Effect of Dietary Energy and Protein Content on Growth and Carcass Traits of Pekin Ducks20 March 2015
Two experiments by researchers in the US and China examined the effects and interactions of dietary energy and crude protein on the growth and carcass characteristics of meat ducks.
A study was conducted by researchers at Purdue University to determine the influence of dietary energy and protein concentrations on growth performance and carcass traits of Pekin ducks from 15 to 35 days of age, reports T.J. Applegate.
Together with scientists at Sichuan Agricultural University in China and Maple Leaf Farms, two experiments were conducted and published in the current issue of Poultry Science.
The researchers conclude their results provide a framework for subsequent modeling of amino acid and energy inputs and the corresponding outputs of growth performance and carcass components for these birds.
In Experiment 1, 14-day-old ducks were randomly assigned to three dietary metabolisable energy (ME; 11.8, 12.8 and 13.8MJ per kg) and three crude protein concentrations (15, 17 and 19 per cent) in a 3×3 factorial arrangement, with six replicate pens and 66 ducks per pen. Carcass characteristics were evaluated on days 28, 32 and 35.
In Experiment 2, 15-day-old ducks (six replicate cages; six ducks per cage) were randomly allotted to the nine diets that were remixed with 0.5 per cent chromic oxide. Excreta were collected from days 17 to 19, and ileal digesta was collected on day 19 to determine nitrogen-corrected apparent metabolisable energy (AMEn) and amino acid digestibility.
In Experiment 1, there were interactions (P<0.05) between dietary metabolisable energy and crude protein on bodyweight gain and feed intake, wherein bodyweight gain increased more to increasing dietary crude protein as dietary metabolisable energy increased.
However, feed intake was only influenced by dietary crude protein at 11.8MJ ME per kg and not 12.8 or 13.8MJ per kg. As dietary crude protein increased from 15 to 19 per cent, breast meat yield increased by 10.8 per cent on day 35 (P<0.01).
Conversely, increasing metabolisable energy from 11.8 to 13.8MJ per kg increased dressing percentage, breast skin and subcutaneous fat but decreased breast meat yield (percentage but not weight) on day 35 (P<0.01).
In Experiment 2, the determined AMEn for diets formulated to contain 11.8, 12.8 or 13.8MJ ME per kg were 11.66, 12.68 and 13.75MJ per kg, respectively.
Determined standardised ileal digestible (SID) lysine was 0.95, 1.00, and 1.21 per cent for diets formulated to contain 15, 17 or 19 per cent crude protein, respectively.
The best bodyweight gain and feed conversion ratio was obtained when ducks were fed a high dietary AMEn (13.75MJ per kg) and high crude protein (19 per cent, 1.21 per cent SID Lys).
Zeng Q.F., P. Cherry, A. Doster, R. Murdoch, O. Adeola and T.J. Applegate. 2015. Effect of dietary energy and protein content on growth and carcass traits of Pekin ducks. Poultry Science. 94:384-394.
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