Developments and innovations in broiler nutrition in the Netherlands
During the last decades important triggers for innovation have been the reduction of the output of minerals and nitrogen to the environment and the ban by the EU on the preventive addition of antibiotic growth promoters (AGP’s) to feeds. A good protein evaluation system with an accurate estimation of requirements will minimise the output of nitrogen to the environment, improve intestinal health and performance. AGP’s have a direct effect on the numbers of bacteria in the gut but also on the composition of the microbial community in the different segments of the gastro-intestinal tract of broilers. Relative high quantities of DNA from Lactobacillus Acidophilus in the upper gut of young broilers are related to a bad feed utilisation. The effect of immune modulators on performance is not always consistent and depends on source, age and challenge. Future challenges in animal nutrition research are about animal welfare and how to reduce the output of green house gasses in animal husbandry to prevent global warming.
The Netherlands (NL) is a small country, but big in agriculture. With an agricultural export volume of about 58.5 billion Euro NL is the world’s second largest exporter of agricultural and food products after the USA. The net trade surplus of the agricultural sector in NL of 23 billion Euro in 2007 is after the US the second largest in the world, and represents 57% of the total Dutch trade surplus (LEI, 2009). This strong position is built on the leading role of The Netherlands in primary agricultural production, logistics and agricultural research.
In the seventies and eighties of the last century the livestock industry in The Netherlands has developed rapidly. The main reasons for this development were the low transport costs due to the favourable infrastructure and waterways, the high prices of grains within the European Union (EU) combined with the use of cheap imported alternative feed ingredients as tapioca from Thailand and maize gluten feed from the US. All this has led to low feed prices and low feed costs per kg meat, milk or eggs in The Netherlands compared to other European countries. So the turnover of the feed industry in NL could increase for many years with 5 – 10 % annually.
In the nineties, the high stocking density close to a dense human population caused problems with pollution, and led to restrictions for the output of nitrogen, minerals and trace elements to the environment. In the last decade, the risks of a high stocking density have become clearer with the outbreak of contagious diseases. The advantage of the import of cheap raw materials disappeared when the prices of the cereals came down by a changing policy of the EU. By this reason and the environmental restrictions the feed production went down from 16.5 million tons at the start of the nineties to a stable volume of about 14 million tons during the last five years. The production of poultry feeds has been for many years quite constant on a level of 3.5 million tons a year, disregarding the severe outbreak of avian influenza in 2003. Of the 3.5 million ton poultry feed about 1.5 million ton is for broilers and about 2 million ton concerns feed for layers (FEFAC, 2009).
All this made the animal feed industry in NL very competitive, innovative and expanding abroad. The knowledge about the evaluation of raw materials coming from all over the world (CVB-tables), about the nutritional requirements of farm animals, about how to minimise the output of nitrogen and minerals to the environment (phytase is a Dutch invention) has developed well during the last decades within The Netherlands and more specific within De Heus Feeds.
The gross domestic production of poultry meat in NL is 700,000 tons per year. The consumption of broiler meat in The Netherlands comes mainly from breast and processed meat, while the local consumption of grillers and leg meat is relatively low. The average consumption of broiler meat in NL is 18.4 kg per capita or 303,000 ton total per year. The main export markets are Germany and the UK (PVE, 2009). The 44 million broilers in NL are housed on 700 farms. So the average size of the family owned farms is around 70,000 broilers, taking into account the time that the houses are empty and cleaned. The life weight at slaughter varies from 1.7 till 3.5 kg with an average of about 2.3 kg. The broiler houses are well insulated with a good climate control, and cleaned and disinfected after each flock. Feed costs are about half of all production costs. The costs for housing are almost 10%.
The production of broiler meat in NL is not integrated. Slaughter houses, broiler farmers, hatcheries and feed mills operate independently, but they make short term contracts and exchange information. De Heus Feeds has in this highly competitive broiler market a market share of 25 – 30% of the compound feed.
In an open competitive market economy is always a good trigger for rapid developments and innovations. With the decline of prices of cereals in the EU at the nineties adding whole wheat on the broiler farm has become popular saving processing and transport costs. At the beginning about 10% whole wheat was used combined with standard feeds without affecting the performance negatively. Nowadays frequently 20 – 35% whole wheat is used together with concentrates rich in protein.
Environmental problems induced the development of phytase by Gist Brocades and Dutch research institutes. The use of this enzyme has become widespread all over the world when the use became economic by replacing expensive mineral phosphorous and by the beneficial side-effects of phytase by reducing the anti nutritional effects of phytate.
The announcement of the ban of Antibiotic Growth Promoters (AGP’s) in feeds starting in 2006 by the EU has given an enormous boost to research on intestinal health and how to replace these feed additives. Many alternatives for AGP’s have been tested without questioning the mode of action of AGP’s. More recently, efforts have been put to reduce the therapeutic use of antibiotics at farm animals on prescription by veterinarians. Especially the increasing concern about life stock farmers carrying resistant bacteria in their body is an important motive to reduce also the therapeutic use of antibiotics.
Another concern is about animal welfare starting in the UK more than 10 years ago. In The Netherlands a one issue political party on animal welfare is even represented in the parliament. EU regulations for animal welfare especially about housing are nowadays common practise. A new EU regulation starting July 2010 about stocking density related to mortality and foot pad dermatitis will affect the broiler industry. If the norms for mortality or foot pad dermatitis are exceeded the maximum stocking density has to be reduced (EU, 2007).
Also retailers in The Netherlands try to profile themselves recently with themes as sustainability and animal welfare. Special niche markets are being developed with extra added value and more attention for animal welfare.
(a) Protein Evaluation
In The Netherlands the protein requirements for poultry are usually based on the faecal digestibility of amino acids (AA). Minimum requirements are set for the essential amino acids as lysine, methionine + cysteine and hreonine. The other essential amino acids are normally not limiting. If some nonessential AA are not supplied sufficiently these can be synthesized from non limiting essential and other nonessential AA. To ensure that the requirements for all AA are provided, one can formulate requirements for both essential amino acids and crude protein (NRC, 1994). An indirect way to ensure the supply of nonessential AA is by maximising the use of synthetic AA. At De Heus we prefer to formulate diets with protein requirements for essential AA and the sum of all digestible AA (De Lange et al, 2003). Doing so, also the surplus of non limiting essential AA is utilised to meet the requirements for nonessential AA. By this approach and by using well digestible protein sources, the amount of nitrogen at the end of the intestinal tract is minimised to prevent proteolytic fermentation. The fermentation of protein can increase the growth of pathogenic bacteria such as sulphite reducing clostridia and the formation of toxic compounds as ammonia and phenol as is demonstrated after predigestion with in vitro research in the TNO Intestinal Model (TIM-2) to simulate the function of the hindgut (Table 1).
To avoid proteolytic fermentation one can minimise the quantity of fermentable protein (Cone, 2005), closely related to indigestible protein or the difference between ileal digestible protein as described by Bryden et al (2009) and faecal digestible protein.
The objective of a correct feed evaluation is to predict animal performance accurately with different compositions of the feed. The combination of the minimum for digestible AA and a maximum for indigestible crude protein gives a better prediction of animal performance than crude protein (De Lange et al, 2003).
The protein levels in feed depend on age/weight, breed, intake, gain and economy. With the modern broilers there is a good relation between protein level in the feed and animal performance as is shown in trial VK-062, performed by De Heus (Figure 1 and 2).
Figure 2. Feed Conversion Rate per cross breed and per protein level at day 35 at 2 kg Life Weight (correction 0.03 per 100 g LW; VK-062)
After correction for protein requirements for maintenance, the protein conversion expressed as protein requirements per 100 g growth is equal for the main cross breeds during the grower or finisher period (Figure 3). Taking into account the differences in intake and growth, the protein requirements expressed per kg feed are different between the main breeds. There seems to be a continuous improvement in protein efficiency in time when the protein requirements are expressed per 100 g daily gain.
(b) Intestinal health
New molecular DNA based techniques like Terminal Restriction Fragment Length Polymorphism (T-RFLP), as described by Lu et al (1997) reveal the complex microbial societies in many biotopes as the broilers gut. In the ileum of broilers mainly Lactobacilli are dominant, while in the cecum Clostridiaceae related species are abundant (Lu et al, 2003). AGP’s reduce the overall numbers and the numbers of species of gut bacteria in pigs and poultry (Jensen, 1998; Gaskins et al, 2002). Bacteria in the gut may be considered as parasites or commensals, dining at the same table as the host and consuming nutrients. Bacteria like Enterococcus faecium and Clostridium perfringens but also Lactobacillus species hydrolyse bile salts and cause impaired digestion of fat (Knarreborg et al, 2002). Bacteria also trigger the immune system as is shown in germ-free animals, which have a poorly developed immune system. Triggering the immune system leads to an acute phase response with loss of appetite and catabolism of muscle tissue (Gruys et al, 2006). Niewold (2007) hypothesizes that the growth promoting effect of AGP’s relies on an anti- inflammatory effect by inhibiting the production and secretion of cytokines by intestinal inflammatory cells and so reducing the acute phase reaction.
In a cooperative research by Provimi and De Heus Feeds, funded by the Dutch Ministry of Economic affairs, is shown that AGP’s and feed composition have an effect on the microbial composition in the gut, which is related to feed efficiency. Relative high quantities of DNA from Lactobacillus Acidophilus in the upper gut of young broilers are related to a bad feed utilisation, and are affected by feed and AGP’s (De Lange and Wijtten, 2008). Davis et al (2009) showed a relation between the relative numbers of L. Acidophilus in the gut of pigs and a systemic immune response by measuring T-cells in the peripheral blood.
The alternative of De Heus Feeds for the use of AGP’s is called Nutribiotics ®. This concept is based on a high digestibility of protein to prevent the formation of toxic metabolites like ammonia and phenol and to prevent increased numbers of sulphite reducing Clostridia, on natural antimicrobial components to reduce bacterial growth, on a feed form with coarse particles to lower the pH and to increase the retention time of feed in the gizzard, and on a low viscosity of the intestinal content to facilitate digestion. After the ban De Heus has succeeded in continuing the improvement of broiler performance in practise with a FCR of 1.70 – 1.75 at a life weight of 2.3 kg.
The next challenge in research and application into practise is the modulation of the immune system of the broiler chicken. The best way of immune modulation is most probably by stimulating the development of the immune system at a young age and by reducing acute phase reactions at an older age when birds have to grow efficiently. Also modulating the immune reaction to an anti-inflammatory Th2 response instead of a pro-inflammatory Th1 response can help to improve feed and protein conversion. Modulating immunity of young chickens starts with the parent stock. A well developed innate immune system helps in initiating the adaptive immune response (Goddeeris, 2005). Feeding BioMos ®, a yeast cell wall (YCW) product to breeder animals changes the ratio yolk/egg white in breeding eggs and increases the quantity of specific immune globulins in blood against New Castle Disease after vaccination (De Lange, 2007).
In a De Heus experiment (VK-078) adding Fibosel ® to the breeder diet reduces the live weight of the off spring at day 35 compared to the control group (P < 0.05), and tends to improve the not corrected FCR (P < 0.10) compared to the control group (Table 2). Also the interaction between the addition of YCW based products to breeder diets and a challenge with a viscous diet during the grower phase on the FCR tends to be significant (P < 0.10) (Table 2 and 3).
The beneficial effect of an investment in the immune system on a young age seems to depend on a challenge later in life.
Adding Fibosel to a starter diet improves the corrected FCR at 2 kg live weight compared to the BioMos group significantly (P < 0.05) and the difference with the control group tends to be significant (P < 0.10) (Table 4).
IV. FUTURE CHALLENGES
The nearby challenge in broiler nutrition science is to improve animal welfare by reducing mortality and foot pad lesions. The most obvious way to lower mortality is improving health and robustness of the one day old chickens, starting at breeder farms and hatcheries, but also at the start on the broiler farms. Reducing feed intake and average daily gain might be also part of a concept to lower mortality and sudden death. Less foot pad lesions will be pursued by nutrition and improving litter quality by nutritional and other means. The best way to respect the environment at the production of broiler meat is by reducing the output of nitrogen, minerals and trace elements, by improving feed utilisation and by maximising the use of by-products that are less attractive for direct human consumption.
Bryden WL, Li X, Ravindran G, Hew LI, Ravindran V (2009) Ileal Digestible Amino Acid
Values in Feedstuffs for Poultry RIRDC. Canberra, ACT.
Cone JW, Jongbloed AW, Van Gelder AH and De Lange L (2005) Animal Feed Science and
Technology 123-124, 463-472
Davis E, Rehberger J, King M, Brown DC, Maxwell CV, and Rehberger T (2009)
De Lange LLM, Rombouts C and Oude Elferink G (2003) World’s Poultry Science Journal,
International Symposium on Digestive Physiology in Pigs
De Lange LLM, Kocher A and Beeks W (2007) Proceedings 27th Western Nutrition
Conference. Alltech symposium, Lexington, Kentucky, USA
De Lange LLM and Wijtten PJA (2008) Proceedings 33rd
EU (2007) COUNCIL DIRECTIVE 2007/43/EC of 28 June 2007 laying down minimum
rules for the protection of chickens kept for meat production.
Meeting of Dutch speaking
nutrition researchers (NVO) Wageningen, The Netherlands 85-86
FEFAC (2009) Compound Feed Production EU (1989-2008).
Gaskins HR, Collier CT, Anderson DB (2002) Animal Biotechnology 13, 29-42
Goddeeris BM (2005) Conference Antimicrobial Growth Promoters: Worldwide Ban on the
Horizon, Noordwijk aan Zee, The Netherlands
Gruys E, Toussaint MJM, Niewold TA, Koopmans SJ, Van Dijk E, Meloen RH (2006) Acta
Histochemistry 108, 229-232
Jensen BB (1998) Journal Animal Feed Science 7, 45-64
Knarreborg A, Engberg RM, Jensen SK, Jensen BB (2002) Applied and Environmental
Microbiology 68, 6425-6428
LEI (2009) Agri-monitor 2008.
Liu WT, MARSH TL, CHENG H, FORNEY LJ (1997) Applied and Environmental
Microbiology 63, 4516-4522.
LU J, IDRIS U, HARMON B, HOFACRE C, MAURER, JJ, LEE MD (2003) Applied and
Environmental Microbiology 69, 6816-6824.
Niewold TA (2007) Poultry Science 86, 605-609
NRC (1994) Nutrient requirements of Poultry. Ninth Revised Edition edited by National
Academy Press, Washington, D.C. USA
PVE (2009) Statistics Livestock, meat and eggs 2008.
PUBLICATION DATE: 09/03/2010
AUTHOR: L.L. DE LANGE