Efficacy of clove and tulsi supplementation in drinking water in broiler immunity.

BACKGROUND: Medicinal plants or their products are popular substitutes for antibiotics or other synthetic growth promoters for their beneficial effects and cost-effectiveness. Clove (Cv) and tulsi (Ts) are rich in phytochemicals and are used to augment the growth performance of poultry. OBJECTIVES: The current investigation was carried out to evaluate the effects of Cv and Ts supplementation in drinking water on the morphologic and morphometric adaptations in the lymphoid organs. METHODS: The experiment was conducted on 60 broiler chicks, divided into 4 homogenous groups (5 pens/group and 3 broilers/pen) named T0 (control), T1 (0.5% Cv and 2% Ts), T2 (1% Cv and 3% Ts) and T3 (1.5% Cv and 4% Ts). The treatments were administered from days 8 to 28. Lymphoid organs (thymus, spleen and bursa of Fabricius) were collected on days 14, 21 and 28 after sacrificing five broilers from each group. RESULTS: The treatment groups had higher thymus and spleen weights on day 21, whereas the weights of the bursa of Fabricius were higher on days 14, 21 and 28. In the histomorphologic study, no noticeable difference in the histoarchitectures of the lymphoid organs was noticed. However, substantial differences in the cortico-medullary ratio and the number of follicles in the thymus and bursa of Fabricius, respectively, were found in the histomorphometric investigation. CONCLUSION: The inclusion of Cv and Ts in drinking water augments the weight of lymphoid organs with histomorphometric adaptations that might improve the immune status in broilers.

Effects of Dietary Milk Thistle (Silybum marianum) Supplementation in Ducks Fed Mycotoxin-Contaminated Diets.

The medicinal plant milk thistle (Silybum marianum) has been widely used due to its hepatoprotective properties. The main objective of our study was to investigate the health protective effects of dietary milk thistle seed (MS), oil (MO), and seed cake (MSC) in ducks fed diets naturally contaminated with deoxynivalenol (DON; 3.43-3.72 mg/kg feed) and zearalenone (ZEN; 0.46-0.50 mg/kg feed). Female White Hungarian ducks were randomly allocated to four dietary treatments consisting of the control diet (C), the control diet supplemented with 0.5% MS, 0.5% MSC, or 0.1% MO. The feeding of experimental diets did not result in mortality cases, clinical signs of mycotoxicosis, or in differences of clinical chemistry values of blood serum. The positive effect of MO on vacuolar hepatocyte degeneration exceeded that of the MSC on d14 and both MS and MSC on d42. Each treatment was equally effective in the decrease of the severity of solitary cell death and infiltration of lympho- and histiocytes in the liver on d28 as well as in the prevention of lymphocyte depletion in the spleen and bursa of Fabricius on d14. In conclusion, the applied treatments have been proven effective in the prevention of histopathological changes caused by DON and ZEN.

Effect of crude protein reduction in blood, performance, immunological, and intestinal histological parameters of broiler chickens.

We aimed to evaluate the effects of the reduction in dietary crude protein (CP) on blood urea, uric acid, performance, immunity, and intestinal histology of broilers. Four diets were formulated with 22.50%, 21.50%, 20.50%, and 19.50% of CP (1 to 21 days) and 19.20%, 18.20%, 17.20%, and 16.20% of CP (22 to 42 days), meeting the requirements of essential amino acids in all diets. A total of 800 male Ross chicks were randomly allocated to 32 pens, with 25 birds each (n = 8). Blood and intestines had been collected for analysis. Uric acid decreased and urea increased with the reduction of CP (p < 0.05). Reduction in performance and intestinal parameters (villus, crypt, and goblet cells) was observed with the reduction of CP (p < 0.05). Lower levels of CP resulted in alteration (p < 0.05) in CD4 and CD8 lineages (21 and 42 days). Broken-line models estimated (p < 0.05) the CP requirement for growth between 21% and 21.3% (1 to 21 days) and between 17.2% and 17.4% (22 to 42 days) and CP requirements between 17.2% and 18.2% for maximum response of immune cells (42 days). Reduction in dietary CP has a negative impact on performance, immune response, and intestinal histology of broilers, even with adequate levels of essential amino acids.

Effect of a Carotenoid Extract from Citrus reticulata By-Products on the Immune-Oxidative Status of Broilers.

Although carotenoids generally possess antimicrobial and antioxidant properties, the in vivo synergistic action of carotenoid blends derived from plant-based by-products has not been thoroughly studied. Therefore, the carotenoid characterization and antimicrobial potential of Citrus reticulata extract as well as the impact of this carotenoid-rich extract (CCE) dietary supplementation on the performance, meat quality, and immune-oxidative status of broiler chickens were determined. One hundred and twenty one-day-old hatched chicks (Ross 308) were allocated to two dietary groups, with four replicate pens of 15 birds each. Birds were fed either a basal diet (CON) or the basal diet supplemented with 0.1% CCE (25 mg carotenoid extract included in 1 g of soluble starch) for 42 d. ß-Cryptoxanthin, ß-Carotene, Zeaxanthin, and Lutein were the prevailing carotenoid compounds in the Citrus reticulata extract. The CCE feed additive exerted inhibitory properties against both Gram-positive (Staphylococcus aureus) and negative (Klebsiella oxytoca, Escherichia coli, and Salmonella typhimurium) bacteria. Both the broiler performance and meat quality did not substantially differ, while the breast muscle malondialdehyde (MDA) concentration tended to decrease (p = 0.070) in the CCE-fed broilers. The inclusion of CCE decreased the alanine aminotransferase and MDA concentration, and the activity of glutathione peroxidase, while the activity of superoxide dismutase was increased in the blood. Catalase and NADPH oxidase 2 relative transcript levels were significantly downregulated in the livers of the CCE-fed broilers. Additionally, Interleukin 1ß and tumor necrosis factor (TNF) relative transcript levels were downregulated in the livers of the CCE- fed broilers, while TNF and interferon γ (IFNG) tended to decrease in the spleens and bursa of Fabricius, respectively. The present study provided new insights regarding the beneficial properties of carotenoids contained in Citrus reticulata in broilers' immune-oxidative status. These promising outcomes could be the basis for further research under field conditions.

Selenium Deficiency Induces Autophagy in Chicken Bursa of Fabricius Through ChTLR4/MyD88/NF-κB Pathway.

To explore the role of ChTLR4/MyD88/NF-κB signaling pathway on autophagy induced by selenium (Se) deficiency in the chicken bursa of Fabricius, autophagosome formation in the bursa of Fabricius was observed by transmission electron microscopy. Quantitative real-time PCR (qRT-PCR) and Western blot were used to detect the expression of ChTLR4 and its signaling pathway molecules (MyD88, TRIF, and NF-κB), inflammatory factors (IL-1ß, IL-8, and TNF-α), and autophagy-related factors (ATG5, Beclin1, and LC3-II) in the Se-deficient chicken bursa of Fabricius at different ages. The results showed that ChTLR4/MyD88/NF-κB signaling pathway was activated in the chicken bursa of Fabricius and autophagy was induced at the same time by Se deficiency. In order to verify the relationship between the autophagy and ChTLR4/MyD88/NF-κB signaling pathway, HD11 cells were used to establish the normal C group, low Se group, and low Se + TLR4 inhibitor (TAK242) group. The results demonstrated that autophagy could be hindered when the TLR4 signaling pathway was inhibited under Se deficiency. Furthermore, autophagy double-labeled adenovirus was utilized to verify the integrity of autophagy flow induced by Se deficiency in HD11 cells. The results showed that it appeared to form a complete autophagy flow under the condition of Se deficiency and could be blocked by TAK242. In summary, we found that Se deficiency was involved in the chicken bursa of Fabricius autophagy occurring by activating the ChTLR4/MyD88/NF-κB pathway.

Selenium Deficiency Causes Inflammatory Injury in the Bursa of Fabricius of Broiler Chickens by Activating the Toll-like Receptor Signaling Pathway.

The aim of our study was to observe the effect of selenium (Se) deficiency on inflammatory injury in the bursa of Fabricius of broiler chickens and to determine the role of the Toll-like receptor (TLR)/myeloid differential protein-88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway during this process. Here, we revealed that severe inflammatory injury occurred in the broiler bursa of Fabricius with Se deficiency via histopathology. Moreover, the ultrastructural pathological results showed that the nuclear, mitochondrial, endoplasmic reticulum and cytomembrane structures were damaged to varying degrees. Additionally, interleukin-2 (IL-2), interleukin-6 (IL-6), and interferon (IFN-γ) mRNA expression was markedly upregulated in the broiler bursa of Fabricius with Se deficiency. Furthermore, TLR, toll-interleukin-1 receptor domain-containing adapter-inducing interferon-ß (TRIF), MyD88, and NF-κB mRNA expression was also markedly elevated in the broiler bursa of Fabricius with Se deficiency. The above results suggested that Se deficiency increases the expression of numerous proinflammatory cytokines and is probably due to the activation of the TLR/MyD88/NF-κB signaling pathway, which causes inflammatory injury in the bursa of Fabricius of broiler chickens. Our findings provide a theoretical reference for further studying the underlying mechanism of Se deficiency-induced inflammatory injury in the bursa of Fabricius of broiler chickens.

Effects of different concentration of organic and inorganic trace minerals (zinc, selenium, and chromium) supplementation on expression of chTLR4 gene and humoral immune response in broilers.

BACKGROUND AND AIM: Poultry production is the fastest-growing livestock sector in developing countries. In the poultry diet, trace minerals (zinc [Zn], selenium [Se], and chromium [Cr]) are normally administered in the inorganic form which has been traditionally considered as the most cost-effective and easily available but organic forms of these trace minerals have a higher bioavailability, lower dietary inclusion and cause less environmental pollution as compared to inorganic form. This study aimed to investigate the effect of different concentrations of organic and inorganic forms of trace minerals (Zn, Se, and Cr) supplementation (0-35 days) on expression of chTLR4gene and humoral immune response in broilers. MATERIALS AND METHODS: A total of 216 broilers were randomly divided into 12 groups and each group divided into three replicates consisting of six broilers each. T1 (R1, R2, and R3) group was kept as control. T2, T3, and T4 (R1, R2, and R3) groups were supplemented with inorganic form of Zn at 40 mg/kg of feed, organic form of Zn at 40 mg/kg of feed, and 50% organic form of Zn at 20 mg/kg of feed, respectively. T5, T6, and T7 (R1, R2, and R3) groups were supplemented with inorganic form of Se at 0.3 mg/kg of feed, organic form of Se at 0.3 mg/kg of feed, and 50% organic form of Se at 0.15 mg/kg of feed, respectively. T8, T9, and T10 (R1, R2, and R3) groups were supplemented with inorganic form of Cr at 2 mg/kg of feed, organic form of Cr at 2 mg/kg of feed, and 50% organic form of Cr at 1 mg/kg of feed, respectively. T11 and T12 (R1, R2, and R3) groups were supplemented with a combination of all three minerals from inorganic and organic forms, respectively. RESULTS: Reverse transcriptase-polymerase chain reaction gene expression analysis revealed that in bursa of Fabricius, maximum upregulation of chTLR4 (3.0214 fold) was observed in T6 group, and in spleen, maximum upregulation of chTLR4 (3.2140 fold) was observed in T3 group as compared to control group. On day 35, the maximum plasma immunoglobulin G concentration was observed in organic trace minerals (OTMs) supplemented, whereas the minimum concentration was recorded in control group. On day 28 and 35, the overall mean heterophil:lymphocyte ratio showed a significant difference (p<0.05) between control and OTM supplemented groups. A significantly higher immune organ weight (spleen and bursa of Fabricius) was recorded in OTM supplemented group as compared to control and other supplemented group. CONCLUSION: Supplementation of organic form of Zn, Se, and Cr either alone or in combination increase humoral immune response and upregulation of chTLR4 gene expression in bursa and spleen indicates a beneficial effect of OTM in augmentation of immune system in broilers.

Algae-derived polysaccharides supplementation ameliorates heat stress-induced impairment of bursa of Fabricius via modulating NF-κB signaling pathway in broilers.

This study aimed to investigate the protective effects of dietary algae-derived polysaccharides (ADP) from Enteromorpha prolifera against heat stress (HS)-induced bursa of Fabricius injure in broilers, and to elucidate the molecular mechanisms underlying the protective effect. A total of 144 8-week-old male yellow-feathered broilers were randomly allocated into 3 treatments of 6 replicates each (8 broilers per replicate): thermoneutral zone group (TN, fed basal diet); heat stress group (HS, fed basal diet); heat stress + ADP group (HSA, basal diet supplemented with 1,000 mg/kg ADP). Broilers in TN group were raised at 23.6 ± 1.8°C during the whole study. Broilers in HS and HSA groups were exposed to 33.2 ± 1.5°C for 10 h/day. The experimental period lasted for four weeks. The results showed that HS and dietary ADP had no significant effects on bursa of Fabricius index (P > 0.05). HS exposure increased the apoptosis rate of bursa of Fabricius (P < 0.05), and the apoptosis rate was reduced by dietary ADP (P < 0.05). Besides, broilers in HS and HSA groups had a lower glutathione-S transferase (GST) activity and total anti-oxidation capacity (T-AOC), whereas had a higher malondialdehyde (MDA) levels of bursa of Fabricius than those in TN group (P < 0.05). HS exposure elevated the concentration of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-4, and IL-6, while decreased the concentration of interferon-γ (INF-γ) and IL-2 (P < 0.05), and dietary inclusion of ADP reduced the IL-1ß level and increased the IL-2 level of bursa of Fabricius (P < 0.05). Compared with TN group, broilers in HS and HSA groups had lower relative mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and GSTT1 in bursa of Fabricius (P < 0.05). Additionally, HS exposure down-regulated the mRNA expression of inhibitor kappa B alpha (IκBα), IFN-γ, and IL-2, while up-regulated the mRNA expression of nuclear factor-kappa B (NF-κB) p65, TNF-α, IL-1ß, and IL-6 in bursa of Fabricius (P < 0.05). However, dietary inclusion of ADP up-regulated the mRNA expression of IκBα and down-regulated the mRNA expression of NF-κB p65, TNF-α, and IL-6 in bursa of Fabricius (P < 0.05). Furthermore, HS exposure increased the relative protein expression levels of total and nuclear NF-κB p65 (P < 0.05), but dietary ADP supplementation reduced the relative protein expression levels of total and nuclear NF-κB p65 in bursa of Fabricius (P < 0.05). Collectively, dietary ADP ameliorated the impairment of histology, cell apoptosis and immune balance in bursa of Fabricius of heat stressed broilers, which is involved in modulation of NF-κB signaling pathway.

Dexamethasone reduces infectious bursal disease mortality in chickens.

Very virulent infectious bursal disease virus (vvIBDV) causes high mortality in chickens but measures to reduce the mortality have not been explored. Chickens (8-9 weeks) were treated with 3 agents before and during vvIBDV inoculation. Dexamethasone treatment reduced the mortality of infected chickens (40.7% vs. 3.7%; p < 0.001), but treatment with aspirin or vitamin E plus selenium did not affect the mortality. The bursa of Fabricius appeared to have shrunk in both dead and surviving chickens (p < 0.01). The results indicate that dexamethasone can reduce mortality in vvIBDV-infected chickens and may provide therapeutic clues for saving individual birds infected by the virus.

The Protective Role of Selenium in AFB1-Induced Tissue Damage and Cell Cycle Arrest in Chicken's Bursa of Fabricius.

Aflatoxin B1 (AFB1) is a naturally occurring secondary metabolites of Aspergillus flavus and Aspergillus parasiticus, and is the most toxic form of aflatoxins. Selenium (Se) with antioxidant and detoxification functions is one of the essential trace elements for human beings and animals. This study aims to evaluate the protective effects of Se on AFB1-induced tissue damage and cell cycle arrest in bursa of Fabricius (BF) of chickens. The results showed that a dietary supplement of 0.4 mg·kg-1 Se alleviated the histological lesions induced by AFB1, as demonstrated by decreasing vacuoles and nuclear debris, and relieving oxidative stress. Furthermore, flow cytometry studies showed that a Se supplement protected AFB1-induced G2M phase arrest at 7 days and G0G1 phase arrest at 14 and 21 days. Moreover, the mRNA expression results of ATM, Chk2, p53, p21, cdc25, PCNA, cyclin D1, cyclin E1, cyclin B3, CDK6, CDK2, and cdc2 indicated that Se supplement could restore these parameters to be close to those in the control group. It is concluded that a dietary supplement of 0.4 mg kg-1 Se could diminish AFB1-induced immune toxicity in chicken's BF by alleviating oxidative damage and cell cycle arrest through an ATM-Chk2-cdc25 route and the ATM-Chk2-p21 pathway.

Effect of Moringa oleifera leaf powder supplementation on growth performance and intestinal morphology in broiler chickens.

Due to public health hazards of subtherapeutic use of antibiotics in poultry feed, there is a need for alternatives. Moringa oleifera is a phytobiotic, which is reported to possess antimicrobial and immuno-modulatory properties. This study aimed to investigate effects of M. oleifera leaf powder (MOLP) supplementation on growth performance and intestinal microarchitecture of broiler chickens. Day-old broiler chicks (n = 100) were randomly divided into five groups with four replicates each having five birds. Birds were fed a corn-based basal diet or the same diet supplemented with 0.6, 0.9, 1.2 and 1.5% MOLP. Body weight and feed conversion ratio were recorded on weekly basis. On day 35, two birds per replicate were selected to collect samples of duodenum, jejunum, ileum, caecal tonsils and bursa of Fabricius. Tissue samples were stained with haematoxylin and eosin or combined alcian blue and PAS technique. Supplementation of MOLP had no effect on feed intake, feed conversion ratio, bursa weight and intra-epithelial lymphocytes (IEL) count. Birds fed with 1.2% MOLP had higher (p < 0.05) body weight, length and empty weight of small intestine, and weight of empty and filled ceca. Villus height (duodenum, jejunum, ileum), villus surface area (duodenum) and villus height:crypt depth (ileum) were higher (p < 0.05) in 1.2% MOLP group compared with non-supplemented group. In duodenum, total goblet cell count was higher (p < 0.05) in all the supplemented groups when compared with non-supplemented birds. Acidic mucin count was higher (p < 0.05) in duodenum, jejunum and ileum of 1.2% MOLP group compared with the control group. Bursal follicle count was higher (p < 0.05) in 1.2% MOLP group compared with non-supplemented group. In conclusion, dietary supplementation of 1.2% MOLP modulated intestinal microarchitecture and acidic mucin production without any apparent effect on growth.

chTLR4 pathway activation by Astragalus polysaccharide in bursa of Fabricius.

BACKGROUND: The Toll-like receptor 4 (TLR4) pathway involves in the pathogen recognition and defense against infection in mammals. Considering that avian and mammalian TLR are differentially mediated, the action of a natural product on avian TLR4 pathway was unclear. High, medium and low doses of Astragalus polysaccharide (APS), were treated the chicken at 7-days-old age by gavage. The sIgA level in the intestinal fluid, the expression of chTLR4 mRNA/protein in bursa of Fabricius as well as the expression of downstream molecules of chTLR4 (chMyD88, chTRIF, chNF-κB, chIRF3, chIFN-ß and chTNF-α) were measured on alternate days. RESULTS: The content of sIgA and the chTLR4 mRNA expression/protein level were increased in non-dose-dependent manner after APS supplement. Also, the expressions of a subset of MyD88-independent pathway genes were more than MyD88-independent, in particular with low doses of APS supplement for 7 days. CONCLUSIONS: These suggest that administration of APS activates chTLR4 pathway in bursa of Fabricius in MyD88-independent pathway. Meanwhile, low dose of APS shows better performance regarding the activation of chTLR4 and regulation of MyD88-independent pathway.

Alleviation of lead-induced oxidative stress and immune damage by selenium in chicken bursa of Fabricius.

We investigated lead (Pb)-induced oxidative stress and immune damage in the chicken bursa of Fabricius (BF) and the ameliorative effect of selenium (Se). Seven-day-old male chickens were randomly divided into four groups and were provided standard diet and drinking water, Na2SeO3 added to the standard diet and drinking water, standard diet and (CH3COO)2Pb added to drinking water, and Na2SeO3 added to the standard diet and (CH3COO)2Pb added to drinking water for 30, 60, and 90 days. The presence of Pb inhibited total antioxidant capacity (T-AOC), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) activities; decreased glutathione (GSH) content; increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents; inhibited interleukin (IL)-2 and interferon-γ (IFN-γ) messenger RNA (mRNA) expression; and increased IL-4, IL-6, IL-10, IL-12ß, and IL-17 mRNA expression. The presence of Se relieved all of the above Pb-induced changes. There were close correlations among GSH, CAT, T-AOC, SOD, GPx, MDA, and H2O2 and among IL-2, IL-4, IL-6, IL-12ß, IL-17, and IFN-γ. Our data showed that Pb caused oxidative stress and immune damage in the chicken BF. Se alleviated Pb-induced oxidative stress and immune damage in the chicken BF.

Selenoproteins and heat shock proteins play important roles in immunosuppression in the bursa of Fabricius of chickens with selenium deficiency.

Selenium (Se) is necessary for the immune system in chicken and mediates its physiological functions through selenoproteins. Heat shock proteins (Hsps) are indispensable for maintaining normal cell function and for directing the immune response. The aim of the present study was to investigate the effects of Se deficiency on the messenger ribonucleic acid (mRNA) expression levels of selenoproteins and Hsps as well as immune functions in the chicken bursa of Fabricius. Two groups of chickens, namely the control and Se-deficient (L group) groups, were reared for 55 days. The chickens were offered a basal diet, which contained 0.15 mg Se/kg in the diet fed to the control group and 0.033 mg Se/kg in the diet fed to the L group. We performed real-time quantitative polymerase chain reaction to detect the mRNA expression levels of selenoproteins and Hsps on days 15, 25, 35, 45 and 55. Western blotting was used to determine the protein expression levels of Hsps on days 35, 45 and 55, and immune functions were assessed through an enzyme-linked immunosorbent assay on days 15, 35, and 55. The data showed that the mRNA expression levels of selenoproteins, such as Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, Dio3, GPx1, GPx2, GPx3 GPx4, Sepp1, Selo, Sel-15, Sepx1, Sels, Seli, Selu, Selh, and SPS2, were significantly lower (P < 0.05) in the L group compared with the control group. Additionally, the mRNA and protein expression levels of Hsps (Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90) were also significantly higher (P < 0.05) in the L group. The expression levels of IL-2, IL-6, IL-8, IL-10, IL-17, IL-1ß, IFN-α, IFN-ß, and IFN-γ were significantly lower (P < 0.05) and TNF-α was significantly higher (P < 0.05) in the L group compared with the control group. Our results show that immunosuppression was accompanied by a downregulation of mRNA expression levels of selenoproteins and an upregulation of the Hsp mRNA expression levels. Thus, Se deficiency causes defects in the chicken bursa of Fabricius, and selenoproteins and Hsps play important roles in immunosuppression in the bursa of Fabricius of chickens with Se deficiency.

Effect of selenium supplementation on aflatoxin B1-induced histopathological lesions and apoptosis in bursa of Fabricius in broilers.

To investigate the effects of sodium selenite against aflatoxin B1 (AFB 1), 200 male Avian broilers, divided into five groups, were fed with basal diet (control group), 0.3 mg/kg AFB1 (AFB1 group), 0.3 mg/kg AFB1 + 0.2 mg/kg Se (+Se group I), 0.3 mg/kg AFB1 + 0.4 mg/kg Se (+Se group II) and 0.3 mg/kg AFB1 + 0.6 mg/kg Se (+Se group III), respectively. Compared with the control group, decreased relative weight of bursa of Fabricius and contents of serum immunoglobulin, more vacuoles and debris in the bursal lymphoid follicle, and increased percentage of apoptotic bursal cells were observed in the AFB1 group. Sodium selenite, however, could increase the relative weight of bursa of Fabricius and contents of serum immunoglobulin, and ameliorate histopathological lesions. The percentages of apoptotic bursal cells, through flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, in the three +Se groups were lower than those in the AFB 1 group. Compared with the AFB 1 group, moreover, the mRNA expressions of Bax and Caspase-3 by qRT-PCR in the three +Se groups were decreased, while the expression of Bcl-2 was increased. The results indicate that sodium selenite in diet can protect chicken from AFB 1-induced impairment of humoral immune function by reducing bursal histopathological lesions and percentages of apoptotic bursal cells.

Desempenho e resposta imune de frangos de corte alimentados com dietas suplementadas com cromo na forma orgânica / Immune response and performance by broiler chickens dietarysupplemented with chromium in organic form

O experimento foi conduzido com o objetivo de avaliar o efeito da suplementação de cromo-orgânico, sobre o desempenho, biometria dos órgãos digestivos e linfoides, histomoformetria da bolsa cloacal e rendimento de carcaça e cortes nobres de frangos de corte de 1 a 41 dias de idade, naturalmente submetidos a estresse por calor cíclico. Foram utilizados 400 pintos de corte da linhagem Cobb, em um delineamento experimental inteiramente casualizado, com cinco tratamentos: 0; 350; 700; 1050 e 1400 ppb de cromo na ração. Os valores do índice de temperatura de globo e umidade foram respectivamente, 83,39 e 80, para fase de crescimento e terminação. A suplementação do cromo orgânico influenciou (P 0,01) de forma quadrática a conversão alimentar dos animais segundo a equação Y=1,67-0,00016x+0,00000012x² (r² 0,976), na fase de 1 a 21 dias de idade. Os níveis de suplementação do cromo orgânico proporcionaram melhor índice de eficiência produtiva e maior percentual de parênquima cortical nas aves aos 21 dias. Na fase de 1 a 41 dias de idade, verificou-se que o peso de penas foi influenciado positivamente com os níveis de cromo orgânico e que não houve efeito para o desempenho dos frangos. Conclui-se que a suplementação da ração com cromo orgânico melhora desempenho e a resposta imune de frangos de corte frente a condições de estresse por calor.

This study was conducted to evaluate the effect of adding organic chromium dietary supplementation on performance, digestiveand lymphoid organs biometry and histomorphometry of the clocal bursa and on carcass and prime cuts performance of broilersfrom 1 to 41 days old, naturally stressed by heat cyclic. We used 400 chicks Cobb, the experimental design adopted was acompletely randomized, with five treatments: 0; 350; 700; 1050 and 1400 ppb chromium in diet. The supplementation withorganic chromium influenced (p<0,01) quadratic form on alimentary conversion the animals according to the equation Y = 1.67to 0.00016 x 0.00000012 x ² (r ² 0.976) in the period 1 to 21. The levels of supplementation of organic chromium improvementproductive efficiency and percentage of cortical parenchyma of broilers to 21 days. In phase to 1 from 41 days old, it was observedimprovement the feathers weight with levels of organic chromium, and there wasn’t influence on performance of broilers. Thechromium in the organic form improves the performance of broiler chickens and immune response by broiler chickens in cyclic heat stress.