Red Tilapia

Introduction and target

In recent years, the positive performance effects of Progres® have been proven in many farm animal species, such as broilers (Kettunen et al. 2017, Vienola et al. 2018, Lipinski et al. 2021), turkeys (Lipinski et al. 2020), calves (unpublished), piglets (Hasan et al. 2018; Uddin et al., 2021) and sows (Hasan et al. 2018).

For all farm animal species, intestinal functions such as nutrient uptake and regulation of the immune system play a leading role in performance. Studies at the University of Ghent, Belgium, have shown that resin acids of Progres® suppress collagen degradation in the small intestine, thus supporting intestinal barrier functions and reducing inflammations in the alimentary canal.

In the present trial, we studied the effect of resin acid concentrate (RAC) on the production performance of red tilapia fish (Oreochromis niloticus* O. mosambicus). This was the first experiment to study the effect of Progres® in an aquatic species.

Material and methods

Juvenile red tilapia with a mean initial weight of 32.6 ± 0.1 g were randomly divided into 32 tanks of 200 liters, with a water flow rate of 2.0 L/min, 20 fish per tank. The trial was conducted in a 2×2 factorial design, with two water qualities and two dietary treatments.

The Non-treated water was supplied from a pond without UV disinfection and filtration, showing a lot of floating organic material. The Treated water was UV-disinfected and filtered, and transparent. Thus, the treated water represented a better water quality for the fish than the non-treated water.  

For producing the two dietary treatments, a practical tilapia feed (protein 30.87%, fat 9.15%, fiber 4.09%, ash 9.97%, and moisture 6.24%) was coated with fish oil with or without Progres® to produce two Progres® levels: 0 g/ton (Control), and 500 g/ton.  

The fish were fed twice a day, six days per week for 48 days. Water quality parameters were monitored on a daily basis daily.  


No abnormal mortality or behaviour of the fish were observed during the trial. The treated water significantly improved the performance of fish (p < 0.01).

Figure 1. Daily body weight gain of the fish in two water qualities and with or without dietary Progres®

Progres® increased the weight gain in both non-treated and treated water (+5.7% and 2.2%, respectively; Figure 1) and daily feed intake (+ 5.3%; Figure 2) in non-treated water.

Figure 2. Daily feed intake of the fish in two water qualities and with or without dietary Progres®

Progres® improved feed conversion ratio (FCR) by –2.3% in both water conditions (Figure 3) and it also increased the proportion of fish over 170 g in non-treated and treated water by 6.9% and 14.7%, respectively (Figure 4).

Figure 3. Feed conversion ratio of the fish in two water qualities and with or without dietary Progres®
Figure 4. The proportion of fish >170 g in two water qualities and with or without dietary Progres®


In conclusion, for the first time, the performance benefits of Progres® were proven on an aquatic species. All the performance parameters were improved in the Progres® group, in comparison to the control group. It is likely that resin acids have similar positive effects on the intestinal integrity of all farmed animals, including aquatic species.