Impacts of limestone multi-particle size on production performance, egg shell quality, and egg quality in laying hens.

摘要

Effects of feeding single or multi-particle size limestone to laying hens were investigated on egg shell quality, egg production, egg quality and feed intake. A total of 280 laying hens (ISA brown) were used in this 10-wk trial. The hens were randomly assigned to 1 of 4 treatments with 14 replications per treatment and 5 adjacent cages as a replication (hens were caged individually). The experimental treatments were: L, basal diet + 10% large particle limestone; LS1, basal diet + 8% large particle limestone + 2% small particle limestone; LS2, basal diet + 6% large particle limestone + 4% small particle limestone; S, basal diet + 10% small particle limestone. Egg production was unaffected by dietary treatments. Egg wt. and sp. gr., as well as eggshell strength and thickness, after S treatment were lower than after other treatments (P < 0.05). There were no differences in egg yolk height or Haugh units among treatments, but egg yolk colour was lighter after S treatment (P < 0.05). LS1 and LS2 laying hens had higher average feed intakes than other hens (P < 0.05). Overall, results suggest that multi-particle size limestone could be ass effective as large particle size limestone as a supplement for laying hens.