The production of chicken meat increases rapidly worldwide due to higher slaughter weight in a shorter time, high feed efficiency and the price of chicken meat compared to other meats1. However, the use of conventional raw materials, mainly corn, becomes challenging because it increases the demand to produce biofuels2. It is estimated that for the production of balanced feed, the poultry industry requires around 900 thousand tons of corn per year2, thus the high prices of imported corn substantially increase the cost of production3.
Also, feed cost represents up to 70% of the total cost of production and corn could make up to 65% of diets for broilers3. One of the premises of poultry researchers and producers is to find economical, innovative and viable feed alternatives that assure the partial or total substitution of corn without affecting the growth performance and carcass traits of broilers4. The discard corn grain is seed proposed for sowing but failed to meet the standard quality due to broken seeds, with unwanted or contaminated sizes with some non-toxic material.
Thus, discarded corn grain is rich in protein and essential amino acids could use as an alternative feed for animal5,6. In this sense, Castilloand Delgado5 and Viana6 have reported that the use of discarded corn grain as a partial substitute for conventional corn did not depress the egg production and quality in laying hens (38-52 weeks) and batch uniformity in pullets (1-16 weeks). However, no studies reported the use of discarded corn grain as a partial substitute for imported yellow corn in broiler diets. Therefore, the objective of this study was to evaluate the effect of inclusion levels of discarded corn grain on growth performance, edible portions and economic response in broilers.
MATERIALS AND METHODS
All the procedures adopted in carrying out this experiment were approved by the Pan-American Agricultural School, Zamorano, San Antonio de Oriente, Honduras and conducted in accordance with the Guidelines for Experimental Animals.
Experimental location: The study was conducted in June-July/2019 at the Poultry Research and Training Center of the Pan-American Agricultural School (Zamorano), located in Valle del Yegüare at 32 km of the Tegucigalpa road to Danlí. The place is 800 meters above sea level with an average temperature of 26°C.
Experimental animals, treatments and diets: A total of 1200 mixed chickens (male and female) from the Ross 308® one-day-old genetic line were randomly distributed in a completely randomized design with four treatments, six repetitions per treatment and 50 chickens per repetition. The experimental treatments consisted of a basal diet and dietary inclusion of100, 200 and 300 g kg1 of discarded corn grain.
The diets to supply the nutritional requirements of the genetic line under study in the starter (0-10 days), grower (11-24 days) and finisher (25-32 days) phases were formulated. For the formulation of the diets, the chemical composition of imported yellow corn and discarded corn grain reported by the food analysis laboratory of the Pan-American Agricultural School (LAAZ) Zamorano was taken into account (Table 1). The experimental diets are shown in Table 2-4.
Experimental conditions: Each repetition consisted of a pen with a wood chip bed and 11 birds m2. Feed and water were offered ad libitum in hopper feeders and nipple waterers, respectively. The temperature and ventilation inside the house were controlled by gas brooders, curtain and fans. The ship was disinfected according to environmental quality standards. No medications or therapeutic veterinary care were used throughout the experimental stage. The birds against Marek and Smallpox (first day)were vaccinated.