When preparing broiler feeds, how to ensure total performance and profitability? Key to that is a quick adaptation and a smooth transition after hatch. A carefully balanced and well-designed broiler feeding strategy forms part of that approach. Here is how to do that.
The term “survival of the fittest” was first mentioned by the British biologist Charles Darwin in 1859. The phrase originally applied to explaining evolution and diversity in life, spanning out over a series of generations. Yet the term is also applicable to what is happening within one generation on a broiler farm. After all, when broiler chicks receive a good start, they will be fit and ready to take on challenges for the rest of their lives.
However as logical as that all may sound, the practice is not that easy. When care for young animals is suboptimal, consequences can be plentiful. Think of increased mortality, overgrowth of intestinal microbes, leading to a host with different health problems such as diarrhoea, wet litter, foot pad lesions and extra use of antibiotics – or, if that all does not happen, just lower feed efficiency as well as a reduced animal performance. All in all, it leads to less profit for producers in times of small margins.
That is why paying attention to the youngest animals is worth looking into. Extra attention for young animals will lead to robustness and resilience instead of increased mortality. Similarly, a quick and easy transition without stress for broilers after hatching – after all, stress makes a gut leaky. On top of that: economy matters, as a relatively small investment at a young age will lead to a high return rate at marketing.
Before compiling a proper diet for young broiler chicks, it’s important to understand the development of their digestive physiology. After all, adaptation to digest feed takes time, the digestive system needs to develop – this is a process called induction. In addition, the gastro-intestinal tract after hatching is almost sterile and it takes time to establish a good and stable gut microbiome, both in the small intestine, as well as in the caeca.
Time is also an issue when talking about immunity – there is a gap in immunity from innate to adaptive. The first protection in the gut comes through immunoglobulins, from the broiler breeder via the egg yolk. Last but not least, young broiler chicks are very sensitive to protein digestion. When the protein is not digested well, there will be an overgrowth of pathogenic and non-pathogenic microbes in the hind gut. There is always a competition for nutrients going on between the host and the microbes – obviously ideally the host should win that competition, but microbes are required to develop immunity.
There are several issues that need to be solved to make sure that young broilers make it through their first days after hatching. Young broilers are not able to control their body temperature well; it takes a few days before they manage to do so and become ‘homeothermic’.
When putting all these elements together, 4 main objectives can be discerned what to aim for when the broilers reach one to 2 weeks of age.
For broilers at 1 to 2 weeks of age, the main objective should be to reach a stable and diverse gut microbiome. To achieve that, the goal should be to reduce the total numbers of all microbes – that includes the pathogenic ones but also the beneficial ones. More specific, that means trying to reduce the numbers of gram-negative bacteria in the small intestine at a young age. That can be achieved by:
Development of a good immunity should also be a goal to conquer in the first few weeks. After all, at hatch, the animals have innate antibodies (coming mostly from the mother – the maternal antibodies), but these levels decrease whilst specific neonatal antibodies from the adaptive immune system still have to increase. At roughly 2 weeks post-hatching, the level of total amount of antibodies is lowest. The gap between the innate immune system and the acquired immune system therefore needs to be bridged.
The adaptive immune system can be stimulated, through e.g. the addition of specific β-glucans from hydrolysed yeast cell walls as well as proteins, as they are the building stones for the immune system. In addition, microbes can play a role there – indeed, the microbes again. On the one hand they are needed, on the other it’s better not to have too much. When the birds get older, it is good to focus on adding anti-inflammatory substances.
The next question is how to develop a high digestive capacity?
A good walking ability should be an aim. For that purpose, minerals matter. Calcium and phosphorus are required for mineralisation of bones in a ratio of 2.1 to 1. Yet, virtually all of the calcium goes to the bones, whereas approximately 50% of the digested phosphorus is retained in soft tissues, with the other half being retained in bones. That is why the required optimum ratio between digestible calcium and digestible phosphorus is close to 1 to 1. For a good walking ability, the maximum bone ash mineralisation is not required. High calcium levels in starter diets may sound attractive as calcium is cheap. Yet, the combination of high calcium and low phosphorus is detrimental for bone mineralisation and body weight gain. Lastly, coarse limestone is retained longer in the gizzard, which solubilising slowly eventually will lead to a higher digestibility.
Putting all these requirements together, a picture of the ideal feed formulation emerges.
All in all, to achieve total performance and profitability at marketing, the key message revolves around a quick adaptation and a smooth transition after hatch of broiler chickens, fit to survive. Words which, no doubt, Charles Darwin would have agreed with.
This article is a summary of a presentation held during a webinar on Young Animal Care, held by All About Feed together with the Royal Agrifirm Group, in December 2020. It was organised to launch the company’s new young animal nutrition brand ‘Earlyfeed’. The webinar can still be viewed on demand.
Loek de Lange, private consultant Loek’s Feed, the Netherlands and
co-author Vincent ter beek, editor pig progress