细纹狮子鱼的食性及其食物消耗量初探

根据１９８５－１９８６年黄海生态调查收集的胃含物资料，本文建立了胃含物平均重量与鱼体重、体长的关系：Ｗ＝０．１９９８Ｓ＾０．７６９和Ｗ＝０．０１０５Ｌ＾２．２５３细纹狮子鱼的主要食物为Ｔｉ鱼和脊腹褐虾。食物组成随时间和体长不同而变化。小个体的细纹狮子鱼（〈１５ｃｍ）提食更多虾类和其它甲壳类。细纹狮子鱼的食物个体较小，一般小于１０ｃｍ。食物大小随体长变化不大。胃含物内食物的平均个数随体长增长而增加。     

A test of the individual feeding activity and food size preference in rainbow trout using demand feeders

Feeding activity and food size preferences were investigated in three groups of rainbow trout with initial weights ranging from 200 to 1000 g. Fish were given the option of releasing food from either of two demand feeding devices that contained either 6 mm or 9 mm food pellets. Individual biting activity (to activate release of food) was continuously monitored using specially designed passive integrated transponders (PIT-tags). In each of the groups, biting activity was strongly influenced by three individuals, which accounted for 70–85% of the total. Thus, high bite activity by few individuals indicates the development of social dominance hierarchies. There was no statistically significant correlation between number of bites and growth rate, indicating that the fish that operated the demand feeders did not gain any growth advantage. Trout that dominated the actuation of the feeders were found among both medium- and large-sized fish. There was no evidence of active food size selection, and the fish that most frequently operated the feeders defended one area of the tank rather than preferring the trigger that would have delivered food of the optimal size.     

Behavioral response to selected feed attractants and stimulants in Pacific white shrimp, Litopenaeus vannamei

Nine commercial feeding attractants and stimulants for Litopenaeus vannamei were evaluated by observation of behavioral responses in animals allotted in one Y-maze aquarium apparatus. In the validation phase, fishmeal–Brazilian origin (FMBO); fishmeal–Peruvian origin (FMPO); blood meal (BM), meat and bone meal (MBM), squid meal (SM), fish oil (FO) and fish solubles (FS) were evaluated. There was also a control without stimulatory raw material. The tested materials were included at 3% in neutral gelatin pellets (wet basis). In each behavioral observation, two different ingredients were offered at the same time in equal quantities, being allotted in the end of each chamber's arm. In Phase II after system validation, the following commercial attractants were tested: 80% crude protein (CP) vegetable dried biomass (VDB₈₀), 68% CP vegetable dried biomass + glutamate + betaine (VDB₆₈), complex of amino acids (alanine, valine, glycine, proline, serine, histidine, glutamic acid, tyrosine and betaine) with enzymatically digested bivalve mollusk (CAA), condensed fish soluble protein (CFSP), squid liver meal (SLM), betaine (Bet), dried fish solubles–low biogenic amines (DFS_LB), dried fish solubles–high biogenic amines (DFS_HB) and whole squid protein hydrolysate (WSPH). Attractants were used at a 3% level wet basis with neutral gelatin, without any additional ingredient source available. The best four commercial attractants from this phase (CAA, CFSP, SLM and WSPH) were compared under 0.5% and 1.0% levels. In Phase I of the study, a higher percentage of choices were observed for FMPO and FMBO. BM and FO were the least chosen ingredients. In Phase II, the worst results were observed for Bet, DFS_HB and, mainly, for VDB₈₀ and VDB₆₈. When two-by-two comparisons were performed, results suggested that CFSP and CAA were the best commercial attractants tested. In the last phase, both CFSP and CAA at 1.0% level were significantly more chosen by shrimp than CFSP (0.5%), SLM (0.5 or 1.0%) or WSPH (0.5 or 1.0%). At both 0.5% and 1.0% levels, shrimp spent a similar amount of time feeding on CFSP and CAA. However, only CAA was statistically better than SLM and WSPH together. Further work is required to better elucidate the chemical drivers of chemostimulation for L. vannamei for each one of the attractants tested.     

The effect of dietary protein source on growth and carcass composition in juvenile Australian freshwater crayfish

A feed trial was conducted for 12 weeks on juvenile Australian freshwater crayfish (Cherax destructor) (mean weight (SE) 0.82 (0.02)g) maintained on five isoenergetic diets with a protein content of 30%. Diets differed in the primary source of protein used, with meat, snail, soybean, yabby, and zooplankton meals comprising the major protein ingredient, varying from 56–60% of total protein. Mean percentage weight gain per day ranged from 7.57% (yabby meal diet), to 9.42% (snail meal diet). No significant difference occurred in mean weight, percentage weight gain, specific growth rate (%), or survival among diets. A maximum size of 16.44g was attained on the yabby meal diet. Largest mean weight was 8.27g on the snail-based diet. Food conversion ratios were all good, with a minimum value of 0.95 recorded for the snail-based diet. Initial food consumption per day was approximately 5% of mean animal weight, decreasing to around 2.4%, and is collectively described by a power curve. Protein retention ranged from 29.57% in the zooplankton meal diet to 41.15% in the snail-based diet. Carcass composition was influenced by feed type, with the most marked difference occurring in carapace colour. Animals fed the zooplankton-based pellets developed the strongest pigmentation. Recommendations are made for including certain protein-based ingredients in manufactured yabby diets.     

Quantitative proteomic analysis of wheat grain proteins reveals differential effects of silencing of omega-5 gliadin genes in transgenic lines

Novel wheat lines with altered flour compositions can be used to decipher the roles of specific gluten proteins in flour quality. Grain proteins from transgenic wheat lines in which genes encoding the omega-5 gliadins were silenced by RNA interference (RNAi) were analyzed by quantitative 2-dimensional gel electrophoresis (2-DE). The precise effects of the genetic modifications on the proteome were assessed in four homozygous lines generated with the same RNAi construct. Two of the lines showed >80% decreases in omega-5 gliadins with only small changes in the levels of other gluten proteins. In the other two lines, omega-5 gliadins were not detectable by 2-DE. However, there were notable reductions in all omega-1,2 gliadins. Small decreases in several other gluten proteins were also detected in one of the lines. The other line showed notable decreases in three HMW-GS and an s-type LMW-GS, increases in two m-type LMW-GS and several alpha gliadins, as well as increases in both serpins and triticin. The study demonstrates that the same RNAi construct can have differential effects on the wheat grain proteome and highlights the importance of detailed proteomic analyses of transgenic grain prior to selecting lines for further assessment of flour quality and allergenic potential.     

浅析《食品生物化学》课程教学存在的问题及对策

对石河子大学《食品生物化学》课程教学中存在的问题进行剖析,提出从教学计划修订、教学方法革新和专业素养进行课程改革,以期提高食品生物化学的教学质量。     

“社区支持农业”产销科普一体化模式研究--以广州“神农田园”农场为例

随着社会食品安全问题频发,对安全食品的需求与日俱增,在这种矛盾关系下,＂社区支持农业＂模式应运而生。该文从＂社区支持农业＂的概念及其模式中的产销与安全健康、科教一体化模式进行论述,并进行分析。     

《食品分离技术》课程教学的思考与实践

《食品分离技术》课程是食品质量与安全专业的专业选修课。该文着重对食品工业中的常用现代分离技术进行课堂教学的探索,从优化教学内容的组织、增强自学与课堂讨论的引入以及促进实验技能的提升等方面进行了探讨。     

农科院校食品质量与安全教学团队建设探索与实践

根据农科院校食品质量与安全专业的定位和特点,立足于农业院校人才培养的要求,紧扣本科教育质量工程,结合学科发展趋势,围绕教学团队的内涵,重点从团队建设、课程群建设、教材建设和教学改革、产学研结合等方面进行食品质量与安全教学团队建设,为提高食品质量与安全专业人才质量和素质进行了探索与实践,也为其他农科院校食品质量与安全专业的教学提供参考。     

食品微生物学实验课教学改革初探

根据学校特点和食品微生物学实验课程的需要,为培养学生实际操作能力、创新能力以及综合能力,从实验大纲、教学方式和考核方式几个方面提出了食品微生物学实验教学改革的思路和建议。