圆筒吻鮈的年龄生长及鱼体的化学组成和能量密度

On Age,Growth,Chemical Composition and Energy Density in Rhinogobio cylindricus

2010年10月于长江木洞江段采集圆筒吻鮈Rhinogobio cylindricus 107尾,其中1～4龄雌鱼67尾,1～3龄雄鱼40尾,分别测定鱼体脊椎骨轮径、化学组成及能量密度.随着年龄的增加,圆筒吻鮈雌鱼、雄鱼鱼体体长和体质量的特定生长率(SGR)均呈下降趋势,而其肥满度变化趋势不明显.同龄组圆筒吻鮈雌、雄鱼之间各化学组成没有显著差异.其总样本的含水量(WAT)、脂肪质量分数(FAT)、蛋白质质量分数(PRO)、灰分质量分数(ASH)和能量密度(E)的平均值范围分别为68.07%～70.27%,10.43%～11.87%,11.58%～15.65%,3.19%～3.36%和7.61～8.36kJ/g;鱼体含水量随年龄增加呈下降趋势,1龄组鱼蛋白质质量分数显著低于其他3组,4龄组鱼能量密度显著高于其他3组,而脂肪质量分数和灰分质量分数在各年龄组之间差异不显著.蛋白质质量分数与体长和体质量的关系式为PRO=0.331L+8.344(r=0.66,n=107,p<0.05)和PRO=0.026 2 M+12.119(r=0.58,n=107,p<0.05);脂肪质量分数和能量密度与含水量存在显著负线性关系,得到方程FAT=-0.910 WAT+74.31(r=0.82,n=107,p<0.05)和E=-0.378WAT+34.10(r=0.97,n=107,p<0.05).通过讨论认为该种鱼较高的脂肪质量分数与其活动范围小、身体消耗量小及全年不停食的生活习性相关.

107 specimens of Rhinogobio cylindricus including 67 females of 1-4 year age and 40 males of 1-3 year age were collected from Yangtse River in October,2010,and Spine wheel diameter,chemical compositions and energy density measured respectively.The specific growth rate（SGR） of the body length and body weight all decreased with increasing age in both female and male fish,meanwhile fullness varied erratically.There is no significant difference between the female and male in terms of the chemical compositions at the same age.The contents of water（WAT）,lipid（FAT）,protein（PRO）,ash（ASH）,and energy density（E） are in the ranges of 68.07%-70.27%,10.43%-11.87%,11.58%-15.65%,3.19%-3.36%,and 7.61-8.36 kJ/g respectively.WAT decreases with increasing age,and PRO of 1 year age group is significantly lower than the other groups.The E of 4 year age group is significantly higher than the other groups.The relation between the PRO and body length or body weight are expressed as PRO=0.331L＋8.344（r=0.66,n=107,p0.05）,and PRO=0.026 2 M＋12.119（r=0.58,n=107,p0.05）.Both FAT and E are negatively correlated with the WAT,and the regression equations described as FAT=-0.910WAT＋74.31（r=0.82,n=107,p0.05）,and E=-0.378WAT＋34.10（r=0.97,n=107,p0.05）.The discussion suggests that higher lipid content in R.cylindricus might be result from its ecological habits such as small range of activity,low consumption of body,and feeding around the year.