I. INTRODUCTION
Corn is the principal energy source in poultry diets, and it is also an important cereal for humans. In recent years, industry and human consumption of corn has been expanding rapidly, leading to inadequate supplies and high prices. This trend has necessitated a search for feedstuffs that could be used as an alternative to corn in poultry diets. Many studies have been published on replacing corn with alternative feedstuffs in layer diets such as water yam [1], pearl millet [2] as well as sweet potato and cassava meal [3]. One alternative is paddy rice (Momiroman; feed-type rice), which has been advocated for cultivation in Japan and is therefore available for use as a replacement for corn in poultry diets. Our previous results regarding chemical composition, digestibility of crude fiber, gross energy, and metabolizable energy of paddy rice demonstrated that paddy rice can probably be used as a good alternative cereal grain source in poultry diets [4]. Although the nutrient composition of paddy rice is slightly lower than maize, it is higher than for other cereal grains such as sweet potato tubers or cassava meal which are used in animal diets [5].
Currently, using whole grains in poultry diets has gained interest in many countries due to saving the cost of grinding [6]. Ref. [7] reported on the physiological function of the gastrointestinal tract affected by the particle size of feed such as whole grains. In addition, whole-grain feed improves gizzard activity [8] which is associated with increased starch digestibility [9]. Some reports have indicated that diets containing whole grains improve feed utilization [10]. Therefore, whole-grain paddy rice (WPR) was used in this experiment to decrease feed cost and also to increase the use of locally grown grains. It has been reported that WPR could be used as an ingredient in chicken diets [6]. Thus, the aim of this experiment was to study the effect of replacing corn with WPR in laying hen diets on egg production performance and quality.