School of Integrative Biology, The University of Queensland, St Lucia, QLD 4072, Australia.
J Fish Biol. 2009 Jan;74(1):77-89. doi: 10.1111/j.1095-8649.2008.02110.x.
Muscle morphology was investigated in newly hatched barramundi Lates calcarifer larvae incubated at set temperatures (26, 29 and 31 degrees C) prior to hatching. Three days after hatching (the start of exogenous feeding), larvae from the 26 and 31 degrees C treatments were each divided into two groups and reared at that temperature or transferred over the period of several hours to 29 degrees C (control temperature). Incubation temperature significantly affected muscle cellularity in the developing embryo, with larvae incubated at 26 degrees C (mean +/-s.e. 223.3 +/- 7.9) having on average 14.4% more inner muscle fibres than those incubated at 31 degrees C (195.2 +/- 8.8) and 4.8% more than those incubated at 29 degrees C (213.5 +/- 4.7). Conversely, inner muscle fibre cross-sectional area significantly increased at the warm incubation temperature in L. calcarifer, so that the total cross-sectional muscle area was not different between treatment groups. The total cross-sectional area of superficial muscle fibres and the proportion of superficial to total fibre cross-sectional area in just hatched L. calcarifer were also affected by incubation temperature, with incubation at the cool temperature (26 degrees C) increasing both the total cross-sectional area and proportion of superficial muscle fibres. By 9 days post-hatch, the aforementioned differences were no longer significant. Similarly, there was no difference in total superficial fibre cross-sectional area between any treatment groups of L. calcarifer, whereas incubation temperature still significantly affected the proportion of superficial to total muscle fibre cross-sectional area. Larvae hatched and grown at 31 degrees C had a significantly reduced percentage of superficial muscle cross-sectional area (mean +/-s.e. 5.11 +/- 0.66%) compared with those incubated and grown at 29 degrees C (8.04 +/- 0.77%) and 26 degrees C (9.32 +/- 0.56%) and those incubated at 26 degrees C and transferred to 29 degrees C (7.52 +/- 0.53%), and incubated at 31 degrees C and transferred to 29 degrees C (6.28 +/- 0.69%). These results indicate that changes in muscle cellularity induced by raising or lowering the incubation temperature of L. calcarifer display varying degrees of persistence over developmental time. The significance of these findings to the culture of L. calcarifer is discussed.
在孵化前，将新孵化的巴沙鱼（Lates calcarifer）幼虫分别在设定的温度（26、29 和 31°C）下孵化，研究了肌肉形态。孵化后 3 天（开始外源性摄食），将 26 和 31°C 处理的幼虫分成两组，分别在该温度下饲养或在数小时内转移至 29°C（对照温度）。孵化温度显著影响胚胎发育中的肌肉细胞密度，在 26°C 孵化的幼虫（平均值±s.e.223.3±7.9）比在 31°C（195.2±8.8）孵化的幼虫多 14.4%的内肌纤维，比在 29°C（213.5±4.7）孵化的幼虫多 4.8%。相反，在温暖的孵化温度下，L. calcarifer 的内肌纤维横截面积显著增加，因此处理组之间的总肌纤维横截面积没有差异。刚孵化的 L. calcarifer 的浅肌纤维总横截面积和浅肌纤维与总肌纤维横截面积的比例也受到孵化温度的影响，在凉爽的温度（26°C）下孵化会增加浅肌纤维的总横截面积和比例。孵化后 9 天，上述差异不再显著。同样，L. calcarifer 的任何处理组之间的浅肌纤维总横截面积也没有差异，而孵化温度仍然显著影响浅肌纤维与总肌纤维横截面积的比例。在 31°C 孵化和生长的幼虫的浅肌纤维横截面积百分比显著降低（平均值±s.e.5.11±0.66%），与在 29°C（8.04±0.77%）和 26°C（9.32±0.56%）孵化和生长的幼虫以及在 26°C 孵化和转移至 29°C（7.52±0.53%）的幼虫以及在 31°C 孵化和转移至 29°C（6.28±0.69%）的幼虫相比。这些结果表明，L. calcarifer 孵化温度升高或降低引起的肌肉细胞密度变化在发育时间上具有不同程度的持续性。讨论了这些发现对 L. calcarifer 养殖的意义。
