect of crude glycerin addition on the growth
performance, nutrient digestibility and blood hormone levels of Iberian crossbred pigs
kept under intensive conditions. The study was carried out with 80 crossbred pigs (Iberian
gilts Duroc boars) of both sexes over a 101-d period (5473 kg initial BW). Treatments
were arranged in a 2 2 factorial design, the factors being dietary treatment (control or
10% glycerin) and gender (barrow or gilt). Crude glycerin was included as a replacement
for wheat in diets formulated to provide equal net energy and digestible lysine levels.
Glycerin-fed pigs had higher average daily gain and average daily feed intake than pigs fed
the control diet (Po0.05). No differences were found in the gain to feed ratio. With regard
to the gender, barrows consumed more feed, grew more and reached a higher final BW
compared with gilts (Po0.05). Nutrient digestibility was not affected by the glycerin
content or the gender. However, there was a tendency for acyl-ghrelin levels to be higher
in glycerin-fed pigs (P¼0.058). Also, gilts showed increased concentrations of acyl-ghrelin
and lower insulin compared with barrows (Po0.05). In conclusion, 100 g/kg of glycerin
can partially replace wheat without affecting feed efficiency or nutrient digestibility in
Iberian crossbred pigs. However, further research is needed to clarify the potential
relationship between glycerin inclusion levels in the diet and the plasmatic levels of
hormones related to feed intake and energy balance control.