[Glycerol as a feed ingredient for broiler chickens]

In a first trial glycerol was tested as a feed ingredient for broiler chickens. The influence of glycerol supplementation on weight gain, feed intake, feed conversion ratio and N-balance was proved. 90 Broiler chickens (Lohmann Meat) were fed ad libitum in 6 groups with nearly isoenergetic 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 experimental 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/animal.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 feed 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 the 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 glycerol/l varying considerably between the individual animals. In general 25% glycerol in the diet caused the lowest performance and pathological changes in the crop epithelium, liver and kidneys. From the point of view of weight gain, feed intake, and feed conversion ratio as well as N-balance a supplementation of 5 to 10% glycerol seems to be beneficial.