Globally, human demand for meat has increased fourfold over the last fifty years, and demand for chicken meat is increasing most rapidly. In Australia, chicken is the most popular form of meat and demand continues to rise. In fact, it’s predicted that the chicken meat industry will need to increase production by 40% by 2050 to keep up with demand.
As the sector aims to become more efficient, a recent focus has been on moving meat chicken diets away from the traditional soybean meal base.
Sifting the soybean meal from the chaff
As one of the most common sources of protein in meat chicken diets, soybean meal offers an efficient form of protein and metabolisable energy for chickens. As the world’s appetite for meat increases, so does the demand for soybean meal, which raises issues around escalating prices, supply continuity and our reliance on imports.
“Australian chicken meat producers are 100 per cent reliant on the importation of soybean meal from South America so we have little say over what price we pay for it,” said Dr Sonia Liu, a Senior Lecturer in Poultry Nutrition at the University of Sydney who has been undertaking research into soybean alternatives for the meat chicken sector.
“Plantings of soybeans have been rapidly expanding in South America as a result of increased global demand, and production represents a recent threat to tropical biodiversity in Brazil”.
As the chicken meat industry searches for alternatives to soybean meal, the commercial availability of synthetic, feed-grade amino acids has offered the sector a viable supplement to essential amino acids.
Moving to a low-protein diet offers a range of potential benefits, but feeding chickens in a new way requires considerable research to develop a nutritional balance that promotes growth performance at the most efficient price point.
Filling the knowledge gaps
Recent research undertaken by Dr Liu is helping the industry to refine its approach to low-protein diets. An initial study ascertained the importance of individual amino acids on chicken health and performance. Chickens that received a diet deficient in two amino acids (valine and isoleucine) weighed less than chickens fed a control diet (5% and 17% respectively), indicating that these amino acids are critical for optimal metabolism.
In another experiment, Dr Liu compared the performance of meat chickens fed a conventional crude protein diet with chickens fed a diet supplemented with amino acids. Between 7 and 35 days post-hatching, the male chicks showed very similar levels of growth performance regardless of their diet type. However, chicks fed rations with enhanced levels of amino acids put 7% more weight on than those fed the high crude protein formulation.
With an understanding that the incorporation of amino acids has a proven beneficial effect, researchers are now focussed on what function each individual amino acid plays, how amino acids interact with each other and in what quantities they should be fed. Threonine, glycine and serine, leucine, isoleucine, and valine have been identified as the amino acids that need to be better understood by the chicken meat industry, each in their own right as well as in the context of more complex biological processes such as starch-protein digestive dynamics.
‘Potential to halve soybean meal consumption’
In addition to a reduction in Australia’s reliance on soybean meal, Dr Liu’s research has shown some interesting potential outcomes that could potentially extend into animal welfare benefits and sustainability gains.
“These benefits include reduced nitrogen and ammonia levels in the internal shed environment which can contribute to better litter quality”” she said.
In turn, these improvements may reduce the requirement for supplementary ventilation and heating, reducing operating costs and further improving the sector’s energy footprint.
As the industry focusses its research, it becomes more confident in the potential to reduce the reliance on soymeal. Dr Liu’s research to date shows that lowering the dietary crude protein level in Australian poultry diets by just 14% would reduce the amount of soybean meal required by 41%. Identifying the ideal protein ratio will help to determine the most efficient, and therefore cost effective, way of feeding meat chickens while also providing an opportunity to capitalise on secondary benefits.
After successful initial trials, research led by Dr Liu will now be geared towards a better understanding of the practical use of amino acids to provide meaningful data to the industry.
“Current and future research will investigate specific amino acid requirements, digestive dynamics and energy optimisation to maintain the growth performance in meat chickens,” Dr Liu added.