What makes Mdhluvu's MSc research unique is that in South Africa crocodile meat is mainly used for tail meat, and skin export, meaning other parts are of no use, therefore, crocodile farmers are running at a loss. Processing of crocodile meat in fish feed will create job opportunities for people, and allow more farmers to venture into fish farming.
“By 2050 the world human population is expected to reach 9 billion, and the demand for dietary fish protein is expected to skyrocket. For decades, wild captured fish stocks have been the main fish protein source for humans but unfortunately, the stocks are running dry, the aquatic biodiversity has changed due to climate change and over fishing,” says Mdhluvu.
"Researchers across the world have been looking for a protein source rich enough to replace fishmeal in a fish diet. With increased demand in plant-based protein, the prices have become too high, while other sources of protein, such as mopane worms, black soldier fly larvae and fermented feather meal have been used with mixed results,” she adds.
“The results obtained from my research showed that crocodile meat can replace fishmeal in fish diets up to 50% without having a detrimental effect. It also revealed, however, that the crocodile meat meal lacks poly unsaturated fatty acids (PUFA), especially n-3 and n-6, hence reduced growth performance in fish. These PUFA are important for humans, since fish is an important food source that seems to reduce heart disease incidences due to its high levels of PUFA. The PUFA composition is one of the most significant attributes of fish for human nutrition, which is why this finding is concerning.”
Mdhluvu explains that after noticing that crocodile meat is rich in protein and can replace fishmeal in fish diet but is lacking PUFA, she recommend the use of supplemental PUFA sources such as microalgae oil, which could mitigate the negative impact of feeding crocodile meat meal on feed utilization, growth performance, and n-3 long chain PUFA concentration in the kob.
"My MSc research provides the first insights into the use of crocodile meat for fish diets, and showing potential to replace fishmeal in fish, however, it will take a few trials and errors for it to reach fishmeal level.”
Aquaculture in South Africa is still at the developmental stage, with only a few universities in South Africa offering courses on the subject. UMP offers fish studies under agricultural science. Because fishmeal is so expensive, few people explore fish farming in South Africa at the moment. Small scale farmers can only try farming with tilapia, or African catfish but even then not everyone is open to the idea of fish farming. Only a few people are taking the route of fish nutrition, or fish studies, which is why it is still considered a scarce skill.
“I love animals in general, so working with them is a dream come true. Working with fish is a different sphere and absolutely fascinating. The adrenaline rush is what brings me back to them again. I believe in going for unchartered places, places we fear, or believe it belongs to a certain group people, I want to go there, and be the first to pave a way for others. The path I am taking is channelling me into being an animal nutritionist, because not only will I be able to focus on formulating diets for fish but through research I can do it for other animals, using different feed ingredients. However, for now I am focusing on carnivorous fish such as Dusky kob. The fish nutrition field, I believe, will open doors for me.”
Mdhluvu is extending her skills and has registered with the University of Bologna in Italy for a course in Sustainable Development and One Health, which focuses on human, animal and environment interactions.
“As an aspiring animal nutritionist, it is of key importance that the diets we create for the farmed animals do not have any detrimental effect on humans and the environment. Especially in fish, what they consume can be also found in the fish fillet which will be consumed by humans, which means it can affect human health. Therefore, it is important to take note of such. The course explored this effect in great detail,” she adds.
“It was a real eye opener, working with animals and the environment as my career moves forward, the One Health approach should always be at the back of my mind. I need to remember that the diet I create needs to be sustainable, it must not harm my animals, humans and the environment. After all, we really are what we eat.”
Mdhluvu is planning to pursue her PhD in 2022. “Nothing would make me happier than walking across that stage with my red graduation gown and thanking everyone who has helped me in my journey. With that said, I still have a long way to go but I do believe I will make it and become a successful fish nutritionist.”
@ Story by Cleopatra Makhaga. Pictures supplied.