Refaey Mohamed M, Mehrim Ahmed I, Zenhom Osama A, Areda Hamada A, Ragaza Janice A, Hassaan Mohamed S
Animal Production Department, Faculty of Agriculture, Mansoura University, PO 35516 Al Mansoura, Egypt.
Central Laboratory for Aquaculture Research, Agriculture Research Center, Abbasa, Abou Hammad, Egypt.
Aquac Nutr. 2023 Jan 30;2023:1403704. doi: 10.1155/2023/1403704. eCollection 2023.
Azolla is a potential fish feed ingredient due to its high nutritional value, abundant production, and low price. This study is aimed at evaluating the use of fresh green azolla (FGA) as a replacement ratio of the daily feed intake on the growth, digestive enzymes, hematobiochemical indices, antioxidant response, intestinal histology, body composition, and flesh quality of monosex Nile tilapia, (with an average initial weight of 108.0 ± 5.0 g). Five experimental groups were used and differed in commercial feed replacement rates of 0% ( ), 10% ( ), 20% ( ), 30% ( ), and 40% ( ) with FGA for 70 days. Results showed that 20% replacement with azolla gave the highest values of growth performance and hematological parameters and the best feed conversion ratio, protein efficiency ratio, and fish whole body protein content. The highest levels of intestinal chymotrypsin, trypsin, lipase, and amylase were noted in 20% replacement with azolla. Fish fed diets with FGA levels of 10% and 40% showed the highest values for the thickness of the mucosa and submucosa layers among all treatments, respectively, while the length and width of the villi decreased significantly. No significant ( > 0.05) differences in the activities of serum alanine transaminase, aspartate transaminase, and creatinine were detected among treatments. The hepatic total antioxidant capacity and the activities of catalase and superoxide dismutase significantly ( < 0.05) increased while the activity of malonaldehyde decreased with increasing the replacement levels of FGA up to 20%. With increasing levels of dietary replacement with FGA, muscular pH, stored loss (%), and frozen leakage rate (%) were significantly decreased. Finally, it was concluded that the dietary replacement of 20% FGA or less may be considered a promising feeding protocol for monosex Nile tilapia, which may lead to high fish growth, quality, profitability, and sustainability for the tilapia production sector.
满江红因其高营养价值、产量丰富且价格低廉，是一种潜在的鱼类饲料成分。本研究旨在评估用新鲜绿满江红（FGA）替代每日饲料摄入量的比例，对单性尼罗罗非鱼（平均初始体重为108.0±5.0克）的生长、消化酶、血液生化指标、抗氧化反应、肠道组织学、鱼体组成和肉质的影响。实验设置了五个实验组，用FGA替代商业饲料的比例分别为0%（ ）、10%（ ）、20%（ ）、30%（ ）和40%（ ），实验持续70天。结果表明，用满江红替代20%时，生长性能和血液学参数的值最高，饲料转化率、蛋白质效率比和鱼体全蛋白含量最佳。用满江红替代20%时，肠道胰凝乳蛋白酶、胰蛋白酶、脂肪酶和淀粉酶的水平最高。在所有处理中，分别喂食含10%和40% FGA水平饲料的鱼，其粘膜层和粘膜下层的厚度值最高，而绒毛的长度和宽度显著降低。各处理组血清谷丙转氨酶、谷草转氨酶和肌酐的活性未检测到显著差异（>0.05）。随着FGA替代水平增加至20%，肝脏总抗氧化能力以及过氧化氢酶和超氧化物歧化酶的活性显著增加（<0.05），而丙二醛的活性降低。随着FGA日粮替代水平的增加，肌肉pH值、储存损失率（%）和冷冻渗漏率（%）显著降低。最后得出结论，日粮中20%或更低比例的FGA替代可能被认为是单性尼罗罗非鱼一种有前景的投喂方案，这可能会为罗非鱼生产部门带来高产量、高质量、高利润和可持续性。
