RAMESH GUPTA, B(MAJOR)GNANA PRAKASH, MRAJASHEKAR REDDY, AMALARMATHI, M2018-10-162018-10-162008-10http://krishikosh.egranth.ac.in/handle/1/5810081165ABSTRACT : The present study was carried out on Black, Brown and Black random bred strains of Japanese quails (Coturnix coturnix japonica), under selection for high 4-week body weight, maintained at Poultry Experimental Station (PES), College of Veterinary Science, Rajendranagar, Hyderabad. Effects of hatch, strains and sex on body weight, average daily gain (ADG), age at first egg (AFE), egg production (EP) and biochemical parameters were studied. The overall least-squares means for body weights at day-old, 2nd and 4th week of age were 7.94, 59.20 and 141.64 g, respectively. Hatches had significant effect on body weight up to 10 weeks of age. Strain had significant effect on body weights from day-old to 14 weeks of age. The females were significantly heavier than the males from second to 14th week of age. The overall least-squares means ADGs during 0-2, 2-4, 4-6, 6-8, 8-10 and 10-14 weeks of age were 3.66, 5.89, 3.69, 2.72, 1.51 and 0.46 g, respectively. Hatches had significant effect on ADGs at all the ages studied. The ADGs of Black Japanese quails were significantly higher than those of Brown and Black random bred Japanese quails at all the ages. The females had significantly higher ADGs than males up to 10 weeks of age. The overall least-squares mean AFE was 57.80 days. Age at first egg was significantly influenced by strain and also by hatch. Black random bred control strain birds matured earlier than the Black and Brown strains. The overall mean number of eggs produced up to 10, 12, 14, 16 and 18 weeks of age was 6.75, 15.71, 24.01, 34.04 and 44.86, respectively. Hatch had significant influence on egg production up to 14 weeks of age, but not beyond. The Black random bred strain was significantly produce more eggs at all the weeks excluding 8th week than the Black and Brown strain. The overall least-squares means for plasma protein, cholesterol and triglycerides in Black Japanese quails was found as 4.10 g/dl, 150.72 mg/dl and 90.66 mg/dl, respectively. Hatches had significant (P<0.05) effect on plasma cholesterol, but not on others and sex effect was significant on plasma cholesterol and triglycerides. The heritability estimates for the body weights varied from low to high in Black, medium to high in Brown and low to medium magnitude in Black random bred, while these estimates for ADGs were low or moderate to high in magnitude and ranged from 0.09 to 0.56 in black, 0.37 to 0.94 in Brown and 0.15 to 0.86 in Black random bred male Japanese quails. The heritability of AFE was low (0.16) in Black random bred and high (0.69) in Black strain. The heritability estimates for egg production ranged from 0.09 to 0.43 in Black, 0.18 to 0.81 in Brown and 0.02 to 0.54 in Black random bred strain. Heritability estimate was high for (0.90) plasma cholesterol, low for (0.12) plasma protein and low for (0.10) plasma triglycerides. Genetic, phenotypic and environmental correlations for body weight at various ages varied from low to high in magnitude. Genetic correlations were positive in direction, while the phenotypic and environmental correlations were both positive and negative in direction. The genetic correlations among ADGs in Black, Brown strains and Black random bred ranged from -0.89 to 0.92, -0.86 to 0.90 and -0.05 to 0.78, respectively, whereas, the phenotypic correlations varied from -0.74 to 0.31. AFE was correlated positively with body weight at various ages at genetic level in Black strain. Genetic correlations of egg production with body weight at various ages were negative in all three strains. While, the estimates among the EP at various ages had highly positive genetic relations and phenotypic correlations of BW with EP and among EP was low but positive. The genetic correlation of plasma biochemical parameters with body weight at various ages and among the biochemical parameters ranged from -0.96 to 0.48 and 0.13 to 0.24, respectively. The phenotypic correlations plasma biochemical parameters with body varied from -0.20 to 0.13. The expected response to selection in body weight at 4-weeks age in Black, Brown and Black random bred male Japanese quails were 3.62, 6.06 and 6.91g, respectively and the corresponding response in females were 1.11, 2.13 and 12.79 g. Among the fourteen selection indices (I1 to I14) constructed based on the data generated in the present study, I14 consisting of BW4, BW6, AFE, EP10 and EP12 was found to be the best with RIH value (0.92) and δH (4.73) in Black Japanese quails. In the present study, the selection programme for high 4-week body weight yielded satisfactory improvements in body weights and ADGs of selected strains. The traits studied had the heritabilities and correlations ranging from low to high traits indicating the scope for their further genetic improvement by selection coupled with optimum management. The selection indices constructed revealed the possibility of improving the body weights, AFE and EP simultaneously.ennullThesis