In vitro protein digestibility of different grow‐out stages of spotted rose snapper (Lutjanus guttatus,Steindachner, 1869)

The aim of this study was to compare in vitro protein digestibility between two groups of fish, at early (21 g) and late stages (400 g) of spotted rose snapper Lutjanus guttatus, to evaluate the degree of hydrolysis (DH) and total amino acid release (TAAR) using crude extracts from stomach, pyloric caeca and intestine of 13 protein ingredients including marine, animal and plant meals. Degree of hydrolysis and TAAR were measured by a pH‐Stat method, and the PAGE‐Zymogram was also used as complementary technique. Differences in DH were found between both grow‐out stages mainly in the alkaline hydrolysis phase. Fish and squid meals (marine sources) had the highest DH and TAAR, followed by porcine meat and poultry meal by‐products from recycling sources, and soybean and canola meals (plant sources), which represent better protein sources for use in practical diets. Stomach zymograms showed two pepsin isoforms in both grow‐out stages. Pyloric caeca and intestine zymograms showed five bands with proteolytic activity in the early grow‐out stage, whereas four additional bands were found in late grow‐out stage. Alkaline proteases were identified as serine and metalloproteases. Thus, L. guttatus presents an ontogenetically differentiated digestive enzyme pattern that modifies the DH and TAAR of different protein sources.     

Saddleback syndrome in European sea bass Dicentrarchus labrax (Linnaeus, 1758): anatomy,ontogeny and correlation with lateral‐line,anal and pelvic fin abnormalities

This study focused on the anatomy and ontogeny of saddleback syndrome (SBS) in reared European sea bass. The abnormality was detected at an unusually high frequency (12–94%) during a routine quality control in a commercial hatchery. Anatomically the abnormality was mainly characterized by the loss of 1–5 hard spines and severe abnormalities of the proximal pterygiophores (anterior dorsal fin), size reduction of a few lepidotrichia, missing lepidotrichia and/or lepidotrichia of poor ossification (posterior dorsal fin). SBS was significantly correlated with abnormalities of the anal and pelvic fins in all the examined populations. Moreover, in juvenile fish, SBS was significantly correlated with an abnormal lack of sectors of the lateral line. The examination of early larval samples revealed that SBS was ontogenetically associated with severe abnormalities of the primordial marginal finfold, which developed at the flexion stage (ca 8.5–11.0 mm SL). Histologically, these abnormalities were associated with extensive epidermal erosion. The results are discussed in respect of the critical ontogenetic period and the possible causative factors of SBS in European sea bass. It is suggested that causative factors acted during a wide ontogenetic period including flexion and metamorphosis phases.     

果实表皮组织对采后失水影响研究进展

水分是果蔬中含量最丰富的成分，对于维持果实感官品质以及正常的生理代谢活动具有重要意义。然而，采后果实由于被切断了组织与母体的联系，使得果实水分因蒸发和呼吸作用而减少，继而引发了包括失重、皱缩、变色、软化、易遭受病原菌侵染和加速衰老等一系列问题，大大降低了采后果实的耐贮性和抗病性，并直接影响到果实的商品价值和经济价值。尽管采前、采收、采后众多因素均会影响采后果实水分的丧失，但作为控制水分流失的直接屏障，表皮组织在果实水分保持中扮演着至关重要的角色。本文以果实表皮组织作为切入点，着重从果实表皮组织结构（包括表皮细胞、角质层、自然孔道以及毛状体等）、表皮组织化学成分（包括蜡质、角质、多糖和酚类等）、控制果实表皮水分流失的分子生物学机制（包括与水分控制相关的蜡质基因、蜡质代谢调控）等 3 个方面，围绕果实表皮组织对采后失水的影响进行综述；同时，对当前该研究领域存在的问题进行总结，希望这些研究成果能够为更深入探索表皮组织在采后果实品质保持机制和寻求控制果实水分损失方法提供有益的借鉴和参考。     

EGF和FGF-2对猪皮下脂肪神经嵴干细胞增殖和分化的影响

【目的】探究表皮生长因子（epidermal growth factor，EGF）和成纤维细胞生长因子2（fibroblast growth factor 2，FGF-2）对猪皮下脂肪神经嵴干细胞（neural crest stem cells，NCSCs）增殖及分化的影响，以优化猪皮下脂肪神经嵴干细胞的培养条件。【方法】通过体外分离培养原代猪皮下脂肪NCSCs，免疫荧光染色鉴定NCSCs标志物p75 NTR，并用不同浓度的EGF和FGF-2（0和0、10和10、10和20、20和10、20和20、30和30 ng/mL）作用于传代猪皮下脂肪NCSCs，用CCK-8试剂盒测定细胞增殖率，确定细胞生长的最适EGF和FGF-2浓度，将试验分为空白组和最适浓度组，测定两组细胞的生长曲线，成脂化诱导后油红O染色，对比两组细胞的脂滴生成量。【结果】免疫荧光染色结果显示，原代猪皮下脂肪NCSCs经p75 NTR鉴定呈阳性。CCK-8细胞增殖试验结果显示，EGF和FGF-2的浓度均为20 ng/mL时对传代猪皮下脂肪NCSCs的促增殖作用最佳。生长曲线显示，两组细胞均在第5~9天处于对数生长期，第10~15天细胞增殖减缓，逐渐到达停滞期。油红O染色结果显示，最适浓度组胞质内的脂滴生成量远多于对照组。【结论】在培养液中添加20 ng/mL EGF和20 ng/mL FGF-2对猪皮下脂肪NCSCs的增殖和分化有促进作用。     

根际 NaCl 浓度对冰菜形态和生理的影响

【目的】探究根际 NaCl 浓度对冰菜的形态和生理的影响，找到适合植物工厂冰菜营养液栽培的 适宜 NaCl 浓度，为冰菜植物工厂生产管理提供参考。【方法】以水晶冰菜种子为材料，选用日本园试营养液配 方，在人工光下水培，以未添加 NaCl 处理为对照（CK），添加 NaCl 至终浓度分别为 3、6、9、12 g/L（分别记 为 T1、T2、T3、T4）。处理 21 d 后，分析不同 NaCl 浓度营养液中冰菜的形态和生理指标，统计表皮盐囊泡面 积占比和表皮盐囊泡个数，分析不同 NaCl 浓度与冰菜形态和生理的关系。【结果】从形态指标与质量来看，冰 菜在 3 g/L NaCl 浓度营养液中，株高、茎粗、叶面积、地下部鲜质量和地上部鲜质量与 CK 相比无极显著差异 ； 冰菜在 6 g/L NaCl 浓度营养液中株高和地下部鲜质量和地上部鲜质量与 CK 相比显著增高，该浓度对冰菜生长有 一定的促进作用；冰菜在 9、12 g/L NaCl 浓度营 养液中株高、茎粗、叶面积、地上部鲜质量呈下降趋势，与 CK 差异达到极显著水平，表明冰菜在 9 g/L 和 12 g/L NaCl 浓度营养液中生长受到抑制。从生理指标方面来看，冰菜 的可溶性蛋白含量、可溶性糖含量和叶绿素 SPAD 值随 NaCl 浓度升高呈上升趋势，在 12 g/L NaCl 浓度营养液中 可溶性蛋白含量、可溶性糖含量和叶绿素 SPAD 值最高，分别比 CK 增加 50.2%、119.5% 和 77.9%；从表皮盐囊 泡指标来看，冰菜表皮盐囊泡面积占比与表皮盐囊泡个数随营养液中 NaCl 浓度的升高而增大，在 12 g/L NaCl 浓 度营养液中达到最大，分别比 CK 增加 54.9%、182.1%。【结论】 营养液中 3~6 g/L NaCl 浓度最适于植物工厂冰 菜栽培。     

4种蛋白酶对鲢鱼骨汤特性的影响

以鲢脊骨为原料,采用高温蒸煮、酶解、真空浓缩、灌装、灭菌等工序制备鲢鱼骨汤,并研究了4种蛋白酶(中性蛋白酶、碱性蛋白酶、风味蛋白酶、木瓜蛋白酶)对鱼骨汤的氮收率、基本组成、蛋白肽含量、外观、色度和滋味特性的影响。结果表明,与空白样品(未加酶)相比,酶解制备鱼骨汤的氮收率、游离氨基酸含量、钙含量和分子质量小于3 ku的蛋白肽含量显著增加(P0.05),其中采用风味蛋白酶制备鱼骨汤的这4项指标最高,分别比空白样品(未加酶)增加了46.61%、3 478.82%、233.40%和56.25%。外观与色度结果表明,风味蛋白酶制备鱼骨汤颜色为深黄色,b~*值最大(3.24),其次为其他3种蛋白酶制备的鱼骨汤(1.72～2.86),空白样品(未加酶)的最低(-1.78)。电子舌结果表明,风味蛋白酶制备的鱼骨汤鲜味最强,苦味最弱。综上所述,风味蛋白酶制备的鲢鱼骨汤的营养、外观和滋味品质最佳。