Relationships between ultimate pH and antioxidant enzyme activities and gene expression in pork loins

Ultimate pH (pH_u) is a major determinant factor of meat quality. In this study, we investigated the effects of pH_u on the muscle antioxidant capacity, and the relationship between pH_u and muscle antioxidant capacity of pigs. A total of 137 pigs from three pig breeds with the same feeding condition were slaughtered and used to measure the pH_u, superoxide dismutase (SOD), glutathione peroxidase (GSH‐PX), total antioxidant capacity (T‐AOC), and malondialdehyde (MDA) content, and gene expression of SOD1 and GPX4. Loins from 137 pigs of three breeds were classified based on pH_u into three groups: low (L‐pH: ≤5.50), intermediate (I‐pH: 5.51‐5.90), and high (H‐pH: ≥5.91). A majority of loins (47.5%–52%) were classified into the intermediate group. The results suggested that the pH_u value was correlated with the activity of SOD, GSH‐PX, T‐AOC, and MDA, and gene expression of SOD1 and GPX4 in all pigs. In addition, our results also indicated a linear relationship between the pH_u value and antioxidant traits. The pH_u value accounted for 23%–40% of the variation in the antioxidant traits. These results suggested that increased pH_u reduce the lipid peroxidation, and also indicated that pHu may be a key factor explaining the variation in the activity of antioxidant enzymes and gene expression in pork loins.     

Effect of several supplemental Chinese herbs additives on rumen fermentation, antioxidant function and nutrient digestibility in sheep

Two experiments were carried out in this study. Experiment 1 was conducted to examine the effects of several supplemental Chinese herbs on antioxidant function and slaughtered body weight in sheep. Results indicated that Fructus Ligustri Lucidi supplementation improved the blood antioxidant function [higher concentration of glutathione reductase (GR), superoxide dismutase and lower concentration of malondialdehyde] and slaughtered body weight in sheep (p < 0.05). Experiment 2 was conducted to investigate the effect of Fructus Ligustri Lucidi extract (FLLE) on rumen fermentation and nutrient digestibility in sheep. Four levels of FLLE treatments, i.e. 0, 100, 300 and 500 mg/kg dry matter (DM), were used in this part. Addition of FLLE at 300 or 500 mg/kg DM increased total volatile fatty acid (VFA) concentration and propionate proportion, decreased ammonia-N concentration in the ruminal fluid, reduced blood urea nitrogen concentration at 2, 4, 6 and 8 h after morning feeding (p < 0.05). Addition of FLLE at all dosages had no effect on ruminal pH value and acetate concentration at all sampling time points in sheep (p > 0.05). Dynamic degradation coefficient c of maize DM was significantly increased by supplementing FLLE at 300 or 500 mg/kg DM (p < 0.05). Fructus Ligustri Lucidi extract addition had no effect on degradation coefficients a, b, c of DM and nitrogen of soybean meal; a, b of maize DM; a, b, c of maize nitrogen; and a, b, c of neutral detergent fibre (NDF) and acid detergent fibre (ADF) of Chinese wildrye (p > 0.05). Addition of FLLE at 300 or 500 mg/kg DM increased DM and organic matter digestibility of diet (p < 0.05). Fructus Ligustri Lucidi extract addition had no effect on digestibility of diet's NDF, ADF and crude protein (p > 0.05). From the aforementioned results, it is indicated that FLLE improved antioxidant status and slaughtered body weight. Fructus Ligustri Lucidi extract addition has capability to modulate rumen fermentation, increase the maize degradation rate, total volatile fatty acid concentration and propionate proportion in sheep.     

几种中草药对绵羊瘤胃发酵、抗氧化功能和营养物质消化率的影响

本研究包括2个试验。试验一,采用单因素随机区组试验设计研究了黄芪、党参、女贞子对绵羊屠宰体增重和抗氧化功能的影响。试验共4个处理,含3种中草药和1个对照组。每个处理4个重复,每个重复1只羊。中草药添加量为6 g/d。结果表明,女贞子组提高了绵羊屠宰体增重(P<0.05),改善了绵羊血液抗氧化功能,提高了谷胱甘肽还原酶和超氧化物歧化酶活性,降低了血浆丙二醛含量(P<0.05)。其他组对绵羊屠宰体增重和血液抗氧化功能影响不显著(P>0.05)。试验二,采用4×4拉丁方试验设计研究了女贞子提取物对绵羊瘤胃发酵和血液生化指标的影响。试验分4个处理,女贞子提取物的添加量分别为0、100、300 mg/kg和500 mg/kg。结果表明:添加量为300mg/kg和500 mg/kg组在晨饲后2、4、6、8 h显著提高了绵羊瘤胃液总挥发性脂肪酸浓度和丙酸的浓度,降低了瘤胃液氨态氮的浓度和血浆尿素氮的浓度。300 mg/kg和500 mg/kg组显著提高了日粮有机物质和干物质表观消化率(P<0.05)。     

Investigation of lactic acid bacterial strains for meat fermentation and the product's antioxidant and angiotensin‐I‐converting‐enzyme inhibitory activities

In the lactic acid bacteria (LAB) strains screened from our LAB collection, Lactobacillus (L.) sakei strain no. 23 and L. curvatus strain no. 28 degraded meat protein and tolerated salt and nitrite in vitro. Fermented sausages inoculated strains no. 23 and no. 28 showed not only favorable increases in viable LAB counts and reduced pH, but also the degradation of meat protein. The sausages fermented with these strains showed significantly higher antioxidant activity than those without LAB or fermented by each LAB type strain. Angiotensin‐I‐converting‐enzyme (ACE) inhibitory activity was also significantly higher in the sausages fermented with strain no. 23 than in those fermented with the type strain. Higher ACE inhibitory activity was also observed in the sausages fermented with strain no. 28, but did not differ significantly from those with the type strain. An analysis of the proteolysis and degradation products formed by each LAB in sausages suggested that those bioactivities yielded fermentation products such as peptides. Therefore, LAB starters that can adequately ferment meat, such as strains no. 23 and no. 28, should contribute to the production of bioactive compounds in meat products.     

32种中药水提取物的体外抗菌活性研究

本试验提取32味中草药水煎液,采用微量肉汤稀释法测定对标准大肠杆菌和金黄色葡萄球菌的体外抑菌活性．筛选出对金黄色葡萄球菌具有较好体外抑菌活性的中草药11味,并对3株耐甲氧西林金黄色葡萄球菌（MRSA）进行了最低抑菌浓度（MIC）的测定。结果显示：有24味中草药水煎液具有体外抑菌活性．且对金黄色葡萄球菌的抑菌效力大于大肠杆菌．以黄连和黄柏对金黄色葡萄球菌的抑菌效果最好：3株MRSA对筛选的11味中草药中的10味均产生了不同程度的耐药,MIC增加2—4倍,仅香薷对MRSA的MIC减少2—4倍。     

植物提取物对育肥猪生长性能、胴体性状、猪肉品质及抗氧化能力的影响

本试验旨在研究植物提取物对育肥猪生长性能、胴体性状、肉品质及猪肉抗氧化能力的影响。选用20头体重相近[(83.75±5.83 kg)]的PIC猪,随机分为对照组(基础日粮)和试验组(基础日粮中额外添加0.04%植物提取物),每个处理5个重复,每个重复2头猪。结果表明,两组间育肥猪采食量、日增重、料肉比和胴体性状差异不显著(P>0.05)。与对照组相比,试验组肉色a*45min值显著提高(P<0.05),L*96 h值极显著降低(P<0.01);4℃下储存0、3 d和7 d猪肉,试验组肉样中丙二醛(MDA)的含量显著降低,超氧化物歧化酶(SOD)活性显著提高(P<0.05)。因此,饲粮中添加植物提取物有利于储存中猪肉品质的改善。     

Effects of boning method and postmortem aging on meat quality characteristics of pork loin

This work investigated the effects of boning method and postmortem aging on pork loin color, shearing value and sensory attributes. Two experiments were assigned. In Experiment I, 30 Chinese native black pigs were slaughtered and their carcasses were divided into three groups: (i) hot-boning: carcasses were fabricated within 45 min postmortem just after dressing; (ii) cold boning at 24 h: carcasses were fabricated after chilling at 0°C for 24 h; (iii) cold boning at 36 h: carcasses were fabricated after chilling at 0°C for 36 h. In Experiment II, right sides of the second group in Experiment I were used and primal cuts were vacuum packed and aged for 1 day, 8 days and 16 days. Pork loins ( Longissimus lumborum ) were used for color measurement, shearing test, and sensory evaluation. Among three boning methods, cold-boning at 36 h postmortem had the advantages of giving muscles a better color, the lowest cooking loss and cooked shearing value, and the highest sensory tenderness, juiciness, flavor and overall liking. Postmortem aging could improve pork quality characteristics, but it is not the fact that the longer aging time is, the better pork quality would be. Eight days may be enough to obtain an acceptable sensory attribute. These results are meaningful for pork processing and pork consumption.     

外源水杨酸对低温胁迫下海滨雀稗抗寒生理特征的影响

为探讨水杨酸(SA)对海滨雀稗耐寒性的影响,以海滨雀稗“白金”品种为材料,分析了外源水杨酸(1 mmol·L^-1)预处理对适温(30 ℃/25 ℃,昼/夜),冷害(8 ℃/4 ℃)和冻害(2 ℃/-2 ℃)3种温度处理下海滨雀稗生长速率和草坪质量、叶片电导率(EL)和丙二醛(MDA)含量、抗氧化酶超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性、脂肪酸含量及脂肪酸不饱和指数的影响。结果表明,在冷害和冻害下,草坪质量下降,叶片EL增大,MDA含量升高,叶片SOD、POD和CAT活性升高;而外源SA预处理显著缓解低温对海滨雀稗草坪质量的伤害,降低叶片EL和MDA含量,提高SOD、POD和CAT活性。低温下叶片不饱和脂肪酸含量升高,饱和脂肪酸含量下降,而外源SA预处理将进一步显著提高不饱和脂肪酸的含量和脂肪酸不饱和指数。因此,外源SA预处理显著提高冷害和冻害胁迫下海滨雀稗叶片的不饱和脂肪酸含量和不饱和指数,从而维持低温胁迫下细胞膜的稳定性,增强抗氧化能力,缓解低温对植株的伤害而提高耐寒能力。     

Effects of bacterial strains on the development of the ripening flavor of cured pork loins

To determine the effect of bacteria on the development of the ripening flavor of cured meat, pork loins were cured with pickles containing 8 or 16% sodium chloride at 0 and 8°C. The bacterial flora, total free amino acid content and total free fatty acid content in the cured loins, sensory properties of cooked pork loins and the relationships between the proteolytic and lipolytic activities of isolates and curing conditions were investigated. Desirable bacteria, including salt‐tolerant bacteria and lactic acid bacteria, were predominant under the condition of 8% sodium chloride in the pickles and a curing temperature of 8°C. The total free amino acid content and total free fatty acid content at a curing temperature of 8°C were higher than those at 0°C. Cooked pork loins cured in pickles containing 8% sodium chloride at a temperature of 8°C for more than 7 days were preferred in terms of color, flavor and taste. Before the curing procedure, gram‐negative bacteria (Vibrio, Acinetobacter, Pseudomonas and Enterobacteriaceae) were predominant in the pork loins. During the curing period, the numbers of viable gram‐positive bacteria (Micrococcus, Staphylococcus and Pediococcus) increased and the numbers of viable gram‐negative bacteria decreased. Strains of Micrococcus and Staphylococcus with proteolytic and/or lipolytic activities in cured meat also increased during the curing period and were more predominant in the pork loins cured in pickles containing 8% sodium chloride and at a curing temperature of 8°C than in pork loins cured in pickles containing 16% sodium chloride and at a curing temperature of 0°C. The actions of these bacteria were thought to be important factors affecting the flavor of the cured pork. Micrococcus and Staphylococcus with proteolytic activity might contribute to the development of the ripening flavor of ham. The results of the present study together with the results of further investigations on the relationships of the enzyme activities of Micrococcus and Staphylococcus in cured meat with a preferable flavor would be useful for establishing a novel effective method for using bacteria to produce ham of a high quality.     

铝和酸胁迫对苜蓿根瘤菌生长和抗氧化酶系的影响

在铝和酸胁迫下,比较分析了天蓝苜蓿和紫花苜蓿根瘤菌的生长及SOD(超氧化物歧化酶)、CAT(过氧化氢酶)、POD(过氧化物酶)、及GR(谷胱甘肽还原酶) 等抗氧化酶系响应特点。铝胁迫设5个梯度,即0,25,50,75,100 μmol/L;酸胁迫设4个pH水平,即4,5,6,7。结果表明,铝和酸胁迫下,2种苜蓿根瘤菌的OD_A600均显著降低,生长受到抑制,且天蓝苜蓿根瘤菌的OD_A600显著高于紫花苜蓿根瘤菌。在pH水平为4和5时,紫花苜蓿根瘤菌没有生长。在铝毒胁迫下,天蓝苜蓿根瘤菌的SOD酶活性一定程度减小后缓慢上升,而CAT、POD和GR酶活性随铝浓度增大显著下降;紫花苜蓿根瘤菌的SOD,CAT及GR酶活在低Al胁迫下无显著变化,在高铝胁迫下显著下降。随着pH水平的下降,天蓝苜蓿和紫花苜蓿根瘤菌均表现为SOD、CAT、POD、GR酶活性的显著下降。在不同铝及酸胁迫下,天蓝苜蓿根瘤菌各抗氧化酶活性显著高于紫花苜蓿根瘤菌。综合分析认为天蓝苜蓿根瘤菌较之紫花苜蓿根瘤菌有较强的耐酸、耐铝性。     

常用粗饲料营养成分和饲用价值分析

通过常规化学分析法和康奈尔净碳水化合物-蛋白质体系(CNCPS)评定不同粗饲料的营养成分并比较其组成差异,结合粗饲料品质评定预测公式评定其饲用价值。结果表明,1)黑麦草、甘薯蔓与牛鞭草的粗蛋白质(CP)、粗脂肪(EE)、可溶性粗蛋白质(SCP)和非蛋白氮(NPN)含量显著高于玉米秸秆和稻草,中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)含量显著低于玉米秸秆和稻草。 2)黑麦草和甘薯蔓的糖类(CA)、快速降解真蛋白(PB₁)含量显著高于其他粗饲料,甘薯蔓、黑麦草和牛鞭草淀粉和果胶(CB₁)、非结构碳水化合物(NSC)和慢速降解真蛋白(PB₃)显著高于稻草和玉米秸秆。稻草的可利用纤维(CB₂)含量显著高于其他粗饲料,玉米秸秆的碳水化合物(CHO)、不可利用碳水化合物(CC)和中速降解蛋白质部分(PB₂)含量显著高于其他粗饲料。3)不同粗饲料氨基酸(AA)组成差异大,提供限制性氨基酸的潜力不同,黑麦草的总氨基酸(TAA)、必需氨基酸(EAA)和限制性氨基酸(LAA)的含量显著高于其他粗饲料,玉米秸秆和稻草最低。4)黑麦草的可消化干物质量(DDM)和粗饲料相对值(RFV)均显著高于其他粗饲料,甘薯蔓的干物质随意采食(DMI)和RFV显著高于牛鞭草,玉米秸秆和稻草的DMI、DDM和RFV均为最低,且两者差异不显著。因此,黑麦草的营养价值最高,其次为牛鞭草和甘薯蔓,玉米秸秆和稻草最低。     

高寒草地施肥对放牧牦牛抗氧化酶活性的影响

为了评价施肥处理对牧草矿物质元素含量和牦牛抗氧化酶活性的影响,在黄河首曲草地进行草地施肥和草地放牧试验。结果表明,硫酸氨施肥组超氧化物歧化酶（SOD）、谷胱苷肽过氧化物酶（GSH—Px）、过氧化氢酶（CAT）极显著低于（P〈0．01）Ⅱ、Ⅲ组,Ⅱ、Ⅲ组之间无显著差异;铜蓝蛋白（Cp）的含量,硫酸氨施肥组极显著低于Ⅱ、Ⅲ组（P〈0．01）,Ⅱ、Ⅲ组之间无显著差异;血液MDA的含量,硫酸氨施肥组极显著高于Ⅱ、Ⅲ组（P〈0．05）,Ⅱ、Ⅲ组之间无显著差异。在试验结束时硫酸氨施肥组Hb、MCV、MCH都极显著低于Ⅱ、Ⅲ组（P〈0．01）,放牧牦牛出现小红细胞贫血。     

胍基乙酸对肉鹅的生产性能、抗氧化能力和血清生化指标的影响

文章旨在研究胍基乙酸(GAA)对肉鹅生产性能、抗氧化能力和血清生化指标的影响,试验选取30日龄健康肉鹅,随机分为高剂量组、中剂量组、低剂量组和对照组,试验组分别在基础日粮中添加0.02%、0.04%和0.08%的胍基乙酸,对照组不添加,连续饲喂30 d,测定各组肉鹅的平均日增重、平均日采食量、料重比、抗氧化指标、血清生化指标。结果表明,在生产性能方面,各试验组的平均日增重均显著高于对照组(P<0.05),而料肉比均显著低于对照组(P<0.05),各组间的平均日采食量差异不显著(P>0.05);在抗氧化能力方面,各试验组的T-AOC、GSH、SOD活性均显著高于对照组(P<0.05);血清生化指标检测结果表明,各试验组的GPT、GOT、LDH、AKP均低于对照组,且差异显著(P<0.05);而试验组的T3浓度显著高于对照组(P<0.05),其他指标差异不显著(P>0.05)。综上所述,当胍基乙酸用量为0.04%时,可以有效提高肉鹅的平均日增重、减低料肉比,提高机体抗氧化能力,同时有效降低血清中的GPT、GOT、LDH水平,并促进T3的分泌。     

药食同源中草药复方对山羊生长性能、血清生化指标和免疫功能的影响

试验旨在以列入《饲料原料目录》中的某些药食同源天然植物中草药为原料,研究其对山羊抗病促生长、抗氧化、提高免疫力等方面的影响.研究共开展两次试验.试验一:选取健康山羊100只,随机分为5组,每组5个重复,每个重复4只羊.对照组山羊饲喂基础日粮,试验组分别在基础日粮中添加不同的中草药复方,添加量均为2％.预试期20 d,正...     

Investigation of the effect of pork compositions on freezing points in different pork cuts by measuring thermal properties and water mobility and distribution

This work was to compare the difference of freezing point in the four pork cuts (chuck roll, picnic shoulder, loin, and topside) and evaluate the effect of pork compositions on the freezing points. Loin exhibited lower freezing points and accompanied by higher content of unfreezable water, lower relaxation times, and higher proportions of bound water, compared with other pork cuts. Low freezing points of pork may be attributed to high sarcoplasmic protein solubility, due to high sarcoplasmic protein solubility related to increase of bound water proportion and decrease of NMR T₂ relaxometry. In addition, correlation analysis revealed that sarcoplasmic protein solubility and ash content were negatively related to the freezing point, which was verified by a quadratic polynomial correlation between the sarcoplasmic protein solubility and the freezing point in vitro. These results could help to better understand the freezing point of pork and provide more theories for improving superchilled storage.     

Effects of dietary supplementation with conjugated linoleic acid on fatty acid composition and lipid oxidation in chicken breast meat

We investigated the effects of dietary conjugated linoleic acid (CLA) on fatty acid composition and lipid oxidation in breast meat of broiler chickens. Broiler chickens (28-day-old females) were fed diets containing experimental oils at 20 g/kg diet for 28 days. The experimental oils consisted of either a 2:0, 1:1, or a 0:2 (wt : wt) ratio of safflower oil (high linoleic acid content) to a commercial CLA mixture. In this study, dietary CLA supplementation significantly increased the composition and content of CLA in chicken meat. The predominant CLA in meat from birds with supplemented diets was the cis -9, trans -11 isomer. The proportion of saturated fatty acid in meat significantly increased with increasing CLA supplementation, with a corresponding decrease in monounsaturated fatty acid. Dietary CLA also reduced thiobarbituric acid reactive substances (TBARS) values in raw meat during storage at 4°C for 5 days. These results provide evidence that CLA feeding is a practical strategy not only for adding nutritional benefits to chicken meat but also for improving meat quality including oxidative stability.     

酸与碱处理对海带多糖提取及其抗氧化活性的影响

本试验采用柠檬酸提取法和碱提取法从海带中提取多糖组分,以总抗氧化能力和羟自由基（·OH）为衡量抗氧化活性指标,比较这两种提取方法得到海带粗多糖产率和抗氧化活性。试验结果表明：柠檬酸提取法和碱提取法的提取率分别为15.92%和6.05%,所提取的海带粗多糖具有良好的抗氧化活性,且柠檬酸提取法抗氧化活性更高。 [关键词] 柠檬酸提取法|碱提取法|海带多糖|抗氧化活性     

噬菌体裂解酶对白羽肉鸡生长性能、器官指数及血清抗氧化酶活性的影响

为评估噬菌体裂解酶作为一种替抗饲料添加剂应用于畜禽生产的安全性及其应用潜能,将3日龄健康白羽肉鸡在饲喂基础饲粮上添加高剂量(200 mg/kg)、中剂量(100 mg/kg)和低剂量(50 mg/kg)的噬菌体裂解酶制剂(由TSPphg和MMPphg噬菌体裂解酶制得),并将抗生素产品金霉素制剂以50 μg/g的剂量添加...     

Potential effect of the microbial fermented feed utilization on physicochemical traits,antioxidant enzyme and trace mineral analysis in rabbit meat

The study investigated the potential effect of the microbial fermented feed utilization on physicochemical traits, antioxidant enzyme and trace mineral analysis in rabbit meat. A total of 72 six-week-old male rabbits were weighed and randomly divided into four groups (1) (SRKC) control; (2) (SRKP) Lactobacillus plantarum 1 × 10⁶ cfu/g fresh weight (FW); (3) (SRKG) Pediococcus acidilactici 1 × 10⁶cfu/g FW and (4) (SRKPG) P. acidilactici + L. plantarum 1 × 10⁶ cfu/g FW. Performance characteristic, weekly body weight, was positively (p < .05) enhanced, while daily feed intake (DFI) and feed convention ratio (FCR) were not influenced in treatments group as compared to untreated. The water, protein, water holding capacity (WHC) and dry matter (DM) concentration were positively (p < .05) influenced, while ash, pH, lightness, redness and yellowness were not influenced in treated group as compared to untreated. The concentration of glutathione peroxidase (Gpx), superoxide dismutase (SOD) and aspartate aminotransferase (AST) was positively (p < .05) influenced in treatments group as compared to control. Regarding trace minerals, copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) were positively (p > .05) reduced in treated group as compared to untreated. It is concluded that the addition of lactic acid bacteria (L. plantarum and P. acidilactici) in Hybrid pennisetum silage had a constructive influence on rabbit health performance and meat biochemistry.