Adeshina Ibrahim, Paray Bilal Ahamad, Bhat Eijaz Ahmed, Sherzada Shahid, Fawole Olaolu O, Bawa Dalhatu J, da Cruz Thais Pereira, Tiamiyu Lateef O
School of Aquaculture, National University of Agriculture, Port Nove, Benin.
Department of Aquaculture and Fisheries, University of Ilorin, Ilorin, Nigeria.
Aquac Nutr. 2024 Oct 28;2024:5263495. doi: 10.1155/2024/5263495. eCollection 2024.
One of the most farmed fishes is the African catfish, . Its production has increased by 20% annually on average during the last 20 years, but the occurrence of fish diseases, especially bacterial such as infections, is hindering its activities. Also, the incorporation of plant-derived substances in aquafeeds is limited since they frequently contain different antinutritional factors, like nonstarch polysaccharides (NSPs). However, supplementing fish diets with -mannanase could increase growth, antioxidants, and immunity. Despite the advantage of -mannanase, its effects on growth, digestive enzymes, antioxidants, and immunity in African catfish need to be elucidated. This study examined the effects of dietary β-mannanase on the growth performance, liver enzymes, antioxidant profiles, immunity, and protection of African catfish, , against infection. Five isonitrogenous diets were prepared to have 400 g/kg crude protein and supplemented with -mannanase at 0, 1500, 3000, 4500, or 6000 thermostable endo, 1,4--mannanase units (TMUs)/kg diet and fed to 300 juveniles of the African catfish, (mean weight 12.1 ± 0.1 g) for 12 weeks. Then, 10 fish from each tank received an intraperitoneal injection of 0.1 mL of (5.0 × 10 CFU/mL) and observed for 14 days. Results showed dietary -mannanase levels considerably improved growth performance but did not affect fish survival. Also, amylase, protease, and lipase levels were significantly promoted in the fish fed with -mannanase-fortified diets than the control group ( < 0.05). Enhanced gut villi and intestinal absorption areas, haematlogical profiles, and liver enzymes but reduced gut viscosity were observed in fish-fed -mannanase-fortified diets ( < 0.05). In a dose-dependent order, including -mannanase in the meals of African catfish raised the levels of glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione-S-transferase (GST), and glutamate cysteine ligase (GCL) activities and decreased the malondialdehyde (MDA) values in African catfish ( < 0.05). Also, fish immunity was greatly ( < 0.05) enhanced due to supplementation of the diet with -mannanase. In addition, fish-fed diets comprising 6000 TMU -mannanase/kg diet showed the lowest rates of fish mortality (7.5%) ( < 0.05). Therefore, feeding African catfish, , -mannanase enhanced growth performance, increased activity of digestive enzymes, gut morphology, enhanced generation of short-chain fatty acids, digesta potential of hydrogen (pH), and improved antioxidant profiles and immunity at the optimum dose of 5800 TMU/kg diet. Additionally, -mannanase protected African catfish against infection.
养殖最多的鱼类之一是非洲鲶鱼。在过去20年里，其产量平均每年增长20%，但鱼类疾病的发生，尤其是诸如感染等细菌性疾病，正阻碍着其养殖活动。此外，植物源物质在水产饲料中的添加受到限制，因为它们常常含有不同的抗营养因子，如非淀粉多糖（NSPs）。然而，在鱼类日粮中添加β-甘露聚糖酶可以促进生长、提高抗氧化能力和增强免疫力。尽管β-甘露聚糖酶有这些优点，但其对非洲鲶鱼生长、消化酶、抗氧化能力和免疫力的影响仍有待阐明。本研究考察了日粮中β-甘露聚糖酶对非洲鲶鱼生长性能、肝脏酶、抗氧化指标、免疫力以及对感染的抵抗力的影响。制备了五种等氮日粮，粗蛋白含量为400 g/kg，并分别添加0、1500、3000、4500或6000热稳定内切1,4-β-甘露聚糖酶单位（TMUs）/kg日粮，投喂给300尾非洲鲶鱼幼鱼（平均体重12.1±0.1 g），为期12周。然后，从每个水箱中选取10尾鱼腹腔注射0.1 mL（5.0×10⁷CFU/mL），并观察14天。结果表明，日粮中β-甘露聚糖酶水平显著改善了生长性能，但对鱼类存活率没有影响。此外，与对照组相比，投喂添加β-甘露聚糖酶日粮的鱼体内淀粉酶、蛋白酶和脂肪酶水平显著升高（P < 0.05）。在投喂添加β-甘露聚糖酶日粮的鱼中观察到肠道绒毛和肠道吸收面积增加、血液学指标和肝脏酶改善，但肠道粘度降低（P < 0.05）。以剂量依赖的方式，在非洲鲶鱼日粮中添加β-甘露聚糖酶提高了谷胱甘肽（GSH）、谷胱甘肽过氧化物酶（GPx）、超氧化物歧化酶（SOD）、谷胱甘肽-S-转移酶（GST）和谷氨酸半胱氨酸连接酶（GCL）的活性水平，并降低了非洲鲶鱼体内丙二醛（MDA）值（P < 0.05）。此外，由于日粮中添加了β-甘露聚糖酶，鱼类免疫力得到显著增强（P < 0.05）。此外，投喂含6000 TMU β-甘露聚糖酶/kg日粮的鱼死亡率最低（7.5%）（P < 0.05）。因此，以5800 TMU/kg日粮的最佳剂量投喂非洲鲶鱼β-甘露聚糖酶可提高生长性能、增加消化酶活性、改善肠道形态、增强短链脂肪酸生成、消化物氢电位（pH），并改善抗氧化指标和免疫力。此外，β-甘露聚糖酶可保护非洲鲶鱼免受感染。
