EGG QUALITY OF NATIVE CHICKEN UNDER BACKYARD SYSTEM AND WHITE LEGHORN LAYERS UNDER INTENSIVE SYSTEM OF REARING
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Date
2009
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR
Abstract
A study was conducted to evaluate the egg quality in 100 eggs each of
Native chicken (NC) and White Leghorn (WL) during 21 to 40 weeks of age
which included the external and internal quality parameters, fatty acids, yolk
cholesterol and mineral estimation in yolk and albumen. Also, the egg production,
livability and feed intake in NC reared in backyard system and WL layers reared
in cages were studied.
Among the external quality traits, the egg weight (39.35 vs. 49.54 g), egg
length (50.36 vs. 54.02 mm) and breadth (37.55 vs. 40.74 mm) were lower in NC
whereas, the shape index was comparable. Except the albumen width (83.73 vs.
76.54 mm), all the albumen traits were inferior in NC compared to WL with
Albumen height (4.32 vs. 6.41 mm), index (0.05 vs. 0.09 mm), weight (21.92 vs.
31.36 g), per cent (55.65 vs. 63.45) and Haugh Unit Score (71.47 vs. 81.33).
Significantly lower values yolk height (13.94 vs. 15.87 mm) and index (0.35 vs.
0.42) and higher values for yolk per cent (33.62 vs. 27.26) and yolk color index
(8.11 vs. 5.31) were noticed in NC. The yolk width, weight and cholesterol
content were comparable between the breeds. Significantly lower shell weight
(4.21 vs. 4.61 g), higher shell per cent (10.73 vs. 9.30) noticed in NC.
In the egg yolk, the mean values of saturated fatty acids; Palmitic , Stearic,
Arachidic and Behenic acids were comparable between NC and WL eggs,
although these acids when put together, a significantly higher (52.65 vs. 48.62 per
cent) in the former group was noticed. Significantly lower quantity of Linoleic
acid (8.50 vs. 11.53 per cent) the omega-6 category as well as the Omega-6:
omega-3 ratio (2.89 vs. 6.01) was advantageous even though total unsaturated
fatty acid was significantly lower in NC eggs (47.35 vs. 51.38 per cent). On the
other hand, the ratio between saturated and unsaturated acids was significantly
higher in NC egg (1.11 vs. 0.95). The monounsaturated fatty acids, Oleic acid
(31.24 vs. 31.52 per cent) and Palmitoleic acid (4.11 vs. 5.77 per cent) and these
two acids put together (35.35 vs. 37.29 per cent) were non-significant. The total
poly unsaturated fatty acids, including Omega-6 and Omega-3 were comparable
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both in NC and WL eggs. Of the total fatty acids, the mean value of and Omega-3
fatty acids; linolenic acid, EPA and DHA were comparable separately (0.83, 1.61
and 1.06 vs. 0.61, 0.88 and 1.07 per cent). The total of Omega-3 acids was
numerically higher in NC egg (3.49 vs. 2.55 per cent).
The mineral profile of eggs indicated that WL eggs are superior (P<0.05)
in respect of Iron in albumen (2.10 vs. 4.76 ppm), Copper in yolk (1.18 vs. 1.49
ppm) and Magnesium in yolk (0.0088 vs. 0.0125 mg per cent). This indicated the
necessity of inclusion of trace mineral mixture in the diet of native chickens. NC
egg albumen is a rich source of Zinc (1.59 vs. 0.66 ppm).
Late sexual maturity indicated by age at first egg of 185.62 days in NC vs.
141.25 days in WL and poor egg production indicated by 40.23 vs. 121.57 eggs
(28.70 vs. 86.83 per cent) on HH basis and 41.86 vs. 123.60 eggs (29.90 vs. 88.28
per cent) on HD basis up to 40 weeks of age suggest modifications in feeding
patterns of Native chicken. The livability was (88.33 vs. 96.67 per cent) in WL
and NC hens with survivor egg numbers 41.91 and 125.35 eggs per hen.
The feed intake per bird per day was 113 g in WL whereas the native
chicken was being reared by providing only about 20 to 30 g of supplemental feed
per bird per day.
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