Dietary modelling of nutrient densities: Effect and response in different growing phases on growth performance, nutrient digestibility, litter quality and leg health in turkey production.

An experiment was conducted to explore the time bound (different growth phases) effect of different dietary nutrient densities i.e., different energy and protein concentration while maintaining the ratio between the two, all with the same ideal amino acid profile, on litter quality and leg health (footpad dermatitis (FPD) and hock burn (HB)), when fed to growing turkeys. The effects of dietary nutrient modelling on growth performance parameters, water intake and excretion, dry matter (DMD), organic matter (OMD), crude protein (CPD) digestibility coefficients and apparent metabolisable energy (AME) were also examined, when fed to growing turkeys invarying growth phases. At twenty-eight days of age one hundred and seventy five male turkeys (BUT 8) were transferred to 35 floor pens, using stratified randomisation on body weight, 5 birds in a pen, all pens were equipped with plastic feed hoppers and drinkers. The experiment was a randomized block design consisting of 5 treatments (5 levels of CP and ME concentrations and 4 feeding/ growth phases). Each dietary treatment was replicated 7 times with 5 birds in each replicate. Feed and water were offered ad libitum throughout the experiment. Five dietary treatments, containing either 77, 85, 100, 110 or 120% of the crude protein (CP) and metabolisable energy (ME) content recommended by the breed standard. The whole experimental period of 16 weeks starting from 4 weeks of age was divided into 4 weeks standard growth phases: 4-8, 8-12, 12-16 and 16-20 weeks, finishing at 20 weeks of turkey’s age, according to commercial management guide for BUT 8 (Aviagen Turkeys Ltd.). Nutrient density had a positive and linear effect (P<0.001) on weight gain, feed efficiency and dry matter digestibility (DMD) whereas the effect of nutrient density on dietary protein digestibility (CPD) only approached significance (P=0.081). As might be expected increasing nutrient density had a negative and linear effect on feed (P<0.001) and water (P