EVENT EXCERPTS: Natural is future 2.0is a webinar series powered by Natural Remedies Pvt. Ltd. Eminent speakers across the globe are invited to share their thoughts on the most relevant topics of the animal health industry. In June, Mr. Peter Chrystal, the world-renowned expert in poultry nutrition was invited. He has about forty years of experience in the field of both broiler and broiler breeder nutrition. His discussion was aimed at providing hands-on practical perspectives in the management of modern broiler breeders, how to overcome challenges, and to take up opportunities to help the poultry farming community.
Mr. Peter Chrystal started his talk by pointing to the fact, how the physiology of the broiler birds has changed over the past 60 years. The modern broilers are a product of genetic selection for the desired traits of rapid growth with a low-fat deposition. Unfortunately, this is the opposite of what is desired in a broiler breeder and hence the challenges going forward. To tackle the faster growth rate broiler breeders need to be on increased feed restriction, and second, body fat deposition, which is essential for breeder birds, has gone down drastically over the years; this creates problems when birds are at peak production.
He emphasized the two critical stages during the rearing of broiler breeders. First, at nine weeks, which is important for skeletal development, and the second at post-light-up, where it is important to ensure that the females have enough fat pad. Since approximately 20% of the peak, egg laid number is mobilized from the body fat whereas 80% comes from the lipids in the feed. If the bird goes to full peak and doesn’t have enough reserves, it will be unable to perform well at peak.
Bringing the focus to lighting he mentioned that breeders are photorefractory, that is to say, they don’t respond to light until such time that they are mature enough to respond. Hence, during rearing, one either should decline the light or keep the day length constant before light stimulation. This presents challenges, particularly if birds are reared in open-sided houses.
BIRDS DO NOT SEE LIGHT IN LUX, BUT CLUX OR GALLI-LUX.
The Mechanism of light stimulation- in the birds there is mostly hypothalamic stimulation rather than retinal stimulation. The birds do not see light in Lux but Clux or Galli-Lux. The hypothalamus is stimulated, which secretes the luteinizing hormone-releasing (LHR) hormone that stimulates the anterior pituitary gland to release luteinizing hormone (LH), which helps the growth of the follicles. The feedback mechanism of progesterone goes back to the hypothalamus. These rapid changes in the hormone levels are a stressful event, we should keep in mind that the birds are already on feed restriction too. He suggests that farm management must consider boosting vitamins such as α-tocopherol, herbal extract with antioxidant properties, carotenoids; phytogenic compounds that are anti-bacterial and improve gut health, so that they may stimulate feed intake, and also promote follicular development.
Managing ovarian function
Talking about managing ovarian function he mentioned the importance of critical balance between too many follicles or not enough follicles. Ideally, in a breeder bird autopsy, 5–7 large follicles must be seen while the small follicles should be numerous. With too many large follicles, birds will be at excellent peak production but with poor persistence, the causes could be that layers are over-feeding at the onset of lay or possibly improper light stimulation. With insufficient follicles, birds would get to normal peak production but with poor persistence. This is caused due to inadequate light stimulation, a higher incidence of atresia, or a normal decline in follicle number with age.
Photo-stimulation
He emphasized the importance of light-proof housing in other words light controlled housing in broiler breeders and the importance of sudden transition in light duration at 21st week. He explained in detail the effect of light stimulation and the drawbacks of some housing systems.
Practical feeding of breeders
According to him, birds with very little energy will go into negative energy balance; they will lose weight, production, and fertility. Whereas too much energy would lead to a high-fat deposition, causing oviduct problems, and can impact fertility (poor mating success).
He explained the relative energy demand of the birds with reference to age and development of the oviduct and growth of the birds. He showed the importance of maintaining a proper protein-to-energy ratio at different stages of growth and production by comparing results from different scientific publications. He addressed several participant queries as below.
How does debeaking affect production in breeders?
He spoke from his experience and mentioned that if debeaking is performed properly without damaging the tongue, it does not affect the production at all. They routinely use infra-red treatment and they don’t see any impact on the production, but if the birds are stressed during the debeaking process or the debeaking itself is not performed well, it may have an impact on feeding and in turn the performance. He also pointed out that the age when debeaking is performed is important if debeaking is performed on day-old birds with the infrared method, rarely much impact is seen, while a hot blade cut might create problems when not performed well.
What is the role of body weight and feed intake after photo stimulation on ovarian function, at the first egg in broiler breeder females?
According to him, every flock is different. If the flock is underweight and not ready for sexual maturity and photo-stimulation, there would be a problem if we tried to peak feed it. If the flock is mature and ready to be photo-stimulated, one can go to peak feed and wouldn’t face any problems since she’ll respond amicably. Overfeeding when the flock is not ready for it then one would see prolapse, double yolks even in pullets. It all depends on whether the bird is ready for stimulation of feed and it is a hard question to answer since each flock is very different.
Do you recommend the usage of non-starch polysaccharide (NSP) enzymes or protease enzymes in the broiler breeder diet? If so, is it a growing trend?
He mentioned that he would use an NSP enzyme, the reason being if one is using rice bran or wheat bran in their diet, it evens out the energy of the grain. But it probably has less effect on maize and wheat-based diets. He also suggested the use of a phytase as a single dose, but not a protease.
What is the solution to control multiple ovulations in broiler breeders, apart from feed restriction?
He opined that there isn’t another solution, apart from feed restriction. But he says that there are 2 problems with open-sided houses, during long day length birds would have been over-stimulated, so the only choice one has got is to hold back on the feed. The only other answer would be to go for light-tight housing. If one can’t control the light the only other thing that can be controlled is feed.
How can we prevent oviduct prolapse and egg yolk peritonitis? Are there any predisposing factors to be kept in mind?
He had a clear answer that forced light stimulation before sexual maturity is the reason for prolapse.
Rectal prolapse is seen as early as 4 weeks of age; the role of light might not have a reason in this situation.
He suggested that the dietary fibre is probably high in these cases, hence restricting a maximum of 2.5%-3% crude fibre, especially in the first 5 weeks, would help avoid rectal prolapse.
How do we manage low bodyweight birds to increase their weight to become good layers?
He suggested that a three-way grading must be performed. In the first grading at 4th week the chicks with low body weight should be separated and fed extra, to bring the body weight in line. By the 9th week when the second grading happens, the small birds must be able to get back to the average weight. He opines that in practice reducing weight in heavier birds poses a bigger problem rather than weight gain for lighter birds.
How much should be the maximum bodyweight that we can be permitted above the standard in laying birds that don’t affect production? Is there an upper cap?
According to his experience and a recent scientific article about 150-200 g above the standard has not shown any problems with egg production, except one could expect larger-sized eggs early on.
In the breeders on the onset of lay, we notice calcium tetany cases, what is your opinion?
He points out that he doesn’t believe in feeding a pre-layer diet. But sometimes the farms start feeding a layer diet weeks before the birds are due to lay their first egg. If high levels of calcium are being fed even 1.5% in a typical pre-layer is far too much. He recommends keeping the calcium low, and when the birds go on to lay (about a week before) only then should the birds be shifted on to a layer ration. It is unlikely to notice calcium tetany if this is followed.
How to reduce leg weakness and cage layer fatigue in broiler breeder females? Can we limit the lighting duration to 14 h a day in open-sided sheds as a remedy for this?
According to Mr. Peter Chrystal, leg weakness is not directly related to the length of light. Two-phase layer diet; bring the available phosphorus down as bird’s age and calcium levels must go up. Excess calcium may create more problems than it solves. One shouldn’t see any issues even with a 16 h day length provided that the dietary calcium and available phosphorus are provided correctly. Calcium levels must be going from 3.8-3.9% up to 4.3% at finishing whereas the available phosphorus should be going down from 0.45% to as low as 0.35% at the tail-end and these issues may not occur from a calcium-phosphorus point of view.
Mycoplasma infection is there any chemical or salt that can be used in breeders to control this. He suggests that Macrolide drugs at low doses could be used. But there is resistance to using these drugs in Australia and hence they have been using phytogenic compounds, to boost the bird’s immunity to fight the disease.
Could you shed some light on the usage of potassium carbonate in the breeder layer diet?
Mr. Peter Chrystal suggested that he has used potassium carbonate on and off when they have encountered sudden death syndrome associated with low potassium levels. He recommends that in a hot humid climate there is a need to ensure enough potassium, especially if the diet has low Soya, which is rich in potassium. About 0.6-0.8% potassium should be maintained, no harm supplementing it.
Is there a particular recommended feeding time for broiler breeders?
Ideally, farms could feed the birds twice a day, one in the early morning and another in the afternoon with high calcium. He says he hasn’t seen any difference in the performance of the birds if they were fed before or after lights-on, it is a pattern that the birds get used to. But what is more important is for the manager to be present when the birds are feeding. But he recommends that feeders be charged before lights, in the dark so that the noise doesn’t get the birds excited.
In a particular case, about 80% of birds showed typical T-2 Mycotoxin lesions such as oral ulcers, tongue necrosis, but feed samples tested negative for T-2 toxin. Is there any other reason that this may be happening?
He suggests that the T-2 toxins are powerful; they may occur in pockets in the feed. Sometimes sampling out of a big batch may not be easy and T-2 mycotoxins might not show up in the test analysis. However, the birds are the best indicators of the existence of these mycotoxins. Mycotoxins also conjugate, and hence may show negative results when feed is analysed. But if the birds are showing lesions on the tongue and mouth it is possible that the T-2 toxin is present, and one must treat it with a targeted toxin binder in such cases.
Is excess fat in the grower and pre-layer diet good for peak production?
Birds deposit one-third of the fat that it ingests as body lipid. This is a rule of metabolism. It helps have some fat in the diet, but not so much that we are overfeeding energy. He suggests around 7.5-10L per ton, about 1% added fat, not any more than that.
For supplementing dietary electrolyte balance is it better to use sodium formate instead of Sodium bicarbonate?
He recommends sodium bicarbonate is better, bicarbonate ions are needed in the diet. Sodium formate is a salt of an organic acid so it dissociates easily.
Breeders are fed phase-wise; will delay in the transition from one phase to another affect the production?
Mr. Peter Chrystal answers from his experience that breeder birds don’t like to change, any big changes can lead to performance losses. He prefers to keep an early lay to a late lay diet excluding a mid-lay diet. Keeping the diets similar is important. What he recommends is to keep the energy identical, minor acid profile identical, reducing crude protein in the second phase, changing the calcium and available phosphorus. The diets must fit very closely together, birds don’t realize that they have been moved from one diet to another, and there will be no upsets. It is generally a good practice to bring in the new diet while you still have old feed below, and if the phasing happens over ten days it is ideal since it is the amount of time it takes for the follicles to develop fully, by which time she is used to the phase over.
Contributed by: Dr. Raina Raj, Head of Marketing, Natural Remedies Pvt. Ltd.
