Hatchability Of Total Eggs Research Articles

Improvement of rooster semen freezability and fertility rate after sericin supplementation in freezing semen extender.

Semen cryopreservation result in decreased sperm parameters and fertilization ability. Sericin exhibits antioxidant activity by reducing lipid peroxidation resulting from free radicals, which can potentially improve cryopreservation outcomes. The present study aimed to examine the efficacy of various sericin concentrations supplemented with a rooster semen-freezing extender on post-thaw semen quality and fertilizing ability of sperm after cryopreservation. Semen samples were collected from 40 roosters (5 reps), then were pooled, and divided into four groups by the levels of sericin supplementation (0%, 0.25%, 0.50%, and 0.75%) in a freezing extender. Semen suspensions were loaded in medium straw (0.5 mL) and cryopreserved with the traditional liquid nitrogen vapor method. Post-thawed semen was evaluated for sperm motility, sperm viability, and lipid peroxidation. Also, the fertility test was determined. The results showed that supplementation of the freezing extender with 0.50% to 0.75% sericin resulted in greater total motility and progressive motility and lower malondialdehyde levels than the other groups after cryopreservation (p<0.05). However, the viability of 0.75% decreased compared with the value of 0.50% sericin supplementation (p<0.05). Moreover, the fertility and hatchability of total eggs were significantly higher in the 0.50% sericin group than in the other groups (p<0.05). In conclusion, 0.50% sericin is recommended as an alternative component of the freezing extender to improve cryopreserved rooster semen.

Estimation of repeatability and phenotypic correlation of reproductive traits in zebrafish Danio rerio

This study was conducted to estimate the repeatability and phenotypic correlation of reproductive traits of zebrafish Danio rerio, in captive condition. Breeding trials were conducted on 10 breeding pairs (2 male:1 female). The data on fecundity, fertility, hatchability and survival rate were recorded. The repeatability values were computed as a measure of consistency using the intra-class correlation coefficient. The repeatability estimates for fecundity, fertility, hatchability of total eggs, hatchability of fertilised eggs, survival rate of total eggs and survival rate of larvae were 0.701, 0.406, 0.336, 0.049, 0.295 and 0.314, respectively. Most of the reproductive traits analysed had moderate repeatability values barring the hatchability of fertilised eggs. The phenotypic correlation was calculated using the Pearson correlation method. The phenotypic correlations of fertility with hatchability of fertilised eggs; hatchability of total eggs; survival rate of total eggs and survival rate of larvae were highly significant (p≤0.01). This study provided valuable information on the consistency of reproductive parameters which would serve as model for conducting research in other fish species. Keywords: Genetic parameters, Phenotypic correlation, Repeatability, Reproductive traits, Zebrafish

Hatching Traits and Growth of Turkey (Meleagris gallopavo) Poults under Sudan Conditions

The objectives of this study were to determine the hatchingtraits, brooding growth performance and mortality of turkey (Meleagrisgallopavo) poults under Sudan conditions. Six hundred fertile eggs werebrought from France and hatched in Khartoum during March 8 to April 62011 and poult brooding was conducted at the University of Bahri Farmfrom April 6 to May 4 2011. The results showed that turkey egg had98.83 % fertility, 79.26 % hatchability of total eggs, 80.2 % hatchabilityof fertile eggs, 61.9 % of first class poults from total eggs incubated, 77 %first class poults from eggs hatched. Poults weighed 49.52 100.02, 183.78,332.18 and 548.84 g at one day old and at the end of weeks, 1, 2, 3 and 4,respectively. Mortality was 7.37 % and 100 % for first and second classpoults, respectively. This is the first study done on turkey under Sudanconditions. It is hoped that this study may be a pioneer to invite more indepth research on turkey specially now when poultry industry is booming.

Effect of magnetic field on productive and hysiological performance in broiler breeder

The experiment was conducted to determine the effect of magnetic field on the productive and physiological performance of Ross 308. The experimental flock consist of 60 hens and 10 cocks of broiler breeders, which randomly divided into four groups and distributed on the treatments with three replicates for each treatment. The treatments included the control treatment (T1), exposure the stored semen to 803 gauss magnetic field for 24 hours (T2), exposure the fertile eggs to 250 gauss magnetic field for 72 hours before entered the incubator (T3) and exposure the individual cages to 250 gauss magnetic field for 8 weeks (T4), and the performance traits of hen day egg production, egg weight, recorded from magnetization cages group and compared with control group. The results showed a significant decrease (P≤0.05) in fertility and hatchability of total eggs in T2 compared with other groups, and there was no significant difference in the hatchability of fertile eggs and embryonic mortality among treatments, egg weight and the hen day egg production. (HD).

Egg production, fertility, hatchability and immune responses of some chicken strains under high ambient temperatures.

This experiment was designed to investigate and compare the egg production, fertility, hatchability and immune responses of some local developed Egyptian chicken strains under high ambient temperatures. A total of 108 (26weeks old) laying hens of Matrouh, Silver Montazah, Mandarah and Inshas (9 hens×3 replicates×4 strains) were used to evaluate the impact of thermal stress (24-34ºC) during summer season (June, July and August) on egg production, fertility, hatchability and immune responses. The obtained results revealed that final body weight (FBW/g) and body weight change (BWC/g) among different chicken strains were not affected. The daily feed consumption (FC/g) and feed conversion ratio (FCR) for Silver Montazah and Inshas strains were significantly (p≤.05) higher than those of Matrouh and Mandarah strains. The mean egg production (EP/%) and egg mass (EM) for Silver Montazah and Inshas strains were significantly (p≤.05) higher than those of Matrouh and Mandarah strains. The highest percentages of hatchability of total eggs (HTE) and fertile eggs (HFE) were recorded in Inshas chickens, while the lowest value was recorded in Mandarah chickens. Also, the highest embryonic mortalities (p≤.05) and lowest chick weight at hatch (CWH/g) were recorded in Mandarah chickens compared with the other strains. The highest values for antibody titres against phytohemagglutinin-P (PHA-P) were recorded in Mandarah chickens, while the least values were recorded in Inshas chickens.

Effects of dietary supplementation with vitamin E, selenium yeast or both on egg incubation response, embryonic development, keet quality, and posthatch growth of helmeted guinea fowl breeders.

This study investigated the effects of dietary supplementation with vitamin E (vit. E), selenium yeast (Se yeast), or both on egg incubation response, embryonic development, keet quality, and posthatch growth of helmeted guinea fowls. Two hundred and forty 24-week old helmeted guinea fowl hens (average weight 1.75+0.22kg) and cocks (average weight 2.15+0.20kg) were assigned into 24 pens; each pen housed 10 hens and 2 cocks. There were four dietary treatments consisting of a basal diet (control), basal diet supplemented with vit. E (30IU/kg), Se yeast (0.3mg/kg Se), or both. Six pens were assigned to each treatment. Egg incubation response were estimated using 504 settable eggs sampled from each treatment collected during 15 to 17weeks in lay. A total of 72 fertile eggs sampled from each treatment were used for the estimation of embryonic development. Quality of day-old keets hatched was scored based on physical conditions, while posthatch growth was measured for 21days. Guinea fowl breeders fed diet supplemented with both vit. E and Se yeast produced the highest (P < 0.05) number of fertile eggs, percentage fertility, number of hatchlings, hatchability of total eggs, and hatchability of fertile eggs. Supplementation with vit. E + Se yeast resulted in the heaviest (P < 0.05) embryo weight, relative embryo weight, least (P <0.05) yolk sac weight, and relative yolk sac weight on 25days of incubation. Hatchlings from breeders fed diet supplemented with Se yeast and vit. E + Se yeast showed normal swallowed yolk. Supplementation of maternal diet with vit. E, Se yeast, and vit. E + Se yeast resulted in improved (P < 0.05) feed conversion ratio of subsequent hatchlings during 1 to 7-day posthatch growth. It can be concluded that dietary supplementation of vit. E + Se yeast in guinea fowl breeders resulted in improved egg fertility, hatchability, heavier embryo weights, hatchlings of good quality, and improved posthatch growth during the first 7days.

Fecundity and egg hatchability of Dastarcus helophoroides adults fed on different types of artificial diets

Both fecundities and egg hatchabilities were compared among three populations of Dastarcushelophoroides Fairmaire adults (Coleoptera: Bothrideridae) fed on three types of artificial diets (Diet of formula 1 composed of silkworm pupa powder, dried yeast powder, sucrose, peptone, egg yolk powder and poplar branch powder. Diet of formula 2 composed of silkworm pupa powder, dried yeast powder, sucrose, egg yolk powder, poplar branch powder, cricket powder, benzoic acid and distilled water. Diet of formula 3 composed of pine bark powder and Monochamus alternatus larva powder). for 90 days. The three diets showed no significant difference regarding the average number of eggs deposited by all D. helophoroides females (16622.3–23874.7); the average number of eggs per female (1278.6–1836.5); and the average number of eggs per female per day (14.2–20.4). The number of eggs one cluster contained mainly (82.06–82.66 %) lied in 1–100 eggs, and the average number of eggs per cluster ranged from 61.7 to 63.1. In the first 10-day period, the number of eggs deposited by all females fed on formula 1 was significantly larger than that on formula 3. The eggs deposited in the last four 10-day periods were more than in the former five 10-day periods, on formula 3. There were no significant differences in hatchability of total eggs among the three artificial diets, and the average corrected egg hatchability ranged from 82.85 to 84.78 %. No significant differences in the adult mortality and mean weight gain of D. helophoroides were found after feeding on three artificial diets. Our results suggest that D. helophoroides adults were not specialized on the diet, and the diet types might have little effect on fecundity and egg hatchability in D. helophoroides, as long as sufficient nutrition was supplied.

The effects of broiler breeder age on intestinal development during hatch window, chick quality and first week broiler performance

This study was carried out with the aim of determining the effects of breeder age on incubation results, intestinal development during hatch window, chick quality and first week broiler performance. A total of 4800 eggs were obtained from commercial Cobb 500 broiler breeder flocks at 33 and 62 weeks old. Of these 33 and 62 weeks old flocks, 31.4% and 7.0% were hatched 24 h before pull time and 51.2% and 56.0% were hatched 12 h before pull time, respectively. Hatchability of fertile eggs and hatchability of total eggs were found higher in 33 weeks old flock than the other. The chick hatch weight was determined as 39.5 g and 41.4 g in 33 and 62 weeks old flocks, respectively. Chick weight/initial egg weight rate was found to be higher as 67.3% in the 33 weeks old flocks. On hatching day, chick length were also higher in 62 weeks old flock. Relative yolk-free chick weight was higher in 33 weeks old (85.0%) flock than the other (82.0%). Intestine weight rate was higher as 5.27% in chicks from 33 weeks old than the other (5.08%). At 1 week of age, the body weights and weight gains were 165.1 g and 156.0 g, and 125.6 g and 114.6 g in 33 and 62 weeks old flocks, respectively. Higher mortality ratio as 3.6% was observed in 62 weeks old flock. In conclusion, intestinal development during hatch window, incubation parameters, chick quality and first week broiler performance is affected by breeder age.

Effect of egg weight on hatching characteristics of emu eggs

The study was carried out to investigate the effects of egg weight on hatchability traits in emu (Dromiceius novaehollandiae) eggs. Emu eggs (393) that hatched from 3 different egg weight groups (below 500 g (G 1), 501 to 600 g (G 2) and above 601 g (G 3)) were used in the experiment. Hatching traits such as percentage of infertile eggs, early embryonic mortality, late embryonic mortality, dead-in-shell, chicks hatched out, total egg hatchability, fertile egg hatchability, fertility and chick livability were investigated. The mean±SE percentage of early embryonic mortality, late embryonic mortality, dead-in-shell, chicks hatched out, total egg hatchability, fertile egg hatchability, fertility and chick livability were statistically significant for different egg weight groups. The better hatching traits and livability of chicks were obtained from the medium emu eggs weighed between 501 and 600 g then the heavy (above 601 g) and small (below 500 g) egg weight groups.

The effects of different eggshell temperatures on embryonic development, hatchability, chick quality, and first-week broiler performance

The aim of the current study was to determine the effects of different eggshell temperatures (EST) during 10 to 18 d of incubation on embryonic development, hatchability, chick quality, first-week broiler performance. The EST were maintained within the temperature ranges of 33.3 to 36.7, 37.8 to 38.2, and 38.9 to 40.0°C for the low, control, and high EST treatments, respectively. From d 15 to 18, embryo weight and relative embryo weight were found to be similar in the low and high EST groups. Salable chicks and hatchability of total eggs was found to be higher in the control EST group. Between d 10 and 17 of incubation, embryonic mortality in low, control, and high EST groups was determined to be 1.6, 0.8, and 2.0%, respectively. From d 18 to hatch, embryonic mortality and rate of dead and cull chicks were found to be significantly different. Hatching in high EST group was completed 26 h early, although hatching in low EST group was completed 10 h later than the control EST group. On the of hatching day, chick weight and length were found to be 39.5, 41.0, and 42.5 g, and 18.5, 21.4, and 19.1 cm in low, control, and high EST groups, respectively. The highest residual yolk sac weight and relative residual yolk sac weight were observed in high EST group as 7.7 g and 18.7%. Yolk-free chick weight and relative yolk-free chick weight were highest in the control EST group. At 1 wk of age, the BW in low, control, and high EST groups were determined as 131.1, 140.0, and 140.8 g, respectively. No significant difference was found for feed intake and feed conversion among treatments for wk 1. The mortality during the first week did not differ among groups; however, a higher mortality rate was observed numerically in the high EST group. In conclusion, embryo development, incubation parameters, chick quality, and the first week performance are affected by small changes in the EST.

Effect of Rearing Systems on Reproductive Performance of Turkey

The objective of this study was to determine the effect of rearing systems on reproductive performance of turkey (Meleagris gallopavo). A total of 180 Beltsville Small White and Board Breasted Bronze turkeys were taken for the study and reared under three different rearing system viz. intensive system (full confinement), semi-intensive system (partial confinement and partial day scavenging) and free range system (all-day scavenging). Average egg weight (g), percentage of infertile eggs, embryonic mortalities, total egg hatchability, fertile egg hatchability, fertility and poults survivability values were significantly (P>0.01) higher in turkeys reared under intensive system of management followed by semi intensive system and free range system of management. The highest percentage of dead in shell was found in intensive system and was did not differ significantly from semi intensive and free range system. Hatched weight of poults (g) between semi intensive and intensive system did not differ significantly between them, but both groups found statistically significant (P>0.01) from free range system. From the study, it is concluded that higher reproductive performance was obtained in intensive system of management followed by semi intensive and free range system of management.

Production traits and hatching of a Barred Rock 1 pure line, its feather sexable strains and their crosses

The study was carried out to identify some production traits of the pure Barred Rock 1 (BR1) line and rapid × slow feathering line crosses derived from the BR1 pure line, in addition to F1 crosses of all these dam lines with Rhode Island Red 1 sire line. The BR1 line previously used a brown layer dam line for barred/non-barred day-old chick auto-sexing and synthetic slow and rapid wing feathering lines. Parent lines showed significant differences in sexual maturity and egg production (P &lt; 0.01) and early embryonic mortality (P &lt; 0.05). However, there was no significant difference in weight at sexual maturity, average egg weight, hatchability of fertile eggs, hatchability of total eggs set, and middle and late embryonic mortalities. A significant difference was found among F1 crosses with respect to weight at sexual maturity (P &lt; 0.05), but no significant difference (P &gt; 0.05) could be determined for age at sexual maturity and egg production. Overall, rapid feathering hens had better production traits than slow feathering hens. The dual crossbred parent lines exhibited almost the same level of egg production traits compared with the pure line.

Effect of Dietary Supplementation with Different Level of Zinc on Sperm Egg Penetration and Fertility Traits of Broiler Breeder Chicken

The aim of the present study was to evaluate the effect of zinc as feed additive (0, 50, 75,100 mg/kg diet) on fertility traits and sperm egg penetration of Cobb 500 broiler breeders. A total 132 of (96 females and 36 males) of Cobb 500 broiler breeder chicken, 45 weeks old were used in this study. These birds were randomly distributed equally into four dietary treatments with three replicates each. Each treatment group constituted of 32 females and 12 males. Treatment groups were as following: T1: Birds fed the basal diet without any addition (0 Zn) (control), T2: Birds fed diet supplemented with 50 mg Zn (pure zinc)/kg of diet, T3: Birds fed diet supplemented with 75 mg Zn (pure zinc)/kg of diet and T4: Birds fed diet supplemented with 100 mg Zn (pure zinc)/kg of diet. Hens were artificially inseminated with semen from the same treatments during 51, 54, 57, 60, 63 and 66 weeks of bird ages. Fertility traits involved in this study were percentages of fertility, hatchability of total eggs, hatchability of fertile egg, embryonic mortality. However, sperm egg penetration during 54, 58, 62 and 66 weeks of bird age's. Results revealed that adding zinc to birds diet results in significant (p<0.05) increase regarding fertility, hatchability of total eggs, hatchability of fertile eggs and sperm egg penetration and significant (p<0.05) decrease as regards embryonic mortality. In conclusion supplementing the diet of bird with zinc resulted in significant improvement in fertility traits and sperm egg penetration. Therefore adding zinc to the diet of birds could be used as an efficient tool for improves reproductive performance of chicken.

Heritabilities and genetic correlations for reproductive traits in an F2 reciprocal cross chicken population

Studies estimating genetic parameters for reproductive traits in chickens can be useful for understanding and improvement of their genetic architecture. A total of 1276 observations of fertility (FERT), hatchability of fertile eggs (HFE) and hatchability of total eggs (HTE) were used to estimate the genetic and phenotypic parameters of 467 females from an F2 population generated by reciprocal crossing between a broiler line and a layer line, which were developed through a poultry genetics breeding program, maintained by Embrapa Swine and Poultry, Concordia, Santa Catarina, Brazil. Estimates of heritability and genetic and phenotypic correlations were obtained using restricted maximum likelihood calculations under the two-trait animal model, including the fixed effect of group (hatching of birds from the same genetic group) and the random additive genetic and residual effects. The mean percentages for FERT, HFE and HTE were 87.91 ± 19.77, 80.07 ± 26.81 and 70.67 ± 28.55%, respectively. The highest heritability estimate (h(2)) was 0.28 ± 0.04 for HTE. Genetic correlations for FERT with HFE (0.43 ± 0.17), HFE with HTE (0.98 ± 0.02) and FERT with HTE (0.69 ± 0.10) were positive and significant. Individuals with high breeding value for HTE would have high breeding values for HFE and FERT because of the high genetic association between them. These results suggest that HTE should be included as a selection criterion in genetic breeding programs to improve the reproductive performance of chickens, because HTE had the highest heritability estimate and high genetic correlation with FERT and HFE, and it is the easiest to measure.

Maternal corticosterone reduces egg fertility and hatchability and increases the numbers of early dead embryos in eggs laid by quail hens selected for exaggerated adrenocortical stress responsiveness

Quail hens selected for exaggerated (HS, high stress) rather than reduced (LS, low stress) plasma corticosterone (B) response to brief restraint deposit more B into their egg yolks than do LS hens. Female progeny of HS hens implanted with B also show reduced egg production when compared with female offspring of LS- and HS-control and LS-B-implanted hens. Herein, LS and HS hens were implanted (s.c.) with empty (controls, CON) or B-filled silastic tubes to assess the interactive influences of maternal B-treatment with quail stress line on egg fertility (FERT), total egg hatchability (TOTHATCH) and fertile egg hatchability, and the percentages of embryonic mortality (early dead, ED; late dead) and pipped eggs. Mean FERT was dramatically reduced in eggs of HS compared with LS hens and B-implanted compared with CON-treated hens (P < 0.0001, both cases). Line x implant treatment FERT outcomes partitioned (P < 0.05) as follows: LS-B = LS-CON > HS-CON > HS-B. In addition, TOTHATCH was also affected by line (LS > HS; P < 0.0001) and implant treatment (CON > B-implant; P < 0.0002) and line x implant treatment TOTHATCH means differed (P < 0.05) as follows: LS-CON = LS-B = HS-CON > HS-B. Fertile egg hatchability was reduced (P < 0.05) in HS-B-treated hen eggs when compared with LS-B and HS-CON hen eggs and more (P < 0.05) ED embryos were found in eggs laid by HS-B-implanted hens than in any other treatment group. Late dead and pipped egg percentages were unaffected by any treatment. The findings are important to avian geneticists because they further emphasize the benefits that selection for reduced adrenocortical responsiveness has on hen reproductive performance. The maternal B findings also warn poultry and hatchery managers that unless hen stress during egg formation is avoided, negative consequences in FERT, TOTHATCH, and ED can result, particularly in hens genetically predisposed toward exaggerated adrenal stress responsiveness.

Correlations between breeder age, egg cholesterol content, blood cholesterol level and hatchability of broiler breeders

1. The research was carried out to investigate correlations between breeder age, egg cholesterol content, blood cholesterol level and hatchability of broiler breeders. 2. Egg cholesterol content increased with increased breeder age. The mean yolk cholesterol contents (mg per g yolk) were 10·47 ± 0·28, 15·34 ± 0·65 and 15·64 ± 0·71 mg/g at 28, 45 and 65 weeks of age, respectively. 3. There were positive correlations between yolk weight and yolk cholesterol content (mg/g yolk) (r = 01·941; P < 0·01) and egg cholesterol content (mg/egg) (r = 0·980; P < 0·01). 4. Negative correlations were found between egg yolk cholesterol content and hatchability of fertile eggs (r = −0·345; P < 0·05), fertility ratio (r = −0·609; P < 0·01) and hatchability of total eggs (r = −0·574; P < 0·01). 5. The mean blood cholesterol levels were 165·1 ± 11·04, 166·5 ± 11·97 and 179·5 ± 11·33 mg/dl at 28, 45 and 65 weeks of age, respectively.

Effect of breeder age and breeding season on egg production and incubation in farmed ostriches

1. This research was carried out to investigate changes in egg production and hatchability as influenced by age and breeding season of 10 trios (two females, one male) of ostrich (Struthio camellus) during 1998 to 2002. 2. Breeding season affected number of eggs laid per female per season, average egg weight, length of laying period and clutch sequence. 3. The number of eggs laid per female per season was 25 in the first breeding season and 57 by the fifth breeding season. The laying period lasted 169 d in the first season whereas it was 210 d by the fifth season. The breeding season became longer year by year. 4. The number of clutches was two in the first season, three in the second and 4 in the later breeding seasons: the mean interval between cycles was 9 to 10·6 d and the mean number of eggs in one cycle varied from 12 to 14·4. 5. The breeding season affected the hatchability of fertile eggs, chick weight at hatching, hatchability of total eggs, fertility, malpositioned embryos, deformed chicks and assisted chicks during hatching. The first 4 variables increased and the last three decreased, with each breeding season. 6. Weight loss of eggs and length of incubation were unaffected by the breeding season. Hatchability which was 64·3% in the first season increased progressively and reached 73·1% in the fifth breeding season.

Colleterectomy and its impact on some reproductive behaviour of the tropical Tasar silk moth,Antheraea mylittaDrury (Lepidoptera: Saturniidae)

Summary Morphometry of the colleterial gland and its removal (colleterectomy) were made to observe its effect on egg laying and hatching behaviour in the female Tasar silk moth, Antheraea mylitta D. during three study season. The paired colleterial gland, which is divided into two distinct regions, was found to be attached at the terminal part of a common oviduct and secretes an adhesive substance which pastes the eggs to the substratum during oviposition. Colleterectomy of the female Tasar moth just after mating and thereby removal of the gluing material induced the deposition of loose white eggs and enhanced egg laying capacity and hatching efficiency followed by a shorter incubation period without any adverse effect on the progeny. No marked changes were observed in hatching initiation and duration. Further the overall pattern of egg laying was observed continuously for 3 consecutive days in each brood of control females, while the total egg hatchability was recorded for 3 consecutive days in the first...

EFFECT OF REARING AND ADULT FEED RESTRICTION AND PHOTOPERIOD REGIMENS ON THE PERFORMANCE OF FOUR MEAT PARENT CHICKEN GENOTYPES

Two experiments were conducted each involving 2600 birds consisting of four commercial, chicken broiler, parent genotypes. The first experiment was designed to compare full feeding with two rearing feed restriction systems and two photoperiod treatments (1) a constant 14-h daylength and (2) a "17–9–14-h daylength." In experiment 2, adult full feeding was compared with two levels of feed intake restriction and the 17–9–14-h daylength used in experiment 1 was compared with a "simulated natural daylength." The rearing period skip-a-day feeding systems resulted in reduced body weight, delayed sexual maturity, heavier initial egg weight, increased number of hatching eggs, higher fertility, higher hatchability of total eggs set and more broiler chicks compared with full-fed birds. Controlled skip-a-day feeding resulted in reduced body weights, increased egg production, higher egg fertility, higher hatchability and more broiler chickens compared with ad libitum skip-a-day feeding. Body weights were lower with adult feed restriction than with full feeding. The more severe level of feed restriction resulted in fewer eggs produced and reduced egg weights. Restricted-fed birds produced more broiler chicks. There was some evidence that not all genotypes responded to these feeding systems in the same manner. Performance of the 17–9–14-h photoperiod birds was equal or superior to that of birds under either the constant 14-h daylength or the photoperiod with an increasing daylength during the rearing period.

A comparative toxicologic study of a phosphorodithioate in Japanese and bobwhite quail

Guthion had a significant effect on growth of female but not male Japanese quail at a dietary level of 540 ppm; with bobwhite, growth was significantly reduced at 20 ppm. All birds of both species died during the first 10 days of feeding at 1620 ppm. With bobwhite, 80% mortality was obtained at 540 ppm and 30% at 180 ppm whereas there was no increase above normal in mortality of Japanese quail at 180 ppm or 540 ppm. Egg production of Japanese quail was delayed and markedly reduced at 540 ppm; total egg hatchability at 180 and 540 ppm was somewhat lower than obtained in the control birds. Whole blood or brain cholinesterase of both species was inhibited after 4 and 10 weeks at 60 ppm; there was somewhat greater inhibition in bobwhite. Results indicate that bobwhite quail were more sensitive to Guthion than Japanese quail.