Blue Light Color Reduces the Newcastle Disease Post-Vaccinal Reactions of Indian River Broilers under Egyptian Conditions

Tarek Mahmoud Mousa-Balabel* and Karima Mohamed Abdo Abofarag

Department of Hygiene and Preventive Medicine, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh city, P.O. 33516, Egypt.

ABSTRACT

Poultry producers accustomed to use strong prophylactic measures such as routine vaccination to control Newcastle Disease (ND) as a trial to increase their productivity. Despite ND vaccinations, several post vaccine reactions of ND are being reported globally, which are major hindrances to the development of the poultry industry in the developing countries. This experiment was planned to study the effects of blue light colour and vitamin E and Selenium (Se) supplementation before and after Newcastle disease vaccination (NDV-LaSota) on post vaccine reactions (immune response) of a recently imported Indian River (IR) broilers to Egypt. In this study, 180 one-day old IR broiler chicks were used. The chicks were randomly assigned to three treatment groups of 60 each. The chicks in the first group were reared under white light colour (WLC) and kept as a control group. The chicks in the second group were kept under blue light colour (BLC) from an incandescent bulb two days before and after vaccination. Chicks in the third group were kept under white light color and supplemented with vita E and Se in the drinking water (WES) for 2 days before and after vaccination at the rate of 5 g per liter drinking water. The chicks were reared on a deep litter system and housed into three well controlled pens of 5.46 m2 with three replicates of 20 each using a density of 15 birds/m2 in the room. The results showed that the broilers reared under BLC and WES had a significant (p> 0.05) higher body weight gain, with obviously, economic feed conversion ratio (FCR), Newcastle disease virus antibody titer and low heterophil/lymphocyte ratio in comparing with WLC. Poultry producers can use blue light color or vitamin E and Se supplementation shortly before and after the vaccination to reduce the stress of vaccination and the post vaccinal reactions in IR broilers.

Article Information

Received 23 March 2022

Revised 18 April 2022

Accepted 11 May 2022

Available online 02 June 2023

(early access)

Published 14 June 2024

Authors’ Contribution

TMM-B presented the concept and design of the study. Material preparation, data collection and analysis was performed by both authors. The first draft of the manuscript was written by TMM-B, and both authors crrected the manuscript. Both authors read and approved the final manuscript.

Key words

Blue light, IR broilers, Immune response, Post-vaccine reactions, Vitamin E supplementation

DOI: https://dx.doi.org/10.17582/journal.pjz/20220323080346

* Corresponding author: [email protected]

0030-9923/2024/0004-1887 $ 9.00/0

Copyright 2024 by the authors. Licensee Zoological Society of Pakistan.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

INTRODUCTION

The broilers are characterized by rapid growth which has an important position in Egyptian economy (Farghly et al., 2019). Despite the fast growth, there are many factors that pull down the growth of broilers, causing economic losses, such as disease outbreaks (Chung et al., 2019). Under intensive productions, there is a higher risk for transmission of diseases, like Newcastle Disease (ND) which being responsible for most economic losses (Aini, 2006). Vaccination may have negative side effects, which may act against the benefits (Landman, 2012).

ND vaccination is often routinely performed as an integral part of management (Corbanie et al., 2008), to provide some degree of protection against it by stimulating the bird’s immune system to respond more effectively to limit losses if a disease occurs in unvaccinated birds. The common losses from ND are decreased body weights, and poor feed conversion. Poor performance is also associated with increased medication costs, and consequently increased production costs to produce a pound of broiler meat (Butcher et al., 2002).

After vaccination, the vaccine virus infects the target cells and replicates to stimulate the immune system, resulting in a variable normal vaccine reaction (nervous symptoms) such as a wing or leg paralysis and torticollis (Jackwood, 2012). Due to replication in the respiratory tract ND vaccine provoke respiratory distress and sometimes suffocation, but most importantly, the ND vaccines significantly increase the susceptibility of broilers to colibacillosis (Matthijs et al., 2003). A good basic rule is that a mild respiratory reaction should be detected 2 to 3 days after vaccination and should last for 5 to 7 days (Rohollahzadeh et al., 2018).

In many broiler flocks, high mortality was recorded following ND vaccination due to the severity and/or prolonged reactions (Luckert and Saif, 2003). The losses resulting from excessive vaccine reactions are more costly than the actual field challenge to these diseases. Some common factors associated with the excessive vaccine reaction: poorly designeed vaccine, inappropriate age for vaccination and use of aggressive route of vaccination, lack of antibiotic therapy to control the vaccine response, and uneven vaccination in which some birds receive multiple doses and others receive none. However, in the following days, vaccinated birds will horizontally shed the vaccine to pen mates. The horizontal transmission will be variable and there will be additional changes in the maternal antibody levels, further complicating the flock’s reaction. Sanda (2015) proved that three weeks post vaccination, the mean NDV antibody titer was significantly (P < 0.05) higher (1.87±0.18) in chicks given multivitamins before and after the vaccination than (1.39±0.12) of the control.

Proper management of brooding temperature, litter management and drinker sanitation has been important to preventing stress and reducing pathogen load, which is commonly associated with excessive vaccination reactions. It is believed that vitamins and minerals have beneficial effects in improving the productive performance of poultry (Monoura et al., 2008). Like vitamins, importance of certain trace minerals in immune function has been increasingly evident, such as Se which has been found to affect various components of the immune system (Suttle and Jones, 1989). Poultry producer used the dim blue light on their farms to increase their body weight with economic feed conversion ratio (FCR). In addition, it’s lowering the bird activity and increasing the heterophil/lymphocyte (H/L) ratio (Mousa-Balabel et al., 2021).

Considering the above factors, the present study was undertaken to evaluate the immune response of broiler chicks kept under blue light and vaccinated with Newcastle (LaSota) vaccine, and the drinking water of the bird is fortified with a multivitamin-mineral supplement before and after vaccination.

MATERIALS AND METHODS

Experimental birds, design and husbandry

This study was conducted under the temperate climatic conditions at Kafrelsheik Governorate, Egypt, during the months of October and November, 2020. In this study, 180 unsexed day-old commercial Indian River (IR) broiler chicks obtained from a local commercial hatchery in El-Gharbyia Governorate, Egypt. Their average body weight (BW) was 42 ±2.1g and brooded under standard brooding conditions. All birds were received at 33°C which decreased 3°C every week until 21°C at the fifth week on a deep litter system and kept under a light intensity of 40lux and 24h light length from 1 to 7 days of age (Mousa-Balabel et al., 2017). After 7 days, the light intensity was reduced to 15 lux, and the light-dark cycle was 23 h: 1 h. From d 8 to d 35, the chicks were randomly distributed between 3 equal separated environmental light proof rooms (2.6X2.1m each; 60 chicks) with three replicates of 20 chicks each with a trial end stocking density of 34 kg/m2 (equivalent to 15 chicks per square meter) based on chick placement numbers (Rozenboim et al., 2004).

The birds were exposed to three different treatments following their identification with wing rings according to Senaratna et al. (2016). The chicks in the first pen were reared under white light color (WLC) from an incandescent bulb and kept as a control group. While, the chicks in the second pen were kept under blue light color (BLC) from an incandescent bulb two days before and after vaccination and the chicks in the third pen were kept under white light color (WES) and supplemented with vit E and Se (Zoosol Sel-E 200, DSM Nutritional Products Co. Italy) in their drinking water for 2 days before and after vaccination at the rate of 10 g to 2 liters according to Sanda (2015). These treatments were used to assess the effect of BLC and vit E and Se supplementation on IR broiler post vaccinal reactions under the Egyptian conditions. Throughout the duration of the study, all birds in the different treatments were given identical care and management (Xie et al., 2008). The chicks were reared on a deep litter system with water and feeding on commercial feeds (Alnour and Albaraka Company, El-Gharbyia Governorate, Tanta city, Egypt), ad libitum; broiler starter (metabolizable energy [ME] = 3,000 kcal/kg, crude protein [CP] = 23%); broiler finisher (ME = 3,100 kcal/kg, CP = 20%). The starter ration was used for feeding all broiler chicks from day 1 to day 21 of age and the finisher ration was used for feeding all broiler chicks from day 22 to day 35 of age. On 7 and 17 days of age, broilers were vaccinated with Servac Newcastle vaccine (Vet. Ser and Vaccine, Res. Inst., Abbassia, Cairo, Egypt) in the drinking water.

Initially, blood samples were collected from five chickens that were selected randomly before vaccination. Subsequently, blood sample collection was done on day 11 post second Lasota vaccination (11 days after the second vaccine administration) (Xie et al., 2008). The blood samples were drawn from wing vein (4-5ml) into sterile microtubes (one contained anticoagulant EDTA). The coagulated blood samples were centrifuged at 3000 rpm to harvest sera, which were transferred into clean and sterile Microtubes and stored at -20°C until its using for the estimation of NDV antibody titer (Xie et al., 2008). The uncoagulated blood samples were examined for CBCs and differential white blood cell analysis (Chung et al., 2020). Heterophil/ lymphocyte ratios were determined as described by Kaab et al. (2018).

Assessment of NDV antibody titers

The NDV antibody titer in isolated serum samples was measured using haemagglutination-inhibition (HI) test. The HI titer was expressed as the log2 reciprocal of the highest serum dilution producing 100% inhibition of HA activity (Rahimi and Khaksefidi, 2006).

The lymphoid (immune) organs

On day 28, after collecting blood samples, the same birds were weighed and slaughtered. Birds were opened to examine the abdominal cavity and to collect the immune organs (bursa of Fabricius, liver, thymus and spleen) to record their weight according to Cheng et al. (2017).

Performance characteristics

All broilers were individually weighed at the start of the experiment, 7, 14, 21, 28 and 35 days of age and body weight gain (BWG) between them was calculated. The total feed intake (TFI) was weekly calculated. Also, feed conversion ratio (FCR) was determined for relevant time periods. Birds were inspected twice daily (8 a.m. and 8 p.m.) for signs of disease to assess post vaccinal reaction and mortality. Total mortality records throughout the study period were calculated as a percentage of live birds at the start of each treatment according to El-Husseiny et al. (2000). The post vaccinal reaction examination was performed on dead and surviving birds of all groups. Relative weight of internal organs was also measured by following equation:

Relative weight % = organ weight x 100/ body weight

Ethical issues

All experimental procedures performed in the study followed the Guidelines of the Institutional Animal Care and Use Committee of Research Policy on Faculty of Veterinary Medicine, Kafrelsheikh University, Egypt, at which the studies were conducted.

Statistical analysis

Data were reported as means ± SEM and analyzed by one-way ANOVA using Graph Pad prism 5. The significance of difference among the different groups was evaluated by Tukey’s post hoc multiple comparison test. The significance level was set at P < 0.05.

RESULTS

Table I shows the mean output values of broiler performance that were held under various treatments of light and supplemented with vitamin E and Se. Results showed that the BWG at 35 days of age was higher in the birds kept under BLC and WES groups (2192.9±83.22 and 2140.86±62.23g, respectively) compared to those kept in WLC group (1927.48±79.02g).

Regarding the feed intake and mortality percent, Table I reveals that the overall feed intake or consumption was lower in the birds kept under BLC and WES groups (3980±95.03 and 3995±54.58 g, respectively) compared to those kept in WLC group (4115±124.5 g). However, the lowest percentage of livability rate was reported in broilers held under WLC group (93.4 %) compared to BLC and WES groups (100 and 100%, respectively).

The most economic FCR was recorded in the birds kept under BLC and WES groups (1.814±0.002 and 1.866±0.010, respectively) compared to those kept in WLC group (2.134±0.011).

Hematological and biochemical parameters were affected significantly (P<0.05) by blue light and supplemented with vitamin E and Se before and after NDV vaccination. Birds reared in the BLC and WES groups showed higher PCV (26.59±0.012 and 27.65±0.024%, respectively), hemoglobin (8.92±0.032 and 9.43±0.015 g/dl, respectively) and RBCs (2.39±0.045 and 2.17±0.051× 1012/l, respectively) compared to those kept in WLC group (PVC was 22.60±0.036, HB was 7.86±0.045 and RBCs was 1.81±0.032× 1012/l, respectively). While, H/L ratio was decreased (0.466±0.021 and 0.529±0.009, for BLC and WES groups, respectively, in comparison to 0.640±0.017 for WLC group). On the other hand, AST, ALT and the total protein (Albumin and Globulin) were didn’t affect by the treatments (Table II).

Concerning the weight of lymphoid organs as a percent of the final body weight, the data in Table III shows that the weight of lymphoid organs (liver and Bursa of Fabricius) was significantly (P<0.05) increased by rearing the birds in BLC and WES groups. Meanwhile, the spleen and thymus weight were not affected.

The Newcastle disease antibody titers after vaccination, were significantly (P<0.05) increased obviously in the birds reared in the groups of BLC (4.02±0.024) and WES (2.98±0.031) in comparison to WLC (2.12±0.016) group (Table IV).

DISCUSSION

The mechanism of action of blue light increases plasma androgens (Rozenboim et al., 1999) which improve protein synthesis leading to muscle build-up (Crowley and Matt, 1996). The means ± standard errors of growth performance of IR chickens post-vaccination is presented in Table I. The highest (P<0.01) body weight gain was observed in BLC and WES groups in comparison to control (WLC) groups. In conformity with the present study increased body weight was noticed by Dalia et al. (2018) on supplementation with vitamin E and Se in the broiler diet. Similar findings were also reported by Maini et al. (2007); Bobade et al. (2009) in broilers. The total feed intake per broiler during the experimental trial was higher (P<0.05) under blue light and antioxidant (vitamin E and Se) supplemented groups than the control group. These results explain the improved body weight of the birds under the blue light color and antioxidant supplementation in the present study. Also, it confirms the findings of Liu et al. (2008) who observed that there was an increased breast muscle weight in birds reared under blue light at market age. This observation can be explained by the blue light stimulates the myofiber growth of the birds (Velo and Ceular, 2016). Also, the improvement in body weight gain of the antioxidant supplemented group might be due to an excellent chain breaking ability of antioxidant that protects cells and tissues from lipoperoxidative damage (Lin and Chang, 2006). Vitamin E interacts with Se containing enzyme glutathione peroxidase to prevent the oxidative breakdown of cells (Surai, 2000).

The difference in livability percentage of birds under treatments (blue light group and vita E supplementation) and the control group were similar to the results obtained by Bharat et al. (2013) in chicken and by Chung et al. (2005) in breeder hens which supplemented with vitamin E and C. This livability percentage may be related to better immune status as, vitamin E reduces the secretion of immunosuppressive factors and inhibits protein kinase C in cells of monocytes and lymphocytes thereby improve immunological system (Erf et al., 1998).

The birds under BL had an approximate FCR, which was comparable to that of vita E but significantly higher than those of the control group as shown in Table I. These results may be attributed to blue light enhanced the metabolic hormones and productive performance, including carcass weight compared to conventional white lights (Soliman and Hassan, 2019). In addition, Xie et al. (2011) proved that blue light enhanced the intestinal villi growth. Moreover, Kim et al. (2013) observed that blue light color is effective for feed utilization.

Table II shows the relationship between blue light color and vitamin E supplementation and the hematological parameters of broiler chicken. Packed cell volume, hemoglobin and differential leucytic counts were increased under blue light color and vitamin E supplementation. Moreover, red blood cells of birds in the BL group were significantly higher than those of the birds in the control group but were comparable to those of Vita E group. The increased level of the total erythrocyte count, hemoglobin content and packed cell volume might be due to effects on hematopoietic organs. This finding differs from the earlier study of Trans et al. (2000) who observed no significant effect of vitamin E supplementation on any of the hematological parameters (PCV and HB).

Heterophil to lymphocyte (H/L) ratio is a reliable stress indicator. It increases in a stressful condition (Kang et al., 2011). The H/L ratio of the birds kept under blue light and supplemented by vita E was significantly lower than those of the birds in the control group as shown in Table II. The lower heterophil to lymphocyte ratio of the birds under blue and vita E supplementation in the present study is in consensus with the earlier findings of Mohamed et al. (2014) who reported that the H/L ratio of chickens under white light was higher than that of blue light. The findings of Ke et al. (2011) also indicated blue light reduced oxidative enzymes. The poor performance of the birds raised under white light in the present study can be explained by a high heterophil/lymphocyte ratio is negatively correlated with body weight (Al-Murrani et al., 2006). The calming effect of blue light has been ascribed to be responsible for modulating stress impact on the birds (Xie et al., 2008; Firouzi et al., 2014).

The aspartate aminotransferase (AST), alanine aminotransferase (ALT) and the total protein (albumin and globulin) values of the birds across all treatments were similar. These results were explained by good health conditions with less muscle damage (Olanrewaju et al., 2008).

The effect of blue light color and vitamin E supplementation on lymphoid organs of broiler chickens was presented in Table III. The blue light color and vitamin E supplementation did not influence the spleen and thymus weight. On the other side, the liver and Bursa of Fabricius weight of the chickens under BL and vitamin E supplementation were similar but higher than those of the control group (P < 0.05). The improved relative weights of the bursa of Fabricius in the present study corroborate the findings of the previous study that light influences the immune response of birds (Blatchford et al., 2009). It has been shown that that blue light could improve immune function (Xie et al., 2008). These results are contrary to the findings of Dalia et al. (2018) who stated that supplementation of vitamin E and Se did not affect the lymphoid organ weight in broiler.

Singh and Haldar (2005) reported that the enlargement of lymphoid organs could be attributed to three possible reasons such as increase in cell proliferation, decrease in cell death and decline in lymphocytes trafficking to the periphery.

Broiler chickens experience an acute-phase response through vaccination, which reflects the innate immunity and stress related to immunization. Table III also shows antibody titers against the vaccine in the vaccinated three (n = 60 per group) groups. The humoral immune response to the treatment was compared 10 days after the second vaccinations (day 28). HI titer in blue light color and vitamin E supplementation groups was significantly (p < 0.5) higher than those of the control group. This means blue light and vitamin E supplementation introduced a stronger immune response (4.02±0.024 and 2.98±0.031, respectively) while the white light had the lowest response (2.12±0.016).

 

Table I. Effect of blue light and supplemented with vitamin E and Se before and after NDV (Lasota) vaccination on performance of IR broilers (Mean ± SE).

Item	Control	Blue light	Vitamin E	P value
Initial weight (g)	42.52±0.37a	42.10±0.21a	42.14±0.17a	0.5549
Final body weight (g)	1970±59.17a	2235±53.28b	2183±42.28b	0.0030
Body weight gain (g)	1927.48±79.02a	2192.9±83.22b	2140.86±62.23b	0.0023
Feed intake (g)	4115±124.5a	3980±95.03b	3995±54.58b	0.0036
Feed Conversion Ratio (FCR)	2.13±0.01a	1.81±0.002c	1.86±0.01b	0.0021
Livability rate (%)	93.4	100	100

 

Means within each raw having different superscript letters differ significantly at P<0.05.

 

Table II. Effect of blue light and supplemented with vitamin E and Se before and after NDV (Lasota) vaccination on hematological and biochemical parameters of IR broiler.

Item	Control	Blue light	Vitamin E	P-value
PCV (%)	22.60±0.036b	26.59±0.012a	27.65±0.024a	0.0010
HB (g/dl)	7.86±0.045b	8.92±0.032a	9.43±0.015a	0.0041
RBCs (× 1012/l)	1.81±0.032c	2.39±0.045 a	2.17±0.051b	0.0042
WBCs (× 1012/l)	13.78±0.046a	11.44±0.052b	12.98±0.053b	0.0034
Heterophil (%)	37.45±0.044a	30.32±0.021b	31.86±0.031b	0.0022
Lymphocyte (%)	58.46±0.047c	65.02±0.046a	60.15±0.022 b	0.0011
H/L ratio	0.64±0.017a	0.466±0.021c	0.52±0.009b	0.0020
AST (IU/L)	64.01±0.025a	64.66±0.014a	64.99±0.032a	0.1615
ALT (IU/L)	26.42±0.078a	26.99±0.074a	26.82±0.036a	0.1226
Total protein (g/dl)	2.73±0.029a	2.78±0.004a	2.78±0.021a	0.2324
Albumin (g/dl)	1.31±0.009a	1.33±0.010a	1.31±0.013a	0.3412
Globulin (g/dl)	1.42±0.026a	1.45±0.031a	1.47±0.026a	0.1752

 

Means within each raw having different superscript letters differ significantly at P <0.05. RBCs, Red blood cells; PCV, packed cell volume; HB, Hemoglobin; WBCs, White blood cells; H/L, Heterophil/lymphocyte ratio; AST, Aspartate aminotransferase; ALT, Alanine aminotransferase.

 

Clinical signs of various groups and different days

None of the groups showed any clinical and necropsy signs before vaccination. Three days after the vaccination, three cases of paralysis were noticed in the control group, but no clinical cases of the disease were observed in the treating groups. Since on the fourth day after vaccination, the mortality onset was noticed with some signs, including green and watery diarrhea, respiratory signs, head tremors, and torticollis.

Clinical signs of disease were not observed in any of the groups until day 3 post vaccination, control group showed disease signs thereafter. In the other groups from day 15 onwards moderate to severe depression, lameness and/or breathing with open beaks were observed in one to four birds per group. Some of these birds died, the others showed signs of disease up to the end of the experiment.

The group given multi-vitamin supplements (E and Se) before and after LaSota vaccination maintained high antibody titer throughout the period of the study. Rao et al. (2004) reported that vitamins and minerals are important in developing immunity.

In conclusion, the results of this study demonstrated that the BL and vitamin E supplementation are essential for rapid muscle development and improve the post vaccine reactions in IR broilers.

 

Table III. Effect of blue light and supplemented with vitamin E and Se before and after NDV (Lasota) vaccination on weight of lymphoid organs as a percent of the final body weight and on Newcastle disease antibody titers (log10 transformed) of IR broiler.

Item	Control	Blue light	Vitamin E	P-value
Weights of lymphoid organs
Liver %	0.96±0.052c	1.34±0.027b	1.45±0.024a	0.0008
Spleen %	0.12±0.015a	0.12±0.021a	0.12±0.011a	0.5919
Thymus %	0.69±0.023a	0.70±0.034a	0.70±0.052a	0.1516
Bursa %	0.23±0.025b	0.42±0.041a	0.41±0.032a	0.0061
ND antibody tita
Before	1.69±0.016b	1.99±0.021a	2.05±0.029a	0.0052
After	2.12±0.016c	4.02±0.024a	2.98±0.031b	0.0031

 

Means within each raw having different superscript letters differ significantly at P <0.05.

 

Statement of conflict of interest

The authors have declared no conflict of interest.

REFERENCES

Aini, I., 2006. Newcastle disease. In: Diseases of poultry in southeast Asia 1st Ed. (ed. M. Zamri-Saad). UPM Press, Selangor. pp. 225-233.

Al-Murrani, W.K., Al-Rawi, A.J., Al-Hadithi, M.F., and Al-Tikriti, B., 2006. Association between heterophil/lymphocyte ratio, a marker of resistance to stress, and some production and fitness traits in chickens. Br. Poult. Sci., 47: 443-448. https://doi.org/10.1080/00071660600829118

Bharat, R., Bhagwat, S.R., Pawar, M.M., Kulkarni, R.C., Srivastava, A.K., and Chahuan, H.D., 2013. Nutritional strategies to combat the effect of heat stress in chicken. J. Anim. Feed Sci. Technol., 1: 122.

Blatchford, R.A., Klasing, K.C., Shivapra, S., Addelete, H.L., Wakenell, P.S., Archer, G.S., and Mench J.A., 2009. The effect of light intensity on the behavior, eye and leg health, and immune function of broiler chickens. Poult. Sci., 88: 20-28. https://doi.org/10.3382/ps.2008-00177

Bobade, S.P., Sarag, A.N., Rekhate, D.H., Dhok, A.P., and Joge, S.V., 2009. Efficacy of vitamin E and selenium on growth performance of broilers. Vet. World, 2: 20.

Butcher, G.G., Nilipour, A.H., and Miles, R.D., 2002. Feed passage in broilers. A complex problem VM123, one of a series of the veterinary medicine-large animal clinical sciences department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date May 1, 2002. Accessible at http://edis.ifas.ufl. Edu.

Cheng, K., Song, Z.H., Zheng, X.C., Zhang, H., Zhang, J.F., Zhang, L.L., Zhou, Y.M., and Wang, T., 2017. Effects of dietary vitamin E type on the growth performance and antioxidant capacity in cyclophosphamide immunosuppressed broilers. Poult. Sci., 96: 1159-1166. https://doi.org/10.3382/ps/pew336

Chung, E.L.T., Kamalludin, M.H., Jesse, F.F.A., Reduan, M.F.H., Ling, L.W., Mahzan, N.M., Henipah, N.M.A., Loh, T.C., and Idrus, Z., 2020. Health performance and blood profile changes in commercial broilers supplemented with dietary monocalcium phosphate. Comp. clin. Pathol., 29: 573-579. https://doi.org/10.1007/s00580-019-03085-9

Chung, E.L.T., Kamalludin, M.H., Jesse, F.F.A., Reduan, M.F.H., Loh, T.C., and Idrus, Z., 2019. Effect of monocalcium phosphate supplementation on the growth performance, carcass characteristic, gut histomorphology, meat and bone quality of broiler chickens. J. trop. agric. Sci., 42: 1237-1250.

Chung, M.K., Choi, J.H., Chung, Y.K., and Chee, K.M., 2005. Effects of dietary vitamins C and E on egg shell quality of broiler breeder hens exposed to heat stress. Asian-Austral. J. Anim. Sci., 18: 545-551. https://doi.org/10.5713/ajas.2005.545

Corbanie, E.A., Vervaet, C., Van Eck, J.H.H., Remon, J.P., and Landman, W.J.M., 2008. Vaccination of broiler chickens with dispersed dry powder vaccines as an alternative for liquid spray and aerosol vaccination. Vaccine, 26: 4469–4476. https://doi.org/10.1016/j.vaccine.2008.06.055

Crowley, M.A., and Matt, K.S., 1996. Hormonal regulation of skeletal muscle hypertrophy in rats: The testosterone to cortisol ratio. Eur. J. appl. Physiol., 73: 66–72. https://doi.org/10.1007/BF00262811

Dalia, A.M., Loh, T.C., Sazili, A.Q., Jahromi, M.F., and Samsudin, A.A., 2018. Effects of vitamin E, inorganic selenium, bacterial organic selenium, and their combinations on immunity response in broiler chickens. BMC Vet. Res., 14: 249. https://doi.org/10.1186/s12917-018-1578-x

El-Husseiny, O., Hashish, S.M., Arafa, S.M., and Madian, A.H.H., 2000. Response of poultry performance to environmental light colour. Egypt. Poult. Sci. J., 20: 385-390.

Erf, G.F., Bottje, W.G., Bersi, T.K., Headrick, M.D., and Fritts, C.A., 1998. Effects of dietary vitamin E on the immune system in broilers: Altered proportions of CD4 T cells in the thymus and spleen. Poult. Sci., 77: 529-537. https://doi.org/10.1093/ps/77.4.529

Farghly, M.F., Mahrose, Kh.M., Ahmad, E.A.M., Rehman, Z.Ur., and Shengqing, Yu., 2019. Implementation of different feeding regimes and flashing light in broiler chicks. Poult. Sci., 98: 2034-2042. https://doi.org/10.3382/ps/pey577

Firouzi, S., Haghbin, N., Habibi, H., Jalali, S.S., Nabizadeh, Y., Rezaee, F., Ardali, R., and Marzban, M., 2014. Effects of color lights on performance, immune response and hematological indices of broilers. J. Worlds Poult. Res., 4: 52-55.

Jackwood, M.W., 2012. Review of infectious bronchitis virus around the world. Avian Dis., 56: 634-641. https://doi.org/10.1637/10227-043012-Review.1

Kaab, H., Bain, M.M., and Eckersall, P.D., 2018. Acute phase proteins and stress markers in the immediate response to a combined vaccination against Newcastle disease and infectious bronchitis viruses in specific pathogen free (SPF) layer chicks. Poult. Sci., 97: 463–469. https://doi.org/10.3382/ps/pex340

Kang, S., Young-Hyun, K., Yang-Soo, M., Sea-Hwan, S., and In-Surk, J., 2011. Effects of the combined stress induced by stocking density and feed restriction on hematological and cytokine parameters as stress indicators in laying hens. Asian-Austral. J. Anim. Sci., 24: 414–420. https://doi.org/10.5713/ajas.2011.10315

Ke, Y.Y., Liu, W.J., Wang, Z.X., and Chen Y.X. 2011. Effects of monochromatic light on quality properties and antioxidation of meat in broilers. Poult. Sci., 90: 2632–2637. https://doi.org/10.3382/ps.2011-01523

Kim, M.J., Parvin, R., Mushtaq, M.M.H., Hwangbo, J., Kim, J.H., Na, J.C., Kim, D.W., Kang, H.K., Kim, C.D., Cho, K.O., Yang, C.B., and Choi, H.C., 2013. Growth performance and hematological traits of broiler chickens reared under assorted monochromatic light sources. Poult. Sci., 92: 1461–1466. https://doi.org/10.3382/ps.2012-02945

Landman, W.J.M., 2012. The downside of broiler vaccination. Vet. Quart., 32: 121-122. https://doi.org/10.1080/01652176.2012.729657

Lin, Y.F., and Chang, S.J., 2006. Effect of dietary vitamin E on growth performance and immune response of breeder chickens. Asian-Austral. J. Anim. Sci., 19: 884. https://doi.org/10.5713/ajas.2006.884

Liu, W., Chen, Y., Wang, Z., Dong, Y., Cao, J., Xie, D., and Jia, L., 2008. Effect of monochromatic light on the muscle growth and muscle fiber development and testosterone secretion in broilers. Acta Vet. Zoot. Sin., 39: 1759-1764.

Luckert, P.D., and Saif, Y.M., 2003. Infectious bursal disease. In: Diseases of poultry. 11th Ed. Iowa State Press, Blackwell Publishing, London, UK.

Maini, S., Rastogi, S.K., Korde, J.P., Madan, A.K., and Shukla, S.K., 2007. Evaluation of oxidative stress and its amelioration through certain antioxidants in broilers during summer. J. Poult. Sci., 44: 339-347. https://doi.org/10.2141/jpsa.44.339

Matthijs, M.G., van Eck, J.H., Landman, W.J., and Stegeman, J.A., 2003. Ability of Massachusetts-type infectious bronchitis virus to increase colibacillosis susceptibility in commercial broilers: a comparison between vaccine and virulent field virus. Avian Pathol., 32: 473–481. https://doi.org/10.1080/0307945031000154062

Mohamed, R.A., Eltholth, M.M., and El-Saidy, N.R. 2014. Rearing broiler chickens under monochromatic blue light improve performance and reduce fear and stress during pre-slaughter handling and transportation. Biotechnol. Anim. Husband., 30: 457-471. https://doi.org/10.2298/BAH1403457M

Monoura, P., Rahman, M., Khan, M.F.R., Rahman, M.B., and Rahman, M.M., 2008. Effect of vitamins, minerals and probiotics on production of antibody and live weight gain following vaccination with BCRDV in broiler birds. Bangladesh J. Vet. Med., 6: 31-36. https://doi.org/10.3329/bjvm.v6i1.1336

Mousa-Balabel, T.M., Al-Midany, S., and Algazzar, W., 2021. Dim blue light colour reduces the activities and improves the performance of Indian River broilers under Egyptian conditions. J. Hellenic Vet. med. Soc., 72: 3171-3178. https://doi.org/10.12681/jhvms.28511

Mousa-Balabel, T.M., Mohamed, R.A., and Saleh, M.M., 2017. Using different light colours as a stress factor on broiler performance in Egypt. Aust. J. Basic appl. Sci., 11: 165-170.

Olanrewaju, H.A., Thaxton, J.P., Dozier, W.A., Purswell, J., Collier, S.D., and Branton S.L., 2008. Interactive effects of ammonia and light intensity on hematochemical variables in broiler chickens. Poult. Sci., 87: 1407–1414. https://doi.org/10.3382/ps.2007-00486

Rahimi, S.H., and Khaksefidi, A., 2006. A comparison between the effect of a probiotic (Bioplus 2B) and an antibiotic (virginamycin) on the performance of broiler chickens under heat stress condition. Iran. J. Vet. Res., 7: 23–28.

Rao, R.S.V., Raju, M.V.L.N., and Nagalakshmi, D., 2004. Nutritional modulation to enhance immunity in chickens. Poult. Int., April 2004 Watt Publishing Co., pp. 24-29.

Rohollahzadeh, H., Nili, H., Asasi, K., Mokhayeri, S., and Najjari, A.H., 2018. Respiratory and GIT tract immune responses of broiler chickens following experimental infection with Newcastle disease’s virus. Comp. clin. Pathol., 27: 1241-1255. https://doi.org/10.1007/s00580-018-2728-z

Rozenboim, I., Biran, I., Chaiseha, Y., Yahav, S., Rosenstrauch, A., Sklan, D., and Halevy, O., 2004. The effect of green and blue monochromatic light combination on broiler growth and development. Poult. Sci., 83: 842–845. https://doi.org/10.1093/ps/83.5.842

Rozenboim, I., Biran, I., Uni, Z., Robinzon, B., and Halevy, O., 1999. The effect of monochromatic light on broiler growth and development. Poult. Sci., 78: 135-138. https://doi.org/10.1093/ps/78.1.135

Sanda, M.E., 2015. Effects of vitamin mineral supplement on the immune response of broilers to newcastle disease vaccination. Int. J. Agric. Vet. Sci., 1: 10-13. https://doi.org/10.18819/ijavs.2015.1542

Senaratna, D., Samarakone, T.S., and Gunawardena, W.W.D.A., 2016. Red colour light at different intensities affects the performance, behavioural activities and welfare of broilers. Asian-Austral. J. Anim. Sci., 29: 1052-1059. https://doi.org/10.5713/ajas.15.0757

Singh, S.S., and Haldar, C., 2005. Melatonin prevents testosterone induced suppression of immune parameters and splenocyte proliferation in Indian tropical jungle bush quail, Perdicula asiatica. Gen. comp. Endocrinol., 141: 226-232. https://doi.org/10.1016/j.ygcen.2005.01.005

Soliman, E.S., and Hassan, R.A., 2019. Impact of lighting color and duration on productive performance and Newcastle disease vaccination efficiency in broiler 593 chickens. Vet. World, 12: 1052-1059. https://doi.org/10.14202/vetworld.2019.1052-1059

Surai, P.F., 2000. Effect of selenium and vitamin E content of the maternal diet on the antioxidant system of the yolk and the developing chick. Br. Poult. Sci., 41: 235-243. https://doi.org/10.1080/713654909

Suttle, N.F., and Jones, D.G., 1989. Recent developments in trace element metabolism and function. Trace elements, disease resistance and immune responsiveness in ruminants. J. Nutr., 119: 1055-1061. https://doi.org/10.1093/jn/119.7.1055

Trans, B., Inal, F., Bas, A.L., Altunok, V., Elmas, M., and Yazar, E., 2000. Effect of continuous supplementation of ascorbic acid, aspirin, vitamin E and selenium on performance immune response and some biochemical parameters under normal environmental and management conditions in broilers. Arch. Gerflugelk., 65: 187-192.

Velo, R., and Ceular, A., 2016. Effects of stocking density, light and perches on broiler growth. Anim. Sci. J., 88: 386-393. https://doi.org/10.1111/asj.12630

Xie, D., Li, J., Wang, Z.X., Cao, J., Li, T.T. Chen, J.L., and Chen, Y.X., 2011. Effect of monochromatic light on mucosal mechanical and immunological barriers in the small intestine of broilers. Poult. Sci., 90: 2697–2704. https://doi.org/10.3382/ps.2011-01416

Xie, D., Wang, Z., Cao, J., Dong, Y., and Chen, Y., 2008. Effects of monochromatic light on proliferation response of splenocyte in broilers. Anat. Histol. Embryol., 37: 332–337.