基于迁移学习和金字塔卷积网络的河蟹个体图像识别方法研究

针对目前河蟹追溯成本高、消费者无法细粒度地追溯单体河蟹信息等问题,提出一种基于迁移学习和金字塔卷积的河蟹背甲图像个体识别算法。该算法使用金字塔卷积层替换普通残差卷积块构建网络模型,可以从蟹背图像中提取多尺度、深层次的特征信息。结果显示:采用金字塔卷积结构的Resnet34和Resnet50的准确率分别为98.38%、98.51%,与使用普通卷积层的模型相比,准确率提升5.49%、1.3%,而当模型深度达到101层时,模型性能不再明显提升。与使用金字塔卷积结构的全新学习模型相比,迁移学习方法的训练收敛迭代轮次从20轮降低至5轮,此时模型准确率为98.88%,较全新学习的准确率提升0.37%,同时弥补了样本量较少的问题。该研究为河蟹个体识别追溯提供了理论依据和技术支持。     

浙江宁海县渔业规模集约化之路的探讨

要彻底解决海洋渔业面临的种种困难，必须从深层次寻找原因，要转变观念，改变传统模式，通过流转，以组建股份制专业合作社或引进农业龙头企业等形式，走渔业规模集约化之路，实现专业化分工和渔业经济规模化。本文就宁海县海洋渔业为何要实现规模化建设，以及如何实施这一建设谈几点初浅的看法，以期有抛砖引玉之功。     

菲律宾蛤仔土池中间育成的研究

2002~2003年在约80 hm2土池进行了菲律宾蛤仔中间育成试验。试验结果表明,在适时肥水、追肥、清池,水温20~25℃的条件下,放养密度3.0×104~5.0×104枚/m2,放养规格>1.5 mm,平均生长速度>80μm/d,最高可达250μm/d,成活率>80%;不适时肥水、追肥、清池,放养规格又偏小(壳长<0.4 mm)条件下,平均生长速度为26.6μm/d,成活率只有30%。表明放养规格、肥水、追肥、清池及适时疏苗是影响中间育成效果的主要因素。     

应用导管螺旋桨的机帆渔船与拖网匹配试验

七十年代中期以来,中国沿海机动渔船迅速增加,其中250马力以下小型渔船占极大比例。随着海洋捕捞产量增加,海洋鱼类资源状况也在不断恶化,渔获物中优质鱼的比例持续降低。单位马力产量和网次产量下降。因此,必须在国家大力发展远洋渔业的同时,尽快地大幅度减轻对近海渔场的捕捞压     

刺络拔罐配合静力练习治疗急性踝扭伤临床观察

目的分析通过刺络拔罐配合静力练习治疗急性踝关节扭伤的临床疗效。方法收集2009年-2013年病例共71例,根据治疗方案随机分为观察组36例、对照组35例,观察组采用刺络拔罐配合静力练习治疗,对照组采用单纯刺络拔罐治疗。7 d为1个疗程,1个疗程后观察疗效,2个月后复查或随访患者,评价踝关节Kofoed评分。结果两组治疗后临床疗效比较,差异有统计学意义(P<0.05)。2个月后评价踝关节Kofoed评分,观察组与对照组比较,差异有统计学意义(P<0.05)。结论急性踝关节扭伤通过刺络拔罐配合静力练习治疗效果优于单纯刺络拔罐治疗。     

Choline requirements of male White Pekin ducks from 21 to 42 d of age

1. A dose–response experiment with 6 dietary choline concentrations (0, 342, 779, 1285, 1662 and 1962 mg/kg) was conducted with male White Pekin ducks to estimate the choline requirement from 21 to 42 d of age.

2. Ninety 21-d-old male White Pekin ducks were allotted to 6 dietary treatments, each containing 5 replicate pens with three birds per pen. At 42 d of age, final weight, weight gain, feed intake and feed/gain were measured. Liver was collected to determine total liver lipid, triglyceride and phospholipids.

3. Significant positive effects of dietary choline on final weight, weight gain and feed intake were observed. In addition, dietary choline supplementation significantly decreased liver lipid and triglyceride content and increased liver phospholipids of Pekin ducks.

4. According to broken-line regression analysis, the choline requirements of male White Pekin ducks from 21 to 42 d of age for weight gain, feed intake and total liver lipid were 980, 950 and 1130 mg/kg. Pekin ducks needed more choline to prevent excess liver lipid deposition than to maintain growth.     

Functional characteristics of porcine peripheral T cells stimulated with IL-2 or IL-2 and PMA

In human or mouse, mature T cells express either CD4 or CD8, resulting in different functions in the periphery. Interestingly, porcine CD4 and CD8 double positive (DP) T cells are present in the blood, and their proportions change from youth to adulthood. However, the features of these cells in swine are poorly understood. We investigated the fate of porcine peripheral T cells based on their functional characteristics, including proliferation and the expression of CD4 and CD8 co-receptors. The results showed that all the populations changed their CD8 expression in a time-dependent manner and porcine T cells had different proliferative pattern from human T cells. The results further revealed that Th2 cytokines were increased later in porcine T cells compared to human T cells upon stimulation with IL-2 + PMA. Collectively, we found that the fate of porcine peripheral T cells is different from that of human T cells, and the changes occur in a time- and stimulation-dependent manner.     

Effects of the acid-tolerant engineered bacterial strain Megasphaera elsdenii H6F32 on ruminal pH and the lactic acid concentration of simulated rumen acidosis in vitro

The aim of this study was to examine the effects of the acid-tolerant engineered bacterial strain Megasphaera elsdenii H6F32 (M. elsdenii H6F32) on ruminal pH and the lactic acid concentrations in simulated rumen acidosis conditions in vitro. A mixed culture of ruminal bacteria, buffer, and primarily degradable substrates was inoculated with equal numbers of M. elsdenii H6 or M. elsdenii H6F32. The pH and lactic acid concentrations in the mixed culture were determined at 0, 2, 4, 6, 8, 10, 12, 14, 16, and 18 h of incubation. Acid-tolerant M. elsdenii H6F32 reduced the accumulation of lactic acid and increased the pH value. These results indicate that acid-tolerant M. elsdenii H6F32 could be a potential candidate for preventing rumen acidosis.     

Up-regulated expression of PD-1 and its ligands during acute Classical Swine Fever virus infection in swine

In order to investigate the relationship between the PD-1 pathway and impairment of immune responses with the CSFV infection, the mRNA expression of PD-1 and its ligands were evaluated by quantitative polymerase chain reaction (qPCR) during artificial CSFV infection. Simultaneously, expression of IL-2 and IL-10 mRNA were detected. The T cell proliferation and CSFV load in plasma were also measured. Results showed that the expression of PD-1 and its ligands mRNA were significantly increased (p < 0.01) in PBMC from 3 to 7 days post infection (dpi). Meanwhile the level of IL-10 was up-regulated (p < 0.01). The IL-2 mRNA was not obviously changed but it is significantly increased from 14 dpi. The T cell proliferation was notably decreased at 7 dpi. The CSFV load was also increased in plasma. Overall, our results suggest that the expression of PD-1 and its ligands were up-regulated and probably correlated with immune inhibition during acute CSFV infection.     

Effects of sodium butyrate on growth performance,haematological and immunological characteristics of weanling piglets

The experiment was conducted to study the effects of sodium butyrate (SB) on growth, haematological and immunological characteristics in weanling pigs. A total of 100 male piglets (Duroc×Landrace×Yorkshire) with a body weight of 8.0 ± 0.2 kg weaned at the age of 28 days were randomly assigned to two treatments with five replicates and 10 pigs per replicate. Piglets received a basal diet (control group) or diets supplemented with 1000 mg/kg SB. The feeding trial lasted for 21 days. The results showed that dietary SB significantly decreased (p < 0.05) diarrhoea incidence of weaned piglets, but did not affect (p > 0.05) the average daily feed intake (ADFI), average daily gain (ADG) and feed to gain (F/G). Furthermore, piglets fed dietary SB had higher (p < 0.05) serum concentrations of glucose and triglycerides and lower (p < 0.05) serum concentrations of urea nitrogen, cortisol, D‐lactic acid and diamine oxidase when compared with the control group. However, dietary SB did not affect concentrations of serum albumin, total protein, insulin and glucagon (p > 0.05). There were no significant (p > 0.05) treatment effects on serum IgA and IgM, whereas serum IgG concentration and IgA+ cell count in jejunum from pigs fed SB were significantly higher (p < 0.05) than in those given the basal diet. In conclusion, the present study indicated that dietary SB significantly decreased diarrhoea incidence of weaned piglets and increased the efficiency of nitrogen utilization. Also, dietary SB could regulate and enhance the immune function of piglets by increasing the serum IgG concentration and IgA+ cell count in jejunum. Our results suggest that SB may reduce some of the adverse effects of weaning stress and play an important role in maintaining the integrity of intestinal mucosa.