Fish Rearing Lab., Aquaculture Division, National Institute of Oceanography and Fisheries (NIOF), Alexandria, Egypt.
Department of Animal and Fish Production, Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria, Egypt.
J Anim Physiol Anim Nutr (Berl). 2024 Sep;108(5):1370-1382. doi: 10.1111/jpn.13980. Epub 2024 Apr 30.
A 210-day experiment to assess the efficacy of substituting azolla plant powder at levels of 0, 20, 40, and 60% for fish meal on red tilapia fingerlings (RTF, initial weight of 18.23 ± 0.12 g) performance under salinity levels of 5, 18, and 28ppt. Among the various conditions, RTF-fed 20% azolla at 28 and 5ppt salinity showcased the highest specific growth rate (SGR), whereas the lowest SGR was observed in fish-fed 60% azolla at 5ppt salinity. Upon azolla incorporation, noteworthy elevations in phytoplankton, zooplankton, dissolved oxygen (DO), pH, NH, and NO were noted and conversely, azolla introduction led to decreased NH and NO concentrations in all salinity levels. Further, a significant (p < 0.05) interaction between azolla levels and water salinity (S×A) significantly impacted the hematological parameters of RTF. The highest levels of superoxide dismutase (SOD), catalase (CAT), and total protein (TP) were found in RTF-fed 20% azolla at 28ppt salinity, while the lowest CAT and TP levels occurred in RTF-fed 60% azolla at 5ppt salinity. The highest aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were recorded in the RTF group fed 60% azolla at 5ppt salinity, with the lowest values seen in the group given 20% azolla at 28ppt salinity. RTF fed a 20% azolla diet at 18ppt salinity exhibited the highest lysozyme value, in contrast to the lowest value observed in the RTF group fed the control diet at 18ppt salinity. In conclusion, this study recommends the utilization of azolla at inclusion levels ranging from 20 to 40%, as it has the potential to notably enhance the immune system and elevate the survival rate of RTF.
一项为期 210 天的实验旨在评估在盐度为 5、18 和 28ppt 的条件下，用替代水平为 0、20、40 和 60%的满江红植物粉替代鱼粉对红罗非鱼幼鱼（RTF，初始体重为 18.23±0.12g）生长性能的功效。在各种条件下，28 和 5 ppt 盐度下摄食 20%满江红的 RTF 表现出最高的特定生长率（SGR），而摄食 5 ppt 盐度下 60%满江红的 RTF 表现出最低的 SGR。在添加满江红后，浮游植物、浮游动物、溶解氧（DO）、pH、NH 和 NO 显著增加，相反，在所有盐度下，满江红的添加降低了 NH 和 NO 的浓度。此外，满江红水平和水盐度（S×A）之间存在显著的相互作用（p<0.05），显著影响了 RTF 的血液学参数。在 28 ppt 盐度下，摄食 20%满江红的 RTF 具有最高的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和总蛋白（TP）水平，而在 5 ppt 盐度下，摄食 60%满江红的 RTF 具有最低的 CAT 和 TP 水平。在 5 ppt 盐度下，摄食 60%满江红的 RTF 具有最高的天门冬氨酸氨基转移酶（AST）和丙氨酸氨基转移酶（ALT）水平，而在 28 ppt 盐度下，摄食 20%满江红的 RTF 具有最低的 AST 和 ALT 水平。在 18 ppt 盐度下，摄食 20%满江红的 RTF 具有最高的溶菌酶值，而在 18 ppt 盐度下摄食对照饲料的 RTF 组具有最低的溶菌酶值。总之，本研究建议满江红的添加水平在 20%至 40%之间，因为它具有显著增强 RTF 免疫系统和提高其存活率的潜力。
