Supplementation of Lycium barbarum residue increases the growth rate of Tan sheep by enhancing their feed intake and regulating their rumen microbiome and metabolome

Lycium barbarum residue(LBR),a by-product of L.barbarum processing,is packed with bioactive components and can be potentially utilized as a feed additive in animal husbandry.However,the fundamental understanding of its effectiveness on livestock animals is still lacking,particularly in ruminants.To explore the effects of LBR on the growth performance,rumen fermentation parameters,ruminal microbes and metabolites of Tan sheep,sixteen fattening rams(aged 4 mon)were fed a basal diet(CON,n=8)or a basal diet supplemented with 5%LBR(LBR,n=8).The experiment lasted for 70 d,with 10 d adaptation period and 60 d treatment period.The results showed that the LBR enhanced the average daily feed intake,average daily gain(P<0.05),and ruminal total volatile fatty acids(P<0.01)while decreasing ammonia-nitrogen concentration and rumen pH value(P<0.05).Additionally,the LBR improved the relative abundances of Prevotella,Succiniclasticum,Ruminococcus,Coprococcus,Selenomonas,and Butyrivibrio(P<0.05)and reduced the relative abundances of Oscillospira and Succinivibrio(P<0.05).The LBR altered the ruminal metabolome(P<0.01)by increasing the abundances of ruminal metabolites involved in amino acids(e.g.,L-proline,L-phenylalanine,L-lysine,and L-tyrosine),pyrimidine metabolism(e.g.,uridine,uracil,and thymidine),and microbial protein synthesis(e.g.,xanthine and hypoxanthine).In conclusion,LBR had positive effects on the growth rate of Tan sheep as well as on rumen fermentation parameters,rumen microbiome and rumen metabolome.

Effects of Antimicrobial Peptides on Production,Slaughter Performance and Blood Routine of Tan Sheep

[Objectives]This study was conducted to analyze effects of antimicrobial peptides added to the diet of Tan sheep on their production, slaughter performance and blood composition. [Methods] Ninety two four-month-old Tan sheep were randomly divided into two treatment groups according to their body weight, 46 in each group. The control check group(CK) was feed with conventional diet, and the experimental group was fed with the addition of antimicrobial peptide on the basis of the conventional diet, with the added amount of 2.5 g/sheep per day. The experimental period was 60 d. [Results] The incidence rate was 75.06% lower in the experimental group than in the CK. The average daily weight gain per sheep was 11.27% higher in the experimental group than in the CK(P<0.05). The feed conversion ratio was 8.45% lower in the experimental group than in the CK(P<0.05). The average daily gross profit per sheep was 12.12% higher in the experimental group than in the CK. For slaughter performance, the data difference of each item was not significant. The PH at 45 min and 24 h after slaughter was within the normal range of fresh mutton. The cooked meat percentage and water loss rate showed no significant differences(P>0.05). The marbling ranged from 2.45 to 2.50, indicating that the fat content was moderate, and the difference between groups was not significant(P>0.05). The flesh color ranged from 3.00 to 3.15, between light red and bright red, belonging to the normal color of mutton, and the difference between groups was not significant(P>0.05). The shear force was between 2.50 and 2.65, without a significant difference between groups(P>0.05). The white blood cells, lymphocytes and platelets in the experimental group were lower than those in the CK(P<0.01). The erythrocytes and hemoglobin in the erythrocyte group were higher than those in the CK(P<0.05). The neutrophils and monocytes in the experimental group were lower than those in the CK(P<0.05). [Conclusions] This study provides a technical basis for the rational use of antimicrobial peptides and their application in ruminants.

The Effects of Nutrition Lick Brick and Salt Brick as Supplement Feed on the Production Performance of Tan Sheep

In the paper, the effects of nutrition lick brick and salt brick as supple-ment feed on the performance of Tan sheep were studied. 36 fattening Tan sheep with the average weight of about 23 kg were chosen, they were randomly divided into 3 groups according to the weight, and each group had 12 sheep. Control group was fed with normal daily ration, experimental group 1 was fed with normal daily ration＋nutrition lick brick, experimental group 2 was fed with normal daily ration＋salt brick, the experimental period was 60 d. The results showed that 1） compared with CK, daily gain of group 1 improved 17.09%（P〈0.01）, feed conversion ratio reduced 11.69%（P〈0.05）, and average gross profit per sheep improved 51.65 yuan; daily gain of group 2 improved 7.03%（P〈0.05）, feed conversion ratio reduced 4.06%（P〉0.05）, and average gross profit per sheep improved 19.78 yuan; 2） compared with group 2, daily gain of group 1 improved 9.40%（P〈0.05）, feed conversion ratio re-duced 7.96%（P〈0.05）, and average gross profit per sheep improved 31.87 yuan;these indicated that nutrition lick brick and salt brick as supplement feed for Tan sheep both can improve the production performance of Tan sheep, and the supple-mentary feeding effect of nutrition lick brick was better.

In vitro Maturation of Tan Sheep Oocytes

[Objective] This study aimed to investigate the appropriate concentrations of follicle-stimulating hormone（FSH）, luteotropic hormone（LH） and estrodiol（E2） during in vitro maturation of Tan sheep oocytes. [Method] Tan sheep oocytes were divided into five groups for in vitro maturation culture： control group, FSH group（10,50, 100, 200 and 300 μg/ml FSH, respectively）, LH group（5, 10, 20, 50 and 100μg/ml LH, respectively）, E2group（5, 10, 25, 50 and 100 μg/ml E2, respectively）, and FSH ＋ LH group（100 μg/ml FSH ＋ 20 μg/ml LH）. The releasing rate of first polar bodies was analyzed. [Result] The maturation rate of Tan sheep oocytes in 100 μg/ml FSH ＋ 20 μg/ml LH group reached the highest（64.64%）, which was significantly higher than that in other four groups（P〈0.05）; among different FSH concentrations,100 μg/ml FSH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different LH concentrations, 20 μg/ml LH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different E2 concentrations, 50 μg/ml E2 was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）. [Conclusion] Under the experimental conditions, 100 μg/ml FSH ＋20 μg/ml LH was the most appropriate hormone combination for in vitro maturation of Tan sheep oocytes.

The Levels of Genetic Differentiation of Small-Tailed Han Sheep and Tan Sheep Populations Using Structural Loci

Using the method of ＂random sampling in typical colonies of the central area of the habitat＂ and several electrophoresis techniques, the variations of 17 structural loci encoding blood proteins in 60 Small-Tailed Han sheep and 73 Tan sheep were examined and compared with those of 14 other sheep populations in China and other countries to investigate their levels of genetic differentiation. The average heterozygosities of Small-Tailed Han sheep and Tan sheep were 0.2360 and 0.2587, respectively. The average polymorphic information content values were 0.1974 and 0.2102, respectively. The average effective numbers of alleles were 1.5723 and 1.5751, respectively. The coefficients of gene differentiation in the four groups （including 4, 6, 13, and 16 sheep populations, respectively） were 0.049323, 0.059987, 0.1728, and 0.201256, respectively, indicating that the degree of gene differentiation at the structural loci was the least in Hu sheep, Tong sheep, Small-Tailed Hart sheep, and Tan sheep; followed by the above-mentioned four sheep populations and two Mongolian sheep populations; and was the highest in sheep populations belonging to the Mongolian sheep group, South Asian sheep, and European sheep. The earlier researchers＇ conclusions that both Small-Tailed Han sheep and Tan sheep evolved from Mongolian sheep were further verified by the results of this study. Hu sheep, Tong sheep, Small-Tailed Han sheep, and Tan sheep were decreasingly affected by the bloodline of Mongolian sheep to different degrees. The relationships among sheep populations were not closely related to the geographical distances among sheep populations.

Polymorphism of OB Gene and Its Relationship with Growth Traits in Tan Sheep

In order to promote marker-assisted selection of Tan sheep, the polymorphism of OB gene in zan sheep was detected by sequencing and PCR-RFLP tech- niques. The correlation between polymorphism of OB gene and weight of Tan sheep was analyzed. The results indicated that there was a CT point mutation at locus 253 in exon 3 region of OB gene, but no mutant homozygote was found. The results of chi-square test showed that the frequency of BB and AB genotypes was con- sistent with Hardy-Weinberg equilibrium. AB genotype was the dominant genotype controlling weight of Tan sheep with the genotype frequency of 0.05. According to the results of correlation analysis, the mutation exerted significant effects on weight of Tan sheep at 3-month-old and 6-month-old （P 〈 0.05）. Moreover, interac- tions between ~enotvoe and ~ender had no sianificant effect on weight of Tan sheen （ P 〉 0.05 ）.

Developmental Changes of GH Gene in Tan Sheep and Correlation Analysis with Slaughter Traits

[ Objective] The paper was to study the differential expression of growth hormone （GH） gene in different ages and different tissues of Tan sheep. [ Method] Using real-time fluorescent quantitative PCR （RT-PCR） assay, specific primers were designed according to the GH gene sequence published on Gen- Bank. With the total RNA of Tan sheep tissue as the template, the expression levels of GH gene in pectoral muscle, leg muscle and longissimus dorsi muscle at dif- ferent ages were analyzed. [ Result] In three types of muscle tissues, the expression patterns of GH gene in different tissues at the same month of age were pectoral muscle 〉 leg muscle 〉 longissimus dorsi muscle. The expression levels of GH gene were positively correlated with live weight before slaughter, carcass weight and net meat weight, and had significant positive correlation only with net meat weight （ P 〈 0.05 ）. [ Conclusion ] The content of GH gene in different tissues gradually increased with the increasing months of age, and there were extremely significant differences in expression level of GH gene among different months of age or different sites （P〈0. 01）.

SNP Genotyping of Myostatin (MSTN) Gene through Taq Man Probe Assay and Association Study between MSTN Genotypes and Growth Traits of Tan Sheep

To establish a rapid, accurate and economical real-time PCR assay system based on TaqMan probe technology for the detection of genetic variations of single nucleotide polymorphisms （SNPs） in myestatin （MSTN） gene, a pair of TaqMan probes were designed on the polymorphism loci of MSTN gene and used in PCR reaction system for SNP genotyping. Meanwhile, an association study was performed between MSTN genotypes and growth traits of Tan sheep, including birth weight, weaning weight, 3-month weight, and 6-month weight. The results showed that rs417816017 locus of MSTN gene in Tan sheep had two genotypes ： YY and XY. The individuals with genotype XY had a growth advantage over the ones with genotype YY. The results indicate that TaqMan probe-based real-time PCR assay can be used to detect the genotype of MSTN gene, which will provide candidate genes for breeding of Tan sheep.

Polymorphism of Follicle-Stimulating Hormone Receptor Gene in Ningxia Tan Sheep

[ Objective] To study the polymorphism of follicle-stimulating hormone receptor （FSHR） gene in Ningxia Tan sheep and thus to provide a theoretical basis for breeding. I Methodl Genotypes of 111 healthy Ningxia Tan sheep were examined by polymerase chain reaction and restriction fragment length polymorphism （PCR-RFLP）. [ResultS] A 306-bp fragment was amplified. The PCR products digested with restriction enzyme Alu I showed polymorphism with three genotypes, L e., GG, CG and CC. The genotypic frequencies of GG, CG and CC were 0.135 1 （ 15 individuals）, 0.666 7 （74 individuals） and 0.198 2 （22 individuals）, respectively. The allele frequencies of G and C were 0.468 5 and 0.531 5, respectively.[ Conclusion] FSHR aene is Dolvmomhic in Ninaxia Tan Sheeo.

Dynamic changes of genomic methylation profiles at different growth stages in Chinese Tan sheep

Background:Tan sheep,an important local sheep breed in China,is famous for their fur quality.One-month-old Tan sheep have white,curly hair with beautiful flower spikes,commonly known as“nine bends”,which has high economic value.However,the“nine bends”characteristic gradually disappears with age;consequently,the economic value of the Tan sheep decreases.Age-related changes in DNA methylation have been reported and may be responsible for age-induced changes in gene expression.Until now,no genome-wide surveys have been conducted to identify potential DNA methylation sites involved in different sheep growth stages.In this study we investigated the dynamic changes of genome-wide DNA methylation profiles in Tan sheep using DNA from skin and deep whole-genome bisulfite sequencing,and compared the DNA methylation levels at three different growth stages:1,24,and 48 months old(mon1,mon24,and mon48,respectively).Results:In this study,11 skin samples from three growth stages(four for mon1,four for mon24,and three for mon48)were used for DNA methylation analysis and gene expression profiling.There were 52,288 and 236 differentially methylated genes(DMGs)identified between mon1 and mon24,mon1 and mon48,and mon24 and mon48,respectively.Of the differentially methylated regions,1.11%,7.61%,and 7.65% were in the promoter in mon1 vs.mon24,mon24 vs.mon48,and mon1 vs.mon48,respectively.DMGs were enriched in the MAPK and WNT signaling pathways,which are related to age growth and hair follicle morphogenesis processes.There were 51 DMGs associated with age growth and curly fleece formation.Four DMGs between mon1 and mon48(KRT71,CD44,ROR2 and ZDHHC13)were further validated by bisulfite sequencing.Conclusions:This study revealed dynamic changes in the genomic methylation profiles of mon1,mon24,and mon48 sheep,and the percentages of methylated cytosines were 3.38%,2.85% and 4.17%,respectively.Of the DMGs,KRT71 and CD44 were highly methylated in mon1,and ROR2 and ZDHHC13 were highly methylated in mon48.These findings provide foundational information that may be used to develop strategies for potentially retaining the lamb fur and thus improving the economic value of Tan sheep.

Volatile Flavor Composition in Mutton of Ningxia Tan Sheep

[Objective] To analyze the volatile flavor compounds in mutton of different parts of Ningxia Tan sheep. [Method] The volatile flavor compounds in mutton were identified and quantified using the solid phase micro-extraction （SPME） method combined with GC-MS analysis. [ Re- sult ] The proportion of aldehydes in volatile compounds was the highest in the mutton of most parts of Ningxia Tan sheep, but no 4-methyl acid and 4-methyl nonyl acid was detected in the mutton. [ Conclusion]Aldehydes may be important for the volatile flavor of mutton of Ningxia Tan sheep. The study provides a basis for better development and use of Ningxia Tan sheep.

Countermeasures and Recommendations for High Quality Development of Tan Sheep Industry in Ningxia

Tan sheep industry is a characteristic and superior agricultural industry in Ningxia,and it is also an enriching industry that helps in poverty alleviation and increases farmers’income.The local government has been committing to building the"Yanchi Tan Sheep"brand and has made remarkable achievements.In order to explore the resource efficiency and quality of Tan sheep industry,the current situations and advantages of brand development,this paper made an empirical research through field investigations.The research was mainly concentrated on breeding scale,industrial integration,brand building,breeding benefits,and policy support.After a comprehensive evaluation,it came up with the recommendation that the Tan sheep industry should take the high-quality,high-end and green development road.

Expression of Hoxc13 Gene in Skin Tissue of Tan Sheep at Different Stages

[Objectives]The expression differences of Hoxc13 gene in the skin tissue of Tan sheep at different stages were analyzed. [Methods] qRT-PCR was used to analyze the mRNA expression level of Hoxc13 gene in the skin tissue of Tan sheep at different stages(35, 55 d), and the relative quantitative method was used to analyze the expression level. [Results] The content of Hoxc13 gene in the skin tissue of Tan sheep at 55 d was significantly higher than that in the skin tissue at 35 d. Hoxc13 gene was differentially expressed in the skin tissue of Tan sheep lambs at different stages(35, 55 d). [Conclusions] This study provides basic data for further exploration of the growth and development mechanism of Tan sheep.

Effect of Wolfberry Polysaccharide Additive Premixed Feed on Fattening Effect of Tan Sheep

[Objectives]This study was conducted to explore and rationally use the effective value and nutritional components of wolfberry polysaccharide to provide a basis for the use of new feed resources.[Methods]The premixed feed prepared with the wolfberry polysaccharide additive was applied to fattening Tan sheep in Ningxia,and the effect of the wolfberry polysaccharide additive on the fattening Tan sheep was analyzed,so as to provide technical support for the rational utilization of the wolfberry polysaccharide resources.The study adopted a single-factor comparison method,selecting 84 tan sheep in the fattening period with conform gender,feeding management,weight,age,and physiological status,which were divided into 2 test groups and 1 control group,28 in each group.[Results]Within 90 d,the weight gain of the group with 0.1%wolfberry polysaccharide additive increased by 6.98%,showing a significant difference(P<0.05),and the feed conversion ratio decreased by 9.66%,which was significant as well(P<0.05).The gross profit of this group was 125.76 yuan,which was higher than the control group by 57.52 yuan.The group with 0.2%wolfberry polysaccharide additive increased the weight gain by 8.63%,which was significant(P<0.05),and the feed conversion ratio decreased by 10.80%,which was significant as well(P<0.05).The gross profit of group 2 was 125.76 yuan,which was higher than the control group by 63.41 yuan.There were no significant differences in weight gain,feed conversion ratio and gross profit between the groups with 0.1%and 0.2%of wolfberry polysaccharide additive.The results showed that the use of wolfberry polysaccharide additive premixed feed has a positive effect on increasing the weight gain of fattening Tan sheep,reducing the feed conversion ratio,and improving the feed conversion efficiency.The addition of 0.1%and 0.2%of the wolfberry polysaccharide additive premixed feed had no significant differences.[Conclusions]The wolfberry polysaccharide additive has a positive effect on increasing the weight gain of fattening Tan sheep,reducing the feed conversion ratio,and improving the feed conversion efficiency.

PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡的影响

以滩羊后腿肉为研究对象,采用10μmol/L磷脂酰肌醇3激酶(phosphoinositide 3-kinase,PI3K)抑制剂LY294002溶液对滩羊肉进行注射处理,4℃条件下分别贮藏0、2、4、6、8 d,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白质免疫印迹分析PI3K、蛋白激酶B(protein kinase B,AKT)蛋白的表达情况,以此验证PI3K/AKT信号通路抑制的有效性,同时分析滩羊肉贮藏期间能量因子、氧化应激水平、线粒体损伤程度以及胱天蛋白酶(cysteine aspastic acid-specific protease,Caspase)-3活性的变化,以探索PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡途径的诱导机制。结果表明,PI3K和AKT蛋白表达量均减少,验证了PI3K/AKT信号通路被抑制的有效性。与对照组相比,LY294002处理组线粒体ATP、糖原含量、琥珀酸脱氢酶和柠檬酸合成酶活性显著下降(P<0.05);线粒体活性氧(reactive oxygen species,ROS)逐渐增多,氧化应激水平和线粒体膜通透性转换孔(mitochondrial permeability transition pore,MPTP)开放程度增加;膜电位显著下降(P<0.05);凋亡因子Caspase-3活性显著升高(P<0.05),表明PI3K/AKT信号通路通过促进ROS产生并与PI3K相互作用,介导了下游Caspase-3的活化,使线粒体结构与功能受损,导致MPTP开放、膜电位降低,进而诱发细胞凋亡。

饲养方式对滩羊肌内脂肪沉积影响及相关基因表达差异研究

本试验基于转录组学技术探讨舍饲与放牧条件下,滩羊脂肪沉积的差异及相关表达基因的筛选及分析。试验采用随机区组的试验设计方法,将体况相近的12只4月龄滩羊羯羊随机分为2组,每组6只,分别采用放牧和舍饲的饲养模式。于6月龄屠宰取背最长肌与股二头肌。试验结果表明:舍饲滩羊背最长肌肌内脂肪(IMF)含量显著高于放牧组(P <0.05),放牧组滩羊背最长肌IMF含量为(1.4567±0.0987)%,舍饲组滩羊背最长肌IMF含量为(2.0700±0.1493)%。股二头肌IMF含量舍饲组较放牧组高,但差异不显著。与舍饲组滩羊相比,放牧组滩羊背最长肌与股二头肌饱和脂肪酸含量均低,其中背最长肌己酸(C6:0)、癸酸(C10:0)、肉豆蔻酸(C14:0)、十五烷酸(C15:0)、棕榈油酸(C16:1)、十七烷酸(C17:0)、十七碳烯酸(C17:1)、硬脂酸(C18:0)含量显著低于舍饲组(P <0.05),股二头肌十五烷酸(C15:0)、棕榈油酸(C16:1)、十七烷酸(C17:0)显著低于舍饲组(P <0.05),碳原子数≥18的长链脂肪酸和不饱和脂肪酸含量以放牧组滩羊较高,其中背最长肌二十一烷酸(C21:0)和股二头肌十七碳烯酸(C17:1)含量显著低于舍饲组(P <0.05)。基于转录组学分析得知,与舍饲组相比,放牧组滩羊背最长肌脂肪代谢基因表达量显著下调的有酰基辅酶A硫酯酶7(ACOT7)、脂肪细胞分化转录因子(ADIG)与酰基辅酶A氧化酶2(ACOX2)(P <0.05),显著上调的有溶质载体家族7成员8(SLC7A8)、游离脂肪酸受体4(FFAR4)与胰岛素样生长因子2(IGF2)(P <0.05)。放牧组滩羊股二头肌脂肪代谢基因表达显著下调的有ACOT7、ADIG、脂肪酸结合蛋白4(FABP4)与脂肪酶A(LIPA)(P<0.05),显著上调的有花生四烯酸15-脂加氧酶(ALOX15)与二酰基甘油O-酰基转移酶2(DGAT2)(P <0.05)。

纳米硒对滩羊生长性能、血液生化及代谢组的影响

本试验旨在探究不同添加水平的纳米硒对滩羊生长性能、血液生化、抗氧化及代谢组的影响。选取3月龄健康育肥公滩羊60只,按体重相近原则随机分为4组,每组15只,每组3个重复,每个重复5只羊:CON组(含硒0.02 mg·kg^(-1) DM,对照组)饲喂基础日粮,Ⅰ、Ⅱ和Ⅲ组(试验组)滩羊在饲喂基础日粮基础上分别添加0.1、0.3和0.5 mg·kg^(-1)纳米硒。预试期10 d,正试期90 d。结果表明:1)滩羊生长性能组间无显著差异(P>0.05)。2)Ⅰ组滩羊的经济效益(190.52元)高于其他组(187.85、174.92、131.01元)。3)试验组滩羊的血清丙氨酸氨基转移酶活性和尿素含量分别为13.75、13.25 U·L^(-1);8.26、8.11、7.52 mmol·L^(-1);显著低于CON组(23.00 U·L^(-1)、10.19 mmol·L^(-1);P<0.05)。4)Ⅲ组滩羊的血清碱性磷酸酶活性(494.75 U·L^(-1))显著高于其他组(262.75、228.00、250.50 U·L^(-1);P<0.05)。5)Ⅱ组血清球蛋白含量、总抗氧化能力和谷胱甘肽过氧化物酶活性(42.48 g·L^(-1)、9.91 U·m^(-1)、183.93 U·m^(-1))显著高于对照组(34.13 g·L^(-1)、4.93 U·m^(-1)、89.53 U·m^(-1);P<0.05)。6)通过血液代谢组学分析共筛选出21种差异显著代谢产物,主要富集的代谢通路有泛酸和辅酶A生物合成、碳水化合物消化和吸收、维生素消化和吸收等。综上所述,饲粮中添加纳米硒可改善滩羊的机体健康状况,提高抗氧化能力,这可能与代谢通路调控有关;本试验中,滩羊饲料纳米硒最适添加量为0.3 mg·kg^(-1)。

宰后贮藏期间氧化磷酸化调控滩羊肉色泽稳定性的机制

为阐明滩羊肉贮藏期间氧化磷酸化(oxidative phosphorylation,OXPHOS)调控色泽稳定性的机制,以6月龄滩羊背最长肌为研究对象,测定其4℃贮藏0、4、8 d时内源抗氧化物酶体系活性与活性氧(reactive oxygen species,ROS)的含量;采用基于同位素标记相对和绝对定量(isobaric tags for relative andabsolutequantitation,iTRAQ)技术的蛋白质组学研究不同贮藏时间滩羊肉中蛋白质表达情况。结果表明:贮藏0~8 d,内源抗氧化物酶系活性整体呈下降趋势(P<0.05);ROS含量随贮藏时间的延长显著上升(P<0.05);采用iTRAQ技术分析鉴定出8个差异蛋白质为影响滩羊肉色泽稳定性的核心蛋白质,分别为ATP合酶亚基α(ATP synthase F1 subunit alpha,ATP5A1)、ATP合酶亚基O(ATP synthase peripheral stalk subunit OSCP,ATP5O)、ATP合酶亚基D(ATP synthase peripheral stalk subunit D,ATP5H)、细胞色素c氧化酶亚基(cytochrome c oxidase subunit,COX)2、COX5A、琥珀酸脱氢酶复合铁硫亚基B(succinate dehydrogenase complex iron sulfur subunit B,SDHB)、ADP/ATP转位酶(ADP/ATP translocase 1,SLC25A4)和细胞色素c(cytochrome c,CYCS),这些蛋白质主要通过能量代谢过程和氧化还原过程影响滩羊肉色泽稳定性。以上结果表明宰后贮藏期间滩羊肉中抗氧化体系的失效导致ROS含量不断积累,造成肌细胞线粒体完整性受到破坏,促使OXPHOS通路上ATP5A1、ATP5O、ATP5H、COX2、COX5A、SDHB、SLC25A4和CYCS等复合物亚基表达紊乱,引起线粒体复合物结构和功能发生改变,使OXPHOS进程受到阻碍,最终影响滩羊肉色泽稳定性。

滩羊产后血液生化与抗氧化指标变化规律研究

试验通过研究某滩羊场滩羊产后血液生化与抗氧化指标的变化规律,评估该场滩羊产后的健康情况。选取10只体况健康且体重及预产期一致的滩羊,跟踪采集母羊产后0、7、14、21 d的血液,测定血液生化和抗氧化指标。结果显示:滩羊产后0 d血液总蛋白(TP)、球蛋白(GLB)、钙(Ca)、磷(P)、镁(Mg)、游离脂肪酸(NEFA)含量显著低于其他时期(P<0.05),胰岛素(INS)和胰岛素样生长因子-1(IGF-1)含量显著高于其他时期(P<0.05)。滩羊产后14、21 d血液尿素(UREA)含量、总抗氧化能力(T-AOC)显著低于其他时期(P<0.05)。滩羊产后21 d血液瘦素(LEP)含量、超氧化物歧化酶(SOD)活性显著低于其他时期(P<0.05),丙二醛(MDA)含量显著高于其他时期(P<0.05)。研究表明,滩羊产后7 d血液NEFA含量升高,滩羊处于能量负平衡状态,抗氧化水平下降。

宰后贮藏期间滩羊肉线粒体氧化磷酸化与色泽稳定性的关系

为阐明滩羊肉贮藏期间氧化磷酸化与色泽稳定性的关系,以6月龄滩羊背最长肌(longissimus dorsi)为研究对象,测定其4℃贮藏0、1、2、3、4、6、8 d时色泽稳定性与氧化磷酸化各指标的变化。主要研究结果如下:贮藏0~8 d,L^(*)、a^(*)、b^(*)值均呈先上升后下降趋势(P<0.05);R_(630)/R_(580)先上升后下降(P<0.05);高铁肌红蛋白(metmyoglobin,MetMb)相对含量呈下降后上升趋势(P<0.05);氧合肌红蛋白相对含量先上升后下降(P<0.05);脱氧肌红蛋白相对含量变化整体呈下降趋势(P<0.05);线粒体膜通透性显著增大(P<0.05);线粒体膜电位显著降低(P<0.05);线粒体复合物Ⅰ、Ⅱ、Ⅲ、Ⅳ活性显著下降(P<0.05),复合物V活性显著升高(P<0.05);活性氧水平显著上升(P<0.05);超氧化物歧化酶、谷胱甘肽过氧化物酶活性显著下降(P<0.05);过氧化氢酶活性呈先上升后下降趋势(P<0.05);ATP、ADP、AMP含量显著下降(P<0.05)。各肌红蛋白衍生态相对含量、肉色指标与氧化磷酸化各指标互有显著相关性。以上结果表明,宰后贮藏期间滩羊肉中内源抗氧化酶系的失效导致肌细胞内产生过多的活性氧,致使线粒体完整性受到破坏,对线粒体氧化磷酸化相关酶活性产生影响,进而影响肌细胞中高铁肌红蛋白还原酶系统的活力,致使Met Mb无法被还原,最终导致滩羊肉色泽稳定性变差。