海南坡鹿迁地保护现状与建议

迁地保护的海南坡鹿种群可以分为野放、半野放和圈养等3种主要类型。野放种群个体数量最多，约占迁地保护种群个体总数的55．3％；其次为半野放种群，其个体数量占35．6％；圈养种群个体数量最少，只占9．1％。半野放是一种较为稳妥的坡鹿种群恢复方式。在海南坡鹿的迁地保护中，应该增加半野放种群个体数量。本文就海南坡鹿的迁地保护提出了7点保护管理及科学研究建议。     

不同茶叶中游离氨基酸的对映异构体

[目的]游离氨基酸是茶叶的主要化学成分之一,与茶叶的滋味品质密切相关.大多数氨基酸具有手性中心,因此存在滋味特性及生理活性均可能截然不同的L型和D型两种对映异构体.由于检测技术的限制,过去的研究多集中在L型氨基酸上,而茶叶中D型氨基酸罕有系统的研究报道.因此,研究茶叶中游离氨基酸对映异构体,对茶叶化学理论体系的深化及滋...     

热处理浸渍杨木性能研究

【目的】探究不同固化温度对浸渍杨木力学性能、物理性能和甲醛释放量的影响,为浸渍木的加工与应用提供实践指导和理论依据。【方法】以毛白杨锯材径切板为试材,以不进行任何处理锯材为素材,以常压过热蒸汽为介质,选择120,140,160,180℃的固化温度对脲醛树脂浸渍杨木(浸渍材)进行树脂固化处理。【结果】经过高温固化处理的浸渍杨木力学性能相对于素材有所升高,相对于未经高温固化浸渍材有所降低。与素材相比,浸渍材和120,140,160,180℃固化浸渍材的抗弯强度(MOR)分别升高了49.60%,45.21%,43.40%,37.70,24.95%;弹性模量(MOE)分别升高了107.39%,106.83%,92.40%,85.20%,57.35%;硬度值分别升高了65.71%,59.41%,56.06%,50.98%,44.46%;冲击韧性分别降低了7.03%,10.77%,14.73%,16.40%,21.54%。素材、浸渍材以及120,140,160,180℃固化材的阻湿率分别为0,20.0%,26.0%,29.4%,30.0%,33.3%。随着固化温度的升高,固化浸渍材阻湿率升高,尺寸稳定性提高。未经高温固化浸渍材的甲醛释放量为1.66mg/L,120,140,160,180℃固化浸渍材的甲醛释放量分别为1.09,0.91,0.25,0.16mg/L,经过高温固化处理后浸渍材的甲醛释放量明显降低。【结论】热处理对浸渍木物量力学性能及甲醛释放量有明显影响,建议生产中选用160℃作为脲醛树脂浸渍杨木的固化温度。     

三聚氰胺脲醛树脂改性酚醛树脂胶粘剂的研究

采用常规合成的脲醛(UF)或酚醛(PF)树脂胶对多层胶合板贴面时，很容易出现开胶或透胶现象。本研究采用三聚氰胺脲醛(MUF)树脂对PF树脂进行改性，生产浅色改性PF胶粘剂，探讨了MUF与PF树脂摩尔比、混合比、热压条件等对胶液的粘度、缩合度、稳定性、胶层颜色及胶合质量的影响。结果表明，改性后的浅色酚醛树脂胶粘剂筘存性好、固化后胶层近似木材本色、高强耐水、耐候，用来压制的多层实木复合地板可达到GB9846．1～12-88Ⅰ类胶合板要求。     

盐水鸭加工过程中滋味成分变化研究

该文采用高效液相色谱和氨基酸自动分析仪研究了盐水鸭加工过程中的滋味成分变化.盐水鸭加工过程中大部分小肽含量具有减少的趋势.在煮制前的加工中,游离氨基酸含量增加而风味核苷酸含量减少,煮制过程中两者的含量均显著减少.干腌后鸭肉含盐量最高,但经其后工序加工后含量降为适宜食用的3%左右.重要的滋味成分盐水鸭含量均高于对照鸭肉.风味核苷酸和鲜味氨基酸对盐水鸭的滋味具有重要贡献.盐水鸭加工过程中复卤工艺对鸭肉滋味成分作用显著,是构成盐水鸭美味的原因之一.     

不同产地棉籽粕营养成分、代谢能及氨基酸利用率的研究

棉籽粕(cottonseed meal, CSM)是棉籽榨油后产生的副产物,其粗蛋白质含量高,氨基酸种类丰富,是一种潜在的优质蛋白饲料原料。但棉籽粕因游离棉酚等抗营养因子的存在限制了其在畜禽生产中的应用。本文综述了棉籽粕的营养特点、棉籽粕脱毒的常用方法及脱毒棉籽粕在家禽中的应用情况,以期为棉籽粕在家禽生产上的合理应用提供参考。     

Purification and Characterization of an Antioxidant Protein from Pearl Oyster (Pinctada fucata martensii)

Protein from pearl oyster (Pinctada fucata martensii) was purified and characterized. Results showed that the pearl muscle protein (PMP) was composed of a single polypeptide with a molecular weight of approximate 11.6 kDa and contained 95.1% of the protein and 4.92% of the carbohydrate of the oyster. The polypeptide appears to be a glycoprotein, since the Fourier transform infrared (FTIR) spectroscopy of the PMP shows the typical characteristics of protein and polysaccharides. The denaturation temperature of the PMP was 81.3°C by differential scanning calorimetry. Circular dichroism spectroscopy showed that the PMP has a highly ordered structure. The PMP (200 μg/mL) showed a high oxygen radical absorbance activity (ORAC) of 6.57 μmol Trolox/μmol protein. Its antioxidant activity was stable at temperatures from 30–80°C and pH 2–10. The antioxidant activity was significantly inhibited by Zn²⁺, Ca²⁺, and EDTA and enhanced by Mn²⁺. The results suggest that the PMP could be used as a potential natural antioxidant.     

Dietary α‐Ketoglutarate supplementation alleviates harmful effects of high environmental ammonia on grass carp,Ctenopharyngodon idella

Current intensive fish farming usually causes high environmental ammonia (HEA) in ponds that is toxic to fish. α‐Ketoglutarate (α‐KG) can be rapidly transaminated to glutamic acid and further aminated to glutamine. Therefore, we hypothesized that dietary α‐KG supplementation would alleviate HEA toxicity to fish. To test the hypothesis, 270 healthy grass carp (Ctenopharyngodon idella) juveniles were randomly assigned to control, HEA (18.37 mg/L ammonia) and HEA + α‐KG (0.75% of α‐KG) groups. Ammonia and free amino acid content in plasma and brain, liver glutamic pyruvic transaminase and glutamic oxaloacetic transaminase activity, and urea and glycogen content were measured on the first, seventh and 42nd days. Our results showed short‐term HEA exposure (1 day) led to a significant ammonia accumulation in the brain and plasma and significantly decreased glutamic and aspartic acid content in the brain and increased glutamine content in the brain and plasma. The long‐term HEA exposure (42 days) caused significant reductions in glycine and arginine content in the brain tissue. In most cases, dietary α‐KG supplementation alleviated the fluctuations in FAA content in the brain and plasma. Our results suggested dietary α‐KG alleviated HEA toxicity to grass carp.     

Evaluation of fish-meal free diets for rainbow trout, Oncorhynchus mykiss

Eight experimental diets were formulated for rainbow trout using agricultural byproducts as major ingredients. Each experimental diet contained varying amounts of corn grain, corn gluten meal, corn gluten feed and one of the following: 200 g kg^?1 peanut meal, 200 or 400 g kg^?1 soybean meal (SBM), 390 g kg^?1 low-allergen soy flour, 310 g kg^?1 soy protein concentrate, 300 g kg^?1 low-allergen soy protein concentrate or 200 g kg^?1 SBM + 110 g kg^?1 blood meal. One diet contained 200 g kg^?1 SBM and canola oil as the main lipid source. The remaining diets contained 95 g kg^?1 menhaden oil. Fish fed a commercial trout diet exhibited significantly greater weight gain (322%), and a lower feed conversion ratio (0.89) but significantly lower protein efficiency ratio (2.18) than fish fed the experimental diets. Within the experimental diets, fish fed the 400 g kg^?1 soy flour diet and the 400 g kg^?1 soybean meal diet had significantly higher weight gains (276% and 268%) and protein efficiency ratios (2.58 and 2.52), and lower feed conversion ratios (1.02 and 1.03) than fish fed other experimental diets. Fillet flavour varied between treatments. Most notable was the lower fishy flavour and higher chicken flavour of fish fed the diet that contained canola oil rather than menhaden oil. Microscopic evaluation of the liver and five sections of the gastrointestinal tract failed to demonstrate any differences between treatment groups. The ingredient costs of several experimental diets were lower than the estimated cost of a standard commercial trout diet. However, the superior feed conversion ratios of fish fed the control diet resulted in lower feed costs per unit of fish produced.     

5种常用渔药对点篮子鱼幼鱼急性毒性试验

在水温29.2～30.4℃、盐度30～32条件下,进行了敌百虫、甲醛、聚维酮碘、硫酸锌、硫酸铜与硫酸亚铁(5∶2)合剂5种常用渔药对点篮子鱼(Siganus guttatus)幼鱼急性毒性试验。结果显示:5种药物的安全浓度分别为0.91、54.99、17.10、23.88、1.77 mg.L-1。点篮子鱼对5种药物敏感度的大小顺序为:敌百虫>硫酸铜与硫酸亚铁合剂>聚维酮碘>硫酸锌>甲醛。