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Feeding the modern genetic layer

Highly productive breeds are available nearly all over the world and we know very detailed recommendations for feeding different layer hybrids bred by each primary breeding company. Some practical challenges, However, still need to be overcome, says Robert Pottgüter.

High productivity in layers is common under nearly optimal conditions, but how will the modern genetic layer perform under less optimal conditions? Is it possible to fulfil the nutritional recommendations from the breeding companies for different breeds anywhere in the world? We don't know a universally accepted ideal amino acid profile for layers like we do for broilers. Another major problem in feeding modern genetic layers is to determine the energy content of all raw materials with a universally accepted and valid evaluation system. Currently, nearly every country or region works with a different system. In addition, will the typical corn-soy diets that are so widely in use now be as readily available in the future? What are the consequences of the bans on many feed supplements, antibiotic growth promoters (AGPs) and medications? These aspects need to be discussed from a nutritional point of view and also in terms of feed production.

Energy evaluation
One major challenge for all nutritionists is energy evaluation of all available raw materials and complete feed. The majority of the energy in the feed for our birds is based on crude protein, crude fat, crude starch, and sugar. Which measurement should we use: metabolisable energy (ME) expressed as kilocalories (kcal) or as mega-joules (MJ)? Which metabolisable energy system should we use? Should we use the tables from the WPSA (World Poultry Science Association) or should we work with a kilocalorie formula based on the main nutrients mentioned above when we use the well-known kilocalorie unit system? The same question is evident when we work with a ME system expressed as mega-joules. Every energy evaluation system we use must be easy to handle for raw materials and complete feed. It should also be possible to use this system with currently used optimisation programmes to create and optimise practical diets. When nutrient values of raw materials change, it is better to use systems with slight inaccuracies rather than not adjusting matrix data at all. This has to be done, for example, by variation of starch content in grains or protein and fat content in oil seed meal or cakes.

 Robert Pottgüter received his Diplom- Ingenieur- Agrar at the Georg August Universität Göttingen in Germany. He has spent 24 years working as poultry feed product manager for deuka Deutsche Tiernahrung GmbH & Co. KG in Düsseldorf, Germany and, since 2006, as a nutritionist expert at Lohmann Tierzucht GmbH. Feeding modern layers starts with the day-old chick, because during this first period the performance of the layer hen is determined .

With all systems or formulas, energy is the most expensive restriction in feed optimisation. The energy content of the feed also has a major influence on feed conversion ratio (FCR) and overall productivity. As a consequence, everybody should check complete feed regularly for its energy content, especially if the complete feed paid for. In order to accomplish these tasks, it is obvious that a system is needed, which is based on easily analysed nutrients. This requirement is the opposite of a 'scientific only' approach to conduct digestive trials with animals to determine the ME-content of every raw material. This easy-to-use energy evaluation system is needed for raw materials and complete feed as well. The mega-joule formula from WPSA expressed as ME in mega-joules
per kilogramme represents such a system. The formula includes the main nutrients, namely crude protein, crude fat, crude starch and sugar, and is regression-based on animal trials.

Calculating from mega-joules to kilocalories and vice versa is done using the factor 4,187. Which energy evaluation system should we use when enzymes are included in the feed formulation and how will we work with the so-called energy uplift? The energy uplift of NSP enzymes has been determined first with broilers, and depends mainly on improved fat digestibility. However, layer diets are completely different from broiler diets because layer diets, for instance, very often show  low levels of added fat and oil. Should the energy uplift be based on single raw materials and the adjustment of matrix data, or should it be based on a percentage addition to the complete mixture? The uplift depends on the inclusion level of raw materials with higher NSP content, if in fact this uplift really exists. When using energy uplift to calculate the ME value of the diet, the NSP content of the main raw materials needs to be analysed. Although many questions in terms of using enzymes are not yet answered, it is recommended to use NSP enzymes to promote healthier digestion. The enzymes must be used in liquid form and “end-of-line” dosage if the feed has to be heat treated.

Egg weight and quality

Egg weight and quality An important further challenge in feeding layers is the short-term influence on egg weight. The optimal egg weight depends on market demands in different countries, and is impossible to influence very quickly by means of genetic changes. Nevertheless, while every breed is bred for a certain egg weight, it is much easier to adjust egg weight by management and feeding. As we know, the main limiting nutrients for egg weight are methionine, protein and linoleic acid. The content of crude fat and the energy density of the feed also have a big influence on egg weight during the laying period. One of the most common ways to adjust the egg weight is to use a phase-feeding programme. Egg producers in most world markets want to achieve a rapid increase in early egg weight followed by a very gradual increase after peak production. Controlled feeding with the goal of reduced feed intake and adjustment of house temperature are other means by which to influence egg weight. In terms of egg quality, it is important to keep water quality in mind. Egg producers should always ask: “Would I drink this water myself?” The drinking water should be analysed regularly to avoid egg quality problems. Mineral content is an example because it can certainly influence the eggshell strength and overall egg quality. Water is also a carrier of vaccines, medications and sometimes additional vitamins. The water system has to be cleaned regularly to ensure healthy birds and optimal egg quality. In hot climatic conditions, water is also necessary for cooling the birds.

Protein and amino acids
When talking about protein and amino acids, there is much more common knowledge in most countries concerning raw materials. Every breeding company has (to some extent) different recommendations in feeding, especially regarding amino acids for the different breeds. Also, since only the total amino acid content can be analysed easily, the feed has to be formulated based on available amino acids. The better the feed is adjusted in available amino acids, the lower the crude protein content may be. In many situations, this is an easy way to save money on feed formulation. Therefore, all nutritionists should use internationally recognised methods to build the best amino acid matrix for each raw material. For example, a well-known data tool is aminodat by Degussa or similar information from Adisseo and Novus. For all who are involved in feeding layers, it is a general recommendation to create an ideal amino acid profile for layers. This should be the approach used by all scientists working in poultry nutrition.
 
Raw materials
A big challenge in terms of raw materials is to know the actual nutrient content of each batch. Basic nutrients which should be analysed regularly are crude protein and total content of methionine, lysine and threonine (analysis of more amino acids is beneficial if possible). Starch is the most important energy source. It is also necessary to analyse crude fat and the main minerals calcium, phosphorus, sodium and chloride.
 
These are the very essential nutrients in every raw material needed to build a raw material matrix. This matrix needs to be adjusted on a regular basis. It is absolutely impossible to build a matrix based only on “tables from the Internet”. While this seems to be obvious, it is very often forgotten. Standard raw materials for poultry feed are corn (maize) and soya. Concerning these major raw materials, we see increasing prices in the market due to the high demand of soya worldwide and the increasing use of maize for the production of ethanol and bio-energy. In many countries, other grains like wheat, triticale, barley, oats, rye and sorghum are used successfully, together with NSP enzymes.
 
Additionally, every feed producer has to look for grain by-products, such as bran and corn or wheat germ as valuable raw materials for poultry feed. Soya is a major vegetable protein source for poultry diets all over the world. There are other raw materials high in protein content in addition to soybeans, examples being rapeseed or canola meal, sunflower meal, peas, meat and bone meal and fish meal of different varieties. All nutritionists are responsible for looking for and testing new or unknown raw materials for layer diets. With the inclusion of raw materials (grains) that are lower in energy content, we see an increasing demand for fat or oil in layer diets. Fats and oils have the highest energy density of all feed raw materials; up to three times higher than grain. Added fats and oils bind dust and increase the palatability of mash feed, which is often very important for supporting feed intake. Fat is not only an important raw material, as crude fat it also is a very important nutrient.
 
Feeding diets higher in crude fat content promotes good liver health and is beneficial for avoiding fatty liver syndrome. In hot climate feeding, it is also essential to use diets higher in crude fat content and lower starch content in order to reduce heat increment during digestion. It should be basic knowledge to know the fatty acid profile (especially linoleic acid) when using fat and oil as raw materials for layer diets. Increasing or decreasing linoleic acid content of the diet is a well-known method of adjusting egg weight.
 
Other challenges
One of the other challenges for feeding layers includes the use of Salmonella-free feed. This is a standing request of every breeding company because consumers demand and expect Salmonella-free food products. One of the biggest challenges in producing Salmonella-free feed is to avoid any kind of recontamination during delivery and storage of the feed until it is consumed by the birds.
 
Although some special supplements like organic acids are very useful to achieve this aim, the major problem is very often the storage and handling of the feed at the farms. Vegetarian and ecological/bio feed may also be a challenge in the future. In many countries it is necessary to formulate layer feeds without using any raw materials of animal origin, but rather with plant origin ingredients only. Based on our own experience over several decades as a breeding company, it can be said that the feeding of vegetarian feed is no problem in any diets for layer type birds.
 
Feeding modern layers starts with the day-old chick, because during this first period the performance of the layer hen is determined.
 
However, every nutritionist should use raw materials of animal origin such as meat and bone meal when it is possible and legal for use in layer feed. These raw materials are very cost effective in feed optimisation and provide highly available nutrients. Furthermore, ecological/bio feed has become a big challenge in some countries in the northern hemisphere. The main precondition of this feed is that a ban on the inclusion of synthetic amino acids must be observed. In general, this leads to a deficiency of methionine in nearly every diet. As we know, methionine is the first limiting amino acid and this must be taken into account when these diets are formulated. The European ban on all antibiotic growth promoters (AGPs) in all poultry and livestock feed poses a big challenge regarding the use of (alternative) feed additives in layer feed without compromising animal health and performance.
 
Summary
While we may never be able to solve all challenges to feed the modern genetic layer, we have to strive to ensure profitable egg production in all regions of the world. Challenges include the need for a universally accepted energy evaluation system and an equally acceptable amino acid profile as nutritional baselines for layers. Concerning more economical aspects, we need more emphasis on the use of raw materials other than corn and soya as the main raw materials in layer diets.
 
New solutions have to be created to overcome the ban of AGPs and to stress the use of alternatives. Examples of modern supplements are enzymes, particularly phytase and NSP-enzymes, which should be implemented in every layer diet, especially those diets with lower amounts of or no corn (maize). Furthermore, there is an increasing need for an open discussion with consumer advocacy groups and others interested in knowing how quality products are produced with keeping animal welfare aspect in mind.
 
Source: Feed Mix Volume 15 No. 05

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