脱粒滚筒滚幅盘加工与拉伸模设计

脱粒装置是联合收获机的关键工作部件,其结构设计与制造工艺在很大程度上决定着联合收获机的工作性能。脱粒滚筒是脱粒装置核心部件,钉齿式脱粒滚筒主要包括滚筒轴、辐盘、齿杆和钉齿等部件。幅盘是钉齿式脱离滚筒的主要支撑件,其结构、强度、加工工艺性以及选材直接影响着脱离滚筒的使用可靠性。为此,通过对此盘类件的结构、性能及加工工艺分析,合理地设计幅盘拉伸模具,有效地利用激光切割机板材孔类切割的高效性和单点压力机气顶的双重作用,在保证加工质量的同时,最大限度地减少了模具投入和加工工序,降低了制造成本,产生了良好的经济效益。     

Effects of synthetic kisspeptin peptides and GnRH analogue on oocyte growth and circulating sex steroids in prepubertal female chub mackerel (Scomber japonicus)

In recent years, kisspeptin peptides, encoded by kiss genes have been used to manipulate reproductive processes in farmed animals, including fish. Our previous studies demonstrated that the chub mackerel brain expresses kiss1 and kiss2 and intramuscular injection of synthetic Kiss1 pentadecapeptide (Kiss1‐15) but not Kiss2 dodecapeptide (Kiss2‐12) accelerates spermatogenesis in prepubertal male chub mackerel (Scomber japonicus). In the present study, we evaluated their effects in prepubertal female chub mackerel. The gonadosomatic index (GSI) values of experimental fish did not show any significant changes. Condition factor (CF) values increased significantly in Kiss1‐15 treated fish, in comparison with control and GnRH analogue (GnRHa) injected fish. Histologically, only perinucleolar oocytes were found in all experimental fish. However, Kiss and GnRHa treated fish showed a significant increase in the perinucleolar oocyte diameter, in comparison with the control fish. Gene expression analyses revealed decreased expression of gnrh1 in the telencephalon‐preoptic region of the brain of Kiss2‐12 and GnRHa injected fish, in comparison with control fish. In contrast, GnRHa injected fish exhibited higher levels of fshβ in the pituitary, with no changes in the levels of lhβ among different treatments. Levels of circulating sex steroids, testosterone, and estradiol‐17β were significantly higher in Kiss1‐15 injected fish, in comparison with control fish. These results indicate that synthetic kisspeptin peptides and GnRHa can induce oocyte growth in prepubertal female chub mackerel.     

鲐鱼调味煮干品加工技术的研究

根据我国消费、生产现况和鲐鱼的加工特性，在国内外现有的调味煮品加工技术基础上进行了改进，研制出一种新型调味煮干品－鲐鱼鱼肉干。改进后的工艺特点：（１）将采肉后漂洗改为去皮和去皮下脂肪后采肉，避免了鱼皮、皮下脂肪的混入，省去了漂洗、脱水等复杂的工序和设备；避免了水溶性蛋白质等的流失，提高了成品率。（２）产品熬煮后烘干至水份活度０．７０左右，能在常温下保质四个月以上，避免了传统调味煮熟品高糖高盐、容易     

熏烤鲐片的研制

研究了熏烤鲐片的加工技术。用１．３％左右，复合有机酸处理鲐片，收到了抗氧化、去组胺、去腥去脂等综合效果，制品品质和保藏性大大提高。对调味配方、烘干、液熏、烘烤等方面也进行了研究和选择。     

Effects of temperature on development and mortality of Atlantic mackerel fish eggs

The development of Northeast Atlantic mackerel (Scomber scombrus) eggs, obtained from artificial fertilisation during the spawning season in the Biscay Bay area, was monitored at five temperatures (ranging from 8.6 to 17.8 °C). The times to intermediate stages (III–V) and total hatching, obtained in this study, agree with the results of previous studies undertaken some years ago. However, the times over stages IA, IB and 50% hatching indicate that development rates differed significantly between the studies; this could be related to an effect of the previous thermal history of the eggs, or to experimental biases. Daily mortality (Z) during the embryonic period was found to vary between 0.17 and 0.38, using traditional exponential decay models. The estimates of mortality rate were found to range consistently with those derived from previous studies on Northwest Atlantic mackerel eggs without predation. However, the shape of the survivorship-curve during the development pursued in this study has indicated that mortality is not constant in time. Similarly, the suitability of an exponential model to describe daily mortality should be considered.     

Antihypertensive effect of Narezushi, a fermented mackerel product, on spontaneously hypertensive rats

ABSTRACT:   During the fermentation of mackerel to narezushi , the concentration of peptides required to inhibit 50% of the ACE activity in the assay media (IC₅₀), as an index of the angiotensin  I-converting enzyme (ACE) inhibitory activity, was remarkably decreased with a rapid increase in peptide contents. Systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR) decreased between 2 and 4 h after the single oral administration of greater than 10 mg peptide/kg narezushi extract, and recovered to the initial level by 8 h thereafter. The SBP decreased at seven successive daily doses of 10 mg/kg of narezushi extract and then recovered to the initial level 5 days after stopping a total of 10 daily administrations. The extract was administered to five-week-old SHR rats for 70 days and SBP decreased 21 days after starting and continued for 28 days after the end of administration. The peptide-rich fraction from narezushi extract had a powerful antihypertensive effect, whereas the other fraction had a similar, but weak effect.     

Environmental control of Northeast Atlantic mackerel (Scomber scombrus) recruitment in the southern Bay of Biscay: case study of failure in the year 2000

We investigate the effect of strong meteorological perturbations in early spring on the success of mackerel (Scomber scombrus) recruitment in the N/NW Iberian area (southern Bay of Biscay) for the period 1999–2008. In 2000, the year of the most pronounced recruitment failure on record, two consecutive multidisciplinary surveys sampled hydrographic conditions and mackerel eggs, larvae and post‐larvae over the main mackerel spawning grounds of the north and northwest coast of the Iberian Peninsula. Analysis of egg and larval abundance and birthdates based on the otoliths of mackerel juveniles caught between July and October 2000 showed that there were no survivors from the early spring spawns, indicating a massive loss of early spawning effort. Moreover, the abundance of 1‐year‐old mackerel estimated from an acoustic survey carried out in 2001 was the lowest observed within the 1999–2008 time series. This low or null survival from the early spawns in 2000 could be due to the meteorological and oceanographic conditions of that spring, in particular two storm events in April after a relatively calm March. The first storm event from the north caused strong local wind in the southern Bay of Biscay but a weak oceanographic response. The second storm event from the southwest was mainly felt west of Galicia and caused a notable increase in shelf currents and a shift of the hydrographical structure along the shelf. Detailed analysis of strong wind pulses in early spring within the historical recruitment record suggests that strong local turbulence generated by high wind speeds and advection of larvae caused by the enhancement of shelf currents can contribute to reduced recruitment. Our observations indicate that, in 2000, both mechanisms were present.     

夏季东海水团变动特征及对鲐鲹渔场的影响

应用模糊聚类方法，采集东海30个站表层及底层1996-1998年夏季的水温（T）、盐度（S）、溶解氧（DO）、磷（P）、三态氮（N）、硅（Si)、pH值等九个指标的测样数据，对东海水团进行划分，其表层水团配置为大陆沿岸冲淡水（I），黄东海混合水团（Ⅱ）台湾暖流水（Ⅲ），黑潮表层水（Ⅳ）等水团，底层水团配置为黑潮次表层水团（Ⅴ），黄海冷水团（Ⅵ），台湾暖流水（Ⅲ）等水团，并分析了1996-1998年夏季由大陆径流和外海水团热力强弱影响所致的东海水团变动特征及沿岸冲淡水转向问题，同时讨论了东海水团分布与鲐Sheng渔场关系。     

Comparison of Proximate Composition and Fatty Acid Profile of On-Growing and Wild Mediterranean Horse Mackerel (Trachurus mediterraneus)

ABSTRACT

On-growing of horse mackerel is not known in the world. Recently, we have initiated on-growing of the Mediterranean horse mackerel in the Black Sea. Therefore, we aim to compare proximate composition and fatty acid profile of on-growing and wild horse mackerels to evaluate the effect on their nutritional value. Captured horse mackerels less than 13 cm were kept on-growing in sea cages and fed sea bass feed for a year in the southern Turkish Black Sea. Results showed seasonal variations in the proximate contents and fatty acid profile of both on-growing and wild fish groups (p < 0.05). Protein contents of the wild horse mackerel group were significantly higher than the on-growing mackerel group, while the opposite situation was observed for lipid contents (p < 0.05). Despite higher eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels (as fatty acid methyl esters %) of wild horse mackerel in comparison with on-growing group, much higher EPA + DHA contents were accounted for in on-growing fish in the edible portion resulting from higher lipid contents of these samples. The results suggest that lower amounts of fish meat, 50–90 g, from on-growing mackerel would cover the daily suggested value of EPA + DHA; this level is calculated as 51–150 g for wild fish meat.