Abstract
In 4 experiments, each with 300 as hatched day-old broiler
chicks were fed either of the-5 almost iso-nitrogenous and isocaloric diets containing 5.00, 12.60, 22.05, 31.50 or 40.95%
parboiled rice polish (PRP). In the first experiment, broilers
were reared upto 56 days of age, while in experiments 2, 3 and 4,
the birds were grown to some given live weights between 0.5 and
2.0 kg, allowing the rearing period to vary. In experiments 3 and
4 the PRP diets were supplemented with 2% bone meal to increase
the dietary Ca-P availability. The study was aimed at the dietary
PRP effects with different amounts of Ca-P availability on
growth, feeding behaviour, production cost, meat yield and body
composition of broilers.
When PRP effects were assessed to given age, feed intake was
similar but live weight gain and efficiency of feed utilisation
were declined on diets containing increasing levels of PRP. When
broilers were reared on PRP diet to given live weights allowing
rearing period to vary, feed intake decreased with increasing PRP
levels from 5.00 to 31.50% but increased at 40.95% dietary PRP.
The efficiency of feed utilization was improved as the PRP level
was increased up to 22.05% but further increase in dietary PRP
level depressed feed conversion. Experimentation to given live
weights gave a clearer and practical information on PRP effects
on growth than that of effects to given age. Increasing
availability of Ca and P improved feed conversion (FC) as PRP was
increased from 5.00 to 22.05%, but FC declined at further higher
levels of dietary PRP. Time spent on feeding, drinking and
standing were linearly increased, but resting time decreased on diets with increasing PRP.
The study revealed that poorer performance of PRP 1ies
behind the fact that (1) increased phytin P concentration of PRP
diets hinders the availability of Ca and P and (2) extra energy
cost to consume voluminous PRP diets led to poorer feed
utilization. The meat production (breast, thigh, drumstick,
trimmed, wing meat and therefore the total meat) and the
eviscerated yield were not affected by dietary PRP. The study
indicated the possibility of increased meat production on PRP
diets with increased available Ca-P. The increasing PRP diet
tended to decrease the carcass fatness.