Comparative study on some immunological traits in two different genetic groups of chicken

Aim: This study was carried out on one hundred and twenty chicks (60 Libyan native and 60 broiler chicks) to evaluate and compare some productive and immunological characteristics. Materials and Methods: Weekly body weight (from day-old until 6 weeks of age), feed conversion ratio (from 3- 6 weeks of age), phagocytic ability index, count of both heterophils and lymphocytes and its ratio and blood profile were determined. Results: Body weight of Libyan native chickens was dramatically reduced as compared to broiler chickens throughout trial period. Feed conversion ratio of Libyan native chickens was pronounced deteriorated during studied period as compared to broiler ones. The phagocytic ability of Libyan native chickens was more efficient than those of broiler chickens counterparts. The Libyan native chickens were less stressful compared to broiler ones, because of significant decrease of H/L ratio trait in Libyan chickens. Conclusion: It was expected that the broiler chickens were superior in productive traits (body weight and feed conversion ratio) as compared to native chickens. On the other hand, the superiority in immunological parameters such as phagocytic activity and H/L ratio (as a stress measure) was obtained by Libyan native chickens. Consequently, more attention must be considered for Libyan native chicken and using different crossing and selection methods to produce meat and egg native lines for improving its productive traits besides keeping and benefit its outstanding immunological abilities.


Introduction
sub-systems, the humoral, cellular and phagocytic ability [3].To enhance the efficiency of chicken The local fowls of the tropics retain its preference immune system, several lines of chickens have been in its native environment despite of a drastic increase selected divergently against specific antigens [4]. in import of high yielding strains from across the Consequently, these selection processes must affect world.It still has the favor of the local people, the major functions of the immune system, which especially in the rural sector, mainly due to its believed leads to changes in the selected and correlated traits, special capabilities as adaptability to unfavorable resulting in differences in the immune responses environments, resistance to certain disease and meat among the commercial lines.In developing countries, and egg quality.The products from native fowl are the native chicken breeds contain conserved genetic widely preferred especially because of their pigmensystem, with highly level of heterozygosity, which tation, taste and their suitability for special dishes and may provide biological material for the design of are often sold at even higher prices than the same genetic with improved adaptability and productivity products from commercial birds [1].[5].The birds immune system is a complex network Worthy mentioning, characterization and evaluation of specialized organs, glands and cells which are of immune parameters in various genotypes can offer working together to protect the body from the knowledge that can be incorporated into breeding pathogens [2].This system is composed of three basic programs for enhancing the natural resistance to disease in tropical and subtropical environment.brachial vein using sterile disposable syringes and Therefore, the present trial was conducted to evaluate needles and heparinized lab tubes to determine both and compare some productive and immunological H/L ratio and blood profile.A total number of 10 blood characteristics in two genetic groups of chicken samples were obtained (5 from each genetic group) for derived from different genetic origin.
heterophil (H) and lymphocyte (L) enumeration based on the procedures of [7].Briefly, one drop of blood

Materials and Methods
was smeared on each glass slide.After drying, the Chicks and Management: This trial was carried out smears were stained using Wright's stain.corpuscular hemoglobin concentration were The range of high ambient temperature after brooding determined.In addition, the enumeration of white phase was 20-24°C.
blood cells was determined.

Experimental Endpoints
Statistical Analysis: To determine the effect of Body weight: Chick weights were determined from chicken breed, data were subjected to one-way one-day old to 6 weeks of age using an electronic pan analysis of variance with breed as a main effect using balance that was accurate to 0.01 g.
the General Linear Model (GLM) procedure of SAS Feed conversion ratio: Using 60 birds from the two User's Guide, [8].The following model was used; genetic groups (30 each), feed conversion ratio (FCR) Y = + B + +e

Results and Discussion
Phagocytosis: Carbon Clearance (Mononuclear Phagocytic System Function Assay) experiment was Data given in Table -1 showed the body weight of carried out to determine phagocytic ability of chicks broiler and Libyan native chicks upon hatching until 6 based on the method of [6] and modified by [3].weeks of age.Definitely, the superiority in body Briefly, the supernatant fraction of Black India ink weight trait was associated with broiler chicks at all (Design/Hggins, 4415, Sanford, Bellwood, Illinios studied ages.It is unfair to compare between body 60104) was obtained through centrifugation (5000 weight for broilers and native chickens, where no rpm for 30 min).At 6 weeks of age, five chicks from selection improvement is adopted.The body weight of each genetic group were injected with ink at the rate of broiler chicks was twice the weight of the local upon 1 ml/kg body weight into the left wing vein.The blood hatching.It could be also observed that the difference samples at 0, 3 and 10 min after ink-injection were taken between commercial and local chicks in body weight from the opposite wing and immediately transferred trait was increased with age progress, where the body into 2 ml of 1% sodium citrate.The samples were then weight of broiler chicks was almost six times and nine centrifuged at 5000 rpm for 4 min.The relative amount times at 21 and 42 days of age as compared to native of carbon particles remaining in the supernatant was chick's counterparts.In broiler strains, body weight measured spectrophoto-meterically at a wavelength of and carcass traits were under intensive selection for 640 nm using samples at 0 min as the zero value.more than half a century, and are considered as the most important economic traits in broiler breeding Heterophils/Lymphocytes ratio: At 6 weeks of programs [9].Moreover, progress in rapid growth has age, a 3.0 ml blood sample was withdrawn from the been accompanied by an increase in abdominal fat broiler strains, especially in economic characteristics deposition in broilers [10,11].In general, local such as growth rate, feed conversion ratio and viability.chickens are poor performance in terms of growth rate Regarding phagocytic activity, the defensive (hence meat production) and egg production.Most of functions of phagocytosis come into effect immediately them are of small adult size and lay small sized eggs upon the invasion by the foreign materials, whereas when compared to improved commercial broiler or the T cells needs time to be stimulated and proliferate layer birds, respectively [12].
before they respond to the invasion [15].The Phagocytic Feed conversion ratios for commercial broiler activity was measured by injection of Indian ink into and Libyan native chicks between three to six weeks of the birds of the two chicken genetic lines and comparing age are shown in Figure -1.The results revealed that their ability to clear the injected carbon from blood the significant deterioration of feed conversion was circulation over a period.An increase in the percentage associated with Libyan native chicks throughout the of optical density (OD) value would be indicative of experimental period comparable with broiler ones.more carbon present in the sample at the time of The difference was more pronounced with age quantification, in turn less phagocytosis.Figure -2 progress.As known, both body weight and growth rate showed the effect of genetic group of chicken on are a mirror for feed conversion trait.So that, the phagocytic ability.It could be observed that the deterioration of native chicks body weight was due to Libyan native chicks had significantly lower levels of the deterioration of feed conversion character.carbon particles in their blood circulation at 3 and 10 Similarly, the Egyptian native chickens had lower minutes post injection as compared to broiler group.growth rate, poor feed efficiency and lower meat yield Hence, the phagocytic ability of Libyan native chicks [13].Using the same broiler strain, the feed conversion was more efficient compared to the broiler chick ones.ratio from 3 to 6 weeks of age was close to the average The phagocytic activity plays an important role in of feed conversion of the current study (2.5) [14].disease resistance.Birds with higher macrophage Generally, the poultry companies operating in full phagocytic potential and nitrite production could swing for the development and improvement of protect against bacterial, viral, and parasitic infections  Comparative study on some immunological traits in two different genetic groups of chicken [16].The phagocytosis might be under the influence of This finding also indicate that the genetic background B complex [6].It is interesting to note that the different play an important role in the inheritance of H/L ratio genetic origin between broiler and Libyan native trait.chicks may be led to different phagocytic responses.Blood profile is very important to evaluate the Several researchers have reported that phagocytic health status of man and animals.Data presented in activity of chickens is genetically regulated [6,15,17, revealed that there was no significant difference 18 ,19].
between the two genetic groups in erythrocytic values Table-2 shows the effect of genetic group of (packed cell volume, red blood corpuscles, hemoglobin chicken on heterophils, lymphocytes and H/L ratio.It level, mean value of corpuscular volume and mean could be seen that the Libyan native chicks had value of corpuscular hemoglobin concentration) except significantly lower heterophils percentage compared the mean value of corpuscular volume.Concerning to the broiler ones.Opposite trend was noticed for white blood corpuscles, the broiler chicks had significantly lymphocytes percentage, where, the Libyan native higher WBC count as compared to native chick chicks had significantly higher lymphocytes percentage counterparts.In contrast, the significant difference compared to broiler strain.Contrarily, under the Thailand between Thai indigenous chickens and broilers was conditions, there was no significant difference between observed in hemoglobin and MCHC traits, while the Thai indigenous chicken and broiler chicken in both other hematological characters did not statistically heterophils and lymphocytes percentages [20].It is differ in two genetic groups of chicken [20].important to note that the heterophils increase and Conclusion lymphocytes decrease when birds are stressed, so that the ratio between them is an index of response to stressors It was expected that the broiler chickens were [21].There is a genetic component to heterophils and superior in productive traits (body weight and feed lymphocyte responses to stressors [22] and their ratio conversion ratio) as compared to native chickens.On has been used as a selection criterion for heat the other hand, the superiority in immunological resistance in chickens [23].Likewise, the different abilities such as phagocytic activity and H/L ratio (as genetic background between the two genetic groups of stress measure) was obtained by Libyan native chicken may be played an important role in the chickens.This study recommend that it is important to immunocompetence of white blood corpuscles.The pay more attention on Libyan native chickens and genetic variation may exist in the immunocompetence using different crossbreeding and selection methods to of heterophils [22].The Libyan native chicks had produce meat and egg native lines for improving its significantly lower H/L ratio compared to the broiler productive traits besides keeping and benefit its strain.This result indicated that the Libyan chicks outstanding immunological abilities.were less stressful compared to the others under the Author's contribution current environmental conditions.The H/L ratio is a recognized measure of stress in birds [7,23] that has Author read and approved the final manuscript.become a valuable tool in stress research, especially Comparative study on some immunological traits in two different genetic groups of chicken August-Universität Göttingen, Germany.
help on the field trial.

Competing interest
Incorporating some marker genes in Dandarawi chicken to improve: 1.Growth performance and The author declare that he has no conflict of interest.
during 3-6 weeks of age using Where; = overall mean, B = breed effect (i =1, 2), i the following equation: FCR= Feed consumption ÷ e = experimental error.ij Body weight gain.

Figure- 1 .Figure- 2 .
Figure-1.Feed conversion ratio (FC) of broiler and Libyan native chicks during 3-6 weeks of age Figure-2.Phagocytic ability of broiler and Libyan native chicks OD increase percentage = {(OD reading at a considered time -OD reading at zero min) / OD reading at zero min}*100.

Table - 1
. Means±SE of body weight in broiler and Libyan native chicks

Table - 2
. Heterophils (H), lymphocytes (L) and H/L ratio of native and broiler chicks ab -Means within a column with no common superscript differ significantly.

Table - 3
. Blood profile of native and broiler chicks