NUTRIENT REQUIREMENTS OF GROWING AND LAYING JAPANESE QUAIL

Abstract

The methionine requirement and its influence on the fat content of growing Japanese quails (Coturnix coturnix japonica) were determined. Results showed that the requirements for microbiologically available methionie and cystine were 0.433% and 0.334% in a 24% protein diet. Dietary methionine did not have any significant effect on the carcass fat content of cotunix at 5 weeks of age. A corn-soy basal diet has been used to assess the methionine requirement and its influence on the feather loss of laying conturnix under tropical conditions. The microbiological available methionine and cystine requirements for maximum egg yield was found to be 0.375% and 0.30% in a 19.5% protein diet. A daily intake of 79.5 mg available methionine and 52.5 mg available cystine per bird were required to achieve maximum egg production and quality eggs. Dietary methionine did not have any significant effect on the feather loss of laying coturnix. Three consecutive assays each involved the use of 585 day old Japanese quails were conducted to evaluate the biological efficacies of DL-methionine-Na, DL-methionine hydroxy analogue - Calcium (DL-MHA-Ca), and DL-mehionine hydroxy analogue - free acid (DL-MHA-FA) relative to DL-methionine levels of 0.05, 0.10, and 0.15% In the first assay, the basal diet was deficient in methionine and cystine. Best to poorest growth promotion and feed efficiency were generally obtained from the supplements in the following order : DL-methionine, DL-methionine-Na, DL-MHA-FA, and DL-MHA-Ca. In the next assay, the basal diet was only deficient in methionine. Results indicated that at a lower level of supplementation, all methionine analogues were inferior to an isosulfurous level of methionine as judged by weight gain. However, as the level of supplementation increased, dietary methionine source did not have any significant effect on weight gain. In general, best to poorest growth promotion and feed efficiency were obtained from the following order: DL-methionine, DL-methionine-Na, DL-MHA-Ca, and DL-MHA-FA. In the third assay, the basal diet was deficient in methionine but excess in choline. Levels of methionine significantly affected growth in all three assays. A multiple linear regression model was used to describe the weight gain response to supplemental methionine (0.05 to 0.15%) for each source and to obtain biopotency estimates relative to DL-methionine (at 100). Based on the three studies the biopotency (+-SE) of DL-methionine-Na, DL-MHA-Ca, and DL-MHA-FA was 100.89+-7.36%, 68.43+-3.38%, and 86.80+-2.92 relative to DL-methionine. A total of 270 laying quails were utilized to determine the practicality of phase feeding in Singapore. Laying quails were fed the same 20% protein diets until 17 weeks in lay. Thereafter birds were seperated into 5 dietary treatments consisting of feeding either a 20%, 18% or 16% diet throughout 20 weeks of lay and of a stepwise reduction of the protein levels by 2% at the end of phase 2. Results indicated that optimum laying quail production and egg weight were found by conducting a phase feeding program wherein a minimum of 20% protein during phase 1, 18% during phase 2, and 16% during phase 3.