Feed costs are exceptionally high in the broiler chicken industry, prompting farmers and researchers alike to find ways to reduce the cost of feed without compromising bird health. Dr Makiwa Simeon Mthana, a North-West University (NWU) animal science graduate, has come up with a potential solution that uses mushroom biotechnology to enhance the nutritional utility of soyabean replacements.

For his PhD research, Dr Mthana evaluated “smart strategies” such as the use of oyster mushroom spent substrate (OMSS) to enhance the nutritional utility of marula seed (kernel) cake (MSC) and mucuna seed meal (MSM) as soyabean replacements in broiler chicken production. OMSS is a waste by-product of mushroom production.

He was supervised by Dr Doctor MN Mthiyane from the Animal Science subject group, who has published numerous research articles on MSC and MSM in internationally recognised, peer-reviewed scientific journals, and serves as the sub-editor of the Applied Sciences journal.

Owing to the birds’ high meat yields over short production cycles, broiler chicken production is seen as strategically important as a protein-rich food to nourish the rapidly growing human population in South Africa and globally in a relatively environmentally friendlier way.

High feed costs are a stumbling block

Broiler meat is the most consumed animal-derived protein source nationally and around the world. However, broiler chicken feeds are expensive, representing about 65% to 75% of the total variable costs of producing the birds, mainly due to dietary usage of the largely imported soyabean meal as a protein source. This problem has accentuated the need to explore economically sustainable alternative protein sources such as MSC and MSM to replace soyabean meal in broiler diets.

While rich in proteins, energy and other nutrients, both MSC and MSM contain potentially toxic chemical substances called antinutritional factors. These include condensed tannins, 3,4-dihydroxy-L-phenylalanine (L-DOPA), mould-derived mycotoxins and a high fibre content. When consumed with the feed, these antinutritional factors can cause detrimental effects in broiler chickens, leading to poor nutrient digestibility, growth and meat quality in the birds.

As a strategy to counter the deleterious effects of the antinutritional factors, Dr Mthana included OMSS in the diets of chickens. OMSS is rich in antioxidant bioactive compounds andbiodegradative enzymes, with formidable potential to break down toxic antinutritional factors and fibre.

Dr Mthana investigated the effects of OMSS in a study involving 308 broiler chicks, which were randomly allocated to various diets, with and without OMSS. The study concluded that low levels of OMSS (1,25%) could limit the adverse effects of feeds containing MSC and MSM.

Best student poster in national competition

In 2024, Dr Mthana participated in a student poster competition organised by the Animal Feed Manufacturers Association and was named the overall winner of the Best Student Nutrition Poster Award.

The South African Society for Animal Science also awarded Dr Mthana the bronze medal for the best PhD thesis, acknowledging its contribution to the advancement of animal science.

On completing his doctoral studies at the NWU at the end of 2024, Dr Mthana relocated to the University of Mpumalanga. He is now a postdoctoral fellow under the mentorship of Prof Victor Mlambo.

Dr Makiwa Simeon Mthana

Mucuna seed and Mucuna seed meal.