养殖密度对罗氏沼虾生长、性别分化与性腺发育的影响

通过比较4个养殖密度(7.50×104、12.75×104、42.00×104、97.50×104尾/hm~2)条件下罗氏沼虾的生长、存活、性别分化、性腺发育等指标,研究养殖密度对罗氏沼虾生长、性别分化和早期性腺发育的影响。结果显示,在实验密度范围内,养殖密度显著影响罗氏沼虾的生长、规格整齐度、性别分化与性腺发育,随着实验时间延长,密度对生长的抑制效应越明显;7.50×104尾/hm~2组罗氏沼虾体质量增速加速度与97.50×104尾/hm~2组的倍数由养殖10 d时的2.3上升到80 d时的3.4;低密度组罗氏沼虾性别分化与性腺发育比高密度组早约10 d,但规格显著大于高密度组;7.50×104尾/hm~2组雌虾初始平均体长(4.158±0.592)cm比97.50×104尾/hm~2组大1.09 cm;养殖密度对性别比没有影响,但对雌虾成活率影响较大。研究表明,养殖密度显著影响罗氏沼虾生长和性腺发育,合适的养殖密度是预防罗氏沼虾性早熟的有效措施。

Effects of stocking density on growth, sexual differentiation and gonad development of Macrobrachium rosenbergii

The effect of stocking density on growth, sex differentiation and early gonadal development of M. rosenbergii were analyzed by the index (such as growth, survive, sex differentiation and gonadal development) under four stocking densities (7.50×104ind/hm2, 12.75×104ind/hm2, 42.00×104ind/hm2 and 97.50×104ind/hm2). The result showed that: in the stocking densities from 7.50×104ind/hm2 to 97.50×104ind/hm2, the growth, specification uniformity, sex differentiation and gonadal development of M. rosenbergii were significantly influenced by stocking density. With the time prolonged, the more growth inhibitory from stocking density appeared. The body weight gain acceleration of M. rosenbergii in group of 7.50×104ind/hm2 and 97.50×104ind/hm2 increased from 2.3 at 10d to 3.4 at 80d; the sex differentiation and gonadal development time of low stocking density groups is about 10d earlier than that of the high stocking density group, but the sex differentiation and gonadal development specification of low stocking densities is bigger than that of the high stocking densities. The initial average body length of female M. rosenbergii in group of 7.50×104ind/hm2 (4.158±0.592) cm is 1.09cm longer than that in group of 97.50×104ind/hm2; sex ratio was not influenced by stocking density, but the survival rate of female M .rosenbergii was significantly influenced: the external morphology scale and age were delayed by the influence of stocking density. The result showed that the growth and gonadal development were significantly influenced by stocking densities. Suitable stocking density is an effective measure to prevent the precocity of M. rosenbergii. These results provide a basis for the breeding production and genetic breeding of M. rosenbergii.