Dr Godfrey Mhlongo, a recent PhD graduate in animal science from South Africa’s North-West University (NWU), suggests incorporating brown seaweed and spent oyster mushroom substrates into chicken feed to help feed the continent while preserving the environment.
"This strategy can help meet the growing demand for animal protein at a lower cost," he says.
Dr Mhlongo’s research focuses on optimizing a novel and cost-effective brown seaweed ingredient, sea bamboo meal (SBM), in feed for indigenous chickens, using oyster mushrooms to enhance its nutritional value.
His study aimed to evaluate the potential of oyster mushroom spawn—known for producing lignin-degrading enzymes—to improve the nutritive and feeding value of SBM in the diet of Boschveld cockerels.
SBM is rich in bioactive compounds, including proteins, essential amino acids, polysaccharides, polyunsaturated fatty acids, vitamins, minerals, antioxidants, and pigments. These components are known for their antioxidative, antifungal, antibacterial, anti-inflammatory, and antiviral properties, which could significantly boost poultry health, according to the researcher.
Boosted growth
The research involved two feeding trials, with findings published in Poultry Science and Scientific Reports. In the first trial, the inclusion of SBM in the cockerels' diets increased overall feed intake and altered some blood parameters but did not affect growth metrics. In the second trial, oyster mushroom spawn was added to the feed to mitigate the negative effects of fiber and enhance growth metrics.
"The second feeding trial showed that diets containing SBM and spent oyster mushroom substrate improved overall growth metrics, slaughter weight, and breast weight in Boschveld cockerels," Dr Mhlongo reports.
Reduced dependency on traditional feedstocks
He highlights that using SBM and spent oyster mushroom substrate could reduce reliance on conventional feedstocks like corn and soybeans.
"Unlike traditional feedstocks such as corn and soybeans, seaweed meal does not require large amounts of arable land, fresh water, or fertilizers for cultivation. Seaweeds grow rapidly and can be harvested multiple times a year, contributing to biodiversity conservation and reducing chemical use," he explains.
Adopting SBM and spent oyster mushroom substrates in poultry feed across Africa also would result in economic benefits, Dr Mhlongo adds.
"Brown seaweed meal is harvested at no cost and spent oyster mushroom substrate is typically discarded as waste after mushroom production. These resources can be highly beneficial to small-scale farmers with limited financial resources. Moreover, the nutritional potential and sustainability of SBM and spent mushroom substrates can enhance production efficiency and income diversification."
However, Dr Mhlongo emphasizes that to maximize these benefits and promote widespread adoption of this innovative strategy among poultry farmers, it is crucial to address barriers related to knowledge dissemination, infrastructure development, and regulatory frameworks.
Scalability and potential impact across Africa
Regarding the scalability of brown seaweed and spent oyster mushroom substrates for widespread use in chicken feed across Africa, Dr. Mhlongo is optimistic.
"Brown seaweed (Ecklonia maxima) production and processing have significant potential for scaling up in Africa, particularly in South Africa and Namibia, where colder water currents are conducive to kelp growth and harvesting. Favorable environmental conditions, existing industry infrastructure, ongoing research and development, and potential economic advantages support this potential."
However, Dr Mhlongo acknowledges the challenges: "Overcoming regulatory, environmental, and market challenges will be critical to fulfilling this potential in Africa."
Similarly, the production and processing of spent oyster mushroom substrates (SMS) for chicken feed show high scalability potential. "Countries like Kenya, with its substantial mushroom production and growing poultry sector, and South Africa, with its advanced agricultural sector, are well-positioned to support the development and scaling of SMS utilization. Nigeria, with its large poultry industry, also shows increasing interest in innovative agricultural practices."
Dr Mhlongo notes that abundant raw materials, such as brown seaweed, which can be used as substrates for mushroom production, alongside economic benefits, environmental sustainability, research support, and favorable government policies, are all factors that make this approach viable. However, challenges related to processing technology, market development, and supply chain infrastructure must be addressed for widespread adoption.
Study methods and findings
Elaborating on the methods used in the feeding trials, Dr Mhlongo remarks: "The experimental procedures included nutrient digestibility trials, growth performance indices, physiological responses (such as carcass, visceral organs, and blood parameters), and meat quality assessments of Boschveld cockerels."
Discussing the differences in outcomes between the two trials, he notes: "In the first trial, the dietary inclusion of brown seaweed meal improved feed intake, internal organ sizes, and alanine transaminase levels, but it did not affect nutrient digestibility, growth performance, or meat quality. In contrast, the second trial, which included SBM-spent oyster mushroom substrate, resulted in improved growth performance, slaughter and breast weights, and alterations in the sizes of certain organs and blood parameters, without compromising the general health and meat quality of the birds."
Regarding the health implications of altered blood parameters, Dr Mhlongo adds: "The quadratic decline observed in alanine transaminase (ALT) levels with dietary SMS suggests that moderate seaweed levels could protect the birds from liver injuries. However, higher levels of dietary SBM may compromise liver health."
