Immune System Of Broiler Chickens Research Articles

Cytokine and immunoglobulin profiles of Arbor Acres broiler chickens at different stages of physiological development

Cytokine and immunoglobulin profiles of Arbor Acres broiler chickens at different stages of physiological development

Morphogenesis of some organs of the immune system of broiler chickens in the age aspect when adding the feed additive “Amber Chill feed supplement” to the diet

This article uses the results of a comparative morphological study of Ross 308 cross broiler chickens of the experimental and control groups when introducing the feed additive “Amber Chill feed supplement” with drinking water during the technological cycle. The experiments were conducted at the Ural Federal Agrarian Research Center Ural Branch of the Russian Academy of Sciences” in 2023. The inclusion of the feed additive “Amber Chill feed supplement” in the diet of broiler chickens did not have a negative effect on the general condition, safety of poultry, and live weight gain. The hematological parameters of broiler chickens of the control and experimental groups were within the reference values. Histological examination of the organs of the immune system – thymus, spleen, bursa of Fabricius at 10, 20, 35 and 42 days of age revealed the processes of maturation and differentiation of organs and some processes of involution by the end of the technological cycle. A distinctive feature between the groups was the earlier maturation of the immune system organs in broiler chickens of the experimental group, as opposed to the control group.

Internet of Things-based sustainable environment management for large indoor facilities.

Due to global warming and climate change, the poultry industry is heavily impacted, especially the broiler industry, due to the sensitive immune system of broiler chickens. However, the continuous monitoring and controlling of the farm's environmental parameters can help to curtail the negative impacts of the environment on chickens' health, leading to increased meat production. This article presents smart solutions to such issues, which are practically implemented, and have low production and operational costs. In this article, an Internet of Things (IoT) based environmental parameters monitoring has been demonstrated for the poultry farmhouse. This system enables the collection and visualization of crucially sensed data automatically and reliably, and at a low cost to efficiently manage and operate a poultry farm. The proposed IoT-based remote monitoring system collects and visualizes environmental parameters, such as air temperature, relative humidity (RH), oxygen level (O2), carbon dioxide (CO2), carbon monoxide (CO), and ammonia (NH3) gas concentrations. The wireless sensor nodes have been designed and deployed for efficient data collection of the essential environmental parameters that are key for monitoring and decision-making process. The hardware is implemented and deployed successfully at a site within the control shed of the poultry farmhouse. The results revealed important findings related to the environmental conditions within the poultry farm. The temperature inside the control sheds remained within the desired range throughout the monitoring period, with daily average values ranging from 32 °C to 34 °C. The RH showed slight variations monitoring period, ranging from 65% to 75%, with a daily average of 70%. The O2 concentration exhibited an average value of 17% to 18.5% throughout the monitoring period. The CO2 levels showed occasional increases, reaching a maximum value of 1,100 ppm. However, this value was below the maximum permissible level of 2,500 ppm, indicating that the ventilation system was effective in maintaining acceptable CO2 levels within the control sheds. The NH3 gas concentration remained consistently low throughout the duration, with an average value of 50 parts per million (ppm).

Histomorphological changes in the organs of the immune system of broiler chickens when using drug Betulin

Currently, much attention is paid to maintaining the health of poultry and in this regard, the role of the immune system can hardly be overestimated. Specific protective reactions are carried out by immunocompetent cells that are located in the central and peripheral organs of the immune system. The purpose of the research was to study histomorphological changes in the thymus and Bursa fabricii of broiler chickens when using the phytodrug Betulin. The histomorphological changes in the central organs of the immune system (thymus and fabricius sac) of broiler chickens when using Betulin have been presented in the article. Betulin is a natural pentacyclic triterpenoid of the lupan series. It is found in a large number of plants (hazel, calendula, licorice), but it does not occur in free form. On an industrial scale, it is extracted from birch bark – the outer layer of the bark of white birch (Betula alba), hanging (Betula pendula). Its biological activity has been confirmed in the course of scientific research in more than forty international scientific centers. The effectiveness of using triterpene compounds as direct regulators of the activity of the body’s enzymatic systems has been demonstrated. The research was carried out in the veterinary department of poultry at Siberian Scientifi c and Research Institute of Poultry – a branch of the Federal State Budget Scientific Institution “Omsk Agrarian Scientific Center” on broiler chickens of the cross Sibiryak. The chickens of the experimental groups were used Betulin from 7–21 days, the 1st experimental group at a dose of 2,5 mg/kg of live weight, the 2nd – 5,0 mg/kg, the 3rd – 10,0 mg/kg and the 4th – 15,0 mg/kg of live weight. The poultry of the control group did not receive the phytodrug Betulin. Vaccination of chickens was carried out at the age of 7 days against Newcastle disease viruses and infectious bronchitis of chickens, at 14 days against infectious bursal disease. It was found on the base histological studies that Betulin in doses of 10,0 and 15,0 mg/kg of live weight stimulated the proliferation of lymphocytes and differentiation of the central organs of the immune system of broiler chickens.

Supplementation of Biopeptide from Chicken Feet to the Immune System and Growth of Broiler Chicken

The safety of poultry products, especially broiler chickens, can be stated to be relatively low. Antibiotic growth promoter (AGP) is used to improve chicken performance and maintain immunity. The ban on the use of AGP triggers the innovation of other materials to replace the function of AGP. Biopeptide is a solution that can be used. Biopeptides can be made from materials with a high protein content, for example, waste from chicken slaughterhouses. The waste that can be used is chicken feet, biopeptides produced from hydrolytic proteins have antioxidant and antimicrobial properties. These properties can improve the performance and immune system of broiler chickens. The aim of the study was to examine the supplementation of biopeptides from chicken feet on the immune system (total Escherichia coli and internal organ) and the growth of broiler chickens. The research material was 200 day old chickens of broiler strain cobb unsex, which were reared for 42 days of the rearing period. The treatment feeds were P0: basal feed, P1 basal feed + 2% biopeptide, P2: basal feed + 4% biopeptide, P3: basal feed + 6% biopeptide. The collected data were analyzed using analysis of variance with the Tukey test (BNJ). The results showed that biopeptide supplementation from chicken feet had a significant (P<0.05) effect on total Escherichia coli, spleen weight, bursa of Fabricius weight, body weight gain, and feed efficiency for broiler chickens. However, the results of the study had no significant effect (P>0.05) on liver weight and Avian Influenza antibody titers for broiler chickens. Biopeptide supplementation from chicken feet can reduce total Escherichia coli, and spleen weight, and increase the bursa of Fabricius weight, body weight gain, and feed efficiency for broiler chickens. Biopeptide supplementation from chicken feet of 6% gave the best results in body weight gain and feed efficiency.

Effects of Dietary Supplementation of Vitamin E on Growth Performance and Immune System of Broiler Chickens

As a potent antioxidant, Vitamin E may lessen the potentially harmful consequences of such oxidative stress to protect broilers against immune-pathological damage. Broiler chicken growth and viability are enhanced by Vitamin E supplementation. The present study aimed to investigate the effects of Vitamin E dietary supplementation on broiler chickens’ growth performance and health status. A total of 48 one-day-old Ross chicks were randomly divided into two groups of control and treatment (supplementation of Vitamin E at a dose of 300 mg/kg diet) with three replicates per group. The study included an equal number of Ross breed chicks and Vitamin E dosage in two trials on two different dates (January and March, 2022). In both trials, the obtained results indicated no significant changes in weight gain in the control and treatment groups. In both trials, there were no significant differences in the spleen weight of the control and treated groups; however, from day 1 to 28 of the second trial, the bursa of Fabricius was heavier in the treated group than in the control group. Additionally, Vitamin E had no significant effects on the mitogenic responses to phytohemagglutinin (PHA) and Concanavalin A (Con A). Dosages of 20 and 10 µl for both PHA and Con A did not significantly affect the rate of pure lymphocyte proliferation in chicks fed 300 mg Vitamin E /kg feed. Cell-mediated immunity did not differ significantly between the two trials. The percentages of CD4, CD8, Bu1, and MHCII molecules in the spleen and cecal tonsil of the chicks that received Vitamin E 300 mg/kg feed did not change significantly. The antibody titers against infectious bronchitis and infectious bursal disease vaccines showed no significant differences. On day 42, there was a trend toward an increase in antibody titer in the case of the Newcastle disease vaccine. In conclusion, 300 mg/kg of Vitamin E added to the diet did not improve growth performance and immunity in broiler chicks. Keywords: Broiler chicken, Growth performance, Immune system, Vitamin E

Effects of virginiamycin and galbanum (Ferula gummosa boiss) on performance, carcass traits, immune system and blood parameters of broiler chickens

Background: Some medicinal plants can stimulate growth in poultry. Objective: To compare the effects of dietary addition of virginiamycin antibiotic and galbanum plant (Ferula gummosa) on the performance, carcass characteristics, immune system, and blood factors of broiler chickens. Methods: A total of 250 one-day-old male Ross 308 broiler chickens were randomly assigned to five treatments with five replicates (10 birds per replicate). The treatments were: control (basal diet), virginiamycin (basal diet plus 0.1 g virginiamycin/kg of diet) or one of three levels of galbanum powder (2.5, 5, and 10 g galbanum/kg of diet). Results: Body weight gain, feed intake and feed conversion ratio improved in the groups containing galbanum compared to the other groups (p<0.05). The percentage of liver, heart and abdominal fat decreased in the treatments containing 5 and 10 g galbanum compared to the control (p<0.05). Spleen weight and antibody titers against Newcastle disease and SRBC were significantly increased in the treatment containing 10 g of galbanum compared to the other treatments (p<0.05). The addition of galbanum powder resulted in a significant decrease in serum cholesterol, triacylglycerol, and LDL (p<0.05). Additionally, galbanum increased serum total protein, albumin, globulin, and HDL (p<0.05). Conclusion: Galbanum improves performance and the immune system of broiler chickens, and has similar growth promoting effects as virginiamycin.

The effect of different levels of Valine in low protein diets on cellular and humoral immunity of broiler chickens

Different levels of valine in low protein diets have a significant effect on the immune system of broiler chickens. This experiment was performed to evaluate the effect of different levels of valine in low protein diets on the immune response of broiler chickens. This study was conducted using 200 one-day old male broilers of Ross 308 strain in a completely randomized design with 5 replicates and 10 birds per replicate. Experimental treatments were adjusted based on the Brazilian tables and included: control diet with recommended levels of valine, 10% higher than the recommended level of valine and 20% higher than the recommended level of valine diluted in a diet containing 2% protein. The results showed that different levels of valine had no significant effect on the weight of liver, spleen, fabricius bursa and leukocytes (p<0.05). Diets containing 20% valine significantly increased the HI antibody and humoral immunity responses (p<0.05). The initial total antibody response was not affected by the experimental treatments (p<0.05). But the level of 20% valine significantly increased the total secondary response and IgM secondary response to SRBC (p<0.05). Moreover the addition of valine had a significant effect on the injection reaction of PHA-P (p<0.05), and level of 20% valine, significantly increased the cellular immunity of broilers in comparison to the control treatment and lower valine levels. In the present study, the addition of high levels of valine in low-protein diets improved the cellular and humoral immunity of broiler chickens.

Selected prebiotics and synbiotics administered in ovo can modify innate immunity in chicken broilers

BackgroundA previous study showed that prebiotics and synbiotics administered in ovo into the egg air cell on the 12th day of incubation enhance the growth and development of chickens. However, the influence of this procedure on the development and efficiency of the innate immune system of broiler chickens is unclear. Therefore, the aim of this study was to evaluate whether the early (on the 12th day of embryo development) in ovo administration of selected prebiotics (inulin − Pre1 and Bi2tos − Pre2) and synbiotics (inulin + Lactococcus lactis subsp. lactis IBB SL1 − Syn1 and Bi2tos + L. lactis subsp. cremoris IBB SC1 − Syn2) influences the innate immune system.ResultsChickens (broiler, Ross 308) that were treated with Pre1 exhibited a decreased H/L ratio on D7, but an increased H/L ratio was observed on D21 and D35. In the remaining experimental groups, an increase in the H/L ratio was observed on D21 and D35. The oxidative potential of leukocytes measured using the NBT test increased on D21 in Pre2 and Syn1 groups. The rate of the phagocytic ability of leukocytes increased in Pre1 and Syn1 groups on D21. The phagocytic index decreased in Pre1 and Syn2 groups on D21 and D35. Concurrently, the count of WBC in circulating blood decreased on D21 in Pre1, Pre2, and Syn1 groups. The hematocrit value was increased in Syn1 chickens on D21, in Pre1 chickens on D35, and in Syn2 chickens on both time points.ConclusionsEarly in ovo treatment of chicken embryos with prebiotics and synbiotics may temporarily modulate not only the production/maturation of leukocytes but also their reactivity.

Effect of different sources of selenium on performance and characteristics of immune system of broiler chickens

ABSTRACT An experiment was conducted based on a completely randomized design with 500 Ross 308 broiler chickens to investigate the effect of three different sources of selenium on performance and characteristics of immune system. Chickens were arranged in 10 treatments and five repetitions (10 chickens for each repetition). Ten treatments of experimental diet were considered in the study, including a basal diet (control); 0.5, 0.8, and 1.2 mg nano-selenium + basal diet (three treatments); 0.5, 0.8, 1.2 mg selenomethionine + basal diet; and 65, 80, and 100 mg vitamin E + selenium + basal diet. Findings suggested that adding selenomethionine (1.2 mg) to the basal diet resulted in a significant effect on feed conversion ratio and weight of broilers. In fact, weight and bursa of Fabricius were significantly under influence of the diets containing nano-selenium. Moreover, a significant difference was observed in the antibodies produced against Newcastle and influenza as well as the total immunoglobin and IgG produced against sheep red blood cell at two stages in the group treated with nanoselenium. Finally, results indicated that nano-selenium can better improve performance and immune system of broilers compared with diets containing selenomethionine and vitamin E.

Evaluation of Lactoferrin Immunomodulatory Effect on the Immune Response of Broiler Chickens

Immunomodulators are substances that able to regulate or modulate immune responses. In order to investigate the lactoferrin effect on the immune system of broiler chickens,one hundred twenty (1-day-old) chicks of both sexes were randomly allocated into 2 dietary groups (60 chicks/group), group1 (G1): chicks were offered basal diets and kept as control group, group2 (G2): Chicks were offered basal diets supplemented with lactoferrin (250mg/kg diet for 6 weeks). Evaluating the effects of dietary supplementation with lactoferrin on growth performance of broiler chicks, humeral immunity by measuring antibody titer against Newcastle (ND) and Avian influenza (AIV)vaccine, and on innate immunity by measuring some functions of peripheral blood monocytes (PBM) as phagocytic activity, fungicidal activity, nitric oxide (NO) production and reactive oxygen species (ROS) production by tetrazolium reduction test. To study antibacterial effect of lactoferrin, challenge test was carried out using virulent E. coli strain .The results revealed that, lactoferrin improve growth performance and could stimulate the humeral immunity by increasing the antibody titer aginst ND and AIV vaccine .Also lactoferrin could enhance the innate immunity by significant increasing of phagocytic and Fungicidal activities of PBM and its production of ROS and NO. Lactoferrin have the ability to protect broiler chickens from virulent agents as E. coli. Therefore, lactoferrin may be used as immunostimulant, growth promoters and antibacterial agent in broiler chickens.

Effects of 5-hydroxytryptophan and m-hydroxybenzylhydrazine associated to Lactobacillus spp. on the humoral response of broilers challenged with Salmonella Enteritidis

This study investigates the effects of different doses of serotonin, its precursor 5-hydroxytry-ptophan (5HTP), and m-hydroxybenzylhydrazine inhibitor (NSD1015), administered via intraperitoneal for 5 consecutive days, on behavior and average body weight of broilers. We also measured the humoral immune response and quantification of Salmonella Enteritidis in broilers chickens that received the drugs evaluated and a Lactobacillus pool. The study was divided into 3 experiments: Experiment 1 - administration of pharmaceuticals with choice of dosage; Experiment 2 - administration of pharmaceuticals and a Lactobacillus pool in birds that were not challenged with S. Enteritidis, and Experiment 3 - administration of pharmaceuticals and a Lactobacillus pool in birds challenged with S. Enteritidis. The ELISA was used to scan dosages of intestinal IgA and serum IgY. We used colony-forming units to quantify S. Enteritidis. The concentrations of IgA and IgY did not show significant differences (P > 0.05) in Experiment 2. In Experiment 3, NSD1015 associated with Lactobacillus determined higher IgA concentrations, promoting greater stimulus to the immune system than 5HTP. Regarding quantification of S. Enteritidis in the cecal content of birds, 5HTP associated to Lactobacillus determined the smallest number of bacteria, showing possible interaction of 5-hydroxytryptophan and Lactobacillus spp. with the immune system of broiler chickens.

Effects of corticosterone and dietary energy on immune function of broiler chickens.

An experiment was conducted to investigate the effects of dietary energy level on the performance and immune function of stressed broiler chickens (Gallus gallus domesticus). A total of 96 three-day-old male broiler chickens (Ross × Ross) were divided into two groups. One group received a high energy (HE) diet and the other group received a low energy (LE) diet for 7 days. At 5 days of age, the chickens from each group were further divided into two sub-groups and received one of the following two treatments for 3 days: (1) subcutaneous injection of corticosterone, twice per day (CORT group; 2 mg of CORT/kg BW in corn oil) and (2) subcutaneous injection of corn oil, twice per day (Control/Sham treatment group). At 10 days of age, samples of blood, duodenum, jejunum, and ileum were obtained. Compared with the other three groups, the LE group treated with CORT had the lowest average daily gain (ADG) and the poorest feed conversion ratio (FCR, P < 0.05). Furthermore, CORT treatment decreased the relative weight (RW) of the bursa independent of the dietary energy level, but it decreased the RW of the thymus only in the chickens fed the LE diet. By contrast, CORT administration decreased the RW of the spleen only in the chickens fed the HE diet (P < 0.05). The plasma total protein, albumin, tumor necrosis factor alpha, interleukin 2 and immunoglobulin G (IgG) levels were affected by the CORT treatment (P < 0.05); however, these factors were not significantly affected by the dietary energy level. Toll-like receptor-5 mRNA level was down-regulated by CORT injection in the duodenum and ileum (P < 0.05) and showed a trend of down-regulation in the jejunum (P=0.0846). The present study showed that CORT treatment induced immunosuppressive effects on the innate immune system of broiler chickens, which were ameliorated by consumption of higher dietary energy.

The influence of phytoncides on the immune system of broiler chickens and turkeys.

The aim of our study was to investigate the influence of adiSalmoSOL PF dietary supplement, given for 3 days in drinking water, on selected parameters of cell-mediated (Experiment I) and humoral (Experiment II) immunity in chicken and turkey broilers. In Experiment I, birds were randomly divided into two groups of 10 birds each. Group 1 comprised control turkeys or chickens, whereas group 2 birds were administered adiSalmoSOLPF. In Experiment II, a total of 69 chickens were divided into three groups (1-3) of 23 birds each. At the age of 25 days, group 1 was given adiSalmoSOLPF. Birds from groups 1-3 were vaccinated at 28 days of age. Group 2 was given adiSalmoSOLPF after vaccination. In Experiment I, a significant increase in percentages of CD4 + T lymphocytes in the bursa of Fabricius, cecal tonsils and spleen, CD8 + T lymphocytes in the thymus and spleen, CD4 + CD8 + T lymphocytes in the bursa of Fabricius and ileal mucosa and IgM + B lymphocyte in the ileal mucosa were observed in group 2 chickens. In Experiment I, a significant increase in percentages of CD4 + T lymphocytes in the thymus and spleen, CD8+ T lymphocytes in the cecal tonsils and blood, and CD4 + CD8 + T lymphocytes in the thymus and ileal mucosa was recorded in group 2 turkeys. No differences in percentages of IgM + B lymphocytes were observed between turkey groups. In Experiment II, the highest post-vaccination titers of anti-IB antibodies were observed in group 2, but it was not statistically significant. The results of our study indicate that adiSalmoSOLPF showed immunomodulatory activity in chickens and turkeys.

Neopterin and biopterin as biomarkers of immune system activity associated with crating in broiler chickens

Neopterin and biopterin belong to a group of unconjugated pterin derivates. These biomolecules are present in many animal species and perform several functions. Pterin concentrations may provide additional information on the effect of stress on immune system activity. This study focused on an investigation of the effect of crating on plasma concentrations of neopterin and biopterin in broilers. The effects of 2 crating periods (2 and 4 h) were monitored in Hubbard broilers (n = 90) aged 42 d. After a given crating period, randomly selected chickens from each group were sampled immediately and the remaining chickens were sampled after 24 h. Plasma corticosterone increased (P < 0.001) immediately after 2 and 4 h crating, but no difference between the crated and the control noncrated broilers was found 24 h later. Immediately after crating, neopterin in 2- and 4-h broilers did not differ from the control, but 24 h later a decrease (P = 0.011) in plasma neopterin was found in 4-h broilers compared with the control. Simultaneously, 24 h after crating, neopterin levels in 2- and 4-h broilers decreased (P < 0.001) in comparison with the levels immediately after crating. Plasma biopterin was higher (P < 0.001) in 4-h broilers than in the control immediately after the crating. A time of sampling effect (P = 0.016) was found for the heterophil-to-lymphocyte ratio, with heterophil-to-lymphocyte ratio higher 24 h after crating in comparison with its level immediately after the crating. This study shows that crating may significantly affect the immune system of broiler chickens. This is corroborated by the increase in plasma biopterin concentrations in broilers immediately after crating and the decrease in plasma neopterin concentrations in broilers 24 h after crating. The correlations were found for widely used indicators of acute and chronic stress in birds [i.e., plasma corticosterone concentrations (biopterin) and the heterophil-to-lymphocyte ratio (neopterin), respectively].

Fontes de óleo na dieta e sua influência no desempenho e na imunidade de frangos de corte

A composição de ácidos graxos da dieta pode influenciar o desempenho produtivo e o sistema imune de frangos de corte. O objetivo deste estudo foi avaliar o efeito do consumo de óleos ricos em ácidos graxos poli-insaturados ômega-6 (PUFAs n-6) e ômega-3 (PUFAs n-3) sobre o desempenho e a resposta imunológica de frangos de corte frente a um desafio antigênico. Foram comparadas dietas formuladas com 7% de óleo de soja (OS), linhaça (OL) ou sardinha (OP), fornecidas a 240 frangos da linhagem Cobb, divididos em 24 grupos de 10 aves cada, num arranjo experimental 3x2 (3 tipos de óleo e aves vacinadas ou não vacinadas) e 4 repetições. O óleo de soja é rico em ácido linoleico, um PUFA n-6, o óleo de linhaça é fonte de ácido alfa-linolênico, um PUFA n-3, e o óleo de sardinha, de outros PUFAs n-3, como os ácidos eicosapentaenoico e docosahexaenoico. O consumo de ração, o ganho de peso e a conversão alimentar foram avaliados aos 21, 35 e 42 dias. Aos 7 e aos 21 dias de idade, metade das aves recebeu vacina contra doença de Newcastle. Quinze dias após a imunização, avaliou-se a produção de anticorpos pelo método de ELISA, expressa pela densidade óptica a 450 nm (D.O. 450nm). Apenas as aves alimentadas com ração contendo OS apresentaram maior imunidade humoral (P&lt;0,05) após a vacinação. A resposta linfoproliferativa das aves, que expressa a imunidade celular, foi maior entre as aves vacinadas, em comparação às aves não vacinadas (P&lt;0,05), independentemente do óleo utilizado. A fonte de óleo da ração ou a vacinação não influenciaram o ganho de peso das aves (P&gt;0,05). Entre as aves que receberam dieta com OS, as aves vacinadas apresentaram pior conversão alimentar (P&lt;0,05). Nos grupos que consumiram ração com OL ou OP, a vacinação não influenciou a conversão alimentar (P&gt;0,05), considerando todo o período experimental. A utilização de óleo rico em PUFA n-6 na dieta de frangos de corte aumentou a resposta humoral, mas não influenciou a resposta celular frente a um desafio antigênico.

Effects of dietary L-threonine and &lt;i&gt;Saccharomyces cerevisiae&lt;/i&gt; on performance, intestinal morphology and immune response of broiler chickens

The objective of this study was to investigate the effects of four dietary levels of L-threonine (0, 2.5, 5 and 7.5 g/kg) with or without Saccharomyces cerevisiae (SC) on performance, carcass characteristics, intestinal morphology and immune system of broiler chickens. A total of 360 1-d-old male broiler chicks were randomly allocated to eight treatments with three replicates of 15 birds. The experiment was done at 0 to 3 weeks (as starter phase) and 3 to 6 weeks (as grower phase). Growth performance traits including weight gain, feed intake and feed conversion ratio were recorded at the end of each week. At the end of the experiment eight birds per treatment were killed and carcass analysis was done. Sampling for blood evaluation was done on 7, 28 and 42 days of age. Results of this study indicated that use of SC did not affect feed intake, weight gain and feed conversion ratio in chicks in contrast with the L-threonine. Use of L-threonine improved feed conversion ratio and gain of birds. Carcass traits were not influenced by dietary L-threonine and SC supplements. Use of L-threonine increased the intestinal morphology parameters such as crypt depth and villi height and width in both jejunum and ileum segments. On the other hand, villi height and width and crypt depth increased in both jejunum and ileum segments when dietary L-threonine increased. Effect of SC supplement on intestinal morphology was not significant. Results of CBC (cell blood counts) parameters, such as white blood cells, red blood cells, haematocrit and haemoglobin showed that these parameters were not affected by dietary treatments. Furthermore, the immune response (antibody titre) against Newcastle disease was not affected by SC on both 26 and 42 days of age. However, use of L-threonine influenced the chicks’ immune response at 42 days of age. Our results have shown that the supplementation of L-threonine as a source of dietary-threonine in combination with SC improved growth performance and intestinal morphology traits in broilers.

The Effects of H9N2 Influenza A on the Immune System of Broiler Chickens in the Shandong Province

The effects of H9N2 Influenza A on T lymphocyte subsets, immune organs and the production of anti-Newcastle disease antibodies were examined after infection of broiler chickens with strain SD06 of H9N2 influenza virus. Animal models were successfully established and characterized by conventional HA and HI antigen tests. Pathological changes in the thymus, bursa of Fabricius and spleen were observed through microscopic examination. Changes in T lymphocyte subsets and lymphocyte apoptosis were detected by flow cytometry. Effects on the production of anti-Newcastle disease antibodies were examined through the β-trace method. Viruses isolated from infected chickens were confirmed to be H9N2 influenza virus. Immune organ indexes decreased significantly 7 and 14 days after broiler chickens were infected with virus. Microscopic examination showed degeneration in the thymus and bursa of Fabricius and congestive organization in the spleen. Flow cytometry results showed a significant decrease in the numbers of CD4(+) and CD8(+) T cells, as well as the CD4(+) /CD8(+) ratio, compared with controls. Annexin V-FITC/PI double-staining showed that the H9N2 virus promoted the middle and late periods in lymphocyte apoptosis. Anti-NDV antibody titres in infected chickens decreased compared with the control group. All the results showed that H9N2 virus can cause severe immune suppression and immune organ damage in broiler chickens and lead to significant reduction in the effectiveness of Newcastle disease vaccine.

The Effects of Magnetically Treated Water on the Performance and Immune System of Broiler Chickens

The effects of water treatment (tab water (CTW) vs. magnetically treated water (MTW)) on the performance (body weight gain, feed intake, feed conversion ratio (feed/gain)) from day to 32 days of age, water consumption (WC) and Water: feed consumption ratio (WFR) during the first three weeks of age (starter phase), carcass composition at 32 days of age, and antibody responses to SRBS antigens of sexed broiler chickens were investigated. MTW was prepared by exposing the water to a magnetic field of approximately 500 gauss. The exposure of water to the magnetic field slightly increased the pH of water from 7.72 to 7.86. The water treatment influenced WC of birds. The daily WC of birds on the MTW was significantly (P<0.05) lower than those on the CTW during the starter phase. The MTW did not influence the WFR during the starter phase, and performance and carcass composition of birds at 32 days of age. Sex of birds influenced body weight gain, and carcass composition at 32 days of age and WC over the starter phase. Males consumed more water, and had a heavier weight gain with high proportions of thigh and drumstick in their carcasses than females. Sex of birds did not influence feed intake and FCR at 32 days of age, and WFR at the starter phase. Water treatment and sex of bird did not influence antibody responses to SRBC antigens. There were significant interaction between water treatment and sex of birds on feed intake, weight gain, WC, and thigh proportion of the carcass. Males consumed more feed and water and had a higher weight gain than females when they drank the CTW, but not when they drank the MTW. Males had a higher thigh proportion in their carcasses than females when they drank the MTW, but not when they drank the CTW. It is concluded that the exposure of tab water to a magnetic field of approximately 500 gauss reduced water consumption, but did not significantly influence the performance, carcass composition and immune system of broiler chickens. Additionally, magnetically treated water reduced the difference in the performance between sexes of broiler chickens to a non-significant level.

Effect of feed restriction early in life on humoral and cellular immunity of two commercial broiler strains under heat stress conditions

1. An experiment was carried out to evaluate the effect of early feed restriction (FR) on immunocompetence of Ross and Arian chickens with separated sexes under heat stress (HS) conditions. 2. Chickens consumed feed ad libitum (AL) or were restricted on alternate days from 11 to 20 d of age. From 35 to 41 d of age, the HS groups were exposed to a high ambient temperature of 39 ± 1°C for 7 h each day, while the thermoneutral groups (TN) were at 33°C. 3. At 21 and 42 d of age, the percentage of CD4+ (helper T cells) and CD8+ (cytotoxic T cells) were determined by flow cytometry. Antibody response to sheep red blood cells (SRBC) and heterophil/lymphocyte (H/L) ratio were determined on d 21 and 42. 4. On d 21, FR elevated the CD4+, antibody titre and H/L ratio, but it decreased the CD8+ T cells. On d 42, HS decreased CD4+, CD8+, and antibody titre, but it increased H/L ratio. Under TN conditions, FR chickens had higher CD4+ than AL chickens. On d 42, FR/HS chickens had higher CD4+ and antibody titre, but they had lower CD8+ and H/L ratio than AL/HS chickens. 5. On d 42, the TN-Ross strain had lower CD4+, but they had higher CD8+ and antibody titres than the TN-Arian strain. On d 42, the HS-Arian strain had higher antibody titres and a lower H/L ratio than the HS-Ross strain. 6. Male chickens had higher CD4+, CD8+, antibody titres and H/L ratios 25 in all treatment groups. 7. In conclusion, FR early in life reduced some of the negative effects of the heat stress on the immune system of broiler chickens when exposed to high environmental temperatures later in life.