Biopotency of methionine sources and their effects on sexual maturity of growing Japanese quail.

1. Japanese quail were fed on practical diets supplemented with graded amounts of DL-methionine (DL-M), DL-methionine-sodium (DL-M-Na), DL-methionine hydroxy-analogue calcium (DL-MHA-Ca) and DL-methionine hydroxy-analogue free acid (DL-MHA-FA) on an equimolar basis. 2. By the slope ratio assay using quail growth as the criterion, it was deduced that the biological activity of DL-M-Na, DL-MHA-Ca and DL-MHA-FA was approximately 0.96, 0.72 and 0.84 that of DL-M on an equimolar basis. 3. On a weight basis of the commercial products, the efficacies of DL-M-Na, DL-MHA-Ca and DL-MHA-FA were 0.38, 0.62 and 0.74, respectively. 4. Quail fed on the diet with the highest content of methionine had greater ovary weight, oviduct weight, oviduct length and egg production.

An evaluation of the method used in digestibility estimations of a dietary ingredient and comparisons on external and internal markers, and time of faeces collection in digestibility studies in the fish Oreochromis aureus (Steindachner).

Results of experiments carried out on the tilapiine fish Oreochromis aureus (Steindachner) to evaluate the method used in the determination of the apparent dry matter and nutrient digestibilities of an ingredient, together with validity of estimations based on day and night collection of faeces, and internal and external markers, are presented. The apparent dry matter and protein digestibilities of the test diets were linearly correlated to the percent substitution of the test ingredient, percent fibre and ash in the test diets (P less than 0.05); the correlation coefficient for the individual relationships decreased in that order. Dry matter or protein digestibilities were not correlated to the dietary protein content (P greater than 0.05). Similarly there were no statistical differences between digestibility estimations based on faecal material, voided in the day or the night; and estimated using different markers viz crude fibre and Cr2O3. The apparent dry matter and protein digestibilities of the test ingredients, leaf meal, were curvilinearly related to the percent substitution of the ingredient in the test diets. The ingredient digestibilities estimated, using crude fibre as the marker, were consistently higher than those estimated with Cr2O3 (P less than 0.05). The present study suggests that, for ingredient digestibility estimations, test diets prepared by mixing 15-20% of the ingredient to a reference diet would be more desirable.