In a first trial glycerol was tested as a feed ingredient for broiler
chickens. The influence of glycerol supplementation on weight gain, fe
ed intake, feed conversion ratio and N-balance was proved. 90 Broiler
chickens (Lohmann Meat) were fed ad libitum in 6 groups with nearly is
oenergetic diets based on corn and soybean meal with 23% crude protein
and 0; 5; 10; 15; 20 or 25% pure glycerol in the DM. During a feeding
period of 31 days animals had have a very good intake of all experime
ntal diets. The highest weight gains were observed in the groups with
5 and 10% glycerol (34.9 and 35.3 g/animal . d, resp.). However, this
effect was not significant compared to the control group (34.3 g/anima
l . d), but was significant superior to the gain of groups with 20 and
25% glycerol in the diet (30.2 and 26.6 g/animal . d, resp.). The fee
d conversion ratio was unchanged up to 10% glycerol (1.65 kg/kg gain)
and rose to 2.08 kg/kg gain with 25% glycerol. Up to 20% glycerol the
N-balance (1.6 to 1.8 g N/animal . d) was positively correlated with t
he glycerol content in the diet (r=0.98). The estimation of the plasma
glycerol level 2 hours after feeding indicated a remarkable increase
already with a 5% supplementation of glycerol from 0.65 (control) to 4
.36 mmol/l. Further supplementation caused on average 11 to 54 mmol gl
ycerol/l varying considerably between the individual animals. In gener
al 25% glycerol in the diet caused the lowest performance and patholog
ical changes in the crop epithelium, liver and kidneys. From the point
of view of weight gain, feed intake, and feed conversion ratio as wel
l as N-balance a supplementation of 5 to 10% glycerol seems to be bene
ficial.