Department of Fish Pathology and Immunology, Stanisław Sakowicz Inland Fisheries Institute, Olsztyn, Poland.
Department of Microbiology and Clinical Immunology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
BMC Vet Res. 2020 Jun 26;16(1):216. doi: 10.1186/s12917-020-02432-1.
The aim of the study has been to compare the effect of dietary supplementation of β-1,3/1,6-glucan, Lactobacillus plantarum bacteria or their mixture on the growth performance, selected parameters of the immune system as well as the liver and intestinal histology of roach. Fish were fed for 14 days with four different diets, each treatment being carried out in triplicate. In control group, fish were fed dry commercial starter feed Aller Performa 2 (Aller Aqua, Denmark). The other experimental fish groups received the same commercial starter feed supplemented with: 1% β-1,3/1,6-glucan (Leiber® Beta-S) in group G; 10 cfu L. plantarum g in group L; 1% β-1,3/1,6-glucan + 10 cfu L. plantarum g in group G + L. The stimulating effect of the tested preparations was evaluated once the feeding with commercial feed exclusively was resumed and 2 weeks afterwards.
No effect on the survivability and growth performance of the fish was observed in any of the groups. Supplementation of feed with β-1,3/1,6-glucan improved (P < 0.05) selected parameters of innate humoral immunity and the pinocytotic activity of phagocytes. Increased respiratory burst activity of head kidney phagocytes (RBA) was observed in groups L and G + L (P < 0.05), and the effect persisted for 2 weeks after the commercial feed regime was resumed. An analogous tendency was determined for the killing activity of phagocytes (PKA) of the head kidney with respect to Aeromonas hydrophila, although this effect appeared only during the feed supplementation period. Supplying roach with β-1,3/1,6-glucan, singly or with L. plantarum, had no effect (P > 0.05) on the proliferation of mitogen-activated lymphocytes. However, an increase in the number of CD3-positive cells and goblet cells was noticed in the digestive system of the L group fish (P < 0.05).
The results show that feeding fish with added L. plantarum and β-1,3/1,6-glucan stimulates the non-specific resistance mechanisms and raises the counts of intestinal immune cells. Synbiotic may help to control serious bacterial diseases and offer an alternative to antibiotics commonly used in fish farming, and its prolonged immunostimulatory effect could increase fish surviving after release to the natural environment.
本研究旨在比较β-1,3/1,6-葡聚糖、植物乳杆菌或其混合物的饮食补充对斜带石斑鱼生长性能、免疫系统选择参数以及肝脏和肠道组织学的影响。鱼在四种不同的饮食中喂养了 14 天，每种处理重复三次。在对照组中，鱼以干粉商业起始饲料 Aller Performa 2（Aller Aqua，丹麦）喂养。其他实验组的鱼接受相同的商业起始饲料补充：G 组 1%β-1,3/1,6-葡聚糖（Leiber® Beta-S）；L 组 10cfu·mL-1 植物乳杆菌；G+L 组 1%β-1,3/1,6-葡聚糖+10cfu·mL-1 植物乳杆菌。在仅用商业饲料喂养后，评估了测试制剂的刺激作用，并在两周后进行了评估。
在任何一组中，都没有观察到对鱼的存活率和生长性能的影响。饲料中添加β-1,3/1,6-葡聚糖可改善（P<0.05）先天体液免疫的选择参数和吞噬细胞的胞饮活性。头肾吞噬细胞的呼吸爆发活性（RBA）在 L 组和 G+L 组中升高（P<0.05），并且在恢复商业饲料喂养后持续了 2 周。对头肾吞噬细胞的杀伤活性（PKA）对嗜水气单胞菌也有类似的趋势，尽管这种作用仅在饲料补充期间出现。单独或与植物乳杆菌一起向斜带石斑鱼投喂β-1,3/1,6-葡聚糖对有丝分裂原激活的淋巴细胞的增殖没有影响（P>0.05）。然而，在 L 组的鱼的消化系统中观察到 CD3 阳性细胞和杯状细胞的数量增加（P<0.05）。
结果表明，投喂添加植物乳杆菌和β-1,3/1,6-葡聚糖的鱼可刺激非特异性抗性机制并提高肠道免疫细胞的数量。合生元可能有助于控制严重的细菌性疾病，并为鱼类养殖中常用的抗生素提供替代方法，其延长的免疫刺激作用可以提高鱼在释放到自然环境后的存活率。
