Abstract

Seaweeds can play an essential role in controlling antibiotic resistance for bacterial diseases. Three extracts of two brown seaweeds Padina tetrastromatica and Sargassum ilicifolium were investigated as growth promoters and to provide immune protection against Vibrio parahaemolyticus. Extracts of the two seaweeds were administered at 2.5 and 5 g kg⁻¹ with food for 45 days to Penaeus monodon juveniles. The maximum weight gain (6.28 and 7.08 g), specific growth rate (3.39 and 3.32%), and survival rate (78.45 and 82.45%) of the juvenile tiger shrimp were obtained at a dose of 5 g kg⁻¹ with P. tetrastromatica extracted by methanol and ethanol, respectively; which was significantly higher than the other solvents and control group (p < .01). On the other hand, methanol extract of both seaweeds had maximal antibacterial activity against V. parahaemolyticus with zones of inhibition ranging between 20.25 ± 1.00 and 22.00 ± 0.50 mm. The minimal time required for haemolymph clotting was with methanol extracted of P. tetrastromatica at 5 g kg⁻¹, which was significantly lower than the other groups (p < .05). After challenging with V. parahaemolyticus, the total haemocyte count (THC) in P. monodon treated with methanol-extract of P. tetrastromatica diet at 5 g kg⁻¹ was higher (5.42 × 10⁵ cells mL⁻¹) but not significantly different than the other diets (p > .05). However, the administration of 5 g kg⁻¹ methanol and ethanol extract of P. tetrastromatica improved growth performance and the immune capacity of P. monodon by increasing their phenoloxidase activity, superoxide anion concentration, and resistance against V. parahaemolyticus.

• HIGHLIGHTS

• The maximum growth performance and survival of juvenile tiger shrimps obtained with Padina tetrastromatica extract at a dose of 5 g kg⁻¹.

• The methanol extract of P. tetrastromatica and Sargassum ilicifolium had maximal antibacterial activity against V. parahaemolyticus.

• The administration of 5 g kg⁻¹ methanol and ethanol extract of P. tetrastromatica improved growth performance and the immune capacity of P. monodon.

摘要

海藻在控制细菌疾病的抗生素抗性中可以发挥重要作用。研究了两种棕色海藻Padina tetrastromatica和Sargassum ilicifolium的三种提取物作为生长促进剂，并提供了对溶血弧菌的免疫保护。将两种海藻的提取物与食物一起以2.5和5 g kg ^-1的剂量施用给斑节对虾幼体，持续45天。在5 g kg ^-1的剂量下，四疟原虫获得了最大的增重（6.28和7.08 g），比生长率（3.39和3.32％），存活率（78.45和82.45％）分别用甲醇和乙醇萃取；显着高于其他溶剂和对照组（p  <.01）。另一方面，两种海藻的甲醇提取物对副溶血性弧菌具有最大的抗菌活性，抑制范围在20.25±1.00和22.00±0.50 mm之间。血淋巴凝结所需的最短时间是用甲醇提取的四头疟原虫5 g kg ^-1，这明显低于其他组（p  <.05）。用副溶血弧菌攻击后，用甲醇提取的四基质疟原虫处理过的斑节对虾的总血细胞计数（THC）5 g kg ^-1的日粮较高（5.42×10 ⁵细胞mL ^-1），但与其他日粮相比无显着差异（p  > .05）。然而，施用5g kg ^-1的四层疟原虫甲醇和乙醇提取物通过增加它们的酚氧化酶活性，超氧化物阴离子浓度和对溶血弧菌的抵抗力来改善斑节对虾的生长性能和免疫能力。

• 强调

• 用5g kg ^-1剂量的Padinatetrastromatica提取物获得的幼虎虾的最大生长性能和存活率。

• P.tetrastromatica和Sargassum ilicifolium的甲醇提取物对副溶血弧菌具有最大的抗菌活性。

• 施用5g kg ^-1的四层疟原虫甲醇和乙醇提取物改善了斑节对虾的生长性能和免疫能力。