Peptide hydrolysate from fish skin collagen to prevent and treat Aeromonas hydrophila infection in Oreochromis niloticus.

Aquaculture with an intensive system can both increase production and the disease risk. The use of antibiotics to reduce pathogens has bacterial resistance consequence. Peptides have rapidly gained more attention due to their antibacterial and immunomodulatory properties important to combat pathogens. This study aimed to determine the effectiveness of peptide hydrolysate against Aeromonas hydrophila in vitro and in vivo in Nile tilapia. The peptides obtained from fish skin collagen of tilapia, milkfish, and catfish were applied in different doses. Protein content and hydrolysis degree of the peptide were also measured. The peptides were tested in vitro using A. hydrophila. For in vivo test, The peptides and positive control treatments used A. hydrophila bacteria, while negative control treatment used a phosphate buffer saline (PBS). The results showed that all three peptide hydrolysates had similar protein content. The highest hydrolysis degree was shown by milkfish collagen hydrolysate. In vitro assay revealed that 12.5% milkfish skin collagen obtained the highest antibacterial activity. In vivo assay showed that the phagocytic activity, respiratory burst, and lysozyme activity was higher in preventive control than therapy, positive control, or negative control treatments. The growth and survival rate in preventive control was also better than positive control or therapy treatment. This study concludes that the peptide hydrolysate can inhibit the growth of A. hydrophila. Peptide hydrolysate from milkfish skin collagen at 12.5% dose was more effective in preventing the A. hydrophila infection, regarding the immune response, growth, and survival.