Glutathione peroxidase activity,tissue and soluble selenium content in beef and pork in relation to meat ageing and pig RN phenotype

Since glutathione peroxidase (GSHPx) may be important for meat quality, its activity was examined in relation to animal species (beef and pork), muscle type (oxidative and glycolytic), selenium content, meat ageing and RN phenotype in Hampshire crossbred pigs. The GSHPx activity in bovine M. Longissimus dorsi [LD; 1.9 (0.4) U/g, mean (S.D.)] was significantly higher (P<0.001) than in M. Psoas major [PM; 1.5 (0.5) U/g] and the activities in the two muscles were correlated (r=0.66; P<0.001). Pork LD had a several fold lower GSHPx activity [0.4 (0.2) U/g] than bovine muscles but, in contrast, a somewhat higher content of selenium [113 (15) ng/g] than bovine LD [106 (12) ng/g] and PM [95 (17) ng/g]. The proportion of soluble selenium in bovine LD (72%) tended to be higher than that in bovine PM (64%), and it was significantly lower in pork LD (52%). Significant correlations between GSHPx activity and soluble selenium were obtained in both beef and pork. Thus, GSHPx activity varied among single animals, with species and muscle type, whereas meat ageing and pig RN phenotype had no effect.     

Comparison of glutathione peroxidase activity,and of total and soluble selenium content in two muscles from chicken,turkey, duck,ostrich and lamb

Glutathione peroxidase activity (GSHPx), total and soluble selenium in two muscles from five species were compared (chicken, duck, turkey, ostrich and lamb). The highest GSHPx activity, found in duck muscles (4.8 U/g; 3.0 U/g), was significantly higher than that in lamb (1.8 U/g; 1.4 U/g), turkey (1.2 U/g; 0.6 U/g), chicken (1.0 U/g; 0.7 U/g), and ostrich muscles (0.9 U/g; 0.8 U/g). GSHPx activities were significantly higher in the oxidative muscles from chicken (thigh), duck (breast), turkey (thigh) and lamb (PM) than those in the corresponding glycolytic muscles (breast, thigh, breast and LD, respectively). Also the total selenium content was higher in duck muscles (149 ng/g; 139 ng/g), than in lamb (171 ng/g /PM, M. psoas major/ and 86 ng/g /LD, M. longissimus dorsi/), chicken (117 ng/g; 109 ng/g), ostrich (106 ng/g; 103 ng/g) and turkey muscles (110 ng/g; 70 ng/g). The selenium content was significantly higher in the oxidative muscles of lamb and turkey than in the corresponding glycolytic muscles. The percentage of soluble selenium in lamb PM was lower (32%) than that in all other muscles (range 48–76%). The study thus showed considerable variation, among species, of glutathione peroxidase activity, total and soluble selenium content in muscle, which may be important for the oxidative stability and nutritional value of different meat products.     

Glutathione-related enzymic activities in rats receiving high cholesterol or standard diets supplemented with two forms of selenium

Selenium deficiency was produced in rats fed a high cholesterol diet for 57 days (Group 1). It was characterized by an increase in malondialdehyde (MDA) an end product of lipid peroxidation and by the dramatic collapse of selenium-dependent glutathione peroxidase activity (GSHPx) in plasma, erythrocytes and in homogenate supernatant fraction of liver, kidney and heart compared with rats fed a standard diet containing sodium selenite (Group 3). A compensatory rise in the activity of liver glutathione S-transferase (GST) activity and also in glutathione reductase (GSSGR) activity was accompanied by an increase in NADPH-generating enzymes glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Adequate dietary selenium supplementation by Se-rich Spirulina corrected all the selenium deficiency effects (Group 2), then, GSHPx and NADPH-consuming enzymes activities were of the same magnitude as those exhibited by rats fed a standard diet containing adequate selenium in the form of sodium selenite. Based on this study, it is concluded that Se-enriched Spirulina behave as an excellent selenium carrier.     

大豆异黄酮和牛初乳复合制剂对去卵巢大鼠骨质疏松症的改善及抗氧化作用

目的:研究大豆异黄酮和牛初乳复合制剂(复合制剂)对去卵巢大鼠骨质疏松症的改善和抗氧化作用。方法:首先采用生化分析方法测定复合制剂活性氧清除活性,然后取50只去卵巢SD大鼠,随机分为5组:假手术组、去卵巢组、去卵巢加复合制剂低剂量组(117 mg/kg)、去卵巢加复合制剂中剂量组(233 mg/kg)、去卵巢加复合制剂高剂量组(467 mg/kg),连续灌胃给予复合制剂90 d后,测定股骨骨密度及骨Ca含量,测定血清AKP活力和血清Ca、P、Zn含量及血脂水平,分析血液和组织SOD活性及MDA含量。结果:复合制剂清除超氧自由基、羟自由基和H₂O₂的EC₅₀值分别为479.7、1592.3、115.3 μg/mL。与去卵巢组相比,给予复合制剂后,中、高剂量组股骨Ca含量、股骨中点及远心端骨密度明显提高,差异有显著性(p<0.05)。复合制剂能显著提高血清Ca、Zn和HDL-C水平,降低AKP活力和TC水平(p<0.05或p<0.01)。与去卵巢组比,高剂量组能显著提高血液、肝、肾和脾SOD活性(p<0.05或p<0.01),中剂量组能显著提高血液、肾SOD活性(p<0.05);中剂量组能显著降低血液、肝、脾MDA含量(p<0.05),高剂量组能显著降低肝、肾MDA含量(p<0.05)。结论:复合制剂能清除活性氧,预防去卵巢大鼠骨丢失,增加骨密度,增强体内抗氧化能力,对骨质疏松症有较好改善作用。     

Biogenic amines and polyamines in liver,kidney and spleen of roe deer and European brown hare

Cadaverine (CAD), histamine (HIS), tyramine (TYR) and the polyamines putrescine (PUT), spermidine (SPD) and spermine (SPM) were determined in liver, kidney and spleen of hunted roe deer (n = 39) and European brown hare (n = 20) 3 and 6 h post mortem, respectively. Median concentrations (mg/kg fresh weight) of CAD and TYR were <5 mg/kg for organs of both species, whereas median HIS concentrations were higher in spleen (14.6 and 11.6 mg/kg for hare and roe deer, respectively) and lowest in liver. Maximum PUT concentration was 72.9 mg/kg, but median values were ≤7.8 mg/kg. Mean SPD concentrations were 8.5, 10.7 and 42.9 mg/kg for liver, kidney and spleen of roe deer, and 37.2, 24.4 and 52.0 mg/kg for hare. Mean SPM concentrations were higher (94.6, 79.9, 102.2 and 111.2, 82.8, 91.1 mg/kg, respectively). SPM concentrations in the organs of the male roe deer were significantly higher than in those of females. SPM:SPD ratios (weight base) were in the order of 2:1 for spleen, and higher for liver and kidney. SPM and SPD were correlated significantly (r = 0.42–0.47). Although variations of polyamine concentrations are partially associated with species, organ, age and gender, the relative contribution of individual factors deserves further study.     

响应面法优化猪脾免疫活性多肽提取工艺研究

目的通过响应面法,优化猪脾中免疫活性多肽的提取工艺。方法选择适当的酶水解猪脾脏,并在单因素试验的基础上,采用Box—Behnken设计优化提取工艺,建立各因素与提取液中多肽含量的数学模型,最后采用淋巴细胞转化试验初步验证其活性。结果获得了猪脾中免疫活性多肽提取工艺：料液比1：2．6g／mL,温度40℃,pH7．0,胰蛋白酶浓度485U／g,中性蛋白酶浓度1711U／g,每100g含活性多肽2．930g,与理论计算值2．929g基本一致,活性约为对照组的1．5倍。结论确定了猪脾免疫活性多肽最佳提取工艺。     

EFFECT OF A PORCINE PANCREATIC COLLAGENASE ON MUSCLE CONNECTIVE TISSUE

SUMMARY– Porcine and bovine pancreas as well as porcine spleen, liver and kidney were analyzed for possible collagenolytic activity. Both the porcine and bovine pancreas extracts possessed collagenolytic activity at pH 5.5 and 37°C. The ability of the pancreas extract to break down connective tissue was not due to tryptic or chymotryptic activity, but was due to a combination of collagenolytic and elastolytic activity. The collagenase was partially purified using Sephadex chromatography and was shown to degrade collagen into small soluble peptide fragments.     

Effect of dietary inclusion of goat milk on the bioavailability of zinc and selenium in rats

The effects of dietary inclusion of freeze-dried goat and cow milk on the utilization of zinc and selenium, and on the metabolic fate of zinc, were studied in transected (control) and resected rats (resection of 50% of the distal small intestine). Intestinal resection reduced the apparent digestibility coefficient and zinc retention in the cow milk diet, whereas these biological indices were similar in transected (control) and resected rats with standard (without milk) and goat milk diets. The apparent digestibility coefficient and retention of selenium were not affected by intestinal resection in the animals fed with the three diets studied. In transected (control) and resected rats, the apparent digestibility coefficient and retention of zinc and selenium were higher for the goat milk diet than for the other two diets. Zinc deposits in the organs, expressed as microg/g dry weight were in order of decreasing concentrations: femur, testes, sternum, liver, kidney, heart, spleen, longissimus dorsi muscle and brain. Deposits were greatest with the goat milk diet, followed by the standard diet and were lowest for the rats given the cow milk diet, both for transected (control) and resected animals. We conclude that consumption of the goat milk diet produces a greater bioavailability of zinc and selenium and a greater deposit of zinc in key organs, for both the transected (control) and the resected rats, with respect to the standard diet and the cow milk diet.     

农大4号’欧李果实花色苷对D-半乳糖致衰老小鼠保护作用研究

为了研究'农大4号'欧李果实花色苷对衰老小鼠保护作用,采用颈部皮下注射D-半乳糖构建衰老小鼠模型,用不同剂量(高、中、低剂量分别为500、250、125 mg·(kg·d)^-1)的花色苷灌胃小鼠,计算小鼠心脏、肝脏、脾脏、肺脏及肾脏指数,并测定小鼠血清、心脏、肝脏、脾脏和肾脏中总抗氧化能力(total antioxidant capacity,T-AOC)、过氧化氢酶(catalase,CAT)、丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)的指标变化情况。结果表明:与空白组相比,模型组小鼠肝脏指数、脾脏指数和肾脏指数显著下降(P<0.05),血清和各脏器组织中的T-AOC、SOD、GSH-Px、CAT均显著降低(P<0.05),MDA含量显著升高(P<0.05),说明衰老小鼠模型构建成功。与模型组相比,高剂量组的肝脏指数、脾脏指数和肾脏指数显著升高(P<0.05),血清和各脏器中的T-AOC、SOD、GSH-Px、CAT均有显著升高(P<0.05),MDA含量显著降低(P<0.05)。由此得出,'农大4号'欧李果实花色能有效增强小鼠的抗氧化能力,对衰老小鼠有较强的保护作用。     

猪副产物中锌原卟啉形成差异分析

本研究的目的为探究猪副产物间锌原卟啉(Zinc-protoporphyrin,ZnPP)形成的差异性。以猪副产物为研究对象,分析猪副产物间ZnPP含量的差异并以铁螯合酶(Ferrochelatase,FECH)活性为指标探究产生差异性原因。采用紫外分析光谱、荧光光谱及化学模拟实验测定了猪副产物中ZnPP的含量、FECH的活性两个指标,验证了ZnPP与FECH之间的联系。UV-Vis检测结果表明在416 nm有1个强吸收峰,546 nm和584 nm处有两个弱对称吸收峰。以420 nm波长激发,红色素在590 nm处有一个强荧光发射峰,644 nm处有一个弱荧光发射峰,与ZnPP标准品的荧光光谱对比后高度重合,证明从副产物中所提取的红色素为ZnPP。猪副产物间ZnPP的含量存在显著性差异,其中猪肝中ZnPP含量在孵育72 h的条件下达到最大值,此时测得的荧光强度高达25655.44 A.U。而FECH活性测定研究结果表明猪肝中FECH的活性远优于其他副产物。利用皮尔逊(Pearson)相关性分析结果表明ZnPP与FECH之间存在极显著关系。本研究结果进一步确定了肝脏具有良好的ZnPP形成能力,从肝脏中提取的ZnPP可用于改善肉制品的颜色。本研究不仅为副产物附加值利用提供了方向,同时为ZnPP的研究提供新的思路。     

世界人口负增长的趋势展望与影响应对

目的：旨在探讨黄精提取物（Polygonatum sibiricum extract,PSE）对D -半乳糖（D-galactose,D -gal）致衰老小鼠重要脏器的保护作用及其潜在的分子机制。方法：将小鼠随机分为五组（n=10）：对照组、D-gal（500 mg/kg）组、PSE低（0.5 g/kg）、中（1 g/kg）、高（2 g/kg）剂量组。测定小鼠器官指数（胸腺、脾脏、肝脏、肾脏）;测定血清中肌酸激酶（CK）、肌酸激酶同工酶（CK-MB）、谷丙转氨酶（ALT）、谷草转氨酶（AST）、碱性磷酸酶（ALP）、尿酸（UA）、尿素（UREA）、肌酐（CREA）、尿素肌酐比值（BUN/Scr）、肾小球滤过率（eGFR）活性;HE及Masson染色观察各组小鼠皮肤、肝脏、肾脏、心脏、大脑、肺等器官病理学变化;用Real-time PCR法检测各组小鼠肝脏、肾脏、心脏、大脑等组织中p53、p16、p21、RB、HO-1、Nrf2及Keap1 mRNA的表达水平。结果：与D-gal组相比,PSE各剂量组胸腺、脾脏、肝脏和肾脏指数均升高（P<0.05）;此外,在各治疗组中,PSE降低了（P<0.05）小鼠血清中CK、CK-MB、ALT、AST、ALP、UA、UREA、CREA和BUN/Scr水平,升高了eGFR（P<0.05）水平;HE及Masson染色发现,PSE能减轻D-gal对小鼠重要器官造成的病理损伤;与对照组比较,模型组肝、肾、心、脑中p53、p16、p21、RB、Keap1 mRNA表达升高（P<0.05）,HO-1、Nrf2 mRNA表达降低（P<0.05）,与D-gal组比较,PSE各治疗组小鼠肝脏、肾脏、心脏、大脑组织中p53、p16、p21、RB、Keap1 mRNA降低（P<0.05）,HO-1、Nrf2 mRNA升高（P<0.05）。结论：PSE具有延缓衰老作用,其机制可能与其抑制p53/p21和p16-RB通路以及Keap1/Nrf2/HO-1通路有关。     

Bovine muscle 20S proteasome. III: Quantification in tissue crude extracts using ELISA and radial immunodiffusion techniques and practical applications

The 20S proteasome is a large complex (700kDa) that exhibits endo- and exo-peptidase activities with wide specificity. In postmortem muscles, several sets of evidence suggest a possible significant contribution of proteasome to meat tenderisation. Hence, an accurate and rapid quantification procedure is needed to attest that new function during the ageing of meat. In the present work, we developed an ELISA test enabling the quantification of nM concentrations of the 20S proteasome. We further tested the radial immunodiffusion (RID) technique described as a more simple method that can quantitatively determine the concentration of an antigen in a complex mixture. The ELISA test allowed us to quantify the 20S protesome in tissue homogenates and fluids with a recovery of 100%, a coefficient of variation lower than 5% and a detection limit of 9ng/ml. Quantification of the 20S proteasome in various bovine tissue by ELISA showed the highest concentration in liver followed by spleen and kidney, with muscles exhibiting the lowest concentrations. In addition, measurement of the proteasome concentration in eight different bovine muscles with various metabolic profiles led to the conclusion that the relationship between muscle metabolic properties and proteasome concentration is rather complex. Nevertheless, heart muscle exhibited the highest proteasome content (331μg/g wet tissue) whereas the lowest values were found for M. Tensor Fascia Latae (213μg/g wet tissue), a fast twitch white muscle, M. Supraspinatus (209μg/g wet tissue), a slow twitch red muscle and M. Pectoralis profondus (203μg/g wet tissue), an intermediate muscle. As compared to other endogenous peptidases, muscle tissue contains relatively high amounts of proteasome. Hence this complex can be quantified using the RID, which allows quantification of protein in the μg range. Plotting the concentration values determined with both methods for all bovine tissues tested gave a straight line with a correlation coefficient of 0.99.     

L-茶氨酸对大鼠内脏组织抗氧化能力及相关基因表达的影响

目的:通过对大鼠灌胃L-茶氨酸溶液,观察大鼠心脏、肝脏、脾脏和肾脏中抗氧化指标的变化,探究L-茶氨酸对大鼠心、肝、脾和肾抗氧化能力及其相关酶mRNA表达量的影响。方法:64只SD大鼠随机分为对照组、低剂量组、中剂量组和高剂量组4组(每组16只,雌雄各半),分别灌胃0、50、200、400 mg/(kg·d)L-茶氨酸。连续灌胃14 d后采集内脏组织,采用试剂盒检测样品中丙二醛(malondialdehyde,MDA)与一氧化氮(nitric oxide,NO)的含量,以及超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GPX)、过氧化氢酶(catalase,CAT)和一氧化氮合成酶(nitric oxide synthase,NOS)的活性,并采用实时荧光定量聚合酶链反应(real-time fluorescence quantitative polymerase chain reaction,RT-q PCR)法测定相应抗氧化酶的mRNA表达量。结果:L-茶氨酸灌胃影响大鼠心脏组织的NO含量,以及SOD、CAT与NOS活力,其中高剂量组大鼠心脏组织中NO含量最低,SOD与CAT活力最大;同时影响大鼠肾脏中NO的含量,高剂量组最低;但对除上述指标外的肝、脾、肾、心的MDA与NO含量,以及SOD、CAT、GPX与NOS活力无显著影响。低剂量L-茶氨酸灌胃显著抑制肝脏中SOD1 mRNA的表达和脾脏中SOD1、SOD3、GPX1 mRNA的表达;高剂量L-茶氨酸则上调脾脏SOD2 mRNA的表达;同时各剂量组心脏组织中的SOD1、SOD2、SOD3、GPX1 mRNA的表达量都显著增加。结论:L-茶氨酸灌胃增强了心脏的抗氧化能力,其机制可能是通过上调了大鼠心脏中SOD2基因的mRNA的表达,从而增加心脏中SOD的活性,起到抗氧化的保护作用。同时,L-茶氨酸灌胃对大鼠内脏抗氧化功能的影响存在性别差异。     

益生菌契达干酪抗氧化肽的结构及其体内代谢稳定性

本实验分别向契达干酪中添加瑞士乳杆菌和鼠李糖乳杆菌制备益生菌干酪,研究其体内抗氧化活性,并将干酪中的抗氧化肽进行分离纯化,利用高效液相色谱-质谱联用法鉴定其结构,采用荧光标记示踪法研究抗氧化肽体内代谢途径及稳定性。结果表明,与衰老模型组相比,喂养干酪提取液的小鼠血清超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶（catalase,CAT）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）活力显著升高（P＜0.05）,其中含瑞士乳杆菌契达干酪提取液体内抗氧化活性最好,小鼠血清中的SOD、CAT、GSH-Px活力较衰老模型组分别提升了45.98%、35.33%和37.93%,且与正常对照组和VC组无显著差异（P＞0.05）。从瑞士乳杆菌契达干酪提取液中鉴定出6 种抗氧化肽,其中肽段QPHQP抗氧化活性最高。该抗氧化肽在体内的作用顺序为：胃、肠→肾、肝、肺→心脏、脾→脑。除胃肠道外,小鼠肝脏中标记肽蓄积量最高且下降缓慢。由此说明,益生菌干酪在体内仍可起到抗氧化活性,干酪中的抗氧化肽进入体内后经胃肠道消化,随血液循环到达靶器官,且主要蓄积在肝脏并发挥活性。     

Xenobiotic clenbuterol in food producing male pigs: Various tissue residue accumulation on days after withdrawal

Using enzyme-linked immunosorbent assay (ELISA) and liquid chromatography tandem mass spectrometry (LC-MS/MS) the concentrations of clenbuterol (ng/g) were shown to be highest in choroid/pigmented retinal epithelium (choroid/PRE) (499.59±26.36ng/g), followed by hair (fair colored) (207.76±86.88ng/g), liver (25.06±16.72ng/g) and kidney (6.88±3.52ng/g) after 28 days of oral clenbuterol administration in a growth-promoting dose (10μg/kg BW, twice daily) to food producing male pigs, with a high correlation coefficient between the two methods for all study matrices (r=0.8800-0.9999). In the liver as an alimentary tissue and regulatory matrix for the control of clenbuterol abuse, the maximal allowed concentration of 0.5ng/g was achieved in liver tissue (0.40±0.12ng/g) on day 14 and in the kidney (0.28±0.10ng/g) on day 7 after treatment withdrawal. In contrast, the concentration of residual clenbuterol in choroid/PRE (57.49±6.13ng/g) and hair (68.36±3.35ng/g) recorded on day 14 of withdrawal was 143- and 170-fold that measured in the liver, with a similar ratio persisting on day 35 of withdrawal (164:1 and 183:1, respectively). These findings indicated a high accumulation potential of clenbuterol residues in the hair and choroid/PRE as compared with the liver and kidney, pointing to the pig choroid/PRE and hair as useful new matrices in the control of clenbuterol abuse as a growth promotant in food production, especially after prolonged withdrawal.     

菜籽油中芥酸含量对动物食用安全性的影响

采用气相色谱法分析双低冷榨菜籽油和普通菜籽油的芥酸含量;运用掺食法喂饲小鼠含两种菜籽油的饲料(含油量2%),连续饲养5 周,观察小鼠、体质量、摄食量、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白(HDL-C)、脏器( 心、肝、脾、肺、双肾、睾丸、卵巢) 质量的变化;研究菜籽油中芥酸含量对小鼠食用安全性的影响。结果表明,双低冷榨菜籽油芥酸含量为4.744%,普通菜籽油芥酸含量为 32.595%,双低冷榨菜籽油芥酸含量明显低于普通菜籽油。喂饲双低冷榨菜籽油饲料组小鼠血清TC、TG 水平低于普通菜籽油饲料组;血清HDL-C 水平略高于普通菜籽油饲料组;与普通菜籽油饲料组相比,喂饲双低冷榨菜籽油饲料对小鼠血脂水平有良好影响。与正常对照组和双低冷榨菜籽油组相比,普通菜籽油组小鼠心脏质量和肝脏质量明显升高,可能与芥酸使脂肪沉积于心脏和肝脏有关。喂饲两种菜籽油对小鼠体质量、摄食、其他脏器质量均无明显影响。     

Bioavailability of selenium in the defatted dark muscle of tuna

The content and bioavailability of selenium (Se) in the dark muscle of tuna (DMT) were studied. Fluorometric analysis showed that DMT contained 2.0-4.7 µg g^-1 Se. A large part of Se of the DMT was recovered in the dry powder of the defatted fraction prepared by successive treatment with acetone and n-hexane/ethanol. On trypsin digestion of the defatted DMT, release of Se paralleled that of nitrogen and about 70% of Se was released within 4 h. Male weanling ddY mice were fed a Torula yeast-based Se-deficient diet (basal diet) for 3 weeks, and then fed the basal diet or a diet supplemented with a 0.05-0.25 µg g^-1 Se as either sodium selenite or the defatted DMT for a further 1 week. Se contents and GSHPx activities in the liver increased gradually with increases in the amount of supplemented Se. No differences were observed between selenite and defatted DMT in the effect on Se content. At low Se levels, the effect of Se in the defatted DMT on the liver GSHPx activities was inferior to that of selenite, but at a high Se level, Se in the defatted DMT showed a greater effect. The bioavailability of Se in the defatted DMT, as assessed by slope ratio analysis using selenite as the reference Se, was 87% for the liver Se content and 168% for the GSHPx activity. The results indicate that the defatted DMT contains high levels of Se in a nutritionally available form.     

Lead, cadmium, arsenic and mercury in meat, liver and kidney of Swedish pigs and cattle in 1984-88

During the period 1984-88 several hundred samples of meat, liver and kidney from Swedish pigs and cattle were analysed for lead, cadmium, arsenic and mercury. Analysis was performed by AAS and extensive quality assurance was carried out. The mean lead levels in pig meat, liver and kidney were less than 0.005, 0.019 and 0.016 mg/kg, respectively: the mean levels in the corresponding bovine tissues were less than 0.005, 0.047 and 0.097 mg/kg. The mean cadmium levels in pig meat, liver and kidney were 0.001, 0.019 and 0.11 mg/kg, whilst those in the corresponding bovine tissues were 0.001, 0.070 and 0.39 mg/kg. The mean arsenic levels in pig meat, liver and kidney were 0.024, 0.023 and 0.019, respectively and those in the corresponding bovine tissues were lower, none exceeding 0.015 mg/kg. The mean mercury levels in pig meat, liver and kidney were 0.009, 0.015 and 0.019 mg/kg respectively, while those in the corresponding bovine tissues were 0.005, 0.006 and 0.010 mg/kg. A decrease in the levels of both arsenic and mercury in pig tissues was found during the period studied, which may be due to a decrease in the use of fish meal in pig feed.     

Quantification of cadmium and lead in offal by SF-ICP-MS: Method development and uncertainty estimate

Offal of bovine, ovine and porcine are able to accumulate potentially toxic heavy metals, such as Cd and Pb, posing a risk for human health. For this reason, the Commission Regulation no. 466/2001 provided the maximum admitted levels for these metals in this kind of matrix (Cd, 500 ng g⁻¹ in all kinds of offal; Pb, 500 ng g⁻¹ in liver and 1000 ng g⁻¹ in kidney). A method based on sector field inductively coupled plasma mass spectrometry for Cd and Pb quantification in calf liver was developed and further applied to offal of different animals. The uncertainty of measurements was calculated according to the Eurachem/Citac Guide. The method LoDs and LoQs were 3.5 and 11 ng g⁻¹ for Cd, and 2.0 and 6.0 ng g⁻¹ for Pb. The repeatability and the intra-laboratory reproducibility showed relative standard deviations equal to 2.25% and 1.99% for Cd and 1.49% and 6.55% for Pb. Relative expanded uncertainties at the mean value in calf liver were 4.74% for Cd and 13.8% for Pb. In Italian offal the following concentration intervals were found (in ng g⁻¹): (i) Cd: calf, from <3.5 in spleen and lung to 96.4 in kidney; lamb, <3.5 in all offal; pig, 114 in liver and (ii) Pb: calf, from 4.03 in lung to 31.8 in liver; lamb, from 4.71 in heart to 279 in liver; pig, 9.19 in liver.     

Nutritional value of cooked offal derived from free-range rams reared in South Africa

Nutritional value of Dorper (n = 10) and Merino (n = 10) by-products were evaluated. Proximate composition differed between organs and breeds with Merino heart (68.9 g/100 g), spleen (77.2 g/100 g) and testicles (83.7 g/100 g) having higher moisture contents than their Dorper counterparts. Dorper brain (10.1 g/100 g), heart (15.2 g/100 g), spleen (20.4 g/100 g) and testicles (12.9 g/100 g) had higher protein contents than Merino. Dorper organs also tended to have a lower fat content. Amino acid and fatty acid profiles differed between organs and breeds. Few differences were noted in total SFA and MUFA. Dorper heart (1.8%) had significantly lower total PUFA than Merino heart (7.3%). All the organs showed favourable P:S ratios, with the exception of the tongue, heart and stomach. Dorper and Merino brain, lungs and testicles had favourable n − 6/n − 3 ratios. Cholesterol content differed between both organs and breeds. The value of offal as food is discussed further.