西藏牦牛血液酶活性与生产性能的相关性研究

测定了28头西藏牦牛血液中6种酶的活性,探讨了6种酶活性与生产性能的关系。相关分析表明,LDH活性与产奶量、CAT活性与腹毛长呈极显著的正相关（P＜0．01）,AKP活性与体重、Amy活性与体重呈显著正相关（P＜0．05）,SOD活性与体重呈显著负相关（P＜0．05）。逐步回归分析表明,可以用LDH活性预测牦牛产奶量,用AKP、CAT、Amy 3种酶活性预测牦牛体重,用CAT、Amy活性预测牦牛腹毛长。因此,有望将LDH、AKP、CAT和Amy等酶活性作为生化遗传标记应用于牦牛产奶量、体重、腹毛长的选择中。     

Gaq／11和PDGF依赖性信号转导通路在大鼠主动脉再狭窄中的作用

采用大鼠主动脉球囊内皮剥脱术制备主动脉狭窄模型,观察Gop/11和GDGF信号转导通路在大鼠主动脉球囊损伤后狭窄时血管平滑肌细胞（VSMC）增殖和迁移中的作用,实验分假手术组,损伤1d组和损伤14d组,观察形态学变化,检测血管紧张素转换酶（ACE）活性和主动脉磷脂酶C（PLC）活性,用免疫印迹法测定主动脉血小板源生长因子（PDGF）受体β和Gaq/11蛋白含量,结果显示,损伤1d,主动脉内皮完全剥脱,VSMC无明显增殖和迁移,内膜无增厚,与假手术组比较,ACE 性增加382．7％（P＜0．01）,PDGE受体β表达和PLC活性无明显变化,Gaq/11蛋白含量下降20．0％（P＜0．05）,损伤14d组,主动脉局部有新生内皮出现,中层VSMC大量增殖并向内膜下选移,内膜显著增厚,ACE活性,PDGF受体β表达和PLC活性分别较假手术组升高420．2％（P＜0．01）,85．0％（P＜0．05）和186．2％（P＜0．05）,Gaq/11蛋白下降33．1％（P＜0．01）,结果提示,PDGF介导的信号转导通路可能是再狭窄时VSMC增殖的重要信号转导机制。     

竹笋采后木质化与多酚氧化酶，过氧化物酶和苯丙氨酸解氨酶活性的关系（简报）

竹笋采后10d内,PPO,POD和PAL活性呈迅速上升趋势,之后缓慢下降,木质素含量在采后10d内迅速增加,随后缓慢增加,1℃和10℃之间的PPO,POD和PAL活性的差异都达显著水平（P＜0．05）,木质素含量的差异达极显著水平（P＜0．01）。     

60例活动性肝硬变患者血清载脂蛋白AI与B的临床研究

目的：为了探讨活动性肝硬变患者的血清载脂蛋白AI（APOAI）、载脂蛋白B（APOB）与肝细胞损害的严重程度及其预后的关系。方法：采和速度比浊法检测60例活动性肝硬变患者的血清APOAI、APOB水平,并与其他肝脏生化试验进行比较。结果：活动肝硬变代偿性与失代偿性两组APOAI,APOB均有着显著性差异（P＜0．01,P＜0．05）。活动性肝硬变患者的APOAI与总胆红素（TB）、凝血酶原时间（PT）呈负相关性（P＜0．01,P＜0．01,与白蛋白（ALB）,胆碱酯酶（CHE）、纤维蛋白原（FIB）呈显著正相关性（P＜0．01,P＜0．01,P＜0．05）。APOX仅与FIB呈显著相关性（P＜0．05）,好转组与死亡组两组APOAI有显著性差异（P＜0．05）,APOB无显著性差异,结论：检测活动性肝硬变患者血清APOAI,APOB水平有助于判断肝硬变的严重程度,且APOAI比APOB更敏感、可靠。     

双叉奶中合生元对改善肠道菌群功效的研究

目的 对双叉奶中合生元改善肠菌群的功效进行研究分析。方法 依卫生部《新增保健功能评价指标及程序的初步方案》,做动物及人体改善肠道菌群试验。结果 1．双叉奶中合生元对小鼠4种肠道菌群数量的影响：与对照组比较,各剂量组小鼠肠道内肠球菌、肠杆菌数量均无显著性差异（P＞0．05）;低剂量、高剂量组乳酸杆菌数量明显增加,有显著性差异（P＜0．05）,中剂量组乳酸杆菌数量增加显著,有非常显著性差异（P＞0．01）;低剂量、中剂量组双歧杆菌数量明显增加,有显著性差异（P＞0．05）。2．双叉奶中合生元对人体5种肠道菌群数量的影响：与饮用前相比,受试人群肠道内肠杆菌、肠球菌数量均无显著性差异（P＞0．05）;双歧杆菌、乳酸杆菌数量增加显著,有非常显著性差异（P＞0．01）。肠梭菌数量降低显著,有非常显著性差异（P＞0．01）。3．受试人群自觉症状观察：所有人无不良反应,可改善便秘、增加食欲、排气。结论 双叉能奶中合生元对小鼠、人体肠道菌群具改善作用。     

宫颈癌中端粒酶的表达和高危型人乳头瘤病毒感染

目的：研究不同程度子宫颈病变中高危型人乳头瘤病毒HR-HPV感染和端粒酶活性的表达,以探讨两者在宫颈癌及宫颈上皮内瘤变中的作用及相关性。方法：采用第二代杂交捕获技术检测宫颈脱落细胞HPV．DNA含量,并用免疫组织化学EnVision二步法检测宫颈组织标本中端粒酶的表达。结果：（1）端粒酶阳性表达率在对照组、C1NI、CINII、CINⅢ和宫颈癌组分别为10．00％、16．67％、40．00％、70．00％、95．00％,宫颈癌组高于cINⅢ,CINⅢ高于C1NⅡ,C1NII高于CINI,差异均有统计学意5C（X^2=-4．329,P=0．037;xⅫ．327,P=0．038;X^2=4．022,P=0．045）。（2）随着宫颈病变级别的增加,高危型HPV的阳性率和病毒负荷量均增高。高危型HPV的阳性率在宫颈癌和CINⅢ组明显高于对照组、CINI及CINⅡ（X^2=29．501-7．414,P〈0．01）。高危型HPV的病毒负荷量在对照组与其他4组比较,差异均有统计学意K（P〈0．05）;C1NI组分别与CINⅡ、C1NⅢ及宫颈癌组比较差异均有统计学意义（P〈0．05）。（3）随着宫颈病变级别的增加,高危型HPV的阳性率和端粒酶阳性表达率依次递增,两者有明显的相关性（r=0．943,P〈0．01）。结论：高危型HPV感染和端粒酶活性均与宫颈癌前病变及宫颈癌的发生发展密切相关,有望作为子宫颈癌前病变和宫颈癌筛查的监测指标。     

小茴香对肝纤维化大鼠脂质过氧化水平的影响

目的：研究小茴香对肝纤维化大鼠的脂质过氧化水平的影响。方法：取Wister大鼠100只,随机取12只设为正常组,其余采用四氯化碳（CCL4）复合因素法复制肝纤维化大鼠模型,复制成功后随机分为模型对照组、小茴香组和复方丹参组（n=12）;相应药物干预8周后,镜检肝组织形态学改变;全自动生化分析仪检测外周血清丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）水平与血清总蛋白（TP）、白蛋白（ALB）含量;生化法检测肝组织羟脯氨酸（HYP）与血清丙二醛（MDA）含量及超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH—PX）、过氧化氢酶（CAT）活性。结果：HE结果显示：模型组肝脏炎症与脂肪变性明显,经小茴香干预后明显改善。生化检测结果显示：与正常组比较,模型组ALT、AST水平显著升高（P〈0．05）,TP、ALB含量显著降低（P〈O．05）,HYP、MDA含量显著增加（P〈0．05）,而SOD、GSH—PX和CAT活性显著降低（P〈0．05）;与模型组比较,小茴香组ALT、AST水平显著下降（P〈0．05）,TP、ALB水平显著升高（P〈0．05）;HYP、MDA含量显著降低（P〈0．05）,SOD、GSH—PX和CAT活性显著提高（P〈0．05）。结论：小茴香的抗肝纤维化作用可能与调节大鼠脂质过氧化水平有关。     

改良PAS染色法在急性肝损伤中的应用

目的：观察改良肝脏糖原PAS染色法,并观察肝脏糖原染色在急性肝损伤中的应用。方法：复制CCl4急性肝损伤模型,首次100％CCl43 mL／kg皮下注射,此后50％CCl4橄榄油溶液2 mL／kg每周2次共4次皮下注射,诱导大鼠急性肝损伤模型。计算大鼠肝体比;HE染色观察肝组织炎症病理;试剂盒检测血清丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）、总胆红素（TBil）、白蛋白（Alb）。肝脏常规PAS染色与改良PAS染色观察肝糖原染色。结果：与正常组相比,模型组ALT、AST活性与TBil含量明显升高（P＜0．05）,Alb含量明显降低（P＜0．05）;HE染色示,模型组肝小叶结构排列紊乱,肝细胞脂肪变、气球样变明显。常规PAS染色,正常组肝组织PAS染色阳性占肝脏面积为32．38％±5．50％;与正常组相比,模型组肝组织PAS阳性染色明显减少（P＜0．01）,占肝脏面积为8．60％±3．34％。改良PAS染色提示,正常组肝脏可见大量PAS阳性染色,占肝脏面积为75．50％±9．02％;与正常组相比,模型组肝组织PAS阳性染色明显减少（P＜0．01）,占肝脏面积为17．61％±3．53％。在空白对照组与模型肝组织中,肝糖原改良PAS染色阳性率明显高于常规PAS染色法（P＜0．01）。改良PAS染色肝糖原阳性染色面积更真实反映急性肝损伤程度。结论：改良肝脏糖原PAS染色法有助于急性肝损伤程度评估。     

束缚浸水应激对大鼠肝胆汁分泌的影响及其作用机制的研究

目的：通过研究束缚浸水应激对大鼠肝胆汁分泌的影响,探讨其作用机制。方法：实验分6组（n=8）：A组：室温下单纯束缚＋生理盐水;B组：束缚浸水应激＋生理盐水;C组：室温下单纯束缚＋阿托品;D组：束缚浸水应激＋阿托品;E组：室温下单纯束缚＋酚妥拉明;F组：束缚浸水应激＋酚妥拉明。结果：与A组比较,B组肝胆汁分泌量显著减少（P〈0．05）,pH值显著升高（P〈0．01）;与A组比较,C组肝胆汁分泌量变化不明显,只有微量减少：E组与A组相对照肝胆汁分泌量无明显变化,但也有微量减少。与B组比较,D组肝胆汁分泌量有明显变化（P〈0．05）,肝胆汁pH无明显变化;F组与B组对照其肝胆汁分泌量有明显变化（P〈0．05）,肝胆汁pH无明显变化;D组与F组对照肝胆汁分泌量无明显变化,肝胆汁pH无明显变化。结论：束缚浸水应激对大鼠肝胆汁分泌有明显地抑制作用。浸水应激组肝胆汁的分泌量明显减少,肝胆汁的pH明显升高;迷走神经、交感神经在室温单纯束缚的情况下对肝胆汁的分泌影响较小,而在束缚浸水的情况下迷走神经、交感神经对肝胆汁的分泌有较显著的影响（P〈0．05）。     

富硒板党抗疲劳和抗缺氧作用的实验研究

目的：探讨富硒板党抗疲劳、抗缺氧作用及其机制。方法：昆明种小鼠随机分为对照组和富硒板党低、中、高剂量组,小鼠连续灌胃30d,分别测定小鼠负重游泳、抗缺氧时间;测定血红蛋白（Hb）、血乳酸（LAC）、血清尿素氮（BUN）和肝糖原含量;测定乳酸脱氢酶（LI）H）及超氧化物歧化酶（SOD）fi~活性。结果：与对照组比较,富硒板党低、中、高剂量组可延长小鼠负重游泳、抗缺氧时间（P〈O．05,P〈O．01）,明显增加陆和肝糖原舍量（P〈O．05）,明显增加LDH及SOD的活性（P〈0．05,P〈0．01）,降低LAC及BUN的含量（P〈O．05）,与低剂量组比较,中、高剂量组作用效果较好（P〈O．05）。结论：富硒板党具有明显抗疲劳、抗缺氧作用。     

Effects of Zinc Oxide Nanoparticles on Performance,Egg Quality,Tissue Zinc Content,Bone Parameters,and Antioxidative Status in Laying Hens

The objective of this study was to observe the effects of dietary supplementation with zinc oxide nanoparticles (ZnO-NPs) on performance, egg quality, tissue Zn content, bone parameters, superoxide dismutase activity (SOD), and egg malondialdehyde (MDA) content in laying hens. A total of 288 laying hens at 64 weeks of age were randomly assigned to 4 treatments, 6 replicates, with 12 birds each. Experimental diets included the based diet (without Zn supplementation), and basal diet supplemented with 40, 80, and 120 mg Zn/kg from ZnO-NPs. Feed intake and egg mass were significantly higher in the 40 and 80 ZnO-NPs groups than the other groups. The birds in the 80 ZnO-NPs group had significantly higher egg product than the 120 ZnO-NPs and control groups. Egg shell thickness and shell strength significantly increased in the 40 and 80 ZnO-NPs groups. Moreover, Haugh unit significantly improved in the groups supplemented with ZnO-NPs, compared to the control group. Bone-breaking strength was significantly greater in the 80 ZnO-NPs group than the 120 ZnO-NPs and control groups. Also, ash weight was significantly greater in the 40 and 80 ZnO-NPs groups than the control group. There were significant differences among the groups in the Zn content in plasma, tibia, liver, pancreas, and egg. Relative to the control group, ZnO-NPs supplementation significantly increased the activities of SOD in the liver, pancreas, and plasma. The MDA content in egg was significantly reduced in the groups supplemented with ZnO-NPs. In conclusion, this study demonstrates that ZnO-NPs as dietary supplementation can improve the performance of laying hens, and levels of 40 to 80 ZnO-NPs are the optimal concentrations.

     

Effects of dietary zinc on free radical generation, lipid peroxidation, and superoxide dismutase in trained mice.

The purpose of this study was to investigate the effects of dietary zinc on free radical generation, lipid peroxidation, and superoxide dismutase (SOD) in exercised mice. In the first part of the study, 48 male weanling mice were randomly divided into three groups. They were fed a zinc-deficient diet containing 1.6 mg/kg zinc or were pair-fed or fed ad libitum a zinc-adequate diet supplemented with 50 mg/kg zinc. Half of each group received an exercise training program that consisted of swimming for 60 min per day in deionized water. The diets and exercise program persisted for 6 weeks. In the second part of the study, 64 mice were fed zinc-deficient diets for 6 weeks, and then one group was fed the zinc-deficient diet for an additional 3 weeks, and the other three groups were fed diets supplemented with 5, 50, and 500 mg/kg zinc, respectively. Half of each group also received the exercise program. Both blood and liver samples were examined. Free radicals in liver were directly detected by electron spin resonance techniques and the extent of lipid peroxidation was indicated by malonic dialdehyde (MDA). Both CuZn-SOD and Mn-SOD were measured. The results showed that exercise training increased the metabolism of zinc, and zinc deficiency induced an increased free radical generation and lipid peroxidation and a decreased hepatic CuZn-SOD activity in exercised mice. Furthermore, although exercise training had no effect on the level of free radicals in zinc-adequate mice, it could increase the hepatic mitochondrial MDA formation further in zinc-deficient animals and zinc deficiency would eliminate the exercise-induced increase in SOD activities which existed in zinc-adequate mice. A total of 50 mg/kg zinc supplemented in the diet was adequate to correct the zinc-deficient status in exercised mice while 5 mg/kg zinc had a satisfactory effect on the recovery of only sedentary zinc-deficient mice. However, 500 mg/kg zinc had a harmful effect on both sedentary and exercised zinc-deficient animals.     

Preventive Effects of Zinc Against Psychological Stress-Induced Iron Dyshomeostasis, Erythropoiesis Inhibition, and Oxidative Stress Status in Rats

Psychological stress (PS) could cause decreased iron absorption and iron redistribution in body resulting in low iron concentration in the bone marrow and inhibition of erythropoiesis. In the present study, we investigated the effect of zinc supplementation on the iron metabolism, erythropoiesis, and oxidative stress status in PS-induced rats. Thirty-two rats were divided into two groups randomly: control group and zinc supplementation group. Each group was subdivided into two subgroups: control group and PS group. Rats received zinc supplementation before PS exposure established by a communication box. We investigated the serum corticosterone (CORT) level; iron apparent absorption; iron contents in liver, spleen, cortex, hippocampus, striatum, and serum; hematological parameters; malondialdehyde (MDA); reduced glutathione (GSH); and superoxide dismutase (SOD). Compared to PS-treated rats with normal diet, the PS-treated rats with zinc supplementation showed increased iron apparent absorption, serum iron, hemoglobin, red blood cell, GSH, and SOD activities; while the serum CORT; iron contents in liver, spleen, and regional brain; and MDA decreased. These results indicated that dietary zinc supplementation had preventive effects against PS-induced iron dyshomeostasis, erythropoiesis inhibition, and oxidative stress status in rats.     

Regulation of aortic CuZn-superoxide dismutase with copper. Effects in vivo.

Cu2Zn2-superoxide dismutase (CuZn-SOD) was purified from chicken liver. The liver enzyme had a subunit Mr of 16900 and contained equimolar amounts of copper and zinc [0.26% (w/w) for each]. Aortic CuZn-SOD had the same Mr as estimated by gel filtration and cross-reacted with antibodies to the liver enzyme. Both enzymes were inhibited by 1.0 mM-NaCN. Within 24-72 h after hatching, total SOD activity in aorta rose 3-fold over the day-1 level and stayed elevated for 10 days. With low dietary copper, the total SOD activity rose as before, but then decayed progressively to non-detectable levels in 10 days. Both the cyanide-sensitive (CuZn-SOD) and insensitive (mangano-SOD) activities fell, but not at the same rate. When the 10-day-old deficient chicks were injected with 0.5 mumol of CuSO4 intraperitoneally, SOD activity in aorta was restored to control levels in about 8 h. Despite non-measurable SOD activity in aorta, extracts from the 15-day-old-deficient-chick tissue contained as much, or slightly more, immunoreactive CuZn-SOD protein as age-matched control tissue. The data show clearly that dietary copper regulates SOD activity in the aortas of young developing animals. They further suggest that a copper deficiency suppresses CuZn-SOD activity without inhibiting synthesis or accumulation of the CuZn protein in this tissue.     

补锌对酒精性肝病的影响及其分子机制

目的:本研究是为了观察饮食补充锌减轻酒精性肝病损伤的作用及与HNF-4α的关系。方法:选用成年C57BL/6小鼠40只,按随机数字表分为4组(n=10):正常对照组、酒精中毒组、正常补锌组及酒精补锌组,用不同饮食喂养6个月处死,在正常补锌组和酒精补锌组小鼠饮用水中加入硫酸锌,使锌的含量达到75 mg/L。取各组小鼠肝组织进行病理切片及增殖细胞核抗原(PCNA)免疫组织化学染色,RT-PCR检测肝细胞核因子-4α(HNF-4α)含量,Western blot检测肝组织HNF-4α蛋白表达,检测"肝组织超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量"。结果:酒精中毒组小鼠HNF-4α转录及表达均明显低于正常对照组,差异具有统计学意义(P<0.05),该组小鼠MDA含量增高,SOD活性下降与正常对照组相比差异有统计学意义(P<0.05);而酒精补锌组小鼠PCNA阳性肝细胞数目及HNF-4α蛋白表达水平明显高于酒精中毒组,差异有统计学意义(P<0.05),该组小鼠SOD活性增加,MDA下降,与酒精中毒组相比差异有统计学意义(P<0.05)。结论:长期酒精喂养导致小鼠氧化还原失衡,而补锌可逆转该状态。我们推测饮食补锌可能是通过增加HNF-4α的转录及表达而增强酒精喂养小鼠的肝再生,因此,饮食补锌可能对酒精性肝病有较好的影响。     

Effects of Zinc Glycinate on Productive and Reproductive Performance,Zinc Concentration and Antioxidant Status in Broiler Breeders

An experiment was conducted to investigate the effects of zinc glycinate (Zn-Gly) supplementation as an alternative for zinc sulphate (ZnSO₄) on productive and reproductive performance, zinc (Zn) concentration and antioxidant status in broiler breeders. Six hundred 39-week-old Lingnan Yellow broiler breeders were randomly assigned to 6 groups consisting of 4 replicates with 25 birds each. Breeders were fed a basal diet (control group, 24 mg Zn/kg diet), basal diet supplemented with 80 mg Zn/kg diet from ZnSO₄ or basal diet supplemented with 20, 40, 60 and 80 mg Zn/kg diet from Zn-Gly. The experiment lasted for 8 weeks after a 4-week pre-test with the basal diet, respectively. Results showed that Zn supplementation, regardless of sources, improved (P?<?0.05) the feed conversion ratio (kilogram of feed/kilogram of egg) and decreased broken egg rate, and elevated (P?<?0.05) the qualified chick rate. Compared with the ZnSO₄ group, the 80 mg Zn/kg Zn-Gly group significantly increased (P?<?0.05) average egg weight, fertility, hatchability and qualified chick rate, whereas it decreased (P?<?0.05) broken egg rate. The Zn concentrations in liver and muscle were significantly higher (P?<?0.05) in 80 mg Zn/kg Zn-Gly group than that in ZnSO₄ group. Compared with ZnSO₄ group, 80 mg Zn/kg Zn-Gly group significantly elevated (P?<?0.05) the mRNA abundances of metallothionein (MT) and copper-zinc superoxide (Cu-Zn SOD), as well as the Cu-Zn SOD activity and MT concentration in liver. Moreover, the 80 mg Zn/kg Zn-Gly group had higher (P?<?0.05) serum T-SOD and Cu-Zn SOD activities than that in the ZnSO₄ group. This study indicated that supplementation of Zn in basal diet improved productive and reproductive performance, Zn concentration and antioxidant status in broiler breeders, and the 80 mg Zn/kg from Zn-Gly was the optimum choice for broiler breeders compared with other levels of Zn from Zn-Gly and 80 mg/kg Zn from ZnSO₄.     

Resveratrol Attenuates Copper and Zinc Homeostasis and Ameliorates Oxidative Stress in Type 2 Diabetic Rats

Diabetes is a common metabolic disorder characterized by elevated blood glucose level. Trace element homeostasis causes disturbances in diabetes due to hyperglycemia. Superoxide dismutase (SOD), an antioxidant enzyme, contains zinc and copper ions as its cofactors. Defects in SOD level and activity have been observed in diabetes. Resveratrol (RSV) has displayed hypoglycemic effects and is proven to improve oxidative stress. The aim of the present study was to examine the possible effects of RSV on blood glucose level, serum copper and zinc levels, SOD, and a number of other oxidative markers in type 2 diabetic rats. Diabetes was induced in male Wistar rats with administration of streptozotocin and nicotine amide. The studied groups containing six animals per group were as follows: group 1 normal control group; group 2 diabetic control group; groups 3, 4, and 5 diabetic rats that received 1, 5, and 10 mg/kg body weight of RSV, respectively for 30 days. Serum glucose, copper, zinc, SOD activity, total oxidant status (TOS) as well as thiol groups were all measured. Blood glucose in RSV treated groups significantly decreased. Similarly, copper significantly decreased in diabetic groups treated with RSV. Treatment with 10 mg/kg RSV resulted in significantly increased serum zinc. Furthermore, Cu/Zn ratio was observed to decrease in treated groups compared with untreated diabetic control group. RSV treated groups revealed an increased level of SOD activity as well as improved oxidative status. In summary, the results showed that RSV has potential hypoglycemic effect, attenuates trace element homeostasis, and consequently increases SOD activity level.     

Effects of ascorbic acid on cadmium-induced oxidative stress and performance of broilers

The effects of cadmium on performance, antioxidant defense system, liver and kidney functions, and cadmium accumulation in selected tissues of broiler chickens were studied. Whether the possible adverse effects of cadmium would reverse with the antioxidant ascorbic acid was also investigated. Hence, 4 treatment groups (3 replicates of 10 chicks each) were designed in the study: control, ascorbic acid, cadmium, and cadmium plus ascorbic acid. Cadmium was given via the drinking water at a concentration of 25 mg/L for 6 wk. Ascorbic acid was added to the basal diet at 200 mg/kg either alone or with cadmium. Cadmium decreased the body weight (BW), body weight gain (BWG), and feed efficiency (FE) significantly at the end of the experiment, wheras its effect on feed consumption (FC) was not significant. Cadmium increased the plasma malondialdehyde (MDA) level as an indicator of lipid peroxidation and lowered the activity of blood superoxide dismutase (SOD). Liver function enzymes, aspartate amino transferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and gamma glutamyl transferase (GGT) activities were not changed by cadmium. Cadmium ingestion did not alter serum creatinine levels. Although the serum cadmium level was not elevated, cadmium mainly accumulated in the kidneys, liver, pancreas, and muscle. Ascorbic acid supplementation resulted in a reduction of MDA level previously increased by cadmium and a restoration in SOD activity. However, ascorbic acid did not ameliorate the growth inhibitory effect of cadmium nor did it prevent accumulation of cadmium in analyzed tissues. These data indicate that oxidative stress, induced by cadmium, plays a role in decreasing the performance of broilers and that dietary supplementation by ascorbic acid might be useful in reversing the lipid peroxidation induced by cadmium and partly alleviating the adverse effect of cadmium on performance of broilers.     

Effect of dietary copper and zinc levels on tissue copper,zinc, and iron in male rats

The interaction between dietary copper and zinc as determined by tissue concentrations of trace elements was investigated in male Sprague-Dawley rats. Animals were fed diets in a factorial design with two levels of copper (0.5, 5 μg/g) and five levels of zinc (1, 4.5, 10, 100, 1000 μg/g) for 42 d. In rats fed the low copper diet, as dietary zinc concentration increased, the level of copper decreased in brain, testis, spleen, heart, liver, and intestine. There was no significant effect of dietary copper on tissue zinc levels. In the zinc-deficient groups, the level of iron was higher in most tissues than in tissues from controls (5 μg Cu, 100 μg Zn/g diet). In the copper-deficient groups, iron concentration was higher than control values only in the liver. These data show that dietary zinc affected tissue copper levels primarily when dietary copper was deficient, that dietary copper had no effect on tissue zinc, and that both zinc deficiency and copper deficiency affected tissue iron levels.     

Effects of Dietary Selenium, Vitamin E, and Their Combination on Growth, Serum Metabolites, and Antioxidant Defense System in Skeletal Muscle of Broilers Under Heat Stress

This experiment was conducted to evaluate the effects of dietary vitamin E, selenium (Se), and a combination of the two, on the performance, serum metabolites and oxidative stability of skeletal muscle of broilers during heat stress. The broilers raised in either a thermoneutral (23.9°C constant) or heat stress (23.9°C to 37°C cycling) environment were assigned to 6 dietary treatments (0, 0.5, or 1 mg/kg Se; 125 and 250 mg/kg vitamin E; or 0.5 mg/kg Se plus 125 mg/kg vitamin E) from 1 to 49 days of age. At the end of the experiment, blood samples were collected from chicks, the chicks sacrificed, and pectoralis superficialis muscle was used for measurement of malondialdehyde (MDA) concentration and enzyme activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). The heat-stressed chicks consumed less feed, gained less weight, and had higher feed conversion ratio when compared to thermoneutral chicks (P<0.05). Serum concentrations of iron (Fe) and zinc (Zn) were decreased by heat stress (P<0.05), whereas the serum concentrations of copper (Cu), glucose, and uric acid were significantly increased under heat stress (P<0.05). The chicks that received supplemental of vitamin E exhibited significantly higher serum concentrations of Zn (P<0.05) and significantly lower concentrations of Cu, glucose, and uric acid (P<0.05) when exposed to heat stress. Dietary Se also caused a significant decrease in serum glucose, uric acid, and Cu concentrations of heat-stressed broilers (P<0.05), but had no significant effect on Zn concentration (P>0.05). The GPx activity remained relatively constant (P>0.05), though SOD activity and MDA levels in skeletal muscle were enhanced on exposure to heat stress (P<0.05). The heat-stressed chicks that received the combined supplementary level of vitamin E and Se had the lowest concentration of MDA and the highest activity of SOD in the skeletal muscle (P<0.05). Dietary Se also caused a significant increase in enzyme activity of GPx in the skeletal muscle (P<0.05). These results indicate that the derangement of blood parameters and oxidative stability in broilers under heat stress are improved by supplemental vitamin E and Se.