A physiological and biochemical approach to selecting the ideal diet for Ostrea edulis (L.) broodstock conditioning (part A)

To select the best microalgae for Ostrea edulis conditioning, four single species diets were fed to batches of broodstock, which were then compared using physiological and biochemical approaches. Ingestion and absorption were first studied, showing that Chaetoceros gracilis and Skeletonema marinoï were efficiently ingested (4.9–5.3 mg g^?1 h^?1) and absorbed (1.9–2.5 mg g^?1 h^?1) while Tetraselmis suecica led to the lowest physiological responses (0.36 and 0.12 mg g^?1 h^?1 respectively). When O. edulis were fed any microalgae except T‐ISO with only 79 mg g^?1, gonads accumulated carbohydrates from 116 to 141 mg g^?1 and the extent of accumulation depended on the species supplied in the order T. suecica<C. gracilis<S. marinoï. When oysters were fed either of the diatoms (C. gracilis or S. marinoï), an efficient transfer of 20:5(n‐3) to all tissues, including the gonads, was recorded while no enrichment in 22:6(n‐3) occurred in all tissues (polar fraction) when oysters were fed T‐ISO. In contrast (22:5(n‐6)), a characteristic fatty acid of T‐ISO accumulated in all tissues, confirming its allocation despite particularly low ingestion (1.66 mg g^?1 h^?1) and absorption (0.32 mg g^?1 h^?1). When oysters were fed C. gracilis or S. marinoï an efficient transfer of cholesterol and campesterol from diatoms to the gonads was observed, while no sterol accumulation occurred in the gonad when fed T. suecica. Because of low ingestion, absorption and poor biochemical compounds' transfer, T. suecica is not recommended for O. edulis conditioning. T‐ISO also exhibited low physiological performances but due to a specific 22:6(n‐3) enrichment in the gonad neutral fraction (16.1%), its potential role in reproduction should be considered. Chaetoceros gracilis is highly recommended for O. edulis broodstock while a source of DHA other than that provided by T‐ISO should be found due to its poor absorption. Because a mixed diet has been shown to be more efficient for O. edulis broodstock conditioning, complementary trials dealing with the effects of other species rich in 22:6(n‐3) such as Rhodomonas salina or Pavlova lutheri should be performed.     

Contribution of incident solar radiation on leaves and pods to soybean seed weight and composition

The weight and composition of soybean seeds (Glycine Max L. Merrill) depend on changes in carbon and nitrogen assimilate supply during grain filling. Soybean pods and seeds are green, evidencing their capacity to capture light. However, the current physiological knowledge does not consider any effect of incident solar radiation reaching the pods on seed weight and composition. The objective of this work was to investigate the response of seed weight and composition to changes in assimilate supply from leaves, to the incident solar radiation reaching the pods and to the combination of both, changes in assimilate supply from the leaves and incident solar radiation on pods of soybean plants. Field experiments were performed during two growing seasons at Balcarce, Argentina. Treatments modified the amount of assimilates supplied by the leaves (plant shading, defoliation), the solar radiation reaching the pods (pod shading) or both (defoliation and pod shading) during seed filling. Plant shading and defoliation reduced seed weight, oil concentration and oil and protein content and increased the concentration of saturated and poli-unsaturated fatty acids while reduced oleic acid percentage. Pod shading increased the concentration of stearic acid and reduced the concentration of linolenic acid. When pods were shaded on defoliated plants, seed weight and oil and protein content decreased while fatty acid composition was similar to values obtained under defoliation treatment. Based on these results, a conceptual model that considers photoheterotrophic nature of reproductive structures of soybean is proposed. Seed weight, oil and protein content and oil fatty acid composition depended on assimilate availability for the seeds. The response of oil and protein content to assimilate supply depended on whether leaves were present or not. The effect of solar radiation incident on pods depended on the amount of assimilates available for the seeds: (i) when carbon allocated was low (defoliation treatments), pods contributed to seed carbon economy but solar radiation incident on them did not affect fatty acid composition; (ii) when carbon allocated to the seeds was high (intact plants), contribution of pods to seed carbon economy was not significant, but the amount of solar radiation incident on pods produced significant changes in fatty acid composition.     

卵形鲳鲹幼鱼饲料中适宜蛋白能量比的研究

以鱼粉、豆粕为蛋白源,豆油、鱼油为脂肪源,配制9种不同蛋白能量水平的饲料,蛋白质3个水平(38%、43%、49%),每个蛋白水平设3个脂肪梯度(6%、10%、14%),其蛋白能量比为19.3～27.4mg/kJ。卵形鲳鲹初始质量为(25.02±0.16)g,每个处理设3个重复,每个网箱(1.5 m×1.0 m×2.0m)放养卵形鲳鲹苗20尾,养殖试验持续8周。结果显示,卵形鲳鲹特定生长率随饲料蛋白水平的升高而显著升高(P<0.05)。投喂含43%或49%蛋白质、6%脂肪饲料的卵形鲳鲹表现出较好的特定生长率。饲料中不同的脂肪水平未表现出蛋白质节约效应,较高的脂肪水平反而抑制了卵形鲳鲹的特定生长率、饲料效率和蛋白质效率。卵形鲳鲹鱼体蛋白和脂肪含量分别随饲料蛋白质和脂肪水平的上升而显著升高(P<0.05)。在该试验条件下,卵形鲳鲹幼鱼饲料中最适蛋白质、脂肪水平和蛋白能量比分别为43%、6%和24.4 mg/kJ。     

奶牛初乳与常乳中营养成分和免疫物质的特征

初乳是奶牛产后24 h内的乳汁,为犊牛提供天然免疫和早期生长的能量来源,且初乳在医疗保健领域也具有一定的研究价值。初乳在产后一段时间内的物质成分会发生较大的变化,与常乳形成明显的差异。本文对比分析了初乳和常乳中营养物质、免疫活性物质、生长因子以及酶的含量差异,直观地展现了初乳中不同物质的变化过程,针对性地为初乳和常乳的加工制作提供思路,为特异性地开发初乳资源,提升初乳的利用率给出参考依据。     

基于网络药理学及分子对接技术研究黄芪调控仔猪肠道菌群失调性腹泻的作用

【目的】基于网络药理学及分子对接技术研究黄芪调控仔猪肠道菌群失调性腹泻的有效活性成分及其作用机制。【方法】从TCMSP数据库搜集黄芪中药化合物成分,并获取其潜在靶点。利用GeneCards和OMIM数据库搜集肠道菌群失调性腹泻(flora imbalance diarrhea)的作用靶点,将两者预测的潜在作用靶点进行映射,获得共同作用靶点。运用STRING数据库构建靶点蛋白-蛋白相互作用(PPI)关系,用Cytoscape_3.8.0软件对其网络进行拓扑分析,用DAVID数据库对共同作用靶点进行富集分析,用AutoDuck_4.2.6软件对其核心成分与核心靶点进行分子对接。【结果】黄芪含有11个调控仔猪肠道菌群失调性腹泻核心成分,其对应靶点基因65个,疾病靶点854个,交集靶点25个。PPI网络中显示肿瘤坏死因子(TNF)、转录因子AP-1(JUN)、半胱氨酸蛋白酶-3(CASP3)、白细胞介素-6(IL6)、NF-κB抑制剂α(NFKBIA)、IL1B、IL10、细胞肿瘤抗原p53(TP53)、过氧化物酶体增殖物激活受体γ(PPARG)、C-C基序趋化因子2(CCL2)为关键靶点。GO功能和KEGG通路富集分析发现,黄芪有效成分主要通过美国锥虫病、炎症性肠病、阿米巴病、细胞因子-细胞因子受体相互作用、A型流感、疟疾、T细胞受体信号通路、沙门菌感染等信号通路参与转录调控、免疫反应、细胞对脂多糖的反应等生物过程。分子对接结果显示,槲皮素、山奈酚、芒柄花素等核心成分与TNF、IL1B等关键靶点结合紧密,亲和力较好。【结论】黄芪可能通过槲皮素、山奈酚、芒柄花素等主要活性成分作用于TNF、IL1B等靶点,通过参与美国锥虫病、炎症性肠病、疟疾、T细胞受体信号通路、沙门菌感染等信号通路进而治疗仔猪肠道菌群失调性腹泻。     

饲料中维生素K3含量对大口黑鲈消化能力、血清代谢指标、肌肉氨基酸和脂肪酸组成的影响

为研究饲料中维生素K₃含量对大口黑鲈消化能力、血清代谢指标、肌肉氨基酸和脂肪酸组成的影响,在基础饲料中分别添加不同水平的维生素K₃,配制成维生素K₃含量分别为0.78(K0组)、5.80(K5组)、10.82(K10组)、15.84(K15组)和20.85 mg/kg(K20组)的5种试验饲料,对初均重为(12.96±0.07)g健康大口黑鲈幼鱼进行为期8周的饲养试验。结果表明:添加维生素K₃的各组胃和肠道的蛋白酶、淀粉酶和脂肪酶活性均显著低于K0组(P<0.05)。K10组、K15组和K20组的表观消化率和蛋白质表观消化率显著低于K0组(P<0.05)。K20组的血清尿素氮含量显著高于其他4组(P<0.05),血清总蛋白、白蛋白、总胆固醇和甘油三酯含量在各组之间无显著差异(P>0.05)。肌肉必需氨基酸、非必需氨基酸和总氨基酸含量以及必需氨基酸指数在各组之间无显著差异(P>0.05),但是随着饲料中维生素K₃含量的增加,必需氨基酸和总氨基酸含量呈增加的趋势。K15组的肌肉单不饱和脂肪酸含量显著高于其他4组(P<0.05),其中C16∶1n7和C18∶1n5含量均较其他组显著升高(P<0.05)。肌肉饱和脂肪酸和多不饱和脂肪酸含量在各组之间无显著差异(P>0.05)。综上可知,饲料中添加维生素K₃可以改善大口黑鲈肌肉氨基酸组成,但当饲料中维生素K₃含量≥5.80 mg/kg时会使大口黑鲈的消化能力下降,并且高剂量的维生素K₃会改变大口黑鲈的蛋白质和脂质代谢。     

过渡乳营养价值和对犊牛生产性能影响的研究进展

过渡乳是初乳向常乳过渡的乳汁。目前国内对于过渡乳的概念还没有深刻的认识。根据调研,目前在犊牛灌服初乳后,为了节省人力、节约成本,牧场对于过渡乳的使用并不充分,有的完全废弃,有的违规操作进行售卖,而采用代乳粉、常乳等代替过渡乳对犊牛进行饲喂。针对这一问题,本文从过渡乳的定义、营养价值和对犊牛生产性能的影响三个方面进行综述,以为过渡乳的使用以及犊牛7日龄内饲喂方案的制定提供参考。     

Genome-wide association studies of preweaning growth and in vivo carcass composition traits in Esme sheep

Sheep are considered as a major contributor of global food security. Moreover, sheep preweaning growth traits as well as in vivo carcass composition traits such as ultrasonic measurements of Longissimus dorsi muscle depth (UMD) and back-fat thickness (UFD) are crucially important indicators of meat yield and hot carcass composition. Despite their relative importance for productivity and profitability of a sheep production system, detected QTL for these traits are quite scarce. Therefore, we implemented GWAS for these traits using animal mixed model-based association approach provided by GenABEL in Esme sheep. Three genome-wide and 14 individual chromosome-wide associated SNPs were discovered. As a result, ESRP1, LOC105613082, ZNF641, DUSP5, TEAD1, SMOX, PTPRT, RALYL, POM121C, PHIP, LOC101106051, ZIM3, PEG3, TRPC7, FBXL4, LOC105610397, LOC105616489 and DNAAF2 were suggested as candidates. Some of the discovered genes and involved pathways were already annotated to contribute growth and development in various species including human, mice and cattle. All in all, the results of this study are expected to strongly contribute to shed a light on the underlying molecular mechanisms behind growth and carcass composition traits, with potential implications on studies aiming faster genetic improvement, targeted low-resolution SNP panel designs and genome-editing studies.     

稻属间杂种花粉植株的细胞遗传学研究

以栽培稻０２４２８与紧穗野生稻间不育Ｆ１杂种（２ｎ＝２４，ＡＣ）为材料进行花约培养，共接种花约３２６８８个，获得再生绿苗１３株及白化苗两株，愈伤诱导率与分化率分别为０．１４％和３４．７８％。有９朱花粉绿苗长至成熟，均表现长芒、紫柱头、强感光及易落粒等野生亲本的特性。细胞学结果进一步表明，其中４株为二倍体（２ｎ＝２４），形态上琚的Ｆ１杂种相似，花粉母细胞中期Ⅰ亦只能见到少数二价体；另５株则为四倍体（