The effect of glycerol inclusion on broiler performance and nutrient digestibility
Résumé
1. Crude glycerol from biodiesel production was offered ad libitum to broiler chickens in a 21-d feeding and digestibility trial. The study was designed as a 3*2+1 factorial design with 3 levels (33, 67, 100 g/kg) of glycerol from 2 sources, A and B (PRS Environmental Ltd and John Thompson and Sons Ltd) and a control diet. The diets were formulated to contain apparent metabolisable energy (AME) 12.95 MJ/kg (assuming 14.6 MJ/kg for glycerol). 2. No significant interactions occurred therefore only the main effects were discussed. At 7-14 d feed conversion ratio (FCR) showed a significant linear response with increased glycerol inclusion (P<0.05). However quadratic responses on FCR were observed for the 21-28 d period and 7-28 d. 3. Glycerol digestibility was significantly greater with birds offered the 67 g/kg and 100 g/kg glycerol-based diets (P<0.001) in contrast to the digestibility of 33 g/kg glycerol-based diets. 4. Glycerol inclusion level also had an effect on AME, which increased linearly with increasing glycerol inclusion (P<0.05). Birds offered the diets containing glycerol also required less energy per unit gain in contrast to birds offered the control diet (P<0.05). 5. When examining the effect of source of glycerol, source A glycerol, resulted in the highest AME (15.20 vs. 14.72 MJ/kg P<0.05). There was no significant effect of glycerol source on the other performance parameters. 6. Glycerol digestibility was significantly greater with glycerol from source B (John Thompson and Sons Ltd) with a mean value of 0.848 (P<0.004) in contrast to source A (PRS Environmental) glycerol digestibility being somewhat less with a mean value of 0.757. 7. In conclusion, glycerol source did not affect performance and increasing level of glycerol improved FCR with 67 g/kg inclusion resulting in the most efficient conversion of feed to gain without any negative effects upon nutrient digestibility.
Domaines
Biologie animale
Origine : Fichiers produits par l'(les) auteur(s)
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