The tambaqui (Colossoma macropomum), also known as gamitana and cachama, is a highly valued South American freshwater fish and a significant player in Amazonian fish farming. However, for fish farmers, achieving optimal growth and economic viability requires striking a balance between feeding practices and fish health.
A new study conducted by researchers at Embrapa Fisheries and Aquaculture investigates the optimal feeding rate and frequency during the growth phase (95–350 g) of tambaqui in earthen ponds, considering growth performance, blood parameters, liver histology, and the contribution of natural food and fish meat quality.
The study sheds light on the ideal feeding strategy for tambaqui during the initial growth phase.
Why is Tambaqui aquaculture important?
Tambaqui possesses several key characteristics that make it perfect for aquaculture:
- High demand: Consumers love its taste, making it a commercially valuable fish. Currently, tambaqui is commercially produced in Peru, Brazil, Colombia, Venezuela, China, Indonesia, Malaysia, Myanmar, Vietnam, and some African countries.
- Fast growth: Tambaqui gains weight rapidly, leading to quicker harvests.
- Hardy fish: It tolerates low oxygen levels and high ammonia levels, making it adaptable to various pond conditions.
The challenge: optimizing feeding for profitability
While tambaqui is a great candidate for aquaculture, feed represents a significant cost for fish farmers. To maximize profits and ensure tambaqui health, it’s crucial to find the right feeding strategy. This study focused on two key factors:
- Feeding rate: How much food should be provided daily (as a percentage of body weight)?
- Feeding frequency: How often should the fish be fed per day (two or three times)?
Feeding: balancing growth and costs
Researchers studied the impact of feeding rates and frequencies on tambaqui fingerlings (95-350g) raised in earthen ponds. They compared two feeding rates: 3% and 4% of fish body weight per day (3% BW and 4% BW). Additionally, they tested two feeding frequencies: two and three times daily. The 84-day study found no significant differences in growth rate or mortality between any of the groups.
Interestingly, tambaqui fed at a lower rate (3% of body weight) showed lower total food consumption and better feed conversion ratio (meaning they gained more weight per unit of food consumed). This indicates more efficient resource utilization. These fish also had lower fat deposition levels and showed no negative impacts on vital organs.
Fat storage and organ health are affected by diet
The study also revealed a connection between feeding protocols and fat deposition, glycogen storage (an energy source), and liver lipid levels. Fish fed at 3% of body weight showed lower levels of these elements, indicating a potential impact on overall health and energy reserves.
Feeding frequency and cholesterol: a balancing act
Interestingly, feeding fish three times daily at 4% of body weight led to higher levels of cholesterol and triglycerides in plasma. While these are typically associated with negative health effects for humans, further research is needed to understand the implications for tambaqui.
Stress levels and storage time
The study also observed elevated levels of malondialdehyde, a marker of oxidative stress, in fish fed three times daily at 4% of body weight after storage. This suggests that this feeding protocol could contribute to higher stress levels during the rearing period.
Tambaqui’s adaptability: less is more?
The study offered fascinating insights into tambaqui feeding behavior. Fish fed twice daily consumed a greater amount per feeding compared to those fed three times daily. This suggests that tambaqui can adjust their feeding behavior to compensate for lower feeding frequency.
Natural food as a supplement
The research found no significant differences in pond water quality (phytoplankton and zooplankton levels) or sediment chemistry between different feeding groups. However, fish fed at 3% of body weight showed higher stomach content weight, indicating they were actively utilizing natural food sources in the pond to supplement their diet.
Conclusion
Based on these findings, the study suggests that tambaqui weighing between 95 and 350 grams, raised in earthen ponds, can thrive with a feeding regimen of twice daily at 3% of body weight. This approach offers a balance between maintaining healthy growth, minimizing feeding costs, and potentially reducing stress levels associated with more frequent feeding.
The study was funded by “BRSAqua – Structuring actions and innovation to strengthen Aquaculture production chains in Brazil” funded by the Brazilian Development Bank (BNDES), Brazilian Agricultural Research Corporation (Embrapa), and the Ministry of Agriculture, Livestock, and Supplies (MAPA), through the National Council for Scientific and Technological Development (CNPq).
Contact
Ana Paula Oeda Rodrigues
Brazilian Agricultural Research Corporation, Embrapa Fisheries and Aquaculture
P.O. Box 90, Palmas, TO CEP 77008-900, Brazil
Email: anapaula.rodrigues@embrapa.br
Reference (open access)
Rodrigues, A. P. O., Freitas, L. E. L. D., Maciel-Honda, P. O., Lima, A. F., & Lima, L. K. F. D. (2024). Feeding rate and feeding frequency during the grow-out phase of tambaqui (Colossoma macropomum) in earthen ponds. Aquaculture Reports, 35, 102000. https://doi.org/10.1016/j.aqrep.2024.102000
