THE EFFECT OF DIETARY NUTRIENT DENSITY UPON GROWTH, NUTRITIONAL ANATOMY AND PHYSIOLOGICAL IN FOUR DIFFERENT LINES OF SELECTED CHICKENS

Abstract

The study consisted of two experiments of similar design (2 diets x 4 lines x 2 sexes x 4 birds per subcell), which were undertaken consecutively with the same parameters were measured The four lines selected for tweleve generation for increased bodyweight (line W), increased food consumption (line F), decreased food consumption ratio (line E) or at random (line C) were subjected to two different dietary nutrient densities (13.0 MJ ME/kg, with 230 g protein/kg, and 9.5 M] ME/kg with 190 g protein/kg). Each experimental bird was kept in an
individual cage provided with automatic drinkers and individual feed trough. The experiment was ceased until the bird reached the age of 63 days. There were significant (P<.05) interaction between line and diet for both liveweight gain and food intake in each experiment. There was change in ranking of lines in liveweight gain for the high to the low nutrient density diet. On the high diet, liveweight gain was the greatest in line W followed by the F, E then line C. On the low diet in Experiment l, the ranking of the F and E rnales were reversed and in Experiment 11, liveweight gain in the E and C lines were similar. However liveweight gain as expected, was the greatest in line W (1160 g/bird) and least in line C (759 g/bird). Food intake was the greatest in line F (3591 g/bird) and least in line C and E (2800 g/bird) as a consequence food conversion ratio was highest in line F (3.95) lowest in line E (3.44). Metabolizable energy and nitrogen retention were highest in line E (1 1.08 MJ ME /kg and 19.13 g N/kg) and lowest in line F (10.78 MJ ME /‘kg and 14.93 g N/kg). Birds given the high diet retained more nitrogen than those given
the low diet. Body fat was highest in F line (14.86 %) and lowest in E line (7.39 %). Body protein was unefiected by line, diet and “sex. Expressed as a proportion of liveweight, the E line had the heaviest proventiculus (3.6 g/kgW), gizzard (27.8 g/kgW) and intestine (16.8 g/kgw), whilst the F line had the smallest proventiculus (3.1 g/kgW), gizzard (21.6 g/kgW), but largest liver (21.8 g/kg W) and about four times more abdominal fat than the E line.