Among all the farm animal sectors, aquaculture holds the highest expected global growth rate in the near future. Amid the remarkable growth of aquaculture, the industry faces a pressing challenge: bacterial diseases in aquatic farmed species, impacting both performance and requiring medical interventions. To address this issue, it’s crucial to explore innovative solutions. One such solution is Progres, whose impact on white shrimp was presented at the Aquaculture Europe Conference 2023 in Vienna.

Progres® Liquid, a resin acid-based product developed by Hankkija Oy and owned by AB Vista, UK, has proven its excellence as a feed ingredient for pigs, poultry, and ruminants. Progres® includes tall oil fatty acids (TOFA), featuring 9% natural coniferous resin acids like abietic, dehydroabietic, neoabietic, and palustric acids, known for their antimicrobial and anti-inflammatory properties. Numerous scientific studies have thoroughly documented how Progres® benefits animal production performance and intestinal health.

Progres® and White Shrimp: A Pioneering Research Endeavor

The first study of Progres® as a dietary component for a farmed crustacean species, the white shrimp (Litopenaus vannamei), was conducted in the Kasetsart University, Thailand, by Dr. Orapint Jintasataporn and her team. The experiment focused on the effects of Progres® on the performance, immunity and disease resistance of white shrimp. The experimental model included an 8-week period without intentional challenge factor, followed by a one-week period with Vibrio parahemolyticus challenge. The very promising results of the experiment were showcased as a poster presentation in the Aquaculture Europe 2023 meeting in Vienna, Austria, on September 18–21.

Experimental Setup

The experiment was carried out in 30 aquariums with 120 liters of 15 ppt saline water. Juvenile white shrimp were stocked at 200 shrimp/m3, 25 individual/aquarium. The water in each aquarium was aerated to maintain DO >5 mg/l, and 20% of water was changed every 3 days. Commercial-type shrimp feed, based on soybean meal, wheat flour, fishmeal, poultry meal and corn gluten was amended with Progres® as follows:

The dietary treatments

  • T1; Control, : Progres® Liquid 0 g/ton
  • T2; Progres® Liquid 0.5 g/ton
  • T3; Progres® Liquid 1.0 g/ton

Feed was applied to the shrimp 3 times/day at 3-5% of body weight. Uneaten feed was siphoned out 1 hour after feeding, dried in hot air and weighed. Shrimp weight, weight gain, feed intake and feed conversion ratio (FCR) were recorded every 2 weeks and survival rate every 4 weeks. At the 8-wk time point, 6 shrimp/tr. were sampled for haemolymph, hepatopancreas and intestinal contents.

The experiment continued by allocating 3 replicate aquariums/tr. into a 7-day challenge period which started by a subcutaneous injection of the virulent EMS strain of Vibrio parahemolyticus (6.9*107 cfu/ml) to each shrimp. The survival rate was monitored daily. On day 7 post-challenge, the shrimps were sampled as described earlier.

The haemolymph samples were analysed for several parameters relating to immunity and oxidative status. Density of Vibrio spp. in samples was determined by plate culturing. The study was conducted in a completely randomize design. Data was analysed with one-way ANOVA, followed by Duncan’s Multiple Range Test, using p<0.05 as a limit for statistical significance.

Results and Key findings

Progres®-treated shrimp exhibited improved weight, weight gain, and feed conversion ratios compared to the control group.

Post-challenge survival rates were significantly higher in Progres®-treated groups.

Progres® positively influenced various immunological and antioxidative functions in shrimp, indicating enhanced disease resistance.

  • On day 1, the mean shrimp weight was 2.46 g, with no difference between treatments.
  • Compared to the control treatment, shrimp weight, weight gain and FCR were improved by both Progres®-doses from the 4-wk time point onwards (p <0.05).
  • Post-challenge survival rate was increased by Progres® from 32.5% in the control group to 55.0 and 65.0% in T2 and T3, respectively (p <0.05); Figure 1.
  • Compared to the control group, the haemocyte count, phenoloxidase activity, lysozyme activity, superoxide dismutase activity and glutathione concentration in haemolymph were all significantly higher in Progres®-treated groups.
  • The density of Vibrio spp. in tissues was reduced by Progres® both before and after the challenge; Figure 2.
Table 1. Effect of the treatments on parameters measured at the 8-week time point (pre-challenge) and 7 days post-challenge, with statistical evaluation by ANOVA and Duncan’s Multiple Range Test.

Discussion and conclussion

Vibrio spp. was present already before the intentional challenge, but the background Vibrio strains had a low virulence and did not markedly impair the survivability of the shrimp. In contrast, the EMS strain used for the intentional Vibrio challenge had a high virulence, and it caused a rapid decline in the survival rate of the shrimp.

Dietary Progres® at 0.5 and 1.0 kg/ton significantly and markedly improved the performance and survival rate of the shrimp, implying a better production potential for Progres®-fed white shrimps in Vibrio-infested surroundings.  

The decreased Vibrio load in the tissues post-challenge and the parameters analysed from haemolymph indicate that Progres® positively affected several immunological and antioxidative functions and the disease resistance of the shrimp.

The results indicate that Progres® Liquid holds at least the same potential in farmed crustacean species than it has in the pig-, poultry-, and ruminant sector.   

In conclusion, TOFA may become a successful dietary strategy for supporting the performance, immunity and disease resistance of white shrimp.   

Additional Information

e-Poster presentation:

Kettunen, Vuorenmaa and Jintasataporn: Effects of dietary tall oil fatty acids with resin acids on the performance and immunity of juvenile white shrimp (Litopenaeus vannamei) with and without an intentional Vibrio parahemolyticus challenge