SOME QUANTITATIVE GENETIC TRAITS IN VIETNAMESE INDIGENOUS NOI CHICKEN FROM 0 TO 28 DAYS OLD

The aim of this study is to characterize some quantitative traits of Noi chicken, one of the Vietnamese famous native breeds for meat quality and fighting, at the stage of 0-28 days old. Therefore, 742 chicks were used to measure, record, analyze and evaluate on these traits. As results, there was significant difference in observation traits among stages of age (P=0.000). Interesting, the wings (+64.88%) and keel lengths (+58.83%) rapidly developed within the first week of life, followed by the most of other dimensions, especially breast diameter (+31.85%), thigh diameter (+71.17%) in the second week of age. An increase in the size of the measurements was due to development of the skeleton at observing time points along the experiment. However, there was strong development of muscle tissue in the second week of life as rate of the breast and thigh diameter was greatest. Noi chicks consumed amount of feed of 16.54 g/bird/day and gained a weight of 6.98 g/bird/day. Thus, their feed conversion ratio was 2.37 at the stage of 0-28 days old. Perhaps a direct positive relationship between observed traits and age were randomly established according biological characteristics of animal. This work provided initial benchmarks of Noi chicks for further studies.


Introduction
Noi, one of famous local chicken breeds, are playing an important role in increase of farmer's income in rural area of Vietnam. Although Noi is known as an excellent breed with good meat quality, adaptability and natural disease resistant, there is not any evidence for these. Similarly to some countries in the world, Vietnam also increases in demands of native chicken products, in which Noi chicken seems first choices for Southern consumers. At householders in the Mekong delta, Noi is popularly raised in many different ways (backyard, semiscavenging, intensive/semi-intensive conditions, etc.) for commercial objectives as well as householders own consumption. Until now, a few of studies worked on Noi chickens indicated that (i) most of males had the black-red mixed feather color (~42% of population), while females were in brown commonly (~55.6% of population). Most of their shanks were in yellow (42.5-46.4%). Body weight of adult male and female was 2.89 kg/bird and 1.77 kg/bird, respectively ; (ii) Earlier studies also indicated that if Noi was raised as a backyard chicken at householders, laying on hers first egg was later than other Vietnamese local chicken breeds. A hen produced around 48.35 eggs/year with an average weight of 48.87 g/egg (Cv% = 3.68) and a yolk percentage of 37.77% (Quyen and Son, 2008); (iii) Polymorphisms on some genes such as GH, GHR, GHSR, insulin gene  PRL, VIP, VIPR-1, BMPR-IB, MTNR1C, NPY, DRD2, and IGF-I (Vu and  were found in Noi chickens; and (iv) Recently, genotypes at the NPY/DraI, VIPR-1/TaqI and VIPR-1/HhaI mutation points significant associated with total egg production of laying Noi chickens of 20 laying weeks were also found (Ngu et al., 2015). Generally, although there are many previous studies, most of them focused on traits for genetics and egg performance in Noi chickens. Therefore, growth, feed intake, feed conversion ratio and some measurements in Noi chicks from birth to 28 days old will be characterized in this study.

Experimental management
A total of 742 chicks generated from the Noi resource population in two previous studies Ngu et al., 2015) was allotted to 6 private cages with a density of 0.3 m 2 / bird in an opened housing system. One month before the arrival of the chicks, the house was washed, cleaned and sprayed by water, detergent, antiseptic and lime.
The infrared light and thermometer were used to keep a stable warm temperature (around 30 o C) for chicks during experiment time. Ad libitum feeding was offered to Some quantitative genetic traits in Vietnamese indigenous Noi chicken from 0 to 28 days old 143 chicks according to instruction of GreenFeed Vietnam Join stock Company. It is declared that GF1312 feed for backyard chicks is made by main feed stuff ingredients such as soybean cake, fish meal, rice bran, broken rice, corn, wheat bran, cassava mi, amino acids, vitamins and minerals (Table 1). Along the experiment, clean water mixed with ProBAC (containing Bacillus subtilis, Bacillus licheniformis, Bacillus clausii and Bacillus coagulans with concentration of ≥10 11 CFU/g, 1g ProBAC for 5 litters of water) was fully provided for chicks. Supplementation of multivitamins was done at time points of high temperature or after vaccinating with Gumboro and IBV vaccines at the fifth and fourteenth day of age, respectively.

Measured parameters
Body weight, average daily gain, feed intake, feed conversion ratio, beak length, skull length, skull width, neck length, back length, wings length, thigh length, tarsus length, keel length, breast diameter, and thigh diameter (Francesch et al., 2011;Ojedapo, 2013) were collected on all experimental chickens at every week of age.

Statistical analysis
Chicks were divided into three different groups of hatching weight (µ±σ) or various stages of age before using R software (ver. 3.4.2) for analyzing statistics. Measurements at various time points were analyzed by descriptive statistics. General Linear Model was applied to analyze effects of groups of hatching weight or stages of age on observed traits.

Results and discussion
In this study, it was demonstrated that all measurements were increased due to aging of chicks (Table 2). These increments were significantly found among different stages of age (P=0.000) (Table 3). Wings length (64.88%) and keel length (58.83%) developed very early with the highest rate in the first week of life, followed by developing rate of beat length (14.03%), skull length (7.71%), skull width (9.47%), neck length (24.07%), back length (25.29%), thigh length (25.95%), shank length (24.87%), breast diameter (31.85%), thigh diameter (71.17%) at the second week compared with other weeks. No highest measurement was found at the third week of rearing period. Based on our observation, at the end of the second week old, some of chicks could fly 1-2 m far and 0.2-0.4 m high although the first few feathers on their wings had just formed. The early development of wings length and feathers helps the chicks fly and move faster at the beginning of feeding as natural competition among them. This also helps raiser easily to assess health status of herd. It is also known that Aseel is also one of famous fighting chicken breeds in India. Recently, Rajkumar et al. (2017) reported that at 28 days old, Aseel' shank length was 43.5 mm higher than Noi' one (25.89 mm) in this study. Rajkumar et al. (2017) implied that because of fighting purpose, Aseel cocks were selected with longer and stronger shanks and legs either naturally or by farmers. Noi chicks in this study were not selected for those.
In the rural area of Vietnam, besides development of industrial poultry farms investigated by companies, most of the households are dependent on indigenous chickens for their livelihoods and their own consumption. Unfortunately, large amount of genetic potential of the indigenous chicken breeds has not been fully recognized, realized, and utilized. Probably, data linkage among research programs was not good for further objectives. Many studies on the quantitative genetic traits (morphology, productivity and economic efficiency, etc.) in indigenous chickens were done well, but the collected data have no breadth, depth, uniformity and completeness. Therefore, it is not easy to summarize all of them in a set and some data are still absent in Table 5. Comparing the obtained data in this study with the other data in previous studies in population of Vietnamese native breeds at the first month of age could be fixed for every trait.
A linear increase of the average daily gain, feed intake and feed conversion ratio by aging was found statistically significant in this study (P=0.000) (  (Table 5). Differences in weight gain, feed consumption and feed conversion ratio among chicks may be due to influence of breeds, nutrition management, nursing conditions, etc. through underdeveloped and developing countries. Furthermore, it was shown that the hatching weight of Abor Acres (44.7 g/bird) was 1.18 to 1.73 times higher than that of other native breeds (ranged from 25.9 to 38.0 g/bird) and 1.28 times compared with Noi chicks. Hatching weight may be influenced by the size, weight and quality of the eggs which they are not easy quickly to improve by genetic and nutritional means. 10 BW: body weight (g/bird); BL: beak length (mm); SL: skull length (mm); SW: skull width (mm); NL: neck length (mm); BaL: back length (mm); WL: wings length (mm); TL: thigh length (mm); ShL: shank length (mm); KL: keel length (mm); BD: breast diameter (mm); TD: thigh diameter (mm).

Conclusion
Study on quantitative traits in Noi chicks at the first month of age indicated a linear increase in body measurements, growth and feed conversion ratio, at which the length of wings developed very early in the first week of life, followed by the other dimensions, remarkably the development of breast and thigh diameter, in the second week. In general, the development of observed parameters is due to aging.