Influence of rare earth elements on production performance in post peak layer chickens

A biological study was conducted to determine the effect of dietary supplementation of different levels of rare earth elements (lanthanum and cerium) on egg production, feed intake, feed efficiency and egg weight in laying hens. A total of 96 White Leghorn laying hens of 52 weeks of age were used in 8 weeks feeding trial. Birds were randomly allotted to three dietary treatments each with four replicates with 8 hens per replicate. Treatment groups consisted of basal diet supplemented with 0, 250mg (lanthanum 100mg and cerium 150 mg) and 500mg/kg (lanthanum 200mg and cerium 300 mg) of rare earth elements. Daily records of egg production and egg weight were maintained. Feed consumption of all three treatment and control groups was recorded every week and the mean feed intake per bird and feed efficiency per egg was calculated. The results of study showed that rare earth elements (lanthanum and cerium) supplemented at 250mg/kg of layers had significantly (P<0.05) decreased feed intake at first and second month, whereas in 500mg/kg experimental group feed intake had significantly (P<0.05) decreased in the first month but no significant changes was found in the second month of the trial. Hen day egg production, feed efficiency were significantly (P<0.05) increased in 250mg/kg, 500mg/kg experimental groups at first and second month of the trial. Significantly (P<0.05) increased egg weight were found in 250mg/kg rare earth elements supplemented groups at the end of first and second months, whereas in 500mg/kg experimental group, egg weight significantly (P<0.05) increased in the first month of the trial but no changes were found in the second month of the trial. Hence it was concluded that at low dose of rare earth elements, the birds had a significant effect in feed intake, hen day egg production, feed efficiency and egg weight.