Future of Poultry Nutrition: How to Feed Chickens More Sustainably19 November 2014
Finding solutions to the challenge of producing poultry more sustainably was the theme of a recent conference in the UK. The meeting explored all aspects of sustainability – economics, environment and ethics. Feed accounts for a high proportion of the total costs and the ecological impact of poultry production and it formed the focus for a key session, reports Jackie Linden.
Projected growth in the human population, the higher standard of living in developing countries and the forecast increased consumption of animal proteins will challenge the agricultural community even more in the years to come to produce twice the amount of food with half the resources.
Addressing these sometimes competing challenges was at the heart of the sessions on the future of feeding at the 31st Poultry Science Symposium, organised by the UK Branch of the World’s Poultry Science Association (WPSA) under the theme ‘Sustainable Poultry Production in Europe’. It was held in the English city of Chester in September 2014.
Future Feedstuff Supply and the Use of Co-Products in Poultry Feeds
Not only will the poultry sector be challenged to play its role in increasing food production using less natural resources, it also needs to meet the demands of consumers and society in general, said Piet van der Aar, research coordinator at Schothorst Feed Research, The Netherlands.
Those consumer concerns include animal welfare, use of antibiotics, biosecurity, environmental effects, price/quality ratio, product diversification, food safety and consumer behaviour. All of these demands will affect production systems, feed composition, and thus the feedstuffs that will be used.
Mr van der Aar illustrated the possible conflicts with the example of the Dutch retailers association, CBL, which has announced its view of the country’s broiler industry in the future as producing 2.2-kg birds at 56 days of age under conditions of 16 hours of light and eight hours of darkness. Both ammonia emissions and mortality should be reduced, the latter to 1.3 per cent from the current 3.5 per cent average.
However, Mr van der Aar said, this will increase feed requirements by 25 per cent, adding an extra 120,000 hectares to the land required to produce the same number of chicken in the Netherlands. This would have a large effect on greenhouse gas (GHG) emissions and the additional land is likely to be in South America, which might not be popular with consumers.
One solution, he said, would be to increase the use of by-products in poultry feeds, which would have the effect of lowering the nutrient density of the diets but birds are able to utilise the nutrients effectively as long as the gizzard is developed.
Looking firstly at protein sources, Mr van der Aar said the EU is just 33 per cent self-sufficient in feed proteins, relying heavily on imports of soybean meal, sunflower and rapeseed meal.
In fact, he showed that wheat produces almost as much protein per hectare as soybeans. Pulses, such as peas and beans, produce slightly more protein but even if we could produce more, they are more likely to go into feeds for pigs than poultry because of their lower digestibility.
Some alternative protein sources, such as insects, algae, seaweed and yeast protein concentrates appear to offer potential in terms of the nutritional composition and/or protein yield but they do not always deliver reduced environmental impacts. For high-moisture materials, such as seaweed, the drying process can increase the carbon footprint to above that of traditional feed ingredients.
Any new protein source for poultry feeds will need to have consistent nutrient composition, a small ecological footprint, a low cost per unit of key nutrients and be free of both food safety issues and antinutritional factors, and Mr van der Aar showed that will be challenging. Furthermore, the energy:protein ratio will be important, he said.
He foresees the market diversifying in three different segments in future:
- The current high-output, low-cost production systems will continue across much of the world, based on highly digestible feed ingredients.
- Another segment will be based on fibre-rich ingredients in less nutrient-dense diets, leading to slower growth rates.
- And thirdly, there is likely to be small segment – limited to the EU and other developed countries - catering to regional tastes, based on local grown and possibly organic feed sources.
In all three sectors, Mr van der Aar predicts that the diets will become less nutrient-dense, allowing for the incorporation of more co-products and alternative proteins.
And among those alternatives, he sees the greatest potential in algal and insect proteins. Purified protein concentrates are likely to be too expensive to be included in diets other than starter feeds, he said.
Mr van der Aar concluded that, in the year ahead, most poultry feeds will still need to be highly digestible. Thanks to innovation in enzymes (which improve the digestibility of alternative feedstuffs) and increased supplementation with amino acids, feeds will be formulated with both a lower ecological footprint and using ingredients that compete less for resources with human foods.
Overcoming Limiting Factors for Nutritional Efficiency in Broilers
What do we mean by nutritional efficiency and how does it differ from traditional feed efficiency?
Brett Roosendaal, commercial nutritionist with Rainbow Farms (Pty) Ltd in South Africa explained that feed efficiency has for a long time been defined as the amount of feed required to produce a kilo of liveweight gain in broilers. However, this definition is being challenged as to its usefulness; it is a general term and is affected by many factors.
More specific and meaningful measures for the efficiency of energy and nutrient utilisation of the major cost components in poultry diets are required, he said.
The starting point for feed specification should be feed intake, he said, as it is directly correlated with growth rate and is governed by the first limiting nutrient, yet in commercial broiler production, the desired feed intake is often not achieved, for a variety of reasons.
Using published research, he showed the nutritional responses of broilers to protein, lysine, energy, starch and fibre.
The large contribution of energy to total feed and production cost requires that our focus is on improving energy utilisation, he said.
He showed how the systems used for the evaluation of feedstuffs in terms of energy, protein and minerals can greatly contribute to sustainability.
Feed structure too can be important in determining efficiency, Mr Roosendaal showed, through the effects of particle size. In Europe, the feeding of whole grains to broilers is widely practised but rare elsewhere. Feed particle size can be affected by many factors.
Poor pellet quality can increase the balanced protein required to achieve the same response, while using good quality pellets rather than mash can give a 10 per cent difference in growth rate and four or five points of feed conversion.
Mr Roosendaal explored the optimisation of the microflora in the bird’s gastrointestinal tract, which can have a large effect on nutritional efficiency of the host. The millions of microorganisms vary in their effects; some compete with the bird for nutrients and they vary in their effects on the immune response.
Finally, moving on to the role of feed additives, he showed how superdosing with phytase can increase liveweights and decrease feed conversion ratio. There are very many feed additives and Mr Roosendaal stressed the need to evaluate them accurately.
In his presentation, he showed that nutritional efficiency can be determined as improving the proportion of dietary nutrients into carcass lean tissue so the birds performs as closely as possible to its genetic potential.
The same factors that affect nutritional efficiency also influence economic measures of efficiency, for example, feed cost per kilo of liveweight gain or egg or even per kilo of meat per square metre of floor space, measures that are already commonplace in the industry.
Looking ahead, Mr Roosendaal said, the industry could soon routinely be using sustainability measures such as nitrogen and phosphorus excretion per bird and carbon dioxide equivalent per kilo of meat produced.