WHEAT IN BROILER FEED: ADVANTAGES AND USE OF WHOLE DISADVANTAGES

1Polytechnic University of Madrid

2Cobb Spain, Madrid

Using whole wheat as a supplement to commercial feed is not a new concept. It has been a common practice in Northern Europe for more than 30 years (Forbes and Covasa, 1995; Engberg et al., 2004). Compound unpigmented feeds for broilers contain approximately 50-60% wheat.

Grinding and granulation, together with transport, represent a high energy cost to manufacture a ton of feed.

Hence, the high use of whole wheat in countries like Denmark, where farmers plant the grain and raise chickens simultaneously.

Whole Wheat And Digestive Physiology

In recent years, as a result of the ban on the use of antibiotics as preventives in the EU, the use of whole wheat has been extended to reduce the problem of wet litter and its impact on carcass quality.

It has been shown that coarse grindings facilitate the functioning of the digestive system, improving the health status of the GIT of birds (Jiménez-Moreno et al., 2019).

In Spain, the main reason for including whole wheat in the feed was to control the problem of wet litter due to its effects on intestinal health and the functioning of the gastrointestinal tract (GIT) (Ravindran et al., 2006; Husveth et al., 2015).

The inclusion of whole wheat improves the functioning of the gizzard and reduces the incidence of proventriculitis, so, despite the high cost, its practical use increases.

To understand that whole wheat, at a physiological level, corresponds to the use of very coarse grindings; therefore, the physiological mechanisms that explain its activity are similar.

Beneficial effects

Recent data on the benefit of whole wheat on economic performance is conflicting.

To ensure success, feeding based on the inclusion of whole wheat should be started no earlier than 7 days of age with levels below 5-8%.

In the finishing phase, levels of around 4-5%, are recommended, taking into account possible problems in the slaughterhouse (contamination of the carcass and fasting hours).

The beneficial effects of the coarse grinding of ingredients (and therefore of whole wheat) are related to improvements in the functioning of the GIT and, in particular of the gizzard, where it improves the functioning with an increase in size and a reduction in pH which benefits the activity of pepsin and enzymes.

A functional gizzard increases the intensity of antiperistaltic movements, improving the motility of the walls and the integrity of the digestive mucosa (Svihus et al., 2004, 2010; Mateos et al., 2012; Jiménez Moreno et al., 2019).

Therefore, the positive effect of whole wheat will be more significant when there are digestive problems.

Recent research shows that the inclusion of whole wheat influences the control and prevention of specific processes and pathogenic microorganisms such as Salmonella, Clostridium, and coccidiosis. For example, Engberg et al. 2 (2004) found that whole wheat reduced the number of Enterobacteriaceae and Clostridium perfringens in broilers.

USE OF WHOLE WHEAT Methodologies

There are several criteria for using whole wheat in feed:

AIn the most daring criterion, whole wheat is included at moderate to high levels (between 10 to 20% in the withdrawal feed) in substitution for commercial feed.

The great advantage of this strategy is the reduction in the cost per ton of feed and the increase in the factory’s production capacity.

The most significant drawback is that dilution (top dressing) modifies the nutritional profile of feeds, which can be a problem when high levels of whole wheat are used in commercial feeds with low safety margins.

In addition, with a high level of whole wheat for long periods of the bird’s life, we run the risk of a higher incidence of subclinical coccidiosis as a consequence of reducing the doses of coccidiostat below what is recommended.

BA second criterion for its use, and, probably the most widely used in practice, consists of substituting a percentage of the wheat in the conventional diet (incorporated into the pellet or in the mash, where appropriate) for whole wheat.

In this case, the nutritional value of the feed is not diluted, but the economic savings are limited to the lower energy costs in its manufacturing (milling and granulation).

In both cases, when adding whole wheat separately from the feed, it should be considered that the whole wheat does not undergo any heating process. Therefore, there is a possibility of microbiological contamination.

On the other hand, the inclusion of whole wheat modifies the texture and palatability of the feed, which can lead to preferences for the compound feed or the whole grain by the bird.

This preference can vary from farm to farm with 2 key factors to consider: chicken age and presentation (mash vs. crumble) and particle size (fine vs. coarse).

A third system to include whole wheat in feed, consists of adding it in a mixer together with the rest of the ingredients already ground to make the compound feed.

It is important to consider that the young chick (6 to 8 days of life):

Tends to reject eating whole wheat as grain size does not match beak size.

The wheat remains longer in the gizzard than the mash. Therefore, it tends to accumulate in this organ, and the birds tend to reduce their consumption since their appetite is reduced due to “feeling full.”

Excess wheat in the gizzard also slows down the speed of transit of whole wheat.

To avoid problems with full digestive systems and possible contamination in the processing plant due to the use of whole wheat, the withdrawal time of poultry feed before transport must be considered.

Once mixed, it is passed through the granulator, obtaining a granule of medium quality (whole grain impairs the quality of the granule, but wheat “per se” tends to improve it).

The biggest drawback of this system is that the savings in the cost of manufacturing the feed are minimal, but on the contrary, the needs of the bird are better respected.

Therefore, including whole wheat in the chicken feeding program allows for many variations, depending on the farm type and management, which can lead to contradictory results.

In this regard, the effects are usually less advantageous and even detrimental in relation to feed consumption. When wheat is offered as a free choice, there is no sequential phase of learning before consumption with changes in the texture of the supplied feed and its palatability. As well as lacking certain nutrients when