MVSc

A detailed study was undertaken to establish the dietary protein and energy requirements of ducks for growth and also to ascertain the optimum age at slaughter in white pekin ducks. An attempt was made to study the general trend of growth in pekin ducks fed with different levels of protein and energy. An exhaustive review of literature has been presented on the effects of dietary protein and energy levels on growth and associated traits in pekin ducks.

Five hundred and four (504) one-day old ducklings of white pekin breed were used for the study. Two feeding trials each for a period of ten weeks were carried out using nine experimental diets containing three levels of protein (17,20 and 23 per cent) and three levels of metabolisable energy (2400, 2600 and 2800 K Cal ME/kg). In each trial, the diets were fed to nine groups consisting of 28 ducklings in four replicates of seven ducklings each. The effects of protein and energy on production traits revealed the following:

The requirements of dietary protein for optimum growth of white pekin ducks were 23 per cent until third week, 20 per from fourth to sixth week and 17 per cent from seventh to tenth week of age. The metabolisable energy requirement for optimum growth was proved to be 2400 K cal ME/kg diet from day-old to ten week of age throughout. The weekly body weights of ducklings receiving 20 and 23 per cent protein were significantly better until sixth week. Even though, ducklings receiving 17 per cent dietary protein were significantly lighter until sixth week, they recouped body weights by compensatory growth from seventh week onwards.

The ducklings receiving dietary energy level 2600 K cal ME/kg have shown significantly higher weight gain and live body weight at first week. The second and third week gains and body weights were significantly higher in ducklings receiving 2400 and 2600 K cal ME/kg diet. The ducklings receiving 2800 K cal ME/kg showed significantly lower body weights and gains until third week. The weekly gains and body weights at sixth week were statistically comparable among the three energy levels studied.

Rapid growth at early ages with 20 and 23 per cent protein was observed until fourth week. The growth was slow with 17 per cent level and peak gain occurred at fifth week. Protein x energy interaction effects on weekly body weights were non-significant. The interaction effects were significant in respect of sixth week weight gains, and feed intake at first week, fifth and sixth week of age. The feed intake at second and third week showed significant increase with increasing levels of protein. The energy level 2800 K acl ME/kg diet reduced feed intake markedly until third week. The cumulative feed intake at tenth week ranged from 7.879 to 9.423 kg per duckling, among experimental diets.

The weekly feed-gain rations and cumulative feed efficiencies revealed poor conversion rates beyond eighth week of age. The cumulative efficiencies at sixth week were 3.2, 3.3 and 3.4 with protein levels 17, 20 and 23 per cent respectively. The ready-to-cook yield at fifth, eight and tenth week were 66.39, 68.76 and 69.69 per cent respectively. The processing yields and losses, serum protein and haemoglobin levels; and the moisture, crude protein and ether extractives in liver and thigh meat were not significantly influenced by dietary protein and energy levels, and ages at slaughter.

The marketing age in pekin duck was found optimum at sixth week on the basis of live body weight, feed conversion efficiencies and economics. Based on the above findings it was concluded that white pekin ducks require 20 per cent protein and 2400 K cal ME/kg diet until sixth week of age. In this study, the highest margin of return over feeding cost recorded with the above diet was Rs. 10.11 per duckling, at sixth week. Therefore, age for marketing pekin ducks was found ideal at sixth week on feeding medium level of protein with low energy density diet.