Abstract
The experiment was conducted to investigate the growth response, carcass characteristics, meat
quality of rice fed fast and slow growing chicken genotypes under intensive care and management.
The total of 360 DOC from two genotypes was reared in a common brooder house for the first week
separately. The experimental design was 2×3 factorial experiment where 2 genotypes and 3 diets. Isocaloric and iso-proteinous diets were formulated following the standard of commercial broiler
requirement; T- based on corn (0% rice), T2-50% corn replaced by rice and T3-100% corn replaced by
rice. From experiment I, it shows that broilers consumed the highest amount of feed (2823.9 g/bird)
with an average FCR of 1.74 while the lowest feed consumption (2241.7 g/bird) with FCR of 4.15 was
observed in native chicken. Broiler showed significantly (p<0.01) higher growth performance as
compared to native chicken. Live weight, dressing percent, breast, liver and abdominal fat
percentage were significantly (p<0.01) higher in broiler while skin with feather, blood, wing, head,
neck, gizzard, shank were significantly (p<0.01) higher in native chicken. Cooking loss and drip loss
were significantly (p<0.01) higher in broiler while WHC, raw pH and cook pH were significantly
(p<0.01) higher in native chicken breast meat. However, the diet had a significant (p<0.01) effect on
water holding capacity but the highest water holding capacity was found in the T1 dietary
treatments. CIE L* (lightness), a* (redness), b* (yellowness), saturation index was significantly
(p<0.01) higher in broiler while hue angle was higher in native chicken breast meat. No significant
(p>0.05) differences were found among the dietary treatments. The interaction between genotyре
and diet found significantly (p<0.01) different in b* (yellowness) and saturation index value. The
lowest and significant (p<0.01) discoloration (Hue angle) found in broilers compared to native
chicken. The interaction between genotype and diet found significantly different in b* (yellowness)
and saturation index in thigh meat. L* (lightness), b* (Yellowness) and saturation index were
significantly (p<0.05) higher in broiler drumstick meat. Hue angle was significantly higher in native
chicken. However, interaction between genotype and diets found significantly different in L*
(lightness), b* (yellowness) and saturation index in drumstick meat. The CIE L* (lightness), a*
(redness) values were significantly (p<0.05) higher in the liver of broilers. The interaction between
genotype and diets found significantly (p<0.05) different in a* (redness) and saturation index in the
liver. Significantly (p<0.01) higher tenderness and juiciness were found in broiler breast meat than
nativ chicken. Overall consumer acceptability did not differ significantly (p>0.05) between genotypes
and among diets. Very high positive correlation associations (r>0.90) were observed between live
weight and dressing percent, breast; dressing percent and breast; skin with feather and breast. On
the other hand, very high negative correlation associations (r>-0.90) were observed between live
weight and head; dressing percent and head. Very high positive correlation association (r>0.90) were
not observed among the variables. Second experiment was conducted in Japan to compare broiler
and local chicken (Niigata Jidori) in expt. II light of growth performance and protein metabolismrelated parameters. Twenty 14-day-old chicks were housed individually in wire cages, fed
experimental diets, and provided water ad libitum for 2 weeks. Growth performance, nitrogen
retention, concentrations of free amino acids in muscles, as well as mRNA expression of liver IGF-1,
breast muscle atrogin-1, and proteasome C2 subunit were determined. Body weight gain, feed intake,
and feed efficiency were significantly higher (p<0.01) in broilers than in Niigata Jidori. Muscle
weights (breast and thigh) and nitrogen retention were significantly higher (p<0.05) in broilers than
in Niigata Jidori. Concentration of free amino acids, viz., Asp Glu, Ala, Cys, Tyr, Lys and Arg in
breast muscle were significantly higher (p<0.05) in broilers than in Niigata Jidori. No significant
(p>0.05) differences were found in concentrations of Thr, Ser, Gly, and Val, Met, Ile, Leu, Phe, and
His. There were no significant (p<0.05) differences in mRNA expressions of liver IGF-I, breast muscle
atrogin-1, and proteasome C2 subunit between broilers and Niigata Jidori. The growth performance
of broiler and Niigata Jidori varied significantly but there was no change in mRNA expression
related to protein metabolism between the two breeds. This study provides an important insight on
the growth performance and meat characteristics of rice fed fast and slow growing chicken
genotypes. It can be concluded that rice could be used as alternative to corn in the chicken ration.