School of Molecular and Life Sciences, Curtin University, Bentley, WA, Australia.
Department of Fisheries Biology & Genetics, Faculty of Fisheries, Patuakhali Science and Technology University, Patuakhali, Bangladesh.
PLoS One. 2020 Nov 12;15(11):e0242079. doi: 10.1371/journal.pone.0242079. eCollection 2020.
The present study investigates if the total replacement of dietary fishmeal (FM) with poultry by-product meal (PBM), supplemented with methionine influences the muscle fatty acids composition, normal gut morphology, histological traits of the liver, muscle, and gill, liver enzymes, immune and antioxidant response, and stress-related gene in juvenile barramundi, Lates calcarifer in relation to growth and feed utilization. Barramundi (3.58±0.01g) were randomly distributed into six 300 L seawater recirculating tanks (25 fish/tank) and fed two formulated isonitrogenous and isolipidic diets for 6 weeks. The control diet had FM as the sole animal protein source, whereas other test diet had only PBM as an animal protein source. Dietary PBM affected the fish performance and feed utilization. Regarding muscle fatty acid profile, total saturated fatty acids and monounsaturated fatty acids elevated while total PUFA particularly n-3 LC-PUFA and EPA decreased in PBM fed fish than control diet fed fish. Liver, muscle, gill, and intestinal histology showed no obvious alteration in control diet fed fish, however, more lipid droplets and hepatic vacuolization in the liver, necrotic myotome in muscle, hyperplasia in secondary lamellae in gill and short and broken folds in the intestine were observed in PBM fed fish. Similar to light microscopy observation of intestinal morphology, the transmission electron microscopy (TEM) analysis revealed shorter and smaller microvilli in fish fed PBM. Histopathological alterations in the liver of PBM fed fish were further associated with the elevated levels of aspartate aminotransferase (AST) and glutamate dehydrogenase (GLDH) and the significant upregulation of stress-related genes, HSP70 and HSP90. Also, a negative influence on lysozyme activity, and antioxidant enzymatic activities were recorded in fish fed PBM. Overall, it can be concluded that a total substitution of FM protein by methionine supplemented PBM negatively influenced the growth performance, liver health, histological traits of different organs, immune and antioxidant response, and expression of stress-related genes in juvenile barramundi.
本研究探讨了用蛋鸡副产物粉（PBM）完全替代饲料中的鱼粉（FM），并补充蛋氨酸，是否会影响幼鱼（Lates calcarifer）肌肉脂肪酸组成、正常肠道形态、肝脏、肌肉和鳃的组织学特征、肝酶、免疫和抗氧化反应以及与应激相关的基因，同时考察其对生长和饲料利用的影响。将 3.58±0.01g 的幼鱼随机分配到六个 300L 的海水循环水箱（每个水箱 25 条鱼）中，并用两种等氮等脂的配方饲料喂养 6 周。对照组饲料以 FM 作为唯一的动物蛋白来源，而其他试验组饲料仅以 PBM 作为动物蛋白来源。饲料 PBM 影响了鱼的生长性能和饲料利用率。就肌肉脂肪酸组成而言，与对照组相比，PBM 组的总饱和脂肪酸和单不饱和脂肪酸升高，而总多不饱和脂肪酸（PUFA）特别是 n-3 长链多不饱和脂肪酸（LC-PUFA）和 EPA 降低。对照组鱼的肝脏、肌肉、鳃和肠道组织学未见明显变化，但 PBM 组鱼的肝脏中出现更多的脂滴和空泡化、肌肉中出现坏死的肌节、鳃中次级鳃片增生以及肠道中短小而断裂的褶皱。与肠道形态的光镜观察相似，透射电子显微镜（TEM）分析显示 PBM 组鱼的微绒毛更短、更小。PBM 组鱼肝脏的组织病理学变化与天冬氨酸转氨酶（AST）和谷氨酸脱氢酶（GLDH）水平升高以及应激相关基因 HSP70 和 HSP90 的显著上调有关。此外，还记录到 PBM 组鱼的溶菌酶活性和抗氧化酶活性受到负面影响。总的来说，用补充蛋氨酸的 PBM 完全替代 FM 蛋白会对幼鱼的生长性能、肝脏健康、不同器官的组织学特征、免疫和抗氧化反应以及与应激相关的基因表达产生负面影响。
