Commercial aquaculture is still looking for ways to maximise growth performance while safeguarding animal welfare, sustainability and consumer safety. Here, flavonoids, a subgroup of naturally occurring polyphenols, have great potential as natural growth promoters. A recent study has measured the effects of dietary flavonoids on Tilapia growth—and achieved stunning results!
With the phytogenic feed additive Anta®Ox Aqua, the fish in the study clearly showed better growth performance. These effects are due to Anta®Ox’s anti-inflammatory capacities, which protect the animals from infection. Anta®Ox Aqua therefore has the potential to act as a natural alternative for antibiotics, especially in terms of promoting growth.
Moreover, the study showed a remarkable relation between tank size and weight gain. With the same stocking density, fish in smaller tanks put on more weight than those in tanks almost three times as large. Future trials will have to show what this weight gain is related to. For the time being, it is safe to say that smaller tanks may be more efficient than bigger ones and that better, natural and healthy weight gain is possible in any tank size with Anta®Ox.
Scientific details of the study
A feeding trial with 468 all-male red strain tilapia fingerlings was conducted in an indoor recirculating aquaculture system (RAS) using fresh water at 28°C. Fish were kept in 6 tanks of 2 different sizes (45 L and 125 L) at same stocking density (0.8 fish / L). Tanks were divided into 2 treatment groups (AO, N). In group AO a flavonoid additive (Anta®Ox Aqua, Dr. Eckel Animal Nutrition, Germany) was dosed at 500 g / t. Fish growth was measured at three time points (day 0, 22 and 68) by sampling 10 fish / tank and measuring standard-length and body weight.
Results: Overall growth and the influence of the feed additive
Overall growth was within expected values. During the 68 days trial period fish grew on average from 0.41 g to 6.25 g live body weight and from 22.8 mm to 56.7 mm mean body length. Specific growth rate (SGR) was 3.92 % per day.
Weight gain was higher in the AO treatment group than in the N control group (see Fig. 2). Fish of the AO groups achieved a higher mean body weight than the negative control group (+16% in small tanks and +14% in big tanks). Analysis of variance of a linear model, explaining log (weight) with ‘system’ and ‘feed’ as explanatory factors, revealed that the ‘system’ effect was highly significant (p < 0.001) and the influence of the ‘feed’ treatment was significant (p < 0.02).
From the results we conclude that addition of plant-derived flavonoids, as delivered by the tested feed additive, can improve growth of Tilapia fingerlings. The influence of tank size (at same stocking density) is remarkable and needs further investigation. The study results are of interest for tilapia hatcheries and hatchery feed producers worldwide and for practitioners doing feeding trials with Tilapia.
Fig. 1: Relationship between body length and body weight of individual Tilapia fingerlings during 68 days trial period. Shapes representing sampling time points.
Fig. 2: Development of body length during 68 days trial period at different time points, split by feed treatment and tank size. Colors representing feed treatments.