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Crocodile meat meal for juvenile dusky kob

Short or long-term supplementation using omega-3-rich oils is proposed for crocodile meat meal (CMM)-fed juvenile dusky kob (Argyrosomus japonicus).

A preliminary study in South Africa investigated the effect of replacing fishmeal with raw or cooked crocodile meat meal on feed utilization, growth performance, blood parameters, and tissue nutrient composition in juvenile dusky kob (Argyrosomus japonicas). It concluded that crocodile meat has good characteristics as a fishmeal substitute. 

“Using crocodile meat as an alternative source of protein for carnivorous fish, such as the dusky kob, could be an ingenious strategy that adds value to the crocodile farming enterprise, while ensuring economically and environmentally sustainable dusky kob aquaculture,” Reginah M. Mdhluvu et al. said in the study published in Aquaculture Reports. 

As a fishmeal substitute, however, the study showed that CMM compromised growth of juvenile dusky kob. It likewise had an adverse impact on the level of the polyunsaturated fatty acids (PUFA) in fish fillet. PUFA composition is one of the most significant attributes of fish for human nutrition. 

“The use of supplemental PUFA sources such as microalgae oil could mitigate the negative impact of feeding CMM,” they wrote.

The team from the University of Mpumalanga took note of the crocodile meat portion that is usually discarded at a time when fishmeal is increasingly becoming an unsustainable aquafeed ingredient. 

Crocodile is farmed for skin and meat. Per 2015 figures, an estimated 1,000 tons of crocodile meat were officially traded globally. Only the tender tail fillet, which makes up for 33 per cent of the carcass weight, is used for human consumption. This leaves 67 per cent with scant or no commercial value.

Dried CMM was homogenized into a powder using a blender before being incorporated into experimental diets.