Physicochemical and Antioxidant Properties of Gelatin and Gelatin Hydrolysates Obtained from Extrusion-Pretreated Fish (Oreochromis sp.) Scales

Fish gelatin and its hydrolysates exhibit a variety of biological characteristics, which include antihypertensive and antioxidant properties. In this study, fish gelatins were extracted from extrusion-pretreated tilapia scales, and then subjected to analyses to determine the physicochemical properties and antioxidant activity of the extracted gelatins. Our findings indicate that TSG2 (preconditioned with 1.26% citric acid) possessed the greatest extraction yield, as well as higher antioxidant activities compared with the other extracted gelatins. Hence, TSG2 was subjected to further hydrolyzation using different proteases and ultrafiltration conditions, which yielded four gelatin hydrolysates: TSGH1, TSGH2, TSGH3, and TSGH4. The results showed that TSGH4 (Pepsin + Pancreatin and ultrafiltration < 3000 Da) had a higher yield and greater antioxidant activity in comparison with the other gelatin hydrolysates. As such, TSGH4 was subjected to further fractionation using a Superdex peptide column and two-stage reverse-phase column HPLC chromatography, yielding a subfraction TSGH4-6-2-b, which possessed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity compared with the other fractions. Further LC-ESI/MS/MS analysis of TSGH4-6-2-b suggested two novel peptides (GYDEY and EPGKSGEQGAPGEAGAP), which could have potential as naturally-occurring peptides with antioxidant properties. These promising results suggest that these antioxidant peptides could have applications in food products, nutraceuticals, and cosmetics.     

汝城白毛茶对中老年人高脂血症的降脂作用

汝城白毛茶是一个由野生毛叶茶（Ｃａｍｅｌｉａｐｔｉｌｏｐｈｙｌａ）驯化栽培后开发的新绿茶产品。用该茶对６４例高脂血中老年患者的临床试验结果表明，虽然汝城白毛茶和普通绿茶（对照）均有良好的降脂效果，它们在血清胆固醇、甘油三酯、乳糜微粒和β－脂蛋白４个指标上的效果差异甚至达到极显著水平，但前者比后者效果更好、更快，两种茶的效果差异达极显著水平。汝城白毛茶的降脂作用不受年龄、性别的影响，也无明显副作用，但停饮后与其他降脂药物一样，其降脂作用消失。本试验提示，供试的两种绿茶对减肥均无效。     

QTL Analysis for Traits Associated with Feeding Value of Straw in Rice(Oryza sativa L.)

Genetic improvement of the digestibility of rice strew for increasing the utilization of the whole rice plant as feedstuffs is an important way to solve the feedstuffs shortage in southeastem China. To elucidate the genetic basis of the traits affecting the digestibility of rice straw, a rice population of 111 recombinant inbred lines (RILs) derived from a cross of Nekken 2xGaya was used to map the quantitative traits loci (QTLs) for in vitro dry matter digestion (IVDMD), the percentages of nonstructurel carbohydrate (NSC) and acid detergent fiber (exclusive of residual ash, ADFom) in 2005 and 2006. IVDMD was positively correlated with NSC, and negatively correlated with ADFom. A total of 16 QTLs were detected in the two years, and the amounts of variation explained by individual QTLs ranged from 6.9% to 15.5%. Some QTLs for IVDMD and ADFom on chromosome 2 were detected in the two years. On chromosome 2, the interval RM475-RM3515 contained QTLs for IVDMD in the two years and for NSC in 2006 only, while the interval RM3874-RM5305 influenced ADFom in the two years and NSC in 2005 only. At those loci, Gaya contributed favorable alleles to IVDMD and NSC, while Nekken 2 contributed positive alleles to ADFom.     

微波消解-原子荧光光谱法快速测定食品中汞和砷的方法研究

建立了一种采用微波消解一次样品前处理、原子荧光法依次快速测定食品中汞和砷的方法。通过条件优化,该方法汞和砷的检出限分别为0.023μg/L、0.119μg/L;试样测定精密度(RSD),汞和砷分别为6.2%、3.3%;加标回收率,汞和砷分别在96.0%~105.0%、95.9%~102.5%。标准物质测定结果符合要求。该法简便、快速、灵敏,能够满足食品的检测要求。     

Associative effects between fresh perennial ryegrass and white clover on dynamics of intake and digestion in sheep

The aim of this study was to determine the associative effects between fresh perennial ryegrass and fresh white clover on intake and digestion in sheep. Five proportions of ryegrass and white clover, ranging from 0 to 1 in 0·25 increments (DM basis), were allocated to two groups of five sheep according to a replicated 5 × 5 Latin square design, and intake behaviour and digestive parameters including methane (CH₄) emissions were measured. Feeding behaviour was affected through increased forage intake when the proportion of white clover was increased, and there were positive associative effects on intake, eating time and eating rate during the main meals consumed immediately after feed was given. These effects seemed to be related to a greater motivation to eat, rather to more efficient digestion, as no difference on DM digestibility (average 766 g kg^?1) was detected. There were no differences in CH₄ yield (average 18·1 g kg^?1 DM intake) among the treatments. The optimal proportion of white clover fed with ryegrass to optimize intake and digestion was between 0·25 and 0·50. These results indicate that mixing perennial ryegrass and white clover positively affects forage intake in sheep and their motivation to eat.     

碱预处理提高香蕉茎秆厌氧消化产气性能的研究

为有效利用香蕉茎秆资源,提高其厌氧消化效率,采用碱法对香蕉茎秆固体剩余物进行预处理,探讨不同预处理条件下香蕉茎秆厌氧消化产气性能的影响。结果表明：当NaOH浓度为8%时,对香蕉茎秆原料半纤维素、纤维素、木质素降解率达最高,分别为22.5%、9.1%、13.7%;6% NaOH处理组30 d累积产气量最高可达3 775 mL,比对照组提高24.2%,单位干物质产气量达377.5 mL/g TS。碱预处理可有效提高香蕉茎秆产气潜力。     

应用灰色系统理论和模糊数学对油用向日葵区试组合的评价分析

运用灰色系统理论和模糊数学对2005年和2006年全国（西北组）油用型向日葵（简称油葵）区试杂交种的亩产量、株高、盘径、茎粗、叶数、百粒重、生育期、籽实含油率、倒折率等9个性状进行了分析和综合评价,结果表明：L405的综合表现最好,其综合评价系数为0．7619;其它依次为其它依次为M0415,L406,澳葵62,M0411,TK5001和G101,综合评价系数分别为0．6353,0．6076,0．4539,0．3732,0．2658,0．2639;白葵杂8号综合表现最差,其综合评价系数仅为0．2184。这一结果与各杂交种在各地的生长情况基本一致。     

合浦珠母贝对不同种类及浓度的单胞藻摄食与消化效果研究

从单胞藻粒径大小、表面结构、生化组成及饵料浓度等角度开展了合浦珠母贝（Pinctada fucata）对不同种类及浓度的单胞藻摄食与消化效果研究。投喂粒径大小相近的牟氏角毛藻（Chaetoceros muelleri）和湛江叉鞭金藻（Dicrateria zhanjiangensis）混合藻,粒径大小不同的亚心形扁藻（Platymonas subcordiformis）和海水小球藻（Marine chlorella）混合藻,用细胞计数法检测剩余混合藻中各单胞藻浓度。分别投喂以上4种不同浓度梯度的单胞藻,观察比较粪便中单胞藻消化状况。结果显示,合浦珠母贝对粒径大小相近的单胞藻没有表现出明显的选择性摄食（P>0.05）,对粒径较大的单胞藻摄食率明显高于粒径较小的单胞藻（P<0.05）;随着投喂单胞藻浓度的升高,合浦珠母贝对单胞藻的消化程度降低。 

     

龙牙檧木新品种引种栽培试验

从韩国引进龙牙檧木新品种进行根段繁殖、区域栽培和反季节栽培试验,结果表明,建国1号、高品芽、紫号、新区4个引进品种的耐寒性差,均不能在延边地区自然越冬;在温室进行反季节栽培,引进品种的嫩芽产值为90.2元.m-2,是国产种源的1.7倍,经济效益显著,是冬季温室水培的优良品种。     

Cottonseed meal protein hydrolysate stimulates feed intake and appetite in Chinese mitten crab,Eriocheir sinensis

One hundred and twenty crabs (initial weight: 51.32 ± 0.06 g) were fed three experimental diets with cottonseed meal protein hydrolysate (CPH) at 0, 6 and 12 g/kg for 60 days. The results showed that CPH0.6 diet significantly improved the 1‐hr feed intake, protease activity and weight gain of crabs. In thoracic ganglia, 4E‐binding protein (4E‐BP) expression level of crab fed the diets containing CPH was significantly higher than CPH0 group. In cerebral ganglia, protein kinase B and 4E‐BP expression levels of crab fed CPH0.6 diets were significantly lower than CPH0 group. In mid‐intestine, target of rapamycin (TOR) relative expression level of crabs fed the diets containing CPH was significantly lower than CPH0 group. 4E‐BP expression level showed an opposite pattern. In thoracic ganglia, cerebral ganglia and mid‐intestine, leptin receptor expression level of crabs fed CPH0.6 diet was significantly lower than CPH0 group. Neuropeptide Y and neuropeptide Y receptor expression level of crab fed CPH0.6 diet was significantly higher than CPH0 group. In conclusion, our results indicated that dietary supplementation of 6 g/kg CPH could stimulate appetite and quicken feeding rate via the TOR signalling pathway.