Evaluation the role of Apsa-mos® as immunomodulator on the level of antibody titers in broiler chickens vaccinated with Newcastle disease virus.

Article Highlights

1-Apsa-mos^® is immunomodulator in chickens were enhanced its immunity.

2-Apsa-mos^® increase both cellular and Humeral immunity.

3-Histological changes were identical with cellular immunity changes.

Evaluation the role of Apsa-mos® as immunomodulator on the level of antibody titers in broiler chickens vaccinated with Newcastle disease virus.

Thanoon Y. Al-Hbiti and Zahraa A. Al-Noaimy

Department of Pathology and Poultry Diseases, College of Veterinary Medicine, University of Mosul

thanoon_th@uomosul.edu.iq, zahraadil65@uomosul.edu.iq

orcid:0000-0002-0393-4912 orcid: oooo-0001-6971-2784

2020-11-19

2021-04-16

Abstract               

The aim of our study is to evaluate the effect of Apsa-mos® as immunostimulant on the level of antibodies in broiler chickens vaccinated with Newcastle disease live attenuated vaccine (β1 and lasota strain) at 10, 24-day old respectively. Forty, one-day-old chicks were reared in this experiment. They were divide into four groups and treated as follows: Chicks in the 1st group were treated as control one (G1); Chicks in the group 2 (G2), were vaccinated with live attenuated β1 NDV vaccine at 10 days followed by attenuated lasota NDV strain vaccine at 24 days of age, chicks in the group three (G3) were vaccinated as in group 2 but amended with Apsa-mos® at a rate of 1 mg / kg of feed; Chicks in the 4th treatment was given Apsa-mos® only at a rate of 1 mg / kg of feed. Antibody titers after administration of NDV vaccines were estimated using ELISA technique. The results showed a significant difference in the titers between the vaccinated and non-vaccinated birds with higher values when Apsa- mose® was added, in comparison with groups 1 and 4. No significant changes were noticed between granulocytes differential counts and in the values of stress factor of heterophiles/lymphocytes (H/L ratio) in all treated groups. Amending Apsa-mos® to the feeds of the treated birds G3 and G4 has no negative effect on the treated and play a positive role by restoring the normal architecture of lymphoid tissues of bursa of Fabrecious and caecal tonsils. we concluded that the giving of Apsa-mos improve the immune state of the chicks in both types humeral and cellular immunity especially in G3 and decreased the influence of the vaccine in this group and increase the immunity in G4 also Apsa-mos decrease the effect of the vaccine in G3 seen in histological changes in bursa of fabricious and cecal tonsils.

Keywords: Newcastle disease, Vaccine, Immunity, Apsa-mos, Histopathology

تقییم دور Apsa-mos^® کمنظم مناعی على مستوى معیار الأجسام المضادة فی دجاج التسمین المحصن بفیروس مرض نیوکاسل

ذنون یونس الحبیطی و زهراء عادل النعیمی

فرع الأمراض وأمراض الدواجن، کلیة الطب البیطری، جامعة الموصل، العراق

الخلاصة

الهدف من دراستنا هو تقییم تأثیر ابساموس کمنبه مناعی على مستوى الأجسام المضادة فی دجاج التسمین المحصن بلقاح حی موهن لمرض نیوکاسل عترة بیتا- 1وسلالة لاسوتا عند عمر 10، 24 یومًا على التوالی. تمت تربیة أربعین فرخًا عمرها یومًا واحدًا فی هذه التجربة. تم تقسیمها إلى أربع مجموعات وتم التعامل معها على النحو التالی: تم معاملة الکتاکیت فی المجموعة الأولى على أنها مجموعة السیطرة (المجموعة الأولى). تم تلقیح الکتاکیت فی (المجموعة الثانیة) بلقاح حی مضعف من نیوکاسل عترة بیتا فی 10 أیام متبوعا بلقاح لاسوتا الموهن فی عمر 24 یوماً. تم تحصین الکتاکیت فی (المجموعة الثالثة) کما هو الحال فی المجموعة الثانیة فضلا عن استخدام مادة ابساموس بمعدل 1 مجم / کجم من العلف، أعطیت الکتاکیت فی (المجموعة الرابعة) ابساموس فقط بمعدل 1 مجم / کجم من العلف. تم تقدیر عیارات الأجسام المضادة بعد إعطاء لقاحات نیوکاسل باستخدام تقنیة الإنزیم المناعی الممتز. أظهرت النتائج وجود فروق معنویة فی مستوى الأجسام المضادة بین الطیور المحصنة وغیر المحصنة. مع وجود قیم أعلى عند إضافة ابساموس إلى المجموعة الثالثة مقارنة بالمجموعتین الأولى والرابعة. لوحظ بین التعداد التفاضلی للخلایا المحببة وفی قیم عامل الإجهاد فی الخلایا المتغایرة / الخلایا اللیمفاویة (فی جمیع المجموعات المعالجة. تعدیل ابسا موس لتغذیة الطیور المعالجة الثالثة والرابعة. ویلعب دورًا إیجابیًا من خلال استعادة البنیة الطبیعیة للأنسجة اللمفاویة فی کلا من جراب فابریشیا واللوز الاعوریة. إن إعطاء أبسا موس یحسن الحالة المناعیة للکتاکیت فی کلا النوعین من المناعة الخلطیة والخلویة خاصة فی المجموعة الثالثة ویقلل من تأثیر اللقاح فی هذه المجموعة ویزید المناعة فی المجموعة الرابعة کما قلل أبسا موس من تأثیر اللقاح على التغیرات النسیجیة فی جراب فابریشیا واللوز الاعوریة فی المجموعة الثالثة.

Introduction

Newcastle disease (ND) is a major important viral disease of domestic and wild birds caused by para-myxo virus (1). It is characterized by variations in morbidity, mortality, symptoms and lesions (2). The disease is transmitted by direct contact with infected bird secretions (Feces and mouth secretions) (3). There are many strains of virus, lentogenic, mesogenic, and vellogenic strains (4). Three forms of Newcastle disease are recognized: the pneumotropic, viscerotropic and neurotropic forms (3). Prevention and control of the disease is depending on vaccination and biosecurity. Alive attenuated vaccine against ND could be given by, spray oral and eye drop route. While killed vaccine can be used as a booster dose (5). Immunostimulants play an important role in enhancement the immune system of chickens and improve poultry production. Several types of stimulants with different mechanisms and functions. Complex carbohydrates Apsa Mos^® is a wall extract with a high content (6).

Material and methods

Forty broiler chicks (Ross 308) at one-day old of age were reared in the animal house at the college of veteriary medicine, University of Mosul. All environmental requirements of temperature and humidity needed were available for birds in their entire 30 days period of the experiment. Feed and water was available for ad libitum. Chicks were randomly distributed at a rate of 10birds/treatment. Chicks in the 1^st treatment were considered as control one (G1); Chicks in the 2nd treatment were vaccinated with live attenuated vaccine (β1 and Lasota strains), at 10 and 24 days old respectively (G2); Chicks in the 3rd treatment (G3), were vaccinated with live attenuated vaccines (as in G2), and amended with Apsa-mos® at a rate of 1 mg / kg of feed; Chicks in the 4th treatment were given Apsa-mos^® only at a rate of 1 mg / kg of feed. At the end of the experiment (30 days), blood samples were collected from jugular vein and divided into two parts, the first one was gathered in gel tubes for serum collection, while the other part was gathered in anti-coagulant tubes. Serum samples were collected by lifting gel tubes at room temperature for 2 to 3 hours, then were freeze until estimation of Newcastle antibody titers by using ELISA technique with Biochek ELISA kit (Biochek company). The second part of blood was used for estimating differential leucocytes count.

Histological Sections

At the end of the experiment, five chickens were necropsied and both bursa of fabricious and cecal tonsils were collected in neutral buffered formalin 10% for histopathological changes by making 5 µ thickness specimens

Statistical analysis

Statistical analyses of antibody titer levels in different bird groups and differential leucocytes count, were statistically analyzed using one-way ANOVA test. The differences between groups were estimated by using Duncan test with the significances were calculated at a level of P<0.05.

Results

The effects of NDV vaccine and Apsa- mos^® on mean ELISA antibody titers in vaccinated birds at 30 days of age are illustrated in (Table 1). From table it is clear that s/p in broilers of groups 1 and 4 had values less than 0.349, with ELISA mean titers of 20.629± 3.3 and 71.139± 12 respectively, representing a negative detection of antibodies, since the titer range was less than 1158. Values of s/p in broiler chickens of group 2 and 3, in which chicks were vaccinated with NDV vaccines at 10 and 24 days of age were greater than 0.350, with ELISA mean titers of 2670 ± 330.2 and 3677.70 respectively. No significant differences were recorded in ELISA mean titers of broilers in group 1 and 4, in which birds were not vaccinated with NDV vaccine with G4 or without G1 amending with Apsa- mos^®. Significant increase in ELISA titers were recorded in boilers of group 2 in comparison with those titers recorded in broilers of group 1 and 4, but even higher significant increase was noticed after Apsa- mos^® was added to the feed of birds in group 3, in comparison to all three groups 1,2 and 4 ELISA titers. There was a moderate variation in the titers of both G2 and G3 with a coefficient of variance of 39.120 and 41.610 respectively compared to more variable titers in groups 1 and 4, which were 50.61 and 50.61 respectively. The effects of NDV vaccine and Apsa- mos^® on the differential leucocytes count in broiler chickens measured at 30 days of age (Table 2). Almost normal percentages were recorded in all treated groups G1, G2 and G3, when compared with control one, since there were no significant differences between all groups. No stressful adverse effects were recorded through the calculation of the heterophiles / lymphocytes (H/L) ratio 1n all four group. The histological sections of Bursa of fabricia appears in group 2. There is thickening in septum between follicle. necrosis and depletion of lymphocytes in the center of follicle and hyperplasia of epithelium cyst formation due to depletions of lymphocytes (Figure 2) in compared with control group in group 3 the same changes which are seen in group two are seen in group three but in less density. While group 4 appeared significant increase in the density of lymphocyte (Figure 3) in compared with control group.

The results of histopathology of cecal tonsil in group two, there is presence of necrosis and depletion of lymphocytes. The same changes were seen in group 3 in less density. In group 4 there is significant increase in lymphocytes (Figure 4).

Table 1: Effect of Apsa-mos^® on mean ELISA titers at 30 days of age

A, b, c, Means followed by different letters are significantly significant at P<0.05.

Table 2: Effect of Apsa-mos^® on percentage of leucocytes and H/L ratio at 30 days of age

Figure 1: Normal architectural of bursal tissue (control croup). H&E. 576x.

Figure 2: Bursa of fabricious cross section of broiler chicken from G2 at 30 day old showing depletion of lymphocytes in the follicles and cyst formation (red arrow), hyperplasia of epithelium (bBlack arrow). H&E. 448x.

Figure 3: Bursa of fabricia cross section of broiler chicken from G4 at30day old showing increase in the density of lymphocytes inside follicles (arrow). 377x.

Figure 4: Cross section in cecal tonsils of broiler chicken from group 4 at 30-day old showing increase in the density of lymphocytes (arrow). H&E. 320X.

Discussion

In this experiment Apsa-mos^® acts as an immunomodulatory (10,11) by enhancing the production of more antibodies against NDV vaccine in chicks of group 3 compared to the titers in broilers of group 2 which received the vaccine only. The titers of the vaccinated birds with or without addition of Apsa -mos^® were significantly differed from other groups, and occur within the expect range of mean ELISA titers in broilers 1000-4000, when birds vaccinated with live NDV vaccine (Biochek). This finding went in the same way with Parvin et al (7) and Kumar (12). The non-detectable antibodies in non-vaccinated groups were due to the waning of maternal antibodies at 4 weeks of age (14).

No adverse effect was noted when birds were vaccinated with NDV vaccine or with the addition of immunostimulants on the differential granulocytes count which were reflected by the stress factor of the treated birds and these finding were in agreement withRoholla hhhhhzadeh et al (8) and Kumar (12).

Apsa -mos^® addition to the ration of vaccinated and non- vaccinated chickens had its positive effect on the lymphatic tissues of bursa of Fabricious and caecal tonsils reflects its immunostimulant role in restoring the normal architectural shape and details of these lymphoid tissues agreeing in this withCattoli et al (19) and Khalifeh et al (20).

Conclusion

we concluded that the giving of Apsa-mos improve the immune state of the chicks in both types humeral and cellular immunity especially in G3 and decreased the influence of the vaccine in this group and increase the immunity in G4 also Apsa-mos decrease the effect of the vaccine in G3 seen in histological changes in bursa of fabricious and cecal tonsils.

Acknowledgment

The Authors are very grateful to the College of Veterinary Medicine, University of Mosul for their provided facilities, which helped to improve the quality of this work.

Conflict of interest

No conflict.