Corn-based vs wheat-based broiler diets: Establishing which is best for reducing reliance on crude protein
Poultry remains the most popular form of worldwide meat production and responsible sustainable practices will be part of the majority of farmers' routines. Feed management practices, including those that substantially reduce crude protein (CP) in poultry diets, are possibly the most important measure to reduce nitrogen excretion and environmental pollution.
They can also improve bird welfare outcomes and economic benefits, without a negative effect on bird performance. However, excessive CP reduction may compromise growth performance and increase fat deposition. This is often related to dietary essential amino acid (AA) and non-essential AA limitations, but the impact of the feed grain used in reduced CP diets on broiler performance has received little attention.
Performed in collaboration with Peter V Chrystal, Peter H Selle and Sonia Yun Liu of the Poultry Research Foundation within the University of Sydney, Australia, the purpose of this study was to compare corn and wheat-based diets on broiler performance in the context of substantial reductions in dietary CP.
Comparing corn & wheat-based diets
A total of 216 male Ross 308 broilers were fed iso-energetic (12.85 MJ/kg) pelleted diets containing either corn or wheat during the period from 7 to 35 days post-hatch. The diets were formulated to contain 222, 193 and 165 g/kg CP, as illustrated in Table 1.
All diets were formulated to a standardised ileal digestible (SID) lysine level of 11.50 g/kg, glycine equivalents of 14.51 g/kg and the dietary electrolyte balance was maintained at 250 mEq/kg.
Each diet was offered to six replicate cages (6 birds per cage) as a 2 x 3 factorial design of dietary treatments. Weight gain, feed intake, feed conversion ratio (FCR), and relative abdominal fat-pad weight were determined during the study period from 7 to 35 days, with the experimental data then analysed with the SPSS Statistics 24 program.
Significant interactions between treatments
We observed significant interactions between treatments (P < 0.001) for growth performance parameters (Figure 1). Weight gain was inferior by 34.6 percent (1549 versus 2370 g/bird), feed intake by 18.3 percent (2843 versus 3481 g/bird) and FCR by 24.9 percent (1.840 versus 1.473) in comparison to their 165 g/kg CP corn-based diet counterparts.
Broilers offered the 165 g/kg CP corn-based diet had higher weight gains by 7.05 percent (2370 versus 2214 g/bird) than the corresponding 222 g/kg CP diet. Similarly, the 193 g/kg CP corn-based diet supported a weight gain advantage of 8.22 percent (2396 versus 2214 kg/bird).
Also, with the transition from 222 to 165 g/kg CP diets, corn-based diets generated a feed intake increase of 8.51 percent (3481 versus 3208 g/bird); in contrast, wheat-based diets resulted in a decline in feed intake of 18.5 percent (2843 versus 3487 g/bird).
However, corn-based diets increased relative fat-pad weights by a two-fold factor (12.77 versus 6.42 g/bird) but wheat-based diets did not influence fat deposition.
You can read the full scientific paper HERE
by Juliano Cesar De Paula Dorigam, Research Manager in Poultry Nutrition, Evonik, Germany