羊脂肪关键香气成分分析

采用溶剂辅助蒸发装置分离并结合气相色谱-质谱及气相色谱-嗅闻分析加热后羊脂肪的关键香气成分。结果表明:根据谱库检索、保留指数、标准品比对气相色谱-质谱鉴定出58种化合物,其中含量较高的化合物(>3μg/kg)为2,3-丁二醇、乙酸、乙偶姻、丙酸、己酸、2-己醇等。采用稀释法/气相色谱-嗅闻分析检测到37个气味活性区域,根据谱库检索、保留指数、气味特征和标准品比对,鉴定出37种气味活性成分,其中风味稀释(flavor dilution,FD)因子较大(log2FD≥4)的化合物有(E,E)-2,4-庚二烯醛、(E)-2-壬烯醛、(E,E)-2,4-辛二烯醛、(E)-2-癸烯醛、(E,Z)-2,4-癸二烯醛、(E,E)-2,4-癸二烯醛、2-庚醇、三甲基吡嗪、4-甲基噻唑、3-甲硫基丙醛、5-甲基-二氢-2(3H)-呋喃酮、4-乙基苯酚,这些化合物是羊脂肪香气的关键成分。研究结果可为羊脂肪的开发利用及羊肉香精的研制提供一定参考。

哈萨克医习用动物药材羊脂的药理作用

哈萨克族医药历史悠久，药用资源丰富，方法简单易行，疗效确切，具有鲜明的民族特色和学术价值。羊脂是哈萨克民族最常用绿色天然药材和药物基质以及饮食保健品。哈萨克医学中羊脂肪组织或羊脂具有滋润内外“哈普铁克”作用。外可使皮肤防寒、防风、防湿，内可滋补脏器等。现代医学认为羊脂具有维持、调节、保护人体的十大生理平衡的突出作用，属于哈萨克传统医学中常用的重要滋补、抗风湿、止咳、润滑、攻毒、提高免疫的常用动物药之一。

Developmental Changes of the FAS and HSL mRNA Expression and Their Effects on the Content of Intramuscular Fat in Kazak and Xinjiang Sheep

Twenty-four male Kazak sheep and 30 Xinjiang fine wool sheep at different ages were selected to investigate the development-dependent expression levels of fatty acid synthase （FAS） gene and hormone-sensitive lipase （HSL） gene in muscle and their effects on the contents of intramuscular fat （IMF）. Longissimus dorsal muscle was sampled to measure IMF and total RNA was extracted to determine FAS and HSL mRNA expression levels by real-time PCR. The results showed that： l） The IMF content increased continuously with growth and showed significant differences （P 〈 0.05） between different age groups in male Kazak sheep, but in Xinjiang fine wool sheep there was no such difference observed. Furthermore, the IMF contents in Kazak were much higher （P 〈 0.01） than that of the other breed from day 30 to 90. 2） FAS mRNA expression level was the highest （P 〈 0.05） on day 0 in Kazak sheep and then declined with growth, in the other breed the gene showed a d‘ecline-rise-decline-rise＇ expression manner as the animals grew. HSL mRNA expression level had a similar model in two breeds, in Kazak sheep it was the highest on day 0 （P 〈 0.05） and in Xinjiang fine wool sheep on day 30 （P 〈 0.01）, then both decreased after this term. 3） In male Kazak sheep, FAS and HSL mRNA expression level were both negatively related to IMF content （r= -0.485 （P = 0.02）, r= -0.423 （P = 0.05））, and the ratio of FAS/HSL expression exhibited significantly negatively related IMF contents. In male Xinjiang sheep, there were no obvious relationship between FAS and HSL expression and IMF content （P 〉 0.05）.

Growth Performance and Carcass Traites of F1 Crossbreds from Afshari x Zandi and Fashandi x Zandi Sheep under Feedlot Condition

In order to evaluate the effect of crossbreeding on growth performance and carcass traits, Afshari and Fashandi rams crossed with Zandi ewes. 45 Afshari x Zandi and 30 Fashandi x Zandi lambs recorded in a period of 100 days feedlot. Daily weight gain and dry matter intake significantly affected by crossbreeding which were the highest in Afshari x Zandi group （0.180 ± 0.004 and 1.415 ±0.025, respectively）, but it had no effect on feed conversion ratio. The genetic group affected final feedlot weight, empty body weight, warm carcass weight and carcass efficiency which Afshari ± Zandi group had higher amounts （44.70 ± 1.25 kg, 38.85 1.05 kg, 22.63 ± 0.95 kg and 58.63 ±0.77%, respectively）. The breed of ram lambs had no significant effect on the percentage of thigh, loin, shoulder＇, brisket, fat tail, tallow and total removal fat; however the percentage of thigh was different between two crossbred groups. Lean and fat percentage was higher in Fashandi x Zandi crosses.

Effect of Different Levels of Flax Seed Powder as a Source of Omega-3 on the Carcass Characteristics of Karadi Lambs

This experiment was conducted at College of Agriculture, University of Sulaimany to study the effect of different levels of Flax seed powder （FP） as a source of omega-3 on the carcass characteristics of Karadi Iambs. It used 20 male Karadi lambs, with an average live-weight of 28 ± 0.398 kg and 4-5 months. They were randomly distributed to 4 treatments. FP was supplemented at the levels of 3%, 6% and 9% compared with the control group for 88 days. At the end of the experiment 12 lambs were slaughtered after overnight fasting of feed. Carcasses were chilled for 24 h at 4 ℃. Then, several measurements of carcass characteristics were taken. The results showed： no significant differences have been shown in relation to daily feed intake, live weight gain and feed conversion ratio. The treatment 9% recorded the highest in hot carcass weight （HCW） and cold carcass weight （CCW）, rib eye area （REA） and the lowest fat thickness of subcutaneous fat as compared to other treatments. While, no significant differences in dressing percentage （DP） were seen between treatments. Generally percentage of tail fat related to carcass weight and subcutaneous fat to intermuscular fat ratio decreased with FP supplementation. About carcass cuts, significant （P 〈 0.05） differences were seen in percentage of major carcass cuts （leg, rack, loin and shoulder） and secondary cuts （neck, foreshank, flank and breast cuts） relative to cold carcass weight. It can be concluded that using Flax seed powder （FP） as a source of omega-3 supplementation improved carcass characteristics and efficiency of meat production.

The Influence of Forage/Concentrate Ratio and Full Fat Soya By-Pass Supplementation on the Fatty Acids Profile from the Carcase of Fatting Lambs

There was organized a 2×2 factorial type experience in which it has been aimed the influence of forage/concentrates ratio and the effect of supplementing the ratio with full fat soya by-pass （FFS） on the production performance and carcass fatty acid profile of fattening lambs. 32 Tsigai lambs were divided into 4 groups and were fed with 2 different diets regarding the forage/concentrates ratio （35/65 and 65/35, on a DM basis）, containing or not 5% FFS （full fat soya treated with formaldehyde 12.5%）. Including FFS in diet and the ratios rich in concentrates determined a significant improvement in weight gain （P〈0.01）, in the degree of food recovery and in fatty acid profile from the carcass. It has been significantly increased （P〈0.01） the weight of polyunsaturated fatty acids （PUFA） from intramuscular fat （longissimus dorsi-LD and femoral biceps-FB） and the deposit fat （subcutaneous-SC and perirenal-PR） and decreased the proportion of saturated （SFA） and monounsaturated fatty acids （MUFA）. Most significant differences were recorded about PUFA from Omega-3 series （C18：3 n-3, EPA C22：3 n-3, DPA and DHA） and CLA isomers （conjugated linolenic acid： C 18：2 C9, tl I＋C 18：2 t10, C 12）. The best profile of fatty acids, considered in light of the influence on human health （high concentration of Omega 3 fatty acids and CLA and low in SFA） was established in LD, for lambs fed with diets high in concentrates and which contained FFS （HC/S）.

Effect of Various Sources of Fat Ingredients on the Properties of Goat Milk Ice Cream

Goat milk ice cream was made with various sources of fat ingredients such as cream, soybean oil, rice bran oil and butter with the purpose of seeking the fat ingredient source instead of fat source from cow origin. The physical properties and the sensory evaluation of ice cream were then investigated. The firmness of goat milk ice cream mixed with rice bran oil, butter and cream were not significantly different before aging at 4 ℃ for 8 h. All of them gave the overrun between 51%-63% and the one with butter was the highest. The meltdown rate of all types of fat ingredients are not significantly different, being in the range of 0.86-0.88 g/min. According to sensory evaluation, the cow milk ice cream with cream was mostly accepted in all attributes such as appearance, smoothness, whiteness, melting in mouth and odor while the goat milk with cream and butter are the second and third. Nevertheless, the goat milk ice cream with soybean oil and rice bran oil were moderately accepted in overall preferences.