The increasing global demand for aquaculture has drawn attention to the challenges associated with sustainable fish feed sources. Researchers have recently explored the use of quinoa husk (Chenopodium quinoa) as a viable replacement for fishmeal, demonstrating significant benefits for the growth and health of Pangasianodon hypophthalmus (striped catfish) exposed to multiple environmental stressors.
Traditional aquaculture practices rely heavily on fishmeal derived from wild-caught forage fish, which is increasingly unsustainable. With projections indicating aquaculture production could reach 202 million tons by 2030, there is pressing need to find cost-effective alternatives to meet this demand. Recent studies highlight quinoa as one such alternative, noted for its impressive nutritional profile and potential to improve fish health even under stress conditions.
The current investigation aimed to evaluate the replacement of fishmeal with varying proportions of quinoa husk: 0%, 15%, 20%, 25%, 30%, and 35%. The study was conducted over 105 days at the National Institute of Abiotic Stress Management, India. Researchers assessed growth performance metrics such as growth rate, feed conversion ratio (FCR), and protein efficiency ratio (PER), as well as examining various health indicators under stress conditions involving ammonia and arsenic toxicity combined with high temperatures.
Results indicated remarkable improvements when fishmeal was replaced with 25% quinoa husk. Specifically, the highest growth rates were observed at this level of substitution, with results highlighting maximum growth performance metrics showing percentages exceeding 26% across different parameters. The research underscored quinoa's capability to not only support growth but also to mitigate the adverse effects of oxidative stress encountered by fish.
Oxidative stress is commonly exacerbated by environmental toxins such as ammonia and arsenic. Fish exposed to these stressors often experience elevated levels of reactive oxygen species (ROS), leading to cellular damage. The study found significant reductions in oxidative stress markers, such as superoxide dismutase (SOD) and catalase (CAT) activities, particularly among fish fed the 25% quinoa diet, showcasing quinoa's antioxidant properties. Reports indicated these antioxidant responses could potentially safeguard fish physiology against multi-stress factors.
Importantly, the research also measured neurotransmitter enzyme activities, including acetylcholinesterase (AChE) levels, which were significantly improved with quinoa supplementation. This enrichment is particularly valuable as it suggests enhanced neurological function and overall fish welfare, reinforcing the potential of quinoa husk as not just a nutrient source but also as an agent for improved health outcomes.
Among other health indicators, blood glucose levels, total protein, and immunoglobulin concentrations were positively affected by the inclusion of quinoa husk. Enhanced total protein levels indicate improved growth and recovery capabilities, which are particularly relevant for fish reared under stress conditions, where immune responses are frequently compromised.
Histopathological examinations of liver and gill tissues corroborated the biochemical findings, indicating the protective impact of quinoa husk against stress-related lesions. Fish exposed to environmental stressors showed significant tissue damage; conversely, those on the 25% quinoa diet displayed enhanced tissue integrity, again supporting the nutritional and health advantages of this alternative feed.
The findings from this study not only validate quinoa husk as a promising alternative to fishmeal but also underline its multifaceted benefits under environmentally stressful conditions. This research paves the way for more sustainable aquaculture practices, offering substantial opportunities for the implementation of quinoa husk within fish feed formulations, addressing both ecological concerns and species health.
Future studies may explore optimizing quinoa supplementation levels and investigating its effects across additional fish species, enhancing the dialogue around food security and sustainable aquaculture.