亲水液相色谱-串联质谱法测定羊肌肉组织中安乃近代谢物的残留量

建立了羊肌肉组织中安乃近4种主要代谢物——4-甲氨基安替比林、4-氨基安替比林、4-甲酰氨基安替比林和4-乙酰氨基安替比林的亲水液相色谱-串联质谱分析方法。肌肉样品均质后,用体积分数为5%的氨水乙腈提取,提取液用Cleanert PSA初步净化,60℃氮气吹干,乙腈复溶后过MAX（SPE）柱净化,采用亲水液相色谱-串联质谱测定,4种物质均采用外标法定量。结果显示：4-甲氨基安替比林、4-甲酰氨基安替比林和4-乙酰氨基安替比林在添加量为4-200μg/kg范围内线性良好;4-氨基安替比林在添加量为40-2000μg/kg范围内线性良好。在5、50、100、1000μg/kg4个添加量,回收率在75.02%-116.2%范围内。日内变异系数为1.63%-15.12%（n=5）,日间变异系数均小于11%（n=15）。4-甲氨基安替比林、4-甲酰氨基安替比林和4-乙酰氨基安替比林的检测限均为0.5μg/kg,4-氨基安替比林的检测限为5μg/kg。该方法灵敏度高、重复性好,适用于羊肌肉组织中安乃近4种主要代谢物的大批量样品检测。

两种胰蛋白酶酶解羊肌肉总蛋白样品的质谱分析

目的比较国产和进口两种胰蛋白酶对蛋白质的酶解效果,为后续蛋白质组学稳定研究提供依据。方法用超声破碎法提取羊肌肉组织总蛋白,经两种胰蛋白酶酶解后液相色谱串联质谱检测酶解肽段,将结果上传蛋白质序列数据库,利用质谱分析鉴定方法分析比较两种胰蛋白酶的酶解效果,并借助生物信息学工具对所得数据进行分析。结果两种胰蛋白酶酶解同种蛋白质样品产生的肽段长度86%以上均为6—18个氨基酸,适用于质谱检测。酶解后肽段产生的质量国产胰蛋白酶优于进口胰蛋白酶,国产胰蛋白酶比进口胰酶酶解可多鉴定到19%的蛋白质和34%的肽段。结论进口、国产的胰蛋白酶在酶解蛋白质方面均可用于质谱检测前蛋白质的酶解消化。但国产胰蛋白酶价格明显低于进口胰酶,更具应用优势。本研究为评价胰蛋白酶酶解效果提供了一种有效、全面的研究方法。

Quantitative Study on Expression of MSTN Gene in Different Tissues of Tibetan Sheep at Different Ages

[Objective] The aim was to investigate the difference in MSTN gene expression in different tissues of Tibetan sheep at different ages.[Method] According to the sequence（NM_001009428.1）published in GenBank,a pair of specific primers was designed to amplify part of cDNA sequence of MSTN by using QRT-PCR technique.The relative expression level of MSTN gene in rennet stomach,rumen,leg muscle and cardiac muscle of Tibetan sheep at different ages were analyzed.[Result] After normalization with β-actin gene,the relative expression level of MSTN gene in the 6-month-old Tibetan sheep was the highest and it was 2.52 times than that in 12-month-old Tibetan sheep（P0.05）,the relative expression level of MSTN gene in leg muscle was the highest among all tissues and it was 3 984.78 times than that in rumen（P0.01）.[Conclusion] The results established theoretical foundation for the correct use of MSTN antibody.

Study on the Developmental Changes of Muscular GHR mRNA Expression in Sheep

[ Objective] The study aimed to explore the expression of muscular growth hormone receptor gene （GHR） in sheep at the early stage of growth and development. [Method] The GHR mRNA expression levels in longissimus dorsal muscles of male Kazak sheep and Xinjiang fine wool sheep with different ages were quantitatively analyzed by real time PCR. [ Result] Sheep GHR mRNA expression level in longissimus dorsal muscle increased firstly followed by decline, and then kept steady until the end of the experiment, with the expression peak appearing on postnatal day 30. The GHR mRNA expression level of Kazak sheep was extremely lower than that of Xingjiang fine wool sheep from 2 to 90 days old （ P 〈0.01 ）. E Conclusionl Both age and breed had great effects on the expression of muscular GHR gene in sheep.

Study on the Muscle Histological Characteristics of Haimen Goats

[Objective] The aim was to study the effect of the muscle histological characteristics of Haimen goats on meat quality.[Method] Twelve-month-old Haimen goats and Bore × Haimen F1（♂）were used as the materials to systematically research the muscle histological properties of different sexes and muscles.[Result] The results revealed that the muscle fiber area and myofibril diameter,sarcomere length,light band length,dark band length,hall band length of quadriceps femoris of Haimen female goats were extremely significantly higher than male goats（P〈0.01）;However,that of longissimus dorsi muscle was extremely significantly lower than male goats（P〈0.01）.There was significant difference（P〈0.05）or extremely significant difference（P〈0.01）between muscle microstructure and ultrastructure among the same sex and different muscles.There were a large number of mitochondria,glycogen granules and fat droplet within muscle fiber from Haimen male goats,which indicated that oxidative metabolism rate was high,water retention was good and the meat was tender,succulent and distinct.[Conclusion] The study provided theoretical basis for breeding,development and utilization of Haimen goats and variety evaluation of local goats in China.

Slaughter Performance, Muscle Quality and Nutritional Components of Twenty-four-month-old Tibetan Goats

[Objective] This study was conducted to understand goat germplasm char- acteristics. [Method] With some 24-month-old males and females Tibet goats as experimental materials, a slaughter experiment was carried out to determine their slaughter performance, muscle quality and muscle nutritional components. [Result] The body weights of males and females before slaughter were （20.16±1.26） and （19.33±4.86） kg, respectively; the dressing percentages of males and females were （43.86±1.74）% and （44.08±5.46）%, respectively; the meat percentages were （32.43± 1.52）% and （32.72±3.97）%, respectively; and the meat production rates of carcass were （73.28±0.09）% and （73.16±0.85）%, respectively. There were less differences in carcass measurements, carcass segmentation, muscle quality, muscle fiber charac- teristics, muscle nutritional components, muscle mineral contents and heavy metal contents between males and females, while eye muscle area and hind leg meat weight of males were significantly higher than those of females. In muscles of males and females, 18 amino acids were detected totally, EAA/TAA values were （39.23±0.24）% and （38.70±0.15）%, respectively, and EAA/NEAA values were （64.73± 0.65）% and （63.17±0.41）%, respectively. [Conclusion] This study lays a foundation for overall understanding of germplasm characteristics of Tibetan goats.

Slaughter Performance, Muscle Quality and Muscle Nutrients of Twelve-month-old Danba Goat

[Objective] The aim was to discuss the resource characteristics of Danba goat. [Method] Three male and three female goats of twelve-month-old Danba goat were selected to slaughter,and their slaughter performance, muscle qulity and mus- cle nutrients were determined. [Result] The pre-slaughter weights, dressing percent- ages, meat percentages and carcass meat production rates of the male and female Danba goats were （25.83±1.04） and （18.50±2.29） kg, （45.18±0.78）% and （38.89± 2.08）%, （33.76±1.4）% and （28.59±1.99）%, and （74.30±0.85）% and （74.08±0.65）%, respectively. The carcass length, carcass hind leg circumstance, carcass hind leg length, lumbar muscle thickness, hind leg meat yield, shoulder muscle yield and breast meat yield of male goats were significantly higher than those of female goats （P〈0.05）, and no significant differenceswere found in other carcass size and carcass segmentation indices between male and female goats （P〉0.05）. There were small differences in muscle fiber properties, muscle quality, muscle nutritional composition, muscle mineral content and muscle heavy metal content between male and female goats （P〈0.05）. A total of 18 kinds of amino acids were detected in the male and female goats. The EAA/TAAs and EANNEAAs of male and female goats were （39.56±0.26）% and （39.48±0.66）%, and （65.45±0.71）% and （65.43±1.80）%, respec- tively. [Conclusion] This study will provide the basis for the understanding of the resource characteristics of Danba goat.

Slaughter Performance, Muscle Quality and Muscle Nutrients of Twelve-month-old Tibetan Goat

This study aimed to study the germplasm characteristics of Tibetan goat distributed in Sichuan. Three male and three female goats of twelve-month-old Ti-betan goat were selected, and they were slaughtered for analysis of slaughter per-formance, muscle quality and muscle nutrients. The results showed that the pre-slaughter body weights, dressing percentages, meat percentages and carcass meat production rates of male and female Tibetan goats were （14.33±1.53） and （12.50±2.18） kg, （42.11±5.26）% and （43.85±4.51）%, （31.34±3.36）% and （32.84±3.16）%, and （72.34±0.54）% and （72.30±0.78）%, respectively. There were smal differences in car-cass size, carcass segmentation, muscle fiber properties, muscle quality, muscle nu-tritional composition, muscle minerals contents and muscle heavy metals contents between male and female Tibetan goats. A total of 18 kinds of amino acids were detected in the muscle of male and female Tibetan goats. The EAA/TAA ratios and EAA/NEAA ratios of male and female Tibetan goats were （39.18＆#177;0.38）%and （38.70±0.72）%, and （64.31±1.03）% and （63.21±1.92）%, respectively.

Developmental Changes of IGF-Ⅰ mRNA Expression Level in Sheep Muscle

[ Objective] To detect the mRNA of muscle insulin-like growth factorl （IGF-I） in the early development of Kazak sheep and Xinjiang fine-wool sheep, so as to provide information for the research about the early growth and development of sheep. [ Method] With real-time quan- titative PCR, the muscle IGF-I mRNA level was separately detected in two varieties of sheep at 2, 30, 60, 90 and 120 days old. Then the data was analyzed with SPSS software. [ Result] The IGF-I mRNA in sheep muscle first increased and then decreased with ages, peaking at 30 days old in Kazak sheep and at 60 days old in Xinjiang fine-wool sheep. The IGF-I expression level of Kazak sheep had no significant difference with Xinjiang fine-wool sheep at 2 or 90 days old （ P 〉0.05）, but was lower than that of the latter with extremely significant difference （ P 〈0.01 ） from 30 to 60 days old. [ Conclusion] The male Kazak sheep and Xinjiang fine-wool sheep have similar model of developmental changes of muscular IGF-I mRNA, but the expression level is different between these two species.