Augmentation of free amino acids in eggs of red snapper,Lutjanus campechanus as part of the induced spawning protocol

An attempt was made to increase free amino acids (FAA) concentrations in eggs of red snapper Lutjanus campechanus as part of an induced spawning protocol. Mature female red snapper were given intramuscular injections of human chorionic gonadotropin (HCG) at a 1100 IU kg^?1 of female body weight. Immediately after the HCG injection, one set of females received an intramuscular injection of FAA in a buffered saline solution at a dose of 20 mg FAA cocktail kg^?1 of body weight. The FAA cocktail was 25% isoleucine, 25% leucine, 25% lysine and 25% valine on a molecular weight basis. A second set of fish did not receive the FAA supplement. Both sets of fish were equally successful in spawning with ovulation occurring 21–32.5 h post injection. Injection of FAA into brooders as eggs began final maturation and hydration resulted in an increase in leucine (nmoles mg egg^?1) and a slight increase in isoleucine (nmoles egg^?1) in recently ovulated eggs. FAA supplementation via brood injection altered FAA utilization rates by embryos and during larval development, resulted in a greater yolk sac and oil globule reserve in larvae as they approached the time of first feeding.     

Egg quality criteria in Pacific red snapper (Lutjanus peru)

The aim of this study was to evaluate the biochemical parameters used as possible determinants of egg quality in Pacific red snapper (Lutjanus peru). Fertilized eggs of eight spawns were obtained by hormonal induction. Egg quality criteria, including abnormal cleavage (AC), hatching percentage (HR) and survival percentage at first feeding (SR) were recorded. Samples were taken during embryonic development and from yolk‐sac larvae. Proteins, energetic metabolite concentrations and metabolic and digestive enzyme activities were determined using colorimetric methods. Pearson's correlation, and simple and multiple regression models were performed using the biochemical parameters as the independent variables and AC, HR and SR as the dependant variables. Glucose‐6‐phosphatase activity (AC r = 0.87; HR r = ?0.65; SR r = ?0.67) and fructose concentration (AC r = ?0.64; HR r = 0.54; SR r = 0.64) were the only biochemical parameters to be strongly correlated with the three egg quality criteria. The use of multiple regression models increased the regression coefficient of the three quality criteria. Fructose, glucose and glucose‐6‐phosphatase were involved in all multiple regression models. The models proposed in this study may be used to explain egg quality for Pacific red snapper and their use as predictors of egg quality is discussed.     

Evaluation of microalgal diets for the intensive cultivation of the tropical calanoid copepod,Parvocalanus crassirostris

As their natural prey, copepods are considered the ideal diets for hatchery culture of fish larvae. However, intensive cultivation of copepods has proven difficult and low culture productivity is the norm, which severely limits their use in aquaculture. This study investigated the effects of algal diets on a range of productivity‐related parameters, including egg production, hatching success, naupliar and copepodite survival, post‐embryonic development time, population growth and sex ratio of a small‐sized tropical copepod, Parvocalanus crassirostris, which has been identified as a high potential species for aquaculture. The diets tested included three live algal diets: Isochrysis sp. (T‐Iso), Pavlova 50 (Pav) and the diatom Chaetoceros muelleri (Cht); two algal paste diets: Isochrysis sp. (P‐Iso) and Thalassiosira weissflogii (P‐TW), as well as four mixed algae treatments composed of three binary algae diets (T‐Iso + Pav, T‐Iso + Cht and Pav + Cht) and a tri‐algal diet (T‐Iso + Pav + Cht). All parameters examined except sex ratio were significantly affected by the diets. The binary algal diet T‐Iso + Cht produced significant higher total egg production over female lifespan (121.0 ± 5.9 eggs) than all other treatments (P < 0.05). Survival during naupliar and copepodite stage was significantly superior when P. crassirostris were fed either the mixed diet of T‐Iso + Cht or the monoalgal diets of Cht or T‐Iso (P < 0.05) than other diets. These three treatments also had the fastest time of development to adults (ranging from 6.2 to 6.7 days). With an initial 100 adults, the T‐Iso + Cht treatment produced the highest population growth over a 15‐day cultivation period, which was significantly higher than other treatments (P < 0.001). In contrast, the algal paste treatments, including (P‐Iso) produced overall the worst results for various parameters examined. However, the sex ratio of P. crassirostris was not significantly affected by diets and was always heavily skewed towards females (>84% were females) across all treatments. Based on the results of this study, T‐Iso + Cht is recommended for intensive cultivation of P. crassirostris.     

温度和土壤含水量对东亚飞蝗卵孵化的影响

试验采用二因素完全随机区组设计,对温度及土壤含水量与卵孵化的关系进行了系统研究。结果表明：东亚飞蝗的卵在恒温30℃、35℃,土壤含水量20% 的组合情况下,孵化率最高、孵化所需时间最短、孵化整齐度最好。该结果可作为养殖过程中,较理想的孵化蝗卵的温度和土壤含水量的指标。     

南昌地区柳圆叶甲生活史的研究

在实验室和野外条件下,对柳圆叶甲Plagiodera versicolora（Laicharting）的生物学特性进行了系统观察。在野外,越冬成虫于3月下旬至5月中旬陆续出土繁殖,一年能繁殖6～12代。该虫由于成虫产卵持续时间长,完成一个世代的时间短,因此世代重叠现象非常明显。11月上旬后羽化的成虫取食一段时间后蛰伏越冬。成虫产卵有一定的周期性,一般10d为一个周期,每天产卵最少1粒,最多65粒。寄主树叶老嫩程度和气候条件对各世代成虫的产卵具有显著的影响。     

应用灰色关联理论分析禽蛋新鲜度的影响因素

新鲜度是衡量禽蛋品质的一个重要指标,在贮藏过程中受到各种因素的影响。应用灰色关联理论,计算不同贮藏期鸡蛋的哈夫单位与其比重、质量、蛋形指数及蛋壳强度等因素之间的灰色关联度;根据关联度数值,得到各因素对鸡蛋新鲜度的影响程度,并进行理论分析。结果表明,对不同贮藏期的鸡蛋,比重是影响新鲜度的首要因素,而蛋壳强度的影响最小。随着贮藏期的延长,蛋形指数对新鲜度的影响程度逐渐减弱,而鸡蛋质量的影响则逐渐增强。     

减蛋综合征病毒NE4株全基因组序列测定与分析

根据减蛋综合征病毒(EDSV-76)AV-127株的全基因序列(序列号BK000404),用Premier5.0软件设计22对引物,利用PCR方法对EDSV-76病毒NE4株的全基因组进行了分段扩增、克隆和序列测定,并用DNAStar分析软件对各片段的测序结果进行拼接,将该序列与GenBank中已登录的相应序列进行同源性分析,并用六邻体蛋白构建进化树.结果表明:NE4株基因组序列全长33214bp,GC含量为43%,与国际标准株AV-127相比,核苷酸序列同源性为99.6%.碱基的插入或缺失主要在非编码区,在100K蛋白编码区距羧基端1/10处插入了1个碱基C,其ORF编码696个氨基酸,而AV-127株100K蛋白编码709个氨基酸,预计其发挥功能的基团在N端.蛋白同源性分析表明,EDSVNE4株主要蛋白与羊腺病毒OAV(Ovine adenovirusD)、牛腺病毒BAV(Bovine adenovi-rusD)和蛇腺病毒SAV(Snake adenovirus)有较高的同源性,而与禽腺病毒Ⅰ群(CELO)的同源性较低,说明NE4株与禽腺病毒Ⅰ群亲缘关系较远,进化树分析也证实了此特性.     

闽江口和兴化湾浮性鱼卵和仔鱼分布特征的比较

利用2009年4月和9月闽江口和兴化湾海域浮性鱼卵、仔鱼调查资料,比较和分析了这两个海域浮性鱼卵、仔鱼的种类组成、数量分布、产卵场位置和产卵期等特征。结果表明,调查期间闽江口鱼卵、仔鱼共出现4目7科8种,其中鲈形目种类最多。同期兴化湾鱼卵、仔鱼共出现5目9科10种。9月闽江口产卵场主要位于南部水域,与闽江口南支为径流主要通道有关,也与径流所受到柯氏力有关。而兴化湾产卵场则主要位于中部水域,这是外来涨潮水和内湾水交汇的主要海域。闽江口浮性鱼卵、仔鱼的种类主要是洄游性鱼类,例如白姑鱼和小公鱼。而兴化湾是塘鳢科和鰕虎鱼科的鱼类,往往具有地方性栖息习性。在9月,兴化湾海域浮性鱼卵和仔鱼的数量分别是5ind./m₂和9.58ind./m₂,闽江口分别为197.17ind./m₂和20ind./m₂。兴化湾鱼卵和仔鱼的数量远远低于闽江口海域。也就是说,闽江口渔场作为鱼类产卵场,其重要意义要大于兴化湾渔场。     

青藏高原地方鸡种——海东鸡与商品鸡蛋品质分析比较

作者对青藏高原地方鸡种—海东鸡与商品新罗曼鸡的蛋品质及蛋中营养成分进行测定并分析比较。结果表明,海东鸡的蛋重、蛋壳重、蛋白重及蛋白重/蛋重极显著低于新罗曼鸡(P0.01);而蛋形指数和蛋黄重/蛋重极显著高于新罗曼鸡(P0.01);蛋壳厚度和蛋壳重/蛋重海东鸡显著高于新罗曼鸡,且海东鸡的哈氏单位显著高于新罗曼鸡(P0.05);蛋黄和蛋壳强度重二者无显著差异。海东鸡蛋全蛋粗蛋白质含量比新罗曼鸡蛋低21.3%,达到极显著水平(P0.01);粗脂肪含量比新罗曼鸡高18.1%,达到显著水平(P0.05)。     

林下和虫子养鸡的鸡蛋品质对比研究

以林下放养和用虫子饲养的鸡产下的蛋为材料,从鸡蛋的外观和营养成分对两种蛋的品质进行对比研究。结果表明：两种鸡蛋品质存在差异,两种鸡蛋的蛋质量、蛋密度、蛋白质量、蛋白pH值、水分、灰分、蛋白质、脂肪、钙、磷、铁11个指标存在极显著差异（P〈0．01）,蛋黄质量、蛋黄pH值等存在显著性差异（P〈0．05）。