Comparative Effects of Chlorella and Spirulina on Growth, Pigmentation, Breeding, and Stress Tolerance in Guppy (Poecilia reticulata Peters, 1859).

Fish coloration and growth can be enhanced by supplementing Spirulina in feed, though it is relatively expensive. As a cost-effective alternative, Chlorella was used in this study to replace Spirulina. The experiment was conducted by feeding one-day-old guppy (Poecilia reticulata) fry with either a control feed without algal supplementation (C), a diet supplemented with 5% Spirulina (5SP), or a diet supplemented with 5% Chlorella (5CH). After 30 days, the fry fed 5CH had significantly poorer growth performance (p<0.05) compared to 5SP, but not different from the control. Interestingly, there was a trend toward improved final weight and specific growth rate in the 5CH group, though the differences were not statistically significant compared to both 5SP and the control. Similar trends were observed for fry production per female. Additionally, no significant differences were found among treatments in terms of survival (ranged 96-97%), stress tolerance, and most reproductive traits (such as fry size). The colour intensity of fish fed both the 5SP and 5CH diets was significantly enhanced (p<0.05) compared to the control group. In conclusion, supplementing guppy feed with 5% Chlorella can replace Spirulina at the same rate for improving colour intensity, without negative effects on growth, survival, stress, or reproductive performances. However, further studies using higher inclusion levels of Chlorella are recommended, given the slight trend toward improved final weight and fry production in fish fed the Chlorella-supplemented diets. [ABSTRACT FROM AUTHOR]