RESEARCH

Inclusion of whole wheat at 3 levels

In a recent study carried out by our group at the Polytechnic University of Madrid, we studied the effect of the inclusion of whole wheat at 3 levels (control without added wheat and experimental with 3% wheat from 0 to 14 days and then 7.5 o 15% from 14 to 40 d of age depending on treatment) in Cobb 500 chickens fed two nutrient levels (medium and high).

The average levels corresponded to typical feed used in Spain at that time (2,900 to 3,100 Kcal/kg and 1.22 to 0.97% dig. Lys, depending on age).

While high levels correspond to feed with 100 Kcal AMEn/kg and 5% extra digestible Lys in each of the 3 experimental phases (0 to 14 days, 15 to 29 days, and 30 days to slaughter at 40 days of age).

A total of 540 day-old chicks were used. Each treatment was replicated 6 times, and the experimental unit was the pen with 15 chicks each.

The experiment was completely randomized with 5 treatments sorted in a factorial way with feed quality (high vs. medium nutrient density).

and the level of use of whole wheat in direct substitution of pelleted commercial feed (control, medium, and high) as main effects.

The productive data at each change of feed and data on the development of the proventriculus and the gizzard at slaughter were controlled.

The performance data from 0 to 40 days of age and the development of the gizzard at 40 days of age are detailed in Tables 1 and 2, respectively.

a–c Means from the same column that do not share a common superscript differ (P < 0.05). 1 Initial live weight 46.7 ± 0.80 g.

2 n = 18 diet; n = 12 inclusion of wheat. 3 Interactions were not significant (P >0.05).

a-b Means from the same column that do not share a common superscript differ (P < 0.05).

1n = 18 diet; n = 12 inclusion of wheat 2 Interactions were not significant (P >0.05).

From 0 to 40 d of age, the quality of the experimental feed did not affect the birds’ average daily feed intake (ADFI) (124 vs. 127 g/d). Still, the chickens that consumed the high nutrient density feeds grew more (82.7 vs. 80,6 g/d) and had a better FCR (1.503 vs. 1.573) than control chickens.

However, the energy FCR (Kcal AMEn/kg) was similar for both groups (4.73 vs. 4.71).

The inclusion of whole wheat in the feeding program did not significantly affect feed intake (124, 125, and 128 g/d for control, medium, and high percentage of whole wheat, respectively).

However, the ADG (83.6, 81.9, and 79.5 g/d) and FCR (1.486, 1.522, and 1.606) worsened with the use of wheat, specifically with the higher dose (15% vs. 7, 5% vs. 0%). Likewise, the energy FCR worsened with the use of whole wheat (4.55, 4.68, and 4.93).

The use of whole wheat increased empty gizzard weight in absolute (37.1.40.7 and 40.8 g) and relative (1.04, 1.16, and 1.21%) terms, with significant effects (P < 0.05) were detected when comparing the control group vs. the mean of the 2 groups that included whole wheat (37.1 vs. 40.7 g and 1.04 vs. 1.19%, respectively).

Conclusions

Including whole wheat in feeding programs reduces costs and generally improves bird productivity. However, the use of whole wheat in broiler feeding programs should not be considered, in the case of Spain, as an economic strategy but rather to improve digestive physiology to enhance productivity and, therefore, carcass quality.

The use of whole wheat makes more sense in situations of high incidences of digestive problems, for chicken farmers who are also cereal producers, and when feeds with wide safety margins are used.

The main problem associated with whole wheat inclusion in broiler diets is related to reductions in feed intake.

This is more frequent in farms with healthy birds, high levels of wheat inclusion without previous adaptation by the birds, and the use of wheat as a diluent. All of these factors affect the nutritional profile of the feed.