Hengmin Cui

Protective role of sodium selenite on histopathological lesions, decreased T-cell subsets and increased apoptosis of thymus in broilers intoxicated with aflatoxin B1

For evaluating the ability of selenium (Se) in counteracting the adverse effects of aflatoxin B₁ (AFB₁), two hundred 1-day-old 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), 0.3mg/kg AFB₁+0.4 mg/kg Se (+Se group II) and 0.3mg/kg AFB₁+0.6 mg/kg Se (+Se group III), respectively. Compared with control group, the decreased relative weight of thymus and percentages of mature thymocytes, congestion in medulla and much debris in cortex of thymus, and the increased apoptotic thymocytes were observed in AFB1 group. However, supplied dietary sodium selenite could increase the relative weight of thymus and percentages of mature thymocytes, and alleviate histopathological lesions. Compared with AFB1 group, the percentages of apoptotic thymocytes detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method and flow cytometry method in three +Se groups were decreased, the expression of Caspase-3 and Bax, through quantitative real-time PCR and immunohistochemical method, in three +Se groups were decreased, while the expression of Bcl-2 was increased. The results indicate that sodium selenite supplied in the diet, through a mechanism of apoptosis regulation, may ameliorated AFB₁-induced lesions of thymus and accordingly improve the impaired cellular immune function.

The Decrease of Relative Weight, Lesions, and Apoptosis of Bursa of Fabricius Induced by Excess Dietary Selenium in Chickens

Selenium is an essential trace element possessing immune-stimulatory properties. The purpose of this 42-day study was to investigate the effects of excess dietary sodium selenite on immune function by determining morphological changes and apoptosis of bursa of Fabricius. Three hundred 1-day-old Avian broilers were fed on a basic diet (0.2xa0ppm selenium) or the same diet amended to contain 1, 5, 10, and 15xa0ppm selenium supplied as sodium selenite (nu2009=u200960/group). Relative weight of bursa was significantly decreased in the 1, 5, 10, and 15xa0ppm groups at 28xa0days of age, when compared with that of 0.2xa0ppm group. Pathological lesions were progressed with the dietary Se level increased. The gross lesions of bursa involved obvious atrophy with decreased volume and pale color. Histopathologically, decreased number of lymphocytes and loosely packed lymphocytes appeared in the medulla and cortex in the follicles. Ultrastructurally, mitochondria injury and increased apoptotic cells with condensed nuclei were observed. In comparison to that of control group, excess Se (5, 10, and 15xa0ppm) intake increased the percentage of Annexin V positive cells, as measured by flow cytometry. Terminal deoxynucleotidyl transferase 2′-deoxyuridine 5′-triphosphate nick end-labeling assay showed that there were increased frequencies of apoptotic cells in 10 and 15xa0ppm selenium groups. These data suggest that Se supplementation with sodium selenite should be carefully evaluated as excess selenium (more than 5xa0ppm) intake could cause profound immunologic inhibition.

Decreased Percentages of the Peripheral Blood T-Cell Subsets and the Serum IL-2 Contents in Chickens Fed on Diets Excess in Fluorine

Three hundred 1-day-old Avian broilers were divided into four groups and fed on control diet (F 23xa0ppm) and high-fluorine diets (400xa0ppm, high-fluorine group I; 800xa0ppm, high-fluorine group II; 1,200xa0ppm, high-fluorine group III) for 42xa0days (nu2009=u200975/group). The percentages of CD4+ and CD8+ T cells were decreased in three high-fluorine groups when compared with those of control group. Meanwhile, the CD4+/CD8+ ratio were lower in high-fluorine group II at 28xa0days of age and in high-fluorine group III at 42xa0days of age than in control group. Also, the serum interleukin-2 (IL-2) contents were decreased in three high-fluorine groups when compared with those of control group. Histopathologically, the thymus became hypocellular in three high-fluorine groups. It was concluded that dietary fluorine excess (400~1,200xa0ppm) reduced the percentages of T-lymphocyte subsets and the serum IL-2 contents, and cellular immune function could be affected in chickens.

Effect of High Fluorine on the Cell Cycle and Apoptosis of Renal Cells in Chickens

The experiment was conducted with the objective of evaluating the effect of dietary high fluorine (F) on cell cycle and apoptosis of kidney in chickens by the methods of flow cytometry. Three hundred 1-day-old Avian broilers were divided into four groups and fed on control diet (F 23xa0mg/kg) and high F diets (400xa0mg/kg, high F group I; 800xa0mg/kg, high F group II; 1,200xa0mg/kg, high F group III) for 6xa0weeks. As tested by flow cytometry, the percentage of renal cell apoptosis was increased with increasing of dietary F, and it obviously rose in three high F groups when compared with that of control group. Renal cells in G0/G1 phase were much higher, and renal cells in S phase, G2+M phase, and proliferation index value were much lower in high F groups I, II, and III than in control group. The results showed that excess dietary F in the range of 400–1,200xa0mg/kg caused G0/G1 arrest and increased cellular apoptosis in the kidney, which might finally interfere with the excretion and retention of fluoride in chickens.

Effects of sodium selenite on the decreased percentage of T cell subsets, contents of serum IL-2 and IFN-γ induced by aflatoxin B1 in broilers

Aflatoxin B1 (AFB1), especially inducing hepatocellular carcinoma and immunosuppression of animals, poses a serious healthy and economic hazard to both humans and livestock. Animal studies have demonstrated that selenium (Se) provides anticarcinogenic and antimutagenic effects against AFB1. However, the effects of Se against AFB1-induced immunosuppression were rarely reported. To test this, three hundred 1-day-old male avian broilers were divided into five groups and fed on control diet (0.4 mg/kg Se), AFB1 group(0.3mg/kg AFB1+0.4 mg/kg Se), AFB1+Se group I(0.3mg/kg AFB1+0.6 mg/kg Se), AFB1+Se group II(0.3mg/kg AFB1+0.8 mg/kg Se) and AFB1+Se group III(0.3mg/kg AFB1+1.0mg/kg Se) for 21 days (n=60/group). Although the body weight in AFB1 group was lower than that in control group at 14 days of age, there no significant differences on body weight among five groups at 7 and 21 days of age. No evident clinical symptoms were observed among five groups from 7 to 21 days of age. The percentages of peripheral blood CD3(+), CD3(+)CD4(+), CD3(+)CD8(+) and the contents of serum IL-2 and IFN-γ in AFB1 group were decreased, compared with those in control group. Compared with those in AFB1 group, the percentages of CD3(+), CD3(+)CD4(+) and CD3(+)CD8(+) T cells in three AFB1+Se groups were increased from 14 to 21 days of age, and the contents of serum IL-2 and IFN-γ in all AFB1+Se groups were increased from 7 to 21 days of age. On the contrary, the percentages of CD3(+), CD3(+)CD4(+) and CD3(+)CD8(+) T cells, and the contents of Serum IL-2 and IFN-γ in AFB1+Se group III were lower than those in AFB1+Se group II. It was concluded that 0.6 and 0.8 mg/kg Se could increase the decreased percentages of peripheral blood T-cell subsets and the contents of serum IL-2 and IFN-γ induced by 0.3mg/kg AFB1 in the diets, and cellular immune function could be improved in chickens.

Changes of the Serum Cytokine Contents in Broilers Fed on Diets Supplemented with Nickel Chloride

Cytokines are immunoregulatory proteins which play an important role in the immune system. The purpose of this study was to examine the serum cytokine contents including interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-10 (IL-10), interferon gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) induced by dietary nickel chloride in broilers by enzyme-linked immunospecific assay. A total of 240 one-day-old avian broilers were divided into four groups and fed on a corn–soybean basal diet as control diet or the same basal diet supplemented with 300, 600, and 900xa0mg/kg of nickel chloride. During the experimental period of 42xa0days, the results showed that the serum IL-2, IL-4, IL-6, IL-10, IFN-γ and TNF-α contents were lower (pu2009<u20090.05 or pu2009<u20090.01) in the 300, 600, 900xa0mg/kg groups than those in the control group. It was concluded that dietary nickel chloride in the range of 300 to 900xa0mg/kg could reduce the serum cytokine contents, which could finally impact the immune function in broilers.

Decreased antioxidase activities and oxidative stress in the spleen of chickens fed on high-fluorine diets.

Three hundred one-day-old avian broilers were divided into four equal groups of 75 animals that were fed for 42 days as follows: a control diet containing 23 mg fluorine (F)/kg and three high F diets containing 400, 800, and 1200 mg F/kg, respectively, for high F groups I, II, and III. The superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were greatly decreased, while the malondialdehyde (MDA) contents were markedly increased in high F groups II and III. At the same time, mitochondrial injury and expanded endocytoplasmic reticulum were obviously observed in high F groups II and III, and the fluoride contents both in spleen and serum were significantly increased in the three high F groups when compared with those of control group. The results showed that excess dietary F in the range of 800−1200 mg/kg caused obvious oxidative stress, which provided a possible pathway for the apoptosis of splenocytes in chickens.

Cell-cycle blockage associated with increased apoptotic cells in the thymus of chickens fed on diets high in fluorine

Three hundred 1-day-old Avian broilers were divided into four groups and fed on control diet (fluorine 23 mg/kg) and high-fluorine (F) diets (400 mg/kg, high-F group I; 800 mg/kg, high-F group II; 1200 mg/kg, high-F group III) for 42 days (n 1⁄4 75/group). The growth index (GI) was obviously decreased in the three high-F groups, which indicated the inhibited development of thymus. Histopathologically, the population of thymocytes was decreased in the thymic lobule in the three high-F groups. As measured by flow cytometry, thymocytes in G0/G1 phase were significantly increased while thymocytes in S phase, G2 þ M phase and proliferating index (PI) value were obviously decreased in the three high-F groups. Also, the percentage of apoptotic thymocytes was greatly increased in the three high-F groups when compared with that of control group. At the same time, the occurrence frequencies of apoptotic thymocyte were markedly increased in the three high-F groups, with the appearance of dilated endoplasmic reticulum in high-F groups II and III ultrastructurally. The results showed that excess dietary F in the range of 40Three hundred 1-day-old Avian broilers were divided into four groups and fed on control diet (fluorine 23 mg/kg) and high-fluorine (F) diets (400 mg/kg, high-F group I; 800 mg/kg, high-F group II; 1200 mg/kg, high-F group III) for 42 days (n = 75/group). The growth index (GI) was obviously decreased in the three high-F groups, which indicated the inhibited development of thymus. Histopathologically, the population of thymocytes was decreased in the thymic lobule in the three high-F groups. As measured by flow cytometry, thymocytes in G(0)/G(1) phase were significantly increased while thymocytes in S phase, G(2) + M phase and proliferating index (PI) value were obviously decreased in the three high-F groups. Also, the percentage of apoptotic thymocytes was greatly increased in the three high-F groups when compared with that of control group. At the same time, the occurrence frequencies of apoptotic thymocyte were markedly increased in the three high-F groups, with the appearance of dilated endoplasmic reticulum in high-F groups II and III ultra-structurally. The results showed that excess dietary F in the range of 400-1200 mg/kg caused histological lesions, G(0)/G(1) arrest and cellular apoptosis in the thymus, which inhibited the development of thymus and finally led to impaired cellular immune function.

Dietary High Vanadium Causes Oxidative Damage-Induced Renal and Hepatic Toxicity in Broilers

The purpose of this study was to investigate the renal and hepatic oxidative damage and toxicity caused by dietary high vanadium in broilers. A total of 420 one-day-old avian broilers were divided into six groups and fed on a corn–soybean basal diet as control diet (vanadium 0.073xa0mg/kg), and five high vanadium diets (vanadium 5xa0mg/kg, high vanadium group I; 15xa0mg/kg, high vanadium group II; 30xa0mg/kg, high vanadium group III; 45xa0mg/kg, high vanadium group IV; and 60xa0mg/kg, high vanadium group V) throughout the experimental period of 42xa0days. The results showed that the renal and hepatic superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, ability to inhibit hydroxy radical, and malondialdehyde (MDA), glutathione, and vanadium contents were not significantly changed in high vanadium group I and II when compared with those of the control groups. However, the SOD and GSH-Px activities, ability to inhibit hydroxy radical, and GSH content were significantly decreased, and the MDA and vanadium contents were markedly increased in high vanadium groups III, IV, and V. At the same time, the lesions were also observed in the kidney and liver of high vanadium groups III, IV, and V. The renal tubular epithelial cells showed granular degeneration and vacuolar degeneration, and hepatocytes showed granular degeneration, vacuolar degeneration, and fatty degeneration. It was concluded that dietary vanadium in the range of 30–60xa0mg/kg could cause oxidative damage and vanadium accumulation, which induced renal and hepatic toxicity and lesions. The renal and hepatic function was finally impaired in boilers.

Dietary Vanadium Induces Oxidative Stress in the Intestine of Broilers

The purpose of this study was to examine oxidative stress induced by dietary vanadium in the mucosa of different parts of intestine including duodenum, jejunum, ileum, and cecal tonsil. A total of 420 1-day-old avian broilers were divided into six groups and fed on a corn–soybean basal diet as control diet or the same basal diet supplemented with 5, 15, 30, 45, and 60xa0mg/kg vanadium as ammonium metavanadate. During the experimental period of 42xa0days, oxidative stress parameters were determined for both control and experimental groups. The results showed that malondialdehyde content was significantly higher (pu2009<u20090.05 or pu2009<u20090.01) in 30, 45, and 60xa0mg/kg groups than in control group. In contrast, the activities of superoxide dismutase, catalase, and glutathione peroxidase, and ability to inhibit hydroxyl radical, and glutathione hormone content were significantly decreased (pu2009<u20090.05 or pu2009<u20090.01) mainly in 45 and 60xa0mg/kg groups in comparison with those of control group. However, the abovementioned oxidative stress parameters were not significantly changed (pu2009>u20090.05) in 5 and 15xa0mg/kg groups. It was concluded that dietary vanadium in excess of 30xa0mg/kg could cause obvious oxidative stress in the intestinal mucosa, which could impact the antioxidant function of intestinal tract in broilers.