Influence of Dietary Levels of Protein and Energy on Nitrogen and Energy Balance for Egg Production of Japanese Quail

Abstract

A nitrogen and energy balance experiment was carried out to clarify the influence of dietary levels of protein and energy on the utilization of nitrogen and energy in diets for the egg production of Japanese quail. In this experiment, 360 three-month old quail were divided into 12 groups and fed for 60 days 12 designed diets of CP content (%) and ME value (kcal/g) as 14-2.7, 14-3.0, 16-2.7, 16-3.0, 18-2.7, 18-3.0, 21-2.7, 21-3.0, 21-3.3, 24-2.7, 24-3.0, 24-3.3. A variance analysis for the analysis of data obtained were used. The following results were obtained:1) The changes of protein content and energy value in diets did not influence the nitrogen content and energy value in the whole egg, in which was contained an average 1.88±0.02% of nitrogen and an average 1.59±0.03kcal per g.2) Feed intake, egg production rate, egg weight, feed efficiency and body weight increased with increasing levels of CP from 14% to 24%. The effect of ME levels for each of the above egg production characteristics differed with the CP content. Feed intake decreased and feed efficiency increased with the level-up of ME from 2.7kcal to 3.0 and 3.3. For the egg production rate, egg weight and body weight, the effect of 2.7kcal was greater than 3.0 in the range of 14% to 21, and in the level of 24% no difference among ME levels was found.3) The nitrogen conversion rate in eggs lowered with increasing the level-up of CP content, whereas the increasing of ME level brought about an increase of the rate. The nitrogen retention rate in bodys did not differ with the feed compsitions, so that for the nitrogen excretion rate, the reverse relation of the nitrogen conversion rate in eggs was found.4) The energy conversion rate in eggs increased with the level-up of CP content in contrast with the nitrogen conversion rate in eggs. The effect of ME levels for the rate was 2.7kcal higher than 3.0 in the range of 14% to 18 of CP, and in the range of 21% to 24 no difference was found among the ME levels. The energy retention rate in bodys was only 0 to 2%, but it increased with the level-up of CP and ME. From the above changes, the rate of heat loss decreased from 79% to 72 with the level-up of CP, in contrast with the energy conversion rate and the energy retention rate.5) In the case of the diet of 14 per cent CP in which has a lower protein content and a larger calorie-protein ratio, a nitrogen balance was maintained at positive and an energy balance at equilibrium. In this case the poorer egg production was observed. It is considered that the above thing shows that the ingested protein and energy was consumed preferentially for maintenance of body, and the remainder of that for egg production. A laying diet for quail must give her the highest laying performance with relatively higher utilization of nitrogen and energy. From the above results it is said that the CP and ME composition which has the above functions are 24% and 3.0kcal.