The present study was undertaken to investigate the effects of feeding rice
polishings (RP)-containing mash or pelteled diels on growth performance, digestibility
of nutrients. carcass yield and some blood plasma constituents of "mule" ducklings.
Day-old "mule" ducklings were fed a dry-mash corn-soybean-based practical starter
diet (contained 22% crude protein, and 2900 kcal of metabolizable energy per kg) until
the birds were three weeks of age. Then, they were individually leg-banded, weighed
and randomly divided into 8 experimental groups (8 X 30), each with three equal
replications, fed on experimental diets up to 11 weeks of age. Four dry mash and four
peJleted iso-caloric (ME of about 300Q kcal/kg) and iso-nitrogenous (CP of about 18%)
experimental diets containing graded levels of rice polishings (0.0, 15.0, 30.0 or
45.0% of the diet) were formulated. The performance of growing ducklings was
evaluated in terms of live body weight (LBW), daily weight gain (DWG). daily feed
intake (OFI) and feed conversion ratio (FCR). Total mortality and economic efficiency
of feeding (EEF) were also determined. Digestibility coefficients of nutrients of the
exc erlmentat diets were measured when the birds were 10 weeks of age. At the end
c ' study, some measuremenis on carcass yield and components and concentrations
of certain blood plasma constituents (glucose, total protein. triglycerides, Ca and
inorganic P) were performed. The results obtained for the entire experimental period could be summarized
as follows: Regardless of the diot form, increasing dietary RP level from 0.0% (control)
to 45% significantly improved FeR. EEF, N retention and digestibility of CP and EE of
1M experimentai diets, whereas all other criteria were not affect~d. On the other hand,
irrespective of dietary RP !evel, ducklings fed on pellets exhibited superior means for
l.BW, OWG, OFI, FeR and CP and EE digestibility compared with those obtained by
their mash-fed countercarts whe~e3s a\l other criteria were not affected. Dietary RP
level by diet form interactions had no significant effects on all criteria investigated.
Only four ducklings died during the course of this experiment and the deaths were not
related to the dietary treatments. Based on the obtained results, from a practical and
economical paint of view, it is concluded that rice polishings can successfully be used
at inclusion rates of up to 45% of pelleted diets for mule ducklings. with no adverse
effects on growth performance or carcass traits.