饥饿对于花[鱼骨]肌肉和血清主要生化指标的影响

于20.50±2.15℃的条件下,在室内1 m3的水泥池中进行了为期42 d的饥饿实验,分别在实验开始后的1、7、14、28、42 d取样,以观察饥饿对花背部肌肉和血清主要生化指标的影响。结果表明:花对饥饿忍受能力较强,在实验期间无死亡现象;在饥饿初期花首先快速利用肌肉脂肪作为能量供给,后期则主要以肌肉蛋白作为能量来源,肌肉的水分含量不断升高,灰分含量则以不规则的锯齿状变化;花血清中的血糖对饥饿特别敏感,在14 d内显著下降(P<0.05),之后,保持在动态的恒定水平,而总蛋白质、甘油三脂、总胆固醇、谷丙转氨酶、谷草转氨酶、碱性磷酸酶则在饥饿实验中以波浪状变化并呈下降趋势。     

花(鱼骨)耗氧率和窒息点的初步研究

实验测定了花的耗氧率和窒息点,并对耗氧率的昼夜变化规律以及体重对其窒息点的影响进行了研究。结果表明,在实验温度(10~25℃)条件下,花的耗氧率随温度的升高而增大,随体重的增加而降低;耗氧率(R0)与温度(T)和体重(W)的二元线形回归方程是:R0=0.022T-0.001W-0.05,复相关系数为0.926,F检验表明,花的耗氧率与温度和体重之间有极显著复相关关系;花的耗氧率具有昼夜节律性,耗氧高峰出现在凌晨3:00,低谷是在上午11:00;花的窒息点与体重显著相关,窒息点A(mg/L)与体重W(g)的相关关系表示为:A=0.2671W0.2801,随体重的增加而升高。     

武昌南湖花个体生殖力的研究

本文对武昌南湖149尾雌性花Ⅳ期卵巢的个体绝对生殖力(r)和个体相对生殖力(r/L.r/W_n)的研究结果表明:花个体绝对生殖力与体长呈曲线相关,其回归方程为r=2399×10~(-5)·L～(4·500);与纯体重的关系则为直线正相关,其回归方程为r=181W_n-2257;花个体相对生殖力(r/L)随体长、纯体重的增长而增长:个体相对生殖力(r/W_n)与体长、纯体重的关系则基本保持较为稳定的状态。花个体绝对生殖力和相对生殖力(r/L)与年龄、成熟系数、鱼卵直径不同程度地呈正相关关系。花个体绝对生殖力的年增长率与绝对增长数以2冬龄为最高,3冬龄次之。     

海水网箱养殖的关键生物过程研究:花鲈生理代谢

2004年4～12月对爱伦湾抗风浪网箱养殖区养殖花鲈(Lateolabrax japonieus)的现存量、生长进行了实地调查和模型分析.结果表明,7～9月是研究爱伦湾鱼类养殖水域养殖容量的关键季节.夏季鱼类的摄食最活跃,鲈鱼的摄食率为1.4%～4.4%,8月最大.残饵率在11.0%～28.0%之间,7～9月最高.1个养殖周期内,约有38.6 t DO被养殖鲈鱼消耗,7～9月进入耗氧高峰期.养殖鱼类在网箱养殖区域的营养盐循环中起着重要的作用.花鲈4～12月向爱伦湾输出0.8 t氨氮,1.0～1.6 t N.在面积(2.0×105)m2的抗风浪网箱养殖区,养殖鱼类因排泄而再循环的N能满足浮游植物生产所需N的17.2%～27.5%.养殖花鲈因排粪向水体输出12.0 t颗粒物.     

鲈鱼在微冻保鲜过程中的质量变化

以感官评价、细菌总数、T-VBN、pH、ATPase活性、K等作为鲜度指标,研究鲈鱼在微冻(-3℃)保鲜过程中的质量变化规律,评价鲈鱼微冻保鲜的可行性.结果表明,鲈鱼在微冻过程中,①感官评分变化在前、中、后3个10天内下降速度分别为0.07、0.09、0.12分/天,但差异不显著;②细菌总数变化第30天下降至初始菌数的1/100;③T-VBN变化第30天时为0.156 6 mg/g,远未达到2级鲜度指标上限;④pH变化前10天一直下降,第10天最低为6.3,而后缓慢上升;⑤ATPase活性下降速度很快,第20天下降至0.005 3μmol/(min@mg),基本丧失活性;⑥K变化前5天由5.2%迅速升到22.33%,此后上升速度趋于缓慢,第30天达到34.362%.微冻可以明显抑制其细菌总数的增长,并维持其较低的T-VBN和K值.但是,微冻条件下鲈鱼的蛋白质变性速度较快.     

使用颗粒饵料养殖鲈鱼试验

本文报道了颗粒饵料养殖鲈鱼的效果。结果表明；使用颗粒产与使用鱼浆比较，鲈鱼增重率提高２．７０％，饵料系数降低２７．６％。     

花鲈鱼种日摄食节律的初步研究

花鲈鱼种的摄食具有明显的昼夜节律性，其摄食活动主要在白天进行，并以５：００￣６：００和１５：００￣１８：００最为活跃，表现出晨昏摄食的特点，花鲈的日摄食强度随日投饲次数的增加而增大，但增幅逐步减小，日摄食率与日投饲次数之间近似幂函数关系：Ｙ＝５．４４２０Ｘ＾０．１０９，饲料的能量转换效率随日投饲次数的增加而提高，日投喂四次时，接近最高值，若继续增加日投饲次数，能量转换效率不再明显提高。     

花鲈在短期周期性饥饿下的补偿生长

试验设3个饥饿处理组和1个对照组,研究花鲈在短期周期性饥饿下的补偿生长。试验结果表明,不同饥饿处理下的花鲈具有部分补偿生长能力,再投喂下的干物质摄食率(FR)显著高于对照组(P<0.0001),但饲料效率(FE)与对照组相比差异不显著(P<0.05),表明花鲈在短期周期性饥饿下的补偿生长通过提高摄食率实现。花鲈在补偿生长期间的生长效率大幅度提高,在投喂时间为对照组50%的条件下,周期性饥饿7 d(SR77)和周期性饥饿2 d(SR22)组平均特定生长率达到对照组的70.0%。     

Effects of six alternative lipid sources on growth and tissue fatty acid composition in Japanese sea bass (Lateolabrax japonicus)

Ten-week experiment was carried out on Japanese sea bass (5.87 ± 0.02 g) to study the effects of replacement of fish oil with six alternative lipid sources: pork lard, PL; beef tallow, BT; poultry fat, PF; soybean oil, SO; corn oil, CO; and a mixed-fat (MF: tallow, 60%; soy oil, 20%; fish oil, 20%) on growth performance and fatty acid (FA) composition in fillet and liver. Seven isoenergetic and isonitrogenous experimental diets were formulated, containing 10% of added lipid. Fish oil was used in control diet, which was substituted by 50% with the alternative lipid sources in the other six diets.

Weight gain (WG), specific growth rate (SGR), Feed conversion ratio (FCR) feed intake and hepatosomatic index (HSI) of fish fed the experimental diets were not significantly different (P > 0.05). Protein efficiency ratio (PER) in fish fed the PF diet were significantly lower than those of fish fed SO and CO diets. Significant differences in carcass moisture and lipid contents of carcass and liver were observed among fish fed the dietary treatments. Generally, the fatty acid composition of fish fillets and livers reflected the dietary FA composition.     

Daily age and food habits of Lateolabrax latus larvae and juveniles occurring in the innermost shallow waters of Uwajima Bay, Japan

ABSTRACT:   Daily age and food habits of Lateolabrax latus larvae and juveniles were investigated at two different habitats in Uwajima Bay, western Shikoku, Japan. In the shallow zone at Miura, which contained eelgrass beds, larvae occurred from January and were collected abundantly in March. The size, age, and hatch-date distributions suggested that late-hatched specimens stay longer than early-hatched specimens at this station. On the contrary, in the intertidal flats of the Kunomura River mouth larvae were rarely collected, but juveniles were collected in relative abundance from April. The distributions in the intertidal flats station suggested that specimens had migrated from another location and then resided in the intertidal flats. Spatial and temporal trophic variations increased remarkably with metamorphosis, and thus, the spatial differences in growth rate were considered in relation to the trophic diversity of prey items. Our results suggest that the nursery environment, nursery utilization pattern, and food habits of early life stages of L. latus show remarkable flexibility. From the similarity of these ecological aspects with L. japonicus , which is a closely related species, we suggest the important role of the interspecific competition to the realized niche difference between Lateolabrax congeners.