Effect of Slow and Rapid Peroxidation of Corn Oil on the Performance and Energy Storage of Broiler Chicks10 March 2014
Corn oil peroxidation status had some minimal effects on broiler performance to 27 days of age but did result in significant differences in abdominal fat pad weight. This suggests an impact of the treatment on energy utilisation, according to a study in Iowa State University Animal Industry Report 2014.
Summary and Implications
The extraction of corn oil from DDGS has led to an increase in the utilisation of corn oil in poultry diets, according to according to Isa Ehr (Graduate Research Assistant), Brian Kerr (collaborating researcher USDA-ARS) and Michael Persia (Assistant Professor), Department of Animal Science in Iowa State University.
This corn oil has the opportunity to undergo peroxidation during storage or processing, they explain. Therefore, it is important to understand the effects of peroxidation of corn oil on growth and performance of broiler chicks.
Broiler chicks were provided corn-soybean based diets containing unperoxidised corn oil (UPO), slowly peroxidised corn oil (SO; heated for 72 hours at 95°C), and rapidly peroxidised corn oil (RO; heated for seven hours at 185°C). Corn oil was added at a five per cent inclusion for the first 14 days and at 10 per cent inclusion from days 15 to 27. A fourth treatment consisted of a supplemental oil-free diet to be used to determine the nitrogen-corrected apparent metabolisable energy (AMEn) of each corn oil diet.
As expected, the diets without supplemental oil resulted in reduced performance but no significant differences were observed among oil-supplemented birds for body weight gain, feed intake or feed conversion ratio (FCR). There was a significant difference in abdominal fat pad (AFP) weights of the broilers fed RO corn oil compared to the birds fed UPO corn oil.
Analysis of samples for AMEn content is underway and will be reported shortly.
Corn oil peroxidation status had minimal effects on broiler performance but did result in differences in energy utilisation as indicated by AFP weight.
There has been a recent trend to use more corn oil in poultry diets to meet the caloric demands of production.
This need has been met through the use of dried distiller’s grains with solubles (DDGS) or corn oil extracted from DDGS (DCO).
The unintended consequence of using these feed ingredients has resulted in the use of oil with a higher potential for peroxidation. Oxidized oils have the potential to affect adversely bodyweight gain, feed conversion and other performance parameters.
The objective of this experiment was to determine the effects of peroxidative status in corn oil on broiler performance and energy utilisation.
Material and Methods
A total of 240 male Ross 708 hatching chicks were randomly selected and placed into one of four treatment groups.
Each experimental unit consisted of six broiler chicks with 10 replicates for each of the treatments. The treatment diets contained either UPO corn oil, SO corn oil or RO corn oil at five per cent inclusion for the first 14 days and 10 per cent inclusion from days 15 to 27. The fourth treatment diet was free of supplemental oil and used for AMEn determination by the difference method.
All diets were formulated to meet or exceed the NRC nutrient requirements of the birds. The supplemental oil containing diets (UPO, SO, RO) were isonitrogenous. Chicks were housed in Petersime battery cages with continuous light, supplemental heat, and ad-libitum access to feed and water.
Bodyweight gain, feed intake and FCR were measured for the the periods 0-14 and 0-27 days. Abdominal fat pad and excreta collection were performed on day 27.
ANOVA and Student’s t-test were used to analyse the data and separate the means if significant (significance determined at P≤0.05).
Results and Discussion
As expected, birds fed the supplemental oil-free diet exhibited lower performance and smaller abdominal fat pad than birds offered the oil-supplemented diets. There were no significant differences among oil-supplemented birds for bodyweight gain, feed intake or FCR (Table 1), although birds fed either peroxidised corn oil source consistently resulted in the numerically poorest performance.
|Table 1. Effect of peroxidised corn oil on average body weight gain, feed intake and
feed conversion ratio of broiler chicks from 0-14 and 0-27 days of age
|- Bodyweight gain, g/chick||335||362||346||349||7.5||0.10|
|- Feed intake, kg/pen||2.81||2.76||2.69||2.73||0.046||0.32|
|- Feed conversion ratio||1.40 A||1.27 B||1.29 B||1.31 B||0.018||<0.01|
|- Bodyweight gain, g/chick||950 B||1071 A||1032 A||1023 A||22.4||<0.01|
|- Feed intake, kg/pen||9.09||9.04||8.87||8.86||0.153||0.64|
|- Feed conversion ratio||1.60 A||1.41 B||1.43 B||1.44 B||0.016||<0.01|
|Different superscript letters denote statistically significant differences (P<0.05) between treatment group values.
UPO = unperoxidised corn oil; SO = slowly peroxidised corn oil; RO = rapidly peroxidised corn oil
Figure 1 shows a significant reduction in AFP weight of birds fed the RO corn oil compared to birds fed the UPO corn oil, with birds fed the SO corn oil having intermediate abdominal fat pad weights.
These data suggest that the peroxidised oil might have a reduced metabolisable energy value in broiler diets based on the reduced storage in the abdominal fat pad that will be validated with AMEn determination.
Acknowledgements: The authors thank the poultry farm staff at the Iowa State University Poultry Research and Teach Unit for their help in caring for the birds during the experiment.