Talukdar Sandipan, Ghosh Koushik
Aquaculture Laboratory, Department of Zoology, The University of Burdwan, Golapbag, Burdwan, 713104, West Bengal, India.
Department of Zoology, Gorubathan Government College, Fagu, Kalimpong, 735231, West Bengal, India.
Fish Physiol Biochem. 2025 Jan 6;51(1):3. doi: 10.1007/s10695-024-01422-6.
The present study evaluated the potential of Ashoka, Saraca asoca leaf meal (SLM), in carp diets following fermentative processing with a tannase-producing fish gut bacterium, Bacillus subtilis (KP765736). The processing of SLM led to a significant (P < 0.05) reduction in major anti-nutrients (tannin, trypsin inhibitor, and crude fiber), while crude protein content increased. Seven sets of isonitrogenous (35% crude protein) and isocaloric (18.82 kJg) diets were prepared using raw (R1, R2, R3) and fermented SLM (F1, F2, F3) at 10%, 20%, and 30% levels by weight replacing fishmeal and de-oiled rice bran in the reference diet (RD). Diets were fed to rohu, Labeo rohita fingerlings (4.01 ± 0.08 g), for 70 days in triplicate. Fish fed diets containing 30% fermented SLM (F3) exhibited significantly (P < 0.05) better growth (241.25%), improved nutrient utilization, and enhanced activities of digestive enzymes compared to raw SLM-fed groups. Furthermore, tannin accumulation in the liver and muscle was significantly lower (P < 0.05) in fish fed fermented SLM diets compared to those fed raw SLM diets. Additionally, tannin contents in the diets were noticed to be positively correlated (P < 0.05) with tannin accumulation in fish tissues and negatively correlated (P < 0.05) with growth. Hepatic and muscle enzymes associated with carbohydrate metabolism in fish fed RD performed similarly to those reared on fermented SLM diets. Conversely, key enzymes involved in protein metabolism, hexose monophosphate shunt, and the tri-carboxylic-acid cycle showed increased activities in fish fed raw SLM diets, indicating dietary stress and a shift from carbohydrate metabolism to protein catabolism. Moreover, protein, glycogen, and amino acids in hepatopancreas and muscle showed a progressive increase with the gradual inclusion of fermented SLM in the diets. In conclusion, this study might suggest incorporating 30% (w/w) fermented SLM in the diets of rohu without interfering with growth, feed utilization, and metabolic function.
本研究评估了经产单宁酶的鱼肠道细菌枯草芽孢杆菌（KP765736）发酵处理后的无忧花（Saraca asoca）叶粉（SLM）在鲤鱼饲料中的应用潜力。SLM的处理使主要抗营养物质（单宁、胰蛋白酶抑制剂和粗纤维）显著（P < 0.05）减少，而粗蛋白含量增加。使用生的（R1、R2、R3）和发酵的SLM（F1、F2、F3），按重量的10%、20%和30%水平替代参考饲料（RD）中的鱼粉和脱脂米糠，制备了七组等氮（35%粗蛋白）和等热量（18.82 kJ/g）的饲料。将饲料投喂给平均体重为（4.01 ± 0.08 g）的露斯塔野鲮（Labeo rohita）鱼种70天，每组设三个重复。与投喂生SLM饲料的组相比，投喂含30%发酵SLM（F3）饲料的鱼生长显著更好（提高了241.25%），营养物质利用率提高，消化酶活性增强（P < 0.05）。此外，与投喂生SLM饲料的鱼相比，投喂发酵SLM饲料的鱼肝脏和肌肉中的单宁积累显著更低（P < 0.05）。此外，发现饲料中的单宁含量与鱼组织中单宁积累呈正相关（P < 0.05），与生长呈负相关（P < 0.05）。投喂RD饲料的鱼中与碳水化合物代谢相关的肝脏和肌肉酶的表现与投喂发酵SLM饲料饲养的鱼相似。相反，参与蛋白质代谢、磷酸戊糖途径和三羧酸循环的关键酶在投喂生SLM饲料的鱼中活性增加，表明存在饮食应激以及从碳水化合物代谢向蛋白质分解代谢的转变。此外，随着饲料中逐渐添加发酵SLM，肝胰腺和肌肉中的蛋白质、糖原和氨基酸呈逐渐增加趋势。总之，本研究可能表明在露斯塔野鲮饲料中添加30%（w/w）发酵SLM不会干扰其生长、饲料利用和代谢功能。
