The conventional feeding methods for laying hens based on one diet with constant nutrient levels may not result in optimal utilisation of all nutrients (Chah, 1972, Leeson and Summers, 1997). When birds are offered diets with the option of self-selection of nutrients, an increase in protein and energy intake has been observed in the morning around the peak of egg production. Hourly feed intake decreased prior to oviposition, but increased immediately during the time of oviposition. The peak consumption during the evening hours (17:00 – 19:00) was consistent regardless of the time of oviposition (J.H.Choi 2004). Calcium intake is higher later in the day. A study by Chah (1972), demonstrated that a diet with the option of self-selection of nutrients, decreased the total daily protein, energy and calcium intake respectively by 11%, 8% and 26%, compared to hens fed a normal diet.
Commercial laying hens produce the majority of their eggs in the morning (Etches, 1986, Leeson and Summers, 1978, Larbier and Leclercq, 1992). The egg is formed step by step, starts from ovulation and ends by laying an egg. Hens will have higher protein and energy requirements during the morning when albumin is started to form, and a higher calcium requirement during the evening and night when the eggshell formation takes place. Phosphorus is also required mostly during the morning as it is mainly needed to reabsorb calcium to the medullary bone.
Nutreco R&D has been working since 2005 to develop a novel feeding program for laying hens according to the nutrient requirements for egg formation. Eight trials have been performed between 2005 and 2012. The main objective of these trials was to determine the differential energy, protein, calcium and phosphorus requirements in the morning and afternoon when separate diets are fed. All trials contained a single feed control to corroborate the benefit of the split feeding system against the current feeding system applied in the egg industry. Split feeding programs were designed using two diets on the basis of the nutrients required for the egg formation phase:
Morning feed: 40% of daily amounts with higher energy, protein and phosphorus (lower Ca)
Afternoon feed: 60% of daily amount with higher calcium (lower AME, CP and dP)
Optimisation of energy intake
In this trial, the afternoon diet was provided with lower (3% and 5%) energy than the control diet. The single diet (control diet) had the same energy level as the morning diet. The results showed no effect of reduced energy on performance, feed intake and egg quality. The daily feed intake was not different between treatments. The results confirmed that the daily energy intake was significantly reduced due to lower energy intake during the afternoon (Figure 1 and 2). This energy reduction in the afternoon diet, while maintaining the energy levels as recommended in the morning diet, did not affect performances or egg quality, demonstrating that with split feeding, the energy content in the afternoon diet can be reduced by about 5% compared to the standard single diet recommendation.
Optimisation of protein intake
Another trial was performed to evaluate the effects of protein reduction in the afternoon diet on performance, feed intake and egg quality. Protein levels were 8% and 17% lower than the single feed (control diet, based on recommendations). In addition, the energy level was also reduced in the afternoon diet by 3% compared to the morning diet. Energy and protein levels in the morning diets were the same as the control diet.
The results showed that crude protein intake was reduced when the protein content of the afternoon diet had been reduced. No difference in performance was observed with 8% protein reduction in the afternoon diet and a slightly better FCR was also observed. (Figure 3 and 4) When the crude protein was reduced by 17%, a reduction in numbers of egg production was observed with poorer egg mass. Moreover, the feed conversion ratio was impaired significantly.
Optimisation of Ca and digestible P intake
This trial was designed to study the effects of different calcium and phosphorus levels in the morning and afternoon diets. Each treatment had 36 replicates of individually housed laying hens. The peak demand for calcium appears to be in the late afternoon (Hughes, 1972.) Compared to the control diet (single feed) calcium levels can be reduced by 40% in the morning and can be increased 15% in the afternoon diet without impairing production and egg quality. In the same trial, 40% reduction in the morning calcium and 35% increase in the afternoon calcium did not show any extra benefit in terms of eggshell quality compared to the previous one (-40% Ca in the morning and +15% Ca in the afternoon diet). These results are also supported by the findings of Sauveur and Mongin (1974), D. Robinson (1985).
The digestible phosphorus level in the morning diet can be reduced by 12%, compared to the control single diet, without affecting performance, eggshell quality and saleable egg production. Phosphorus reduction in the morning diet had a direct impact on nutrient intake, but not on the total daily nutrient intake. Phosphorus level of the afternoon feed can also be reduced by 15%, as no detrimental effect on performance and eggshell quality was observed.
The wide reduction in phosphorus content in the morning diet can be possible due to the fact that calcium level in the morning diet is also reduced considerably in the split feeding system. As calcium is an antagonist and can bind phosphorus, the lower level of calcium in the gut is translated into more phosphorus available for the animal, and consequently the dietary phosphorus requirement is lower in the morning feed.
Split feeding had no negative effect on shell thickness, weight or shell weight per unit of surface area (SWUSA); compared to a single control diet, rather there were some improvements. The split feeding system significantly reduced the percentage of broken and shell-less eggs compared to the control diet which resulted more saleable eggs.
Split feeding consistently reduces amount of nutrient loss in excreta
Results of another trial demonstrated that split feeding reduces nitrogen, phosphorus and calcium excretion. It could be due to a lower daily nutrient intake and a better utilisation of those nutrients. The lower nitrogen content in manure might indicate a reduction in ammonia emissions and improved air quality.
Conclusions and application
The “Split Feeding System” is an alternative feeding system for feeding layers. It is a tool to adjust the nutrient consumption according to the different requirements throughout the day. Split Feeding brings an option to supply nutrients at optimal level in order to meet the requirements of hens in the egg formation process. It also opens up the opportunity of more profitable and sustainable egg production, with a lower production cost. By implementing split feeding the following benefits can be achieved:
- More profitable egg production, less production cost.
- Improved eggshell quality and increased number of saleable eggs.
- Improved performance and sustainable production.
Published in Poultry Digest, April/May 2013
Split Feeding by Bert V an Gils, Manager Nutritional Technologies, Nutreco Animal Nutrition.