γ-氨基丁酸(GABA)是一种非蛋白质氨基酸,在动物的大脑和中枢神经系统中作为抑制性神经递质发现。它已被证明具有多种生理功能,包括减压和免疫增强。这项研究调查了日粮补充GABA对生长的影响,血清生物化学,先天免疫,在高放养密度下,幼年橄榄比目鱼(Paralichthysolivaceus)的抗病性受到塔达爱德华氏菌的挑战。准备了对照饮食和三种实验饮食,与150毫克/千克(GABA150),200mg/kg(GABA200),和250毫克/千克(GABA250)的GABA添加到每个饮食,分别。将每种实验饮食一式三份地饲喂橄榄比目鱼,初始重量为12.75g±0.3g,在40L罐中以两种放养密度:正常密度(20鱼/罐)和高密度(40鱼/罐)。经过8周的喂养试验,增长,饲料利用,全身近距离构图,血液分析,测量非特异性免疫反应,并进行了挑战测试。在两种放养密度下,饲喂补充GABA的日粮的鱼的体重增加(WG)和特定生长速率(SGR)没有显着差异。然而,正常密度组的WG和SGR显著高于高密度组(p<0.05)。各组之间的饲料效率和蛋白质效率比没有显着差异。此外,全身成分分析无显著差异(p>0.05)。在两种密度下,饲喂GABA的鱼的皮质醇水平没有显着差异,但是高密度组的皮质醇明显高于低密度组。无论密度组如何,血液GABA均以剂量依赖性方式显着增加(p<0.05)。超氧化物歧化酶活性明显高于对照组,但饲喂GABA日粮的鱼的放养密度没有显着影响(p<0.05)。饲喂GABA200和GABA250日粮的鱼中的髓过氧化物酶活性在两种放养密度下均显示出显着较高的水平(p<0.05)。溶菌酶活性在GABA150组中显著高于CON,GABA200和GABA250组(p<0.05)。在用Edwardsiellatarda进行了15天的挑战测试后,GABA150、GABA200和GABA250组的累积生存率显著高于CON组(p<0.05)。结果表明,幼年橄榄比目鱼培养的最佳饲粮GABA水平为150mg/kg,不管饲养密度如何,为了促进增长,豁免权,和抗病性。
Gamma-aminobutyric acid (GABA) is a non-protein amino acid that is found in the brain and central nervous system of animals as an inhibitory neurotransmitter. It has been shown to have a variety of physiological functions, including stress reduction and immune enhancement. This study investigated the effects of dietary supplementation with GABA on growth, serum biochemistry, innate immunity, and disease resistance in juvenile olive flounders (Paralichthys olivaceus) challenged with Edwardsiella tarda under high-stocking density. A control diet and three experimental diets were prepared, with 150 mg/kg (GABA150), 200 mg/kg (GABA200), and 250 mg/kg (GABA250) of GABA added to each diet, respectively. Each experimental diet was fed to olive flounders in triplicate with an initial weight of 12.75 g ± 0.3 g in 40 L tanks at two stocking densities: normal density (20 fish/tank) and high density (40 fish/tank). After 8 weeks of the feeding trial, growth, feed utilization, whole-body proximate compositions, blood analyses, and non-specific immune responses were measured, and challenge tests were performed. There were no significant differences in the weight gain (WG) and specific growth rate (SGR) among fish fed the GABA-supplemented diets at the two stocking densities. However, the normal-density groups showed significantly higher WG and SGR than the high-density groups (p < 0.05). There was no significant difference in feed efficiency and protein efficiency ratio among all groups. Moreover, there was no significant difference in the whole-body proximate composition analysis (p > 0.05). There were no significant differences in cortisol levels in fish fed the GABA at both densities, but the high-density group showed a significantly higher cortisol than the low-density group. Blood GABA significantly increased in a dose-dependent manner regardless of the density groups (p < 0.05). Superoxide dismutase activity showed significantly higher levels than the control group, but there was no significant effect of the stocking densities in fish fed the GABA diets (p < 0.05). Myeloperoxidase activities in fish fed the GABA200 and GABA250 diets showed significantly higher levels at both of the stocking densities (p < 0.05). Lysozyme activity was significantly higher in the GABA150 group than in the CON, GABA200, and GABA250 groups (p < 0.05). After 15 days of challenge tests with Edwardsiella tarda, the cumulative survival rates of the GABA150, GABA200, and GABA250 groups were significantly higher than that of the CON group (p < 0.05). The results suggested that the optimal dietary GABA level for juvenile olive flounder culture is 150 mg/kg, regardless of rearing density, to enhance growth, immunity, and disease resistance.