Effect of mealworm (Tenebrio molitor) larvae enriched with a commercial and skin color in Oscar probiotic, Protexin, on growth performance (Astronotus ocellatus)

Abstract

Introduction: Using live feed as nutritious feed sources that can also contain natural
pigments; is always recommended to strengthen skin pigment, improve growth
performance and increase the general health of ornamental fish. This study was
conducted to evaluate the effect of different levels of mealworms (Tenebrio molitor)
larvae enriched with commercial probiotic, Protexin on some growth factors, survival
rate, and skin color of Oscar (Astronotus ocellatus).
Materials & Methods: First, the mealworms larvae were fed with 0 (control), 0.5, 1,
1.5 and 2% of a commercial Protexin probiotic along with wheat bran powder as the
main feed resource for 14 days. Then, Oscar fish with an average weight of
3.0±0.2 g and an initial length of 2.2±0.3 cm were randomly distributed into 15 glass
aquariums with a density of 20 fish and were fed for 56 days with the enriched
mealworms larvae with Protexin.
Result: Based on the results, weight gain (10.5±0.23 g), body weight gain (7.54 ±0.31
g), daily growth rate (4.56±0.34), specific growth rate (2.11±0.1), and longitudinal
growth (3.5±0.5 cm) in 2% treatment showed a significant difference compared to
the control group and other treatments (P<0.05). The highest feed conversion ratio
was obtained in control (1.25±0.17) and the lowest value was observed in 2%
treatment (0.84±05). However, there was no significant difference in survival
percentage between treatments receiving diets containing larvae enriched with
probiotic, Protexin. The fish skin color according to L* and a* indices in the 2%
treatment had a significant decrease compared to other treatments, especially the
control treatment (P<0.05).
Conclusion: The effect of different levels of mealworms larvae enriched with
commercial probiotic, especially at the level of 2% feed on the growth indices and
skin color of Oscar fish was evaluated as completely positive and significant.