Kinetic studies of the residue of sulfaquinoxaline (SQ) in the organs of broilers and laying hens and in the eggs after withdrawal of the drug from either feed or drinking water revealed that the organs could be grouped into 3, based on the disappearance pattern of SQ.
The pattern from the edible organs and the blood, except the kidney, fat and skin, could be explained assuming a two-compartment model, in which a part of the drug administered was stored in a certain place in the body and released slowly after the initial rapid decrease of residural SQ from the organs. The pattern could be described by the following equation,
y=A₁e^-1.5586t +A₂e^-0.4816t
where A₁ and A₂ are nitial concentrations of SQ in the initial and the latter stages, respectively.
The pattern from the kidney could be explained assuming a two-compartment model with a time lag of 0.3 days, and the following equation was found fit to describe the disappearnce pattern from the kidney.
y=A₁e^{-1.1400(t-0.3)}+A₂e^{-0.5350(t-0.3)}
It was suggested that the drug released from the body were sent to the kidney and excreted into the urine. Thus, the kidney was supposed to work as a main excit of the SQ excretion.
The disappearance pattern from the adipose tissue could be well described by the following equation, suggesting that the adipose tissue may not be the storage place for SQ.
y=A₁e^-1.3593t+A₂e^-0.3611t
The disappearance pattern from the whole egg could be described by the following equation, assuming a two-compartment model.
y=0.937e^-3.4431t+0.163e^-0.2261t
Biological half lives from the edible parts except the kidney and adipose tissue in the initial and latter stages were estimated to be 0.45 and 1.44 days, respectively. Those from the whole eggs were estimated to be 0.20 and 3. 07 days, respectively.

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1. In order to determine the tryptophan requirement of laying hens, 4 experiments were conducted. Single Comb White Leghorn hens older than 15 months were supplied diets with graded levels of tryptophan from 0.086 to 0.32 % ad libitum.
2. The egg production rate (Y₁, %) changed according to the equation Y₁=3.2+0.816X-0.00194X², where X represents mg of daily tryptophan intake/hen. The maximal 89.0% of egg production rate was obtained at 210 mg tryptophan intake/hen/day.
3. The egg production (Y₂, g/hen/day) changed according to the equation Y₂=5.3+0.476X-0.00110X². The maximal 54.9 g/hen/day of egg production was obtained with an intake of 212 mg tryptophan per hen daily.
4. The equation of the response of food intake (Y₃, g/hen/day) was Y₃=3.9+0.687X-0.00162X². The point at which the daily food intake was maximized (111.6g) was computed to be 212 mg tryptophan intake/hen/day.
5. The dietary tryptophan level which maximized the egg production rate, egg production and food intake was calculated to be 0.189%.
6. Plasma tryptophan concentrations increased with dietary tryptophan intakes and then reached a plateau at 191 mg tryptophan intake/hen/day.

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Freshness of table eggs, particularly the days after egg-laying, has been a growingconcern among Japanese consumers. In this study, a procedure of parallel line assay wasapplied to estimate the days of table eggs in markets after their laying, by measuring several parameters showing egg quality and comparing them with those of the eggs laid in thisstation as a standard.
Eggs of two sizes, one was M size (58-64g) and the other L size (64-70g), whichwere laid by hens of two popular strains of White Leghorn in this station, were collectedin April, July, October and January. The eggs were kept at room temperature. Specificgravity, albumen and yolk heights, and Haugh unit of the eggs were measured at 0, 4, 8, 12, and 16 days after laying. Analyses of variance were conducted to evaluate effects ofdifference in seasons, strains of the hens, egg sizes, and days after laying. Regressionequations were obtained to describe the relationship between egg quality and days afterlaying, as a standard line for estimation of days after laying of table eggs.
Table eggs were purchased in 4 seasons from 10 markets in Gifu and Seki cities. Theeggs were kept at room temperature, and their quality was measured at 0, 4, and 8 daysafter the purchase. Covariance analyses were conducted to confirm parallelism between the standard regression line and a line describing the relationship between quality of the table eggsand days after the purchase.
The statistical analyses revealed that the data of specific gravity, except those determined in the summer, were the most suitable to estimate days after laying of the table eggsamong the 4 kinds of parameters showing egg quality. The data of Haugh unit were thesecond, and those of albumen and yolk hights were not suitable.
A procedure to estimate days after laying of table eggs in the market were recommendedbased on the parallel line assay of the data of specific gravity and Haugh unit of the eggs.

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Distribution of fibronectin in the maturing, ovulatory and atretic follicles of chicken wasstudied by immunohistochemical methods. In the mature follicles, fibronectin was distributed within the basal lamina, thecal connective tissue and superficial tunic. Fibronectin inthe theca externa distributed along the collagenous bundles. Fibronectin in the thecal tissueof the stigma appeared in the form of fine strands near the time of ovulation and becamefragmented 2h after ovulation. In the atretic follicle, the amount of fibronectin in the thecaltissue was remarkably reduced.
From the above findings, it is suggested that fibronectin may participate in the processof disintegration of the thecal connective tissue at the time of ovulation and in atresia.

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Observation of hatching eggs production was conducted with the chickens of 3 successive generations of 2 lines of specific pathogen free chicken flocks, maintained in a largebreeding during 1980 to 1982.
The results described below were obtained.
1) There were no significant differences in the age laid the first egg and the age at50% egg production among 2 lines and their successive generations. Ages laid the first eggwere from 135 to 144 days, being 140 days in average. The ages at 50% lay were from165 to 177 days, being 172 days in average.
2) Egg production rates reached the maximum of 80% at 200 to 230 days of age exceptthe second generation of one of the lines, of which egg production tended to decrease withtheir age, and the rate became 60 to 65% at 420 to 430 days of age.
3) Fertilization rates in each generation were over 90%, and the hatching rates were93.0% in average.
4) By grouping the eggs by their weight into 4 classes (S: 50g or less, M: 51 to 55g, ML: 56 to 60g, and L: 61g or more) in each line, there was the tendency that the ratesof S and M were increased while those of ML and L were decreased with their generations.

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