富山武装乌贼个体发育期角质颚表型变化分析

角质颚作为头足类重要的硬组织,记录了其丰富的个体生长信息.在西北太平洋海域,富山武装乌贼(Enoploteuthis chunii)是众多海洋哺乳动物和鱼类的食饵,掌握角质颚的生长变化规律不仅有助于了解其个体发育期摄食生态的变化,还有助于进一步研究其在海洋生态系统中的地位和作用.根据2019年3月和9月于西太平洋海域采...     

基于K-means动态聚类的鸢乌贼角质颚模式识别

本研究采用K-means动态聚类算法,对2014—2019年间采集于西北印度洋、热带东太平洋、中国南海的鸢乌贼(Sthenoteuthis oualaniensis)样本的角质颚进行识别。基于K-means动态聚类算法能够很好地区分来自3个海区的鸢乌贼,对数据进行z-score标准化后,任选2维角质颚形态学参数以曼哈顿距离和欧氏距离进行K-means动态聚类分析,总正确区分率分别为86.7%和88.7%。K-means动态聚类算法对于鸢乌贼角质颚的识别有很大的参考价值,后续改进优化K-means算法使其具有普适性,将会提高鸢乌贼种群的识别能力。     

智利外海茎柔鱼角质颚微结构及其年龄与生长研究

文章利用2010年4-6月智利外海采集的148尾茎柔鱼(Dosidicus gigas)样品,分析了茎柔鱼角质颚微结构,并对其年龄和生长进行了研究。结果表明,茎柔鱼角质颚上颚喙部截面由头盖和脊突两部分向前延伸组合而成,周期性生长带明显,每条生长带由明、暗两条生长纹组成,头盖与脊突部的生长纹交汇于内轴成"<"形。标记轮与异常结构的形成与个体发育期的特殊事件以及外界的突发事件有关。根据角质颚生长纹估算茎柔鱼日龄,推测茎柔鱼样本孵化日期为2009年3-11月,主要为6-7月;胴长与角质颚日龄呈显著的幂函数关系,其中雌性茎柔鱼胴长的平均瞬时生长率(Instantaneous growth rate,IGR)和绝对生长率(Absolute daily growth rates,AGR)分别为0.14%·d^-1和0.60 mm·d^-1,雄性茎柔鱼胴长的平均IGR和AGR分别为0.11%·d^-1和0.47mm·d^-1。研究结果为柔鱼类年龄鉴定和生长估算提供了新方法,并为中国开展头足类相关研究奠定了基础。     

利用角质颚研究头足类的年龄与生长

年龄与生长是渔业基础生物学研究的重要内容。体长频度法估算头足类的年龄并不可靠,然而利用硬组织来研究头足类的年龄和生长是最为有效的方法之一。角质颚作为头足类少数硬组织之一,具有结构稳定、耐腐蚀以及信息储存良好等特点而受到国内外学者的广泛关注。从角质颚的长度、角质颚生长纹的观察、初始纹的形成、生长纹周期性的证实以及日龄鉴定等方面综述了角质颚在头足类年龄和生长方面的研究进展。分析认为,尽管角质颚在头足类的年龄与生长的研究中已取得一定的进展,但是在利用生长纹鉴定年龄的方面还有所欠缺,较为成功仅为真蛸(Octopus vulgaris)和玛雅蛸(O.maya),缺乏对其他头足类种类的研究,需要在以后的研究过程中给予关注。     

The relationship between paralarval feeding and morphological changes in the proboscis and beaks of the neon flying squid <Emphasis Type="Italic">Ommastrephes bartramii</Emphasis>

We compared the diet of Ommastrephes bartramii paralarvae with morphological changes in their beaks and proboscis (fused tentacles). The paralarvae were collected north of the Hawaiian Islands during 2001 and 2002 and ranged in mantle length (ML) from 1.1 to 13.2 mm. They fed on crustaceans, including copepods (copepodite stage) and amphipods. The rostral tips of upper and lower beaks began to protrude anteriorly at around 3–4 mm ML, and the smallest paralarva with identifiable prey in its digestive tract was 4.2 mm ML, which suggests that the paralarvae can masticate prey soon after the beaks protrude. The proboscis separated into two tentacles at 9.3–13.2 mm ML, but the newly formed tentacles were weakly developed even in the largest specimen, suggesting that tentacles do not operate functionally and that the arms are used to capture prey.     

雏鸡断喙角度对成鸡嘴形和体重的影响

雏鸡断喙时，刀片与喙的切角不同，成鸡期嘴形各异，体重及死亡淘汰率不一。研究结果显示，刀片与上喙呈８０‘角瞬间切下，烫１ｓ 止血，成鸡期嘴形最好，经济效益最高。     

The influence of different beak trimming age on performance, H-L ratio and antibody production to SRBC in laying hens

The objectives of this study were to examine the effects of beak trimming age on performance criteria, H-L ratio, antibody production, the percentage of spleen and liver and external appearance. The chicks (Barred Rock) were randomly divided into 4 beak-trimming groups (non-trimmed (control), a trim at 1 d (1D), at 10 d (10D) and at 10 wk (10W)), each of 132 chicks. There were 6 replicate cages at beak trimming groups at rearing period. At 18 wk of age a total of 144 pullets were transferred to the layer house, and the pullets were housed at 323 and 646 cm²/hen with 8 and 4 birds per cage in three-deck layer cages. There were a total of 24 replications with 12 replications equally divided between the high and low density cages, and the beak trimmed treatments were randomly and equally divided within each density. As a result of this experiment differences among groups in body weight in rearing phase were disappear in the laying phase. Low feather condition was found in untrimmed hens. H-L ratio in both pullet and laying phase was higher in hens of untrimmed groups. Cage area affected all examined parameters except that body weight, mortality rate, cracked, broken and unshell egg rates, shell breaking, shape index, shell thickness, meat-blood spot rates, spleen and liver percentages, throat injures and antibody production to SRBC.     

西北太平洋北方拟黵乌贼角质颚色素沉积特性分析

角质颚是头足类重要的摄食器官,是研究头足类摄食生态的重要材料。为研究北方拟黵乌贼角质颚色素沉积特性,根据2018年9—11月中国鱿钓船在西北太平洋生产调查期间采集的268尾北方拟黵乌贼样本,对其渔业生物学数据进行测定,对其角质颚色素沉积等级进行划分,分析色素沉积等级是否存在性别间差异,并拟合色素沉积等级与胴长、体质量和角质颚外形参数的关系。结果发现,9—11月西北太平洋北方拟黵乌贼角质颚色素沉积等级以6级和7级为主,占样本总数的91.11%。色素沉积与胴长、体质量、角质颚外部形态(上头盖长、上脊突长、上喙长、下头盖长、下脊突长和下喙长)的关系均不存在性别间显著性差异,且均呈正相关,其决定系数R2分别为0.980 0、0.671 5、0.761 5、0.916 5、0.918 8、0.677 2、0.807 1和0.915 3。色素沉积等级与性腺成熟度关系也呈正相关,并随着性腺成熟度等级的增大而增大。研究表明,北方拟黵乌贼角质颚色素沉积等级与胴长、体质量、性腺成熟度和角质颚形态参数均呈正相关关系,总体上随着个体的生长而逐步增加。     

断喙对肉鸭啄羽及其生产性能的影响

选择200只1日龄樱桃谷肉鸭,随机分成试验和对照两组,每组100只。试验组于14日龄断喙,对照组正常饲养,观察肉鸭在饲养过程中啄羽情况,测量试验鸭增重、料肉比、死亡率等指标,结果表明肉鸭断喙能有效防止啄羽,提高生产性能,减少死亡率,试验组比对照组每只多增重175g,料肉比低0.3,死亡率降低6%,经济效益显著。