Aeromonas hydrophila is one of the major freshwater fish pathogens. In the current study, a cocktail of D6 and CF7 phages was given orally to Labeo rohita to assess phage survival in fish organs as well as to determine the therapeutic efficacy of phage treatment against fish mortality caused by A. hydrophila. In the phage-coated feed, prepared by simple spraying method, phage counts were quite stable for up to 2 months with a decline of ≤ 0.23 log₁₀ and ≤ 1.66 log₁₀ PFU/g feed during 4 ^oC and room temperature storage. Throughout the experimental period of 7 days, both phages could be detected in the gut of fish fed with phage-coated feed. Besides, both CF7 and D6 phages were also detected in fish kidneys indicating the ability of both the phage to cross the intestinal barrier. During challenge studies with LD₅₀ dose of A. hydrophila, phage cocktail doses of 1 × 10⁶ – 1 × 10⁸ PFU/g feed prevented the mortality in L. rohita with relative percentage survival (RPS) of 8.7–65.2. When challenged with LD₉₀ dose of A. hydrophila, an RPS value of 28.6 was obtained at a phage cocktail dose of 1 × 10⁸ PFU/g feed. The RPS data showed that orally-fed phage cocktail protected the fish against the mortality caused by A. hydrophila in a dose-dependent manner. Simple practical approaches for phage cocktail development, medicated feed preparation and oral administration along with phage survival and protection data make the current study useful for farmer-level application.

嗜水气单胞菌是淡水鱼的主要病原体之一。在当前的研究中， Labeo rohita口服 D6 和 CF7 噬菌体混合物，以评估噬菌体在鱼类器官中的存活情况，并确定噬菌体治疗对嗜水放线菌引起的鱼类死亡的治疗效果。在通过简单喷雾方法制备的噬菌体包被饲料中，噬菌体计数在长达 2 个月内相当稳定，在 4℃ 和室温储存期间，下降量≤ 0.23 log ¹⁰和_≤ 1.66 log ₁₀ PFU/g 饲料。在整个7天的实验期间，在喂食噬菌体包被饲料的鱼的肠道中都可以检测到这两种噬菌体。此外，在鱼肾中也检测到CF7和D6噬菌体，表明这两种噬菌体都具有穿过肠道屏障的能力。在用 LD ₅₀剂量的嗜水气单胞菌进行攻击研究期间，噬菌体混合物剂量为 1 × 10 ⁶ – 1 × 10 ^{8 PFU/g 饲料可防止}L. rohita死亡，相对存活率 (RPS) 为 8.7–65.2。当用LD ₉₀剂量的嗜水气单胞菌攻击时，在1×10 ⁸ PFU/g饲料的噬菌体混合物剂量下获得28.6的RPS值。 RPS 数据表明，口服饲喂的噬菌体混合物以剂量依赖性方式保护鱼免受嗜水放线菌引起的死亡。噬菌体鸡尾酒开发、药物饲料制备和口服给药的简单实用方法以及噬菌体存活和保护数据使当前的研究可用于农民层面的应用。