Poultry nutrition moves towards higher standards

Poultry nutrition has had a rich and fruitful history, utilizing available feed ingredients and state-of-art feed manufacturing technology to supply nutrients for optimum productivity as poultry genetic potential progresses. The future of poultry nutrition will continue to progress to improve production efficiency, but also to address food safety, environmental stewardship, and animal welfare concerns.

By Professor Peter R. Ferket, North Carolina State University, Raleigh, NC USA

Over the past 25 years, poultry nutrition has focused on production efficiency. Today, it strives to maximise biological and economical performance. During the next 25 years, poultry nutrition will focus on production efficiency, biosecurity and food safety, environmental stewardship, and animal welfare.

The performance of poultry has increased tremendously during my lifetime. When I was born in 1957, a 42-day-old broiler weighed 540 g with a feed conversion (FCR) of 2.35. Today, a broiler of the same age weighs 2.8 kg with an FCR under 1.70. Not only has the growth performance of broilers improved significantly during the past 50 years, but also its conformational structure has changed. Similar changes have occurred in turkeys. In 1966, an 18-week-old turkey tom weighed about 8 kg with an FCR of 3.0. Today, a tom of the same age could weigh over 19 kg with an FCR under 2.55. Layer performance has also changed significantly from 1958 until the present day. Over the past 50 years, egg production per hen has increased over 64%, egg mass per hen by 83%, and the amount of feed consumed per gramme of egg produced decreased by over 20%.

Phenomenal progress

What has contributed to this phenomenal progress in poultry production? According to research the author conducted with Dr. Gerald Havenstein at North Carolina State University, 85-90% of the change in growth rate of broilers and turkeys over the past 50 years was due to genetic selection, and 10-15% due to advances in nutrition and management. Obviously, genetics selection has changed the playing field of poultry nutrition. However, have nutritional advances kept pace with genetic potential for growth, and will it continue in the future? To answer this question we must review our history to help us predict our future direction.

What past scientific innovations have changed poultry nutrition and health? During the 1950s and 60s, poultry nutrition focused mainly on vitamin and mineral requirements, and nutrient content of feedstuffs. During the 1960s and 70s, amino acid content of feedstuffs were determined and dietary amino acid requirements for poultry were estimated. During the 1970s and 80s nutrient requirements were further refined in terms their digestibility in feedstuffs. Mycotoxins were also identified and dietary tolerance limits were determined. Research and development of feed additive antibiotic growth promoters and coccidiostats was also active during this period. During the 1980s and 90s, advances in poultry nutrition included computerised least-cost feed formulation, understanding anti-nutritional factors in feedstuffs, the use of supplemental enzymes, the development of the ideal protein concept and formulation for digestible nutrients, and the absorption and utilisation of nutrients. During the 1990s until today, the discipline of nutrition became more integrated with other disciplines. Now, poultry nutritionists consider environmental management, metabolic and physio- logical stress factors, the effects of nutrition on yield and product quality, immunology, and gut health.

More innovations to come

Are the glory days of poultry nutrition behind us? I don’t think so! There are several new innovations that will change the future of poultry nutrition and health. According to the late Peter Drucker, author of “The Practice of Management”, the only way to predict the future is to create it. He also said that economic change is the most powerful engine for human betterment. I think both of these quotes are very appropriate when we consider the future of poultry nutrition. Our world is changing fast! Society is now focused on economic sustainability, consumer confidence, food security, global trade, and information technology. Within the next 25 years, we will have a whole range of new challenges. We must embrace these challenges if the poultry industry is to remain the premier food protein source for a growing and developing world population.

During the next 25 years, I think poultry nutrition will be influenced most by the following innovations:
• Computational knowledge to optimise nutrition and feeding programmes.
• Replacement feed ingredients and their nutritional value enhancement by supplemental enzymes
• Gut ecosystem modulation by pro-nutrient feed additives
• Feed science and feed manufacturing technology
• Perinatal nutrition and epigenetic programming.

Computational knowledge

So much poultry nutrition knowledge cited in retrievable references, but it will become impossible to put all this knowledge into practice as information expands exponentially over the next 25 years. Thanks to advancements in computer technology, the management and application of poultry nutrition knowledge will become accessible. Mechanistic and empirical models have been developed to simulate poultry production and optimise nutritional requirements. These models will be further refined, using new experimental data, to develop optimum feeding programmes for commercial poultry.

As used in many other industries, simulation models will be used to assess risk and optimise economic return. Computational knowledge will include data mining and data analysis, using techniques such as bioinformatics, meta-analysis, and holo-analysis. Bioinformatics will be used to expand our knowledge in poultry nutrition through applications, such as gene sequence analysis, measuring biodiversity and systems biology, analysis of gene expression (genomics), analysis of protein expression (proteomics), and analysis of metabolism (metabolomics). Holo-analysis is a comprehensive or holistic analysis of data from several experiments, quantifying depended responses in terms of available genetic, chronological, environmental, geo-graphical, managerial, dietary ingredient, and nutrient-dependent variables. Applications of holo-analysis in poultry nutrition include: prediction of responses with confidence intervals; quantification of responses to pro-nutrients and nutrients unique in times, place and economics; translation of research conditions to field conditions; and, the discovery of theoretical and predictable independent variables and interactions.

Replacement ingredients, enzymes

Depending on where poultry is produced in the world, the array of caloric feed ingredients available is generally limited to corn, wheat, milo, and some fats and oils. These dietary sources of energy may be most limiting in the future as the global demand for energy increases. The biofuels initiatives will convert tonnes of corn into ethanol, even if cellulosic fermentation progresses as expected. If corn breeders cannot increase the yield of corn to satisfy the increase in demand for food and fuel over the next 25 years, poultry nutritionists will need to learn how to unleash the energy bound within fibrous grains and co-products. The dietary inclusion of many co-products, like distiller dried grains with soluble’s (DDGS), are constrained in poultry feeds because of problems physical and chemical consistency, poor nutrient availability, mycotoxins and other anti-nutritional factors, and their adverse effects on feed manufacturing.

Recently, enzyme supplementation has greatly enhanced the nutritional value of many feed ingredients. As new enzyme products are developed and we learn how these enzymes maintain their activity during feed processing and digestion, enzyme supplementation will become an integral part of closing the energy gap in many cereals and grain byproducts. Supplemental feed enzymes have been shown to reduce adverse effects of anti-nutritional factors, render nutrients more available for digestion and absorption, and allow for greater flexibility and least cost feed formulation. But enzymes could also help modulate or stabilise the gut microflora, thus improving the health and welfare of poultry. Feed enzymes are fermentation products with activities that improve the nutritional value of phytate phosphorus, non-starch polysaccharides, starch, and protein. Early commercial enzymes were characterised by their primary effects. For example, phytate has a primary effect on improving phosphorus utilisation. Pentosanase and amylase has a primary effect on uplifting energy. Protease has a primary effect on uplifting amino acid digestibility. However, we are now learning that these enzymes also have secondary effects with synergistic activities. In the near future we will learn how best to combine these enzyme activities for different nutritional applications.

Gut ecosystem modulation

Food safety and animal welfare will dictate much of poultry nutrition in the future. Feed additive antibiotic growth promoters and coccidiostats that have been used to control gut health in the past will be banned or their use will be significantly restricted in the future. Managing the gut ecosystem and gut health, therefore, will be a major challenge for the poultry industry, and nutrition will play a greater role in managing gut health. Nutritionists will focus their efforts on managing the enteric eco-system with nutriceuticals instead of controlling enteric disease with pharmaceuticals. In the past poultry nutrition focused on the nutritional requirements of the chicken or turkey. In the future, poultry nutrition should be more concerned about feeding the ecosystem, which includes the chicken. The enteric ecosystem of the chicken consumes about 20% of its daily dietary energy needs. The gut accounts for over 70% of the daily protein turnover rate in a bird. The intestinal tract of the chicken contains more than 70% of immune cells found in the body of the chick. There are 10 times more bacterial cells in the gut of a bird than all cells in the chicken itself. So, are we feeding birds, or are we feeding the ecosystem that includes the birds?

We will also see that poultry nutrition will be focused on nutritional strategies that modulate intestinal microflora and promote gut development and health. Gut health is a complex relationship between the diet, the intestinal mucosal, and the intestinal microflora. More research will focus on plant extracts, microbial fermentation products, and direct fed microbials. Indeed, we will also learn how enzymes and other pro-nutrient feed additives will interact with dietary components to stabilise the enteric ecosystem and promote enteric microbial diversity. As gut microbial diversity increases and the enteric ecosystem become more stable, the bird becomes more resistant to the colonisation of enteric pathogens that adversely affect animal health and food safety. Many pro-nutrient feed additives can have synergistic effects on gut health. Their combined benefit may include reduced inflammatory response, enhanced protective properties of the mucosal barrier, stabilised microbial ecosystem, and improved nutrient absorption. I think nutritionists of the future will work more like ecologists and systems biologists and less like applied biochemists as they have in the past.

Nutrient utilisation

Feed science has always been an integral part of poultry nutrition as the dietary inclusion of new ingredients was incorporated into an acceptable feed form. Pellet processing of poultry feed has become a standard practice, mainly to improve feed handling properties and feed utilisation by the birds. Feed conversion improves when pellet quality improves. According to McKinney, the effective caloric value of pelleted feed is over 150 kcal/kg higher than of mash feed because birds spend less time eating and more time resting. This effective caloric value of pelleted feed becomes more important as energy costs increase.

In the future, there will be more research done on cost-effective means to improve pellet quality for poultry. New methods of conditioning feed to improve pellet quality will become essential, especially when feed safety is also considered. Although pellet quality can be improved by reducing particle grind size and increasing the heat processing of feed mash during conditioning and pelleting, the welfare of the bird may be compromised. Chickens and turkeys are seed eaters, and they have a built-in grinding organ called the gizzard. The gizzard does not have to work very hard in birds that consume feed that has been finely ground and manufactured into feed pellets. Because the gizzard is an important pre-digestion organ and “pacesetter” of gut motility in birds, highly processed feeds could result in more gut health problems associated with a microbial ecosystem that is less resistant to pathogens. Public interest in the welfare of birds fed all natural/ antibiotic-free feeds will force the poultry industry to consider alternative feed manufacturing technologies that promote gut health, yet maintain feed conversion efficiency. Because of the rising energy costs, and public concern about animal welfare, traceability, and food safety, the future will see resurgence in feed science research and technology.

Perinatal nutrition

Fifty years ago when genetic selection of broilers and turkeys began, the incubation and neonatal stage of development represented about 25% of a broilers productive life. Today, high meat-yielding poultry reach their market weight within a relatively short period of time, and the incubation and neonatal represents over 50% of the bird’s productive life. Poultry geneticists expect the age to market weight will continue to decrease in the future, so the incubation and neonatal will become of greater relative importance in poultry production. Scientists know that a bird’s ability to achieve their genetic potential for growth depends on early nutrition. Particularly critical to neonatal poultry is nutrient intake, environmental stress resistance, and the development of immunity and a stable gut microflora. We now know there are several dietary factors that have an effect on the neonatal development of poultry. So, neonatal nutrition will become a very active field of research and development in the future. We will see more interest in dietary inclusion of organic acids, nucleic acids, organic trace minerals, plant extracts, and bioactive compounds.

Nutritional jumpstart

Regardless of what you add to the feed, neonatal birds must eat that feed before it expresses its effectiveness. One way to give hatchlings a nutritional jumpstart before they start eating feed is to feed them before they hatch. Over recent years, Dr. Zehava Uni (Hebrew University of Jerusalem) and I have collaborated to develop in-ovo feeding technology: injecting supplemental nutrients into the amnion of the late-term embryo a day before internal pipping.

We have demonstrated that in-ovo feeding can improve hatchability rate and chick quality, increase glycogen reserves, advance gut development, improve skeletal health, and promote muscle development. Using gene array technology, we observed over 50 genes are expressed differently over time by in-ovo feeding. Essentially, in-ovo feeding advances the development of newly hatched chick by 2-3 days, and they are able to consume more feed immediately after hatch. The first few days after hatch is very important period in terms of subsequent welfare and growth performance of the bird. Poultry scientists all over the world are now using in-ovo feeding technology to study perinatal nutrition of chickens, turkeys and ducks. In-ovo feeding and early nutrition will continue to be a very fruitful area of poultry research in the future.

Epigenetic programming

Related to perinatal nutrition is a new emerging science called Epigenetics, which can be defined as any heritable influence on gene activity that does not involve a change in the DNA sequence. Common epigenetic mechanisms that occur during the prepubertal or perinatal development include DNA methylation, histone modification, and regulatory non-coding RNAs. So, how we feed and manage broiler breeders, incubate eggs, or feed and manage hatchlings can determine the physiological response and health of that bird for the rest of its life. Although epigenetics is a new science mainly studied by scientists working with mice and other animal models, soon poultry scientists will apply epigenetic treatments to increase the production efficiency and welfare of poultry.

Epigenetic programming may be used in the future to increase caloric efficiency, enhance nutrient utilisation, improve disease resistance and stress tolerance, and modify behaviour of commercial poultry. The exciting future As they have in the past, nutritionist’s have responded to the production and marketing needs of the poultry industry, using the most cost-efficient nutrient resources available. Poultry nutrition has always been on the forefront of science, and it will continue to be so in the future if there is sufficient academic, social, and economic support. Over the next 25 years, poultry nutrition will be closely integrated with other science disciplines, using biotechnology and computational technology to produce the highest quality poultry products at the lowest cost for consumers who have a diversity of demands. Only time will tell what consumers will demand over the next 25 years, but poultry nutrition will change to accommodate those demands.

caption: In-ovo feeding advances the development of newly hatched chick by 2-3 days, and they are able to consume more feed immediately after hatch. * In the past, poultry nutrition focused on the nutritional requirements of the bird. In the future, however, nutrition should be more concerned about feeding the ecosystem, which includes the chicken or turkey.