16th March 2021
The features and benefits of broiler starter feeds that include AlphaSoy
Strategies to support the gut health and early development of broiler chickens produce long-term performance benefits for the flock.
by: Dr. Helen Masey O’Neill
Senior Manager – Science and Analytics
Today’s modern broiler achieves a dramatic growth rate and is expected to increase its body weight by nearly four times in the first seven days post-hatch. Body weight at seven days of age is commonly accepted as an indicator of final body weight. Leeson and Summers (2005) stated that every extra gram of body weight achieved at day 7 could result in an extra 5g of body weight at day 49.
Figure 1 shows the performance objectives of mixed Ross 308 broilers. Daily weight gain (DWG) as a percentage of total BW is highest in the first days post-hatch and decreases throughout the production cycle. So, there is every reason to pay close attention to early performance. However, this initial phase of life and achieving such high growth rates comes with significant challenges.
Transition from yolk to feed
One of the critical criteria for successful bird growth and development is the transition from the protein-rich yolk matrix to a more complex carbohydrate-rich feed material. While still in the egg, and immediately post-hatch, the developing broiler is supported by nutrients provided by the yolk. These nutrients are only available for a couple of days once the broiler is outside the egg.
The bird gut epithelium is not fully mature until two weeks of age. A poor transition is known to increase early mortality. Early feeding, within hours of hatch, is perhaps the most significant and vital management practice to be implemented in support of this transition period. The presence of feed in the digestive tract stimulates yolk sac utilisation more than when the gut is filled with water alone.
Anti-nutritional factors – the hidden growth inhibitors
There is clear evidence of the negative impact of antinutritional factors (ANFs) on broiler performance. An ANF of concern in starter diets is trypsin inhibitors (TIs) which are present in most oilseeds. Soya contains TIs that interfere with protein digestion and may also interrupt the secretion of pancreatic enzymes (Woyengo et al., 2017), all compromising protein digestibility and reducing growth performance (Clarke and Wiseman, 2007). However, TIs can be removed from soya through heat treatment. Since thermo-mechanical treatment is part of the production process of AlphaSoy™, the TI levels are comfortably below sensitivity levels for young broilers.
The importance of digestibility
Leeson (2008) highlighted that feeding highly digestible ingredients in the first seven days led to a dramatically positive impact on BW compared to conventional ingredients. This early improvement was carried through to final BW. Providing highly digestible nutrients has also been shown to improve gut development (Noy and Sklan, 1998). AlphaSoy™ is a highly digestible processed soy, designed specifically to meet the nutritional requirements of young birds, encouraging early feed intake and therefore growth.
A lack of feed at this early stage can drive the chick to use immunoglobulins in the yolk as a nutrient source, compromising the development of the immune system. The presence of highly digestible feed will prevent this, conserving immunoglobulins.
Development of the digestive tract
The gastrointestinal tract of a newly hatched chick is sterile, and microbial colonization begins almost as soon as the chick is hatched. A healthy microflora is essential for further development of the tract and immune system. The growth of beneficial, and probiotic species can be achieved by feeding probiotic additives directly but will also be supported by feeding ingredients with a high pre-caecal digestibility of amino acids and starch, thus preventing dysbacteriosis.
Feeding ingredients and additives with prebiotic and prebiotic-like components will also support this microflora development. Furthermore, the presence of these species directly supports the development of the tract itself. Once the digestive tract is developed, processed soy can be substituted for standard protein sources, significantly reducing the cost of the feed before intake levels reach a point where using processed soy is less economically viable.
Why feed a specialised starter diet?
A well specified pre-starter diet using highly digestible feed ingredients is likely to stimulate gut development and increase nutrient absorption rate, and will condition the chick for the arrival of subsequent diets. This diet can also be designed with characteristics that promote early feed intake, for example, using colourants and a palatable feed form; pelleted and crumbled feed has also been shown to improve gut development.
Figure 2 shows the significant improvement in 7-day BWG when diets were supplemented with AlphaSoy™ at two different doses, compared to standard soybean products. This improvement can be attributed to the reduction in ANFs, and the higher digestibility, making the protein more available to the birds for growth.
While the first 10-day period represents a quarter of the bird’s life, the feed consumed during the first ten days may only account for 10% of the total production cycle feed intake in terms of weight. This allows slightly more freedom on the cost of the ingredients, meaning more focus can be placed on nutritional quality.
Protein provision in the early stages of life can boost growth, which is why the protein content of starter diets is commonly higher than diets provided at later stages in the production cycle when high protein levels may cause liver problems. Paying extra attention to the formulation and the quality of ingredients in the first days of life will improve health and growth.
Getting it right early delivers long-term benefits
In summary, close attention to early nutrition, with judicious choice of highly digestible ingredients with functional properties supports growth and development of the broiler chick. AlphaSoy™ is new generation processed soya, providing a highly digestible protein source for young birds with additional functionality to support good gut health and performance.
Aviagen. (2014). Ross 308 Broiler: Performance Objectives. [On-line] Available from: http://en.aviagen.com/assets/Tech_Center/Ross_Broiler/Ross-308-Broiler-PO-2014-EN.pdf [Accessed 02.08.18]
Clarke, E. and Wiseman, J. (2007). Effects of extrusion conditions on trypsin inhibitor activity of full-fat soybeans and subsequent effects on their nutritional value for young broilers. British Poultry Science. 48. 703-712.
Leeson, S. (2008). Predictions for commercial poultry nutrition. The Journal of Applied Poultry Research. 17(2). 315-322.
Leeson, S. and Summers, J.D. (2005). Scott’s Nutrition of the Chicken. Publ. Univ. Books.
Noy, Y. and Sklan, D. (1998). Metabolic responses to early nutrition. The Journal of Applied Poultry Research. 7(4). 437-451.
Woyengo, T.A., Beltranena, E. and Zijlstra, R.T. (2017). Effect of anti-nutritional factors of oilseed co-products on feed intake of pigs and poultry. Animal Feed Science and Technology. 233. 76-86.