This research was conducted to evaluate the effects of lysophospholipid (LPL) on growth, biochemical indices, nutrient digestibility, digesta viscosity and liver histology in rainbow trout fed fat powder diets. Three hundred fish with an average individual weight of 25.43 ± 1.93 were divided into five dietary groups each in triplicates. Experimental diets formulated based on addition of four levels of LPL (0, 3, 6 and 9 g kg⁻¹) to a basal diet containing fat powder. There was also a fish oil-based diet as positive control. After 56 days of trial, measuring growth parameters suggested significantly improvement of body weight, specific growth rate and feed conversion ratio in LPL 9 compared to other diets containing fat powder; however, control fish oil diet resulted in the highest values (p < .05). Cholesterol values decreased by addition of LPL to the diets containing fat powder (p < .05). On the contrary, triglyceride concentration increased by LPL administration. Inclusion of fat powder to the diet reduced body fat and fat digestibility (p < .05); however, these parameters were improved by administration of 9 g kg⁻¹ LPL. Also, viscosity of diet and digesta was decreased in LPL 9 (p < .05). Contrarily, ascending trend displayed in lipase activity by increasing LPL levels. Moreover, the replacement of fish oil by fat powder in the diet led to enlargement of hepatocytes nuclei, however, addition of LPL levels reduced nucleus size (p < .05). Also, sinusoids content developed in liver of fish fed fat powder (p < .05). This study suggests that rainbow trout can digest fat powder and also reduces side effects of fat powder with the help of LPL when fat powder is replaced with fish oil.

中文翻译：

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饲喂脂肪粉日粮时溶血磷脂对虹鳟鱼 (Oncorhynchus mykiss) 生长、生化指标、营养物质消化率和肝脏组织形态学的影响

本研究旨在评估溶血磷脂 (LPL) 对虹鳟鱼脂肪粉日粮的生长、生化指标、养分消化率、食糜粘度和肝脏组织学的影响。平均个体重量为 25.43 ± 1.93 的 300 条鱼被分成五个饮食组，每组一式三份。基于向含有脂肪粉的基础日粮中添加四种水平的 LPL（0、3、6 和 9 g kg ^{-1 ）配制的实验日粮。}还有一种以鱼油为基础的饮食作为阳性对照。经过 56 天的试验，测量生长参数表明，与其他含有脂肪粉的日粮相比，LPL 9 的体重、比生长率和饲料转化率显着提高；然而，控制鱼油饮食导致最高值（p < .05)。在含有脂肪粉的日粮中添加 LPL，胆固醇值降低 ( p  < .05)。相反，LPL 给药增加了甘油三酯浓度。日粮中添加脂肪粉会降低体脂和脂肪消化率（p  < .05）；然而，这些参数通过施用 9 g kg ^-1 LPL 得到改善。此外，LPL 9 中日粮和食糜的粘度降低（p  < .05）。相反，通过增加 LPL 水平显示脂肪酶活性呈上升趋势。此外，在饮食中用脂肪粉代替鱼油导致肝细胞核增大，然而，添加 LPL 水平会减小细胞核大小（p < .05)。此外，喂食脂肪粉的鱼的肝脏中出现了正弦曲线含量 ( p  < .05)。这项研究表明，虹鳟鱼可以消化脂肪粉，并且在用鱼油代替脂肪粉时，还可以在 LPL 的帮助下减少脂肪粉的副作用。