Average Number Of Eggs Research Articles

Egg Production of Laying Hens Before and After Force-Molting is not Correlated

Two experiments were conducted to study the relationships of egg production before and after force-molting. Two hundred Single Comb White Leghorn (SCWL) hens at 66 wk of age were either preselected (Experiment 1) or randomly selected (Experiment 2) and subjected to force-molting. After force-molting, approximately 150 hens were transferred into individual laying cages and daily egg production was recorded. The average number of eggs laid during the 44-wk period was 209 per hen in Experiment 1 and 205 per hen in Experiment 2. The number of eggs produced in the second cycle varied from 0 to 297 per hen in both experiments. The number of eggs produced in the first and the second cycle was not correlated (R=0.26, P>.05). The number of eggs produced in the second cycle correlated better to total eggs produced in both cycles than to eggs produced in the first cycle.

Encapsulated egg deposition pattern of Schistosoma japonicum in the peritoneal cavity of mice

Thirty-four albino mice were each exposed to 20 cercariae of Schistosoma japonicum by the intraperitoneal or percutaneous route and killed after 60-127 days. The peritoneal cavity of each mouse was flushed and worms in the portal vein system were perfused with citrated saline. After sedimentation, washings were examined microscopically. Mature worms were only found in the portal vein system. The worm recovery rate was much higher by percutaneous infection (61.2%) than by intraperitoneal (37.1%). The encapsulated egg granulomas were observed either in the peritoneal cavity or on the intestinal wall; the mean number of encapsulated egg granulomas was also higher in the former (1.6) than in the latter (0.6). The average number of eggs per granuloma was very similar by both routes (10.7 and 11.4). The mean size of encapsulated egg granulomas (529 microns) was increased correspondingly with the number of eggs (range 181-985 microns). The percentage of viable eggs within the granulomas in the peritoneal cavity (77%) was much higher than those on the intestinal wall (18%). Encapsulated egg granulomas were usually ovoid although some had an irregular shape.

Effects of temperature on life table parameters ofAgistemus exsertusGonzalez (Acari: Stigmaeidae) and its attack rate onPanonychus citrieggs

Abstract The effects of temperature on life table parameters of Agistemus exsertus Gonzalez were studied using Panonychus citri (McGregor) (Acari: Tetranychidae) eggs as a single food source at 15, 20, 25, 30, and 35°C. The mean length of a generation (T) was 35.9, 18.1, 14.5, 11.4, and 12.6 days, respectively. Average number of eggs produced per female was 66.0, 69.0, 46.5, 25.5, and 18.8 at 15, 20, 25, 30, and 35°C. More than 70% of the A. exsertus eggs developed to adults when they were maintained at temperatures between 20 and 35°C compared with only 41% at 15°C. The highest net reproductive rate (Ro = 25.30) and intrinsic rate of natural increase (rm = 0.2288) were obtained at 20 and 25°C, respectively. The lowest Ro and rm values were 11.98 and 0.0690 at 35 and 15°C. When citrus red mite eggs were provided as prey for A. exsertus adult females at 10, 20, 30, and 40°C, the attack rate (E-) decreased with an increasing number of prey eggs. Significant decreases in E- were observed at 20 and 30°C compa...

Effect of Flushing on Embryos in Early Developmental Stages in Mink (Mustela vison)

Abstract Nutritional flushing of mink females by ad lib. feeding from March 3 or 5, following a two week period of restricted feeding, was evaluated with respect to effects on the number and early development of the eggs shed in females mated once on March 7, 10, 14, 17, 20 and 24. Plasma oestradiol-17β was recorded at mating and at killing 3 or 4 days after mating. The average number of eggs recovered increased for females mated from March 7 to 17, after which time it declined. The number of early embryos was not significantly affected by flushing, but the early development of the eggs was enhanced, documented by a significantly higher percentage of eggs having reached the four-cell stage or more at killing. The effect was most pronounced for females mated early in the breeding season, and then levelled off.

Biology and life table of the predacious mite,Agistemus exsertus Gonz. (Acari: Stigmaeidae)

The predacious mite,Agistemus exsertus Gonz. was reared on 4 types of animal egg diets (eggs ofTetranychus urticae Koch,Eutetranychus orientalis Klein,Brevipalpus pulcher [C. & F.] andBemisia tabaci [Genn.]). Life table parameters of each diet (net reproduction rate [Ro], mean generation time [T], intrinsic rate of increase [rm] and finite rate of increase [erm]) were determined. Eggs ofT. urticae were found to be preferred above other egg diets as food byA. exsertus and promoted a higher rate of oviposition. The intrinsic rate of increase was 0.15 individuals/♀/day; the population multiplied 57.91 times in a generation time of 26.21 days. Rearing on eggs ofB. tabaci exhibited more attractive compared withB. pulcher. The average number of eggs consumed daily by female was 17, 12, 9 and 7 eggs ofT. urticae, E. orientalis, B. tabaci andB. pulcher respectively. In the sex ratio of the progeny, predator females fed inT. urticae andB. tabaci gave rise to more females.

In vitro embryonation of Syphacia obvelata eggs

Mouse infections with the pinworm, Syphacia obvelata, were evaluated as a potential model of human enterobiasis. Eggs of S. obvelata were found to be much less resistant to adverse environmental factors than those of Enterobius vermicularis, perishing rapidly when exposed to desiccation or to water. The average number of eggs produced by a female worm was 317 ± 29 s.d. (range: 266–347), which is about 2–3% of the fecundity of E. vermicularis. Eggs expressed from gravid S. obvelata were incubated under various conditions, but the only reliable method of supporting complete embryonation was culture on a floating cellophane membrane. At 30°C on this substrate, eggs were found to be infective between 6 and 42 h, inclusive. The pre-patent period in mice fed these eggs was 11–15 days. The more fastidious developmental and survival requirements of Syphacia eggs indicate that transmission of this species depends on much more intimate contact between hosts than is required by E. vermicularis.

Pharmacodynamics, pharmacokinetics and faecal persistence of morantel in cattle and goats

Morantel could not be detected (< 0.05 microgram/ml) in the plasma of cattle or goats following the oral administration of morantel tartrate at a dose rate of 10 mg/kg bodyweight. No morantel was detected in the milk of lactating goats except in one animal where a concentration of 0.092 microgram/ml was detected at 8 h after drug administration. Morantel was highly effective against Cooperia oncophora infections in calves treated 6, 9 or 18 days after infection; however, was highly effective against Ostertagia ostertagi only when treated 18 days after infection. Morantel did not affect the fecundity of adult O. ostertagi surviving treatment 18 days after infection which had similar average numbers of eggs in their uteri (range 13.4 +/- 0.73-16.8 +/- 0.98) as did parasites from control animals (range 12.0 +/- 0.70-13.6 +/- 0.66). Morantel could be detected at a concentration of 96 +/- 4.5 micrograms/g (dry weight) in the faeces of a calf 24 h after treatment with 10 mg/kg bodyweight of morantel tartrate. The concentration of morantel in replicate samples of this faeces exposed to natural atmosphere, but not to soil or soil organisms, declined slowly over the following 322 days. At day 322 after the start of the experiment 8.8 micrograms/g of morantel could be measured in the remaining faecal material. Throughout the faecal degradation study the concentration of morantel in the crusts of the replicate sample pats was lower than the concentration in the core samples.

Some Biological Aspects of Paradeontacylix (Trematoda: Sanguinicolidae) Infection in Cultured Marine Fish Seriola dumerili.

Investigations on some biological aspects of the two species of sanguinicolid trematodes, viz. Paradeontacylix grandispinus and P. kampachi, infecting the vascular system of cultured amberjack, Seriola dumerili were conducted. In a survey of 50 naturally infected fish, P. grandispinus was the dominant of the two species. P. grandispinus mostly infected the afferent branchial arteries, while nearly half of P. kampachi infected the sinus venosus and heart. Eggs were first found in the gill filaments in November, about four 'months after introduction of amberjack seedlings to culture site. Egg numbers tended to increase until March (average egg number per gill filament : 452), and decreased toward July. Cercarial invasion to amberjack, determined by transferring fish from an endemic area to an infection-free site at different times of year, started sometime in September, suggesting that the two species of blood flukes matured about two months after invasion to fish.

The Regulation of Numbers of Cysts and Eggs Per Cyst Produced By Globodera Rostochiensis and G. Pallida On Potato Roots At Different Initial Egg Densities

The relation between initial egg density Pi of Globodera rostochiensis pathotypes Ro 1 and Ro 3 and of G. pallida pathotype Pa 3 and the number of cysts producted per g dry haulm (considered to be proportional to size of the food source of the nematodes) Pf on various potato cultivars in ten pot experiments with ranges of initial egg densities was in accordance with the equation Pf = M(1 - e-x) with x = aPiM-1. This indicates a distribution of feeding sites of equal size for female juveniles in the roots according to Nicholson's competition model and adjustment of the population size in the roots by elimination of excess female juveniles by an active mechanism, thus preventing reduction of the size of the surviving females and their mortality by crowding, which would be an inefficient use of the food source. However, relative numbers of eggs per cyst y, were reduced according to the equation ye = me + (1 - me) 0.9z with z = PiT-1e-1 for Pi > Te and y = 1 for Pi < Te because of the adverse effect on the quality of the food source by invasion of the roots by much larger numbers of juveniles than could survive. Te varied between pathotypes, cultivars and experiments and was generally larger than T in the equation for the relation between Pi and final total plant weight. Therefore, the mechanism reducing the average number of eggs per cyst operates independently of that reducing plant size.

Life cycle studies of the tick species, Amblyomma lepidum, Hyalomma anatolicum anatolicum and Rhipicephalus evertsi evertsi under laboratory conditions

Immature stages of Amblyomma lepidum were fed on rabbit ears and the adult ones on calf ear. There was a three-host type of development during an average period of 160.5 days. The mean larval feeding period was 5 days, 7 days for nymphs and 14.5 for females. At 27 ± 1°C and 100% r.h. the engorged larvae required 21 days for moulting and nymphs took 22 days to develop to adults. The pre-oviposition period was 14.2 days and the oviposition period was 21.4 days during which a mean number of 7564.6 eggs were laid. Hyalomma anatolicum anatolicum and Rhipicephalus evertsi evertsi were fed on rabbit ears. The larvae, nymphs and adults of Hyalomma ticks fed for 4.6 and 8.5 days, respectively. The larvae and nymphs of R. e. evertsi fed sequentially on the same host for 14 days while the females took 7.5 days to engorge. At 27 ± 1°C and 75–80% r.h. the engorged larvae and nymphs of H. a. anatolicum moulted after a further 8.5 and 13 days respectively. The engorged nymphs of R. e. evertsi at 27 ± 1°C and 75–80% r.h. moulted 14.5 days after dropping off the host. At 27 ± 1°C and 75–80% r.h. the preoviposition and oviposition periods of H. a. anatolicum were 4.6 and 20.8 days, while those of R. e. evertsi were 5.4 and 14 days. The average number of eggs laid per female under the same conditions (27± 1°C and 75–80% r.h.), was 4684.6 for H. a. anatolicum and 3392 for R. e. evertsi.

Nectomys squamipes (Rodentia: Cricetidae) as an experimental model for Schistosomiasis mansoni.

Twenty specimens of Nectomys squamipes born in captivity, were infected with 500 cercariae by the transcutaneous route. Coprologic examinations were carried out from the 5th to 23rd week after infection. On the 7th, 8th, 12th, 16th, and 23rd weeks the animals were sacrificed and perfused. The oogram was performed in segments of the small intestine (proximal, medial and distal portions) and the large intestine. The average pre-patent period was of 42 days. The average number of eggs varied from 350 on the 6th week, to 800 on the 13th. From the 14th week on, the average number of eggs eliminated was lower than 50 per gram of feces. The recovery of worms kept steady on the 7th, 8th and 12th week (16.85%; 15.45% and 11.95%), decreasing to 7.70% on the 16th week and 8.45% on the 23rd week. The proportion of male/female worms was about the same on the first two weeks, but from the 12th week on, the proportion was: 1.4/1 on the 12th week; 2.5/1 on the 16th week and 1.8/1 on the 23rd week. These observations suggest that N. squamipes may be used as an experimental model for schistosomiasis mansoni, to which it develops resistance mechanism, useful for immunity studies.

The Relation Between Rate of Reproduction and Average Number of Eggs Per Cyst in Globodera Rostochiensis and G. Pallida

Pooled rates of reproduction of Globodera rostochiensis (five pathotypes) and of G. pallida (three pathotypes) from several pot experiments in four years on potato cv. Irene at initial population densities of 1 egg and 5 eggs/g soil were, per nematode species, proportional to average number of eggs per cyst and per pot and, per initial egg density, not correlated with number of cysts produced per egg in the inoculum. This also applied to rates of reproduction of pathotype Ro 1 on cvs Bintje and Mentor in four field experiments at initially 1 egg/g soil. The average number of cysts produced per egg in an inoculum of 5 eggs/g soil by G. rostochiensis in pots was 1.7 times that produced by G. pallida. At initially I egg/g soil the ratio was 1.5. Numbers of cysts of G. rostochiensis pathotype Ro 1 produced per egg in an inoculum of 5 eggs/g soil were proportional to dry haulm weight per pot. At initially 1 egg/g soil pathotype Ro 1 produced more cysts per egg in the inoculum than pathotype Ro 3 but not at initially 5 eggs/g soil. This indicates that the maximum cyst density per g dry haulms of the latter pathotype on cv. Irene was larger than that of the first. No differences between G. pallida pathotypes were apparent.

Fecundidade em Callinectes danae Smith (Decapoda, Portunidae) da lagoa da Conceição, Florianópolis, Santa Catarina, Brasil

The estimate for the average fecundity for the C. danae population of Lagoa da Conceicao (Florianopolis, Santa Catarina) was of 598.885 eggs by female. The average number of eggs and the weight of the mass of eggs, in general, increase with the female size. The variation in colour and in the diameter of the eggs is associated with the degree of development of the embryo.

Biological studies of the predacious miteTyphlodromus pelargonicus a predator of the two spotted spider miteTetranychus urticae on cucumber plants [Acari: Phytoseiidae; Tetranychidae

The predacious miteTyphlodromus pelargonicus El-Badry preyed on the different developmental stages of the two spotted spider miteTetranychus urticae Koch. The development was quickest and the number of prey consumed was highest when individuals were maintained on eggs compared with nymphs or adult female stages. The predator was able to develop and reproduce on the eriophyid miteEriophyes dioscoridis. Soliman & Abou-Awad, nymphs of the tobacco whiteflyBemisia tabaci (Genn.) and pollen grains ofPhoenix dactylifera andRicinus communis. The average number of eggs/♀/day was 1.4, 0.7, 1.2 and 0.9 on eriophyid, whitefly,Ph. dactylifera andR. communis respectively.

The adaptive significance of spawning synchronization in the Caribbean damselfish Stegastes dorsopunicans (Poey)

In the dusky damselfish Stegastes dorsopunicans (Poey) two levels of population reproductive synchrony exist. At one level, there is a broad peak in spawning activity every month between full moon and new moon. Within these lunar peaks of spawning activity, spawning is concentrated on specific days, often flanked by days with no spawning, resulting in spawning peaks within the broader monthly peak. On days of higher spawning activity, more females spawn in a nest that receives eggs, and the average number of eggs a male receives is higher. Larger clutches suffer lower mortality from both complete and partial clutch predation by the father (filial cannibalism). Males are more likely to eat complete clutches when the clutches are small. Fathers also appear to eat a subset of their clutches, but the number of eggs eaten is independent of clutch size, so larger clutches have a lower percentage mortality from partial clutch loss. A separate source of clutch mortality, complete clutch loss to nocturnal predators, affects all clutches equally and does not select for large clutch size and spawning synchrony. The differences in rates of clutch cannibalism between synchronized and nonsynchronized days provides an adaptive explanation for spawning synchrony in this noncolonial fish; female synchrony may have evolved in response to differential egg mortality.

Aspects of the Life History of the Calico Crayfish with Special Reference to Egg Hatching Success

Abstract Life history data were collected on adult (≥25 mm carapace length) female calico crayfish (Orconectes immunis) in conjunction with an egg-hatching study during 1986–1988. Eggs stripped from 10 females in October 1986 and 10 females in September 1987 were pooled each year and hatching success was monitored for samples of 100 eggs placed in each of eight diluter aquaria at 12°C. In fall 1987, berried calico crayfish were cultured at 12, 25, and 30°C and hatching was monitored. Data on length, weight, and number of eggs produced were collected for 28 females in September 1987 and 36 females in April 1988. An additional 456 female crayfish were checked for the presence of eggs. Hatching success was 86% in 1986 and 89% in 1987. The eggs on berried females held at 12°C started to hatch within 33 d. At 25°C, hatching started within 10 d. At 30°C, no hatching occurred, the eggs became orange (indicating death), and most of the eggs later developed fungal infections. The average number of eggs carried was...

Reassessment of Pantothenic Acid Requirement for Single Comb White Leghorn Pullets from 0 to 6 Weeks of Age and Its Subsequent Effect on Sexual Maturity

Two experiments were conducted using a total of 288 Hy-Line W-36 day-old pullets in each experiment. The pullets were randomly assigned to one of the six dietary treatments that consisted 0, .3, .6, .9, 1.8, or 3.6 mg supplemental pantothenic acid/kg of a corn and soybean meal basal diet (4.8 mg/kg). Six replicates of eight pullets per replicate were used per treatment in each experiment. Feed and water were provided for ad libitum access. The pullets were housed in battery brooder pens with raised wire floors. Body weight, body weight gain, average feed consumption per day, total feed consumption, and feed conversion were determined at 3 and 6 wk of age (WOA). The birds were observed for any signs of pantothenic acid deficiency. At the end of a 6-wk experimental period, the pullets previously receiving the diets containing either 0 or 3.6 mg supplemental pantothenic acid/kg of diet were raised to sexual maturity and their age at sexual maturity, body weight at 24 WOA, and average number of eggs per pullet through 32 WOA were measured in both of the experiments.No differences (P>.05) in total body weight, body weight gain, average feed consumption per day, total feed consumption, and feed conversion were observed in any of the supplemental pantothenic acid treatments from 0 to 3 and 3 to 6 WOA. None of birds during the experimental period showed any signs of deficiency. No differences were observed in the subsequent age at sexual maturity, number of eggs laid, and the body weight at 24 WOA. It was concluded from these experiments that Single Comb White Leghorn pullets require at least a total of 4.8 mg/kg pantothenic acid based in a corn-soybean meal diet from 0 to 6 WOA and at subsequent sexual maturity for optimum performance.

Population Biology and Larvae of the Anchialine Crab Munidopsis Polymorpha (Galatheidae) from Lanzarote (Canary Islands)

The galatheid Munidopsis polymorpha Koelbel, 1892, is found at high population density in an anchialine pool (Jameos del Agua) on Lanzarote. Ovigerous females on an average carry 14 eggs. Larval development is advanced. Only 2 zoeal stages, which are unable to undergo locomotion, precede molt to a small crab. Munidopsis polymorpha is not preyed upon in the Jameos del Agua. Population density is regulated less by available food than by the number of available hiding places for resting phases. Population density is probably increased by the fact that the highly territorial crabs periodically alternate in feeding in the same grazing areas and in hiding. The percentage ofovigerous females and the average number of eggs per female is negatively correlated with the number of specimens per area. During the years of investigation from 1976-1989, the number of ovigerous females and the average number of eggs per female have decreased considerably in parts of the pool. Consequently, the general population density has become drastically reduced. This is attributed to the construction and opening of the Jameos del Agua for tourism.

Intraspecific Variation in the Reproductive Capacity of Anopheles stephensi (Diptera: Culicidae)

Intraspecific variation in the reproductive capacity of Anopheles stephensi Liston females was studied under constant laboratory conditions. Of 421 engorged females examined individually throughout their lifetimes, 260 laid a total of 479 egg batches with a maximum of nine ovipositions per female. The number of eggs per oviposition varied from 5 to 247 (average 96.8). The number of ovipositions per female were correlated positively with the average number of eggs per batch and exhibited a negative binomial distribution among females, indicating that a small portion of the population exhibited a particularly high fecundity. Among the ovipositing females, the total fecundity and fertility ranged, respectively, from 5 to 1,084 eggs and from 0 to 1,036 larvae per female. The estimated maximal number of female progeny produced by a female in her lifetime was 317, and the estimates of net reproductive rate (Ro) and capacity for increase (rc) were 25.7 and 0.17, respectively. The number of eggs in the first oviposition was predictive of the total fecundity of a female. The wide range of individual variation in the reproductive capacity of An. stephensi emphasized the requirement for a large sample size for reliable estimation.

Biology of &lt;i&gt;Metadelphax propinqua&lt;/i&gt; (Fieber) (Homoptera, Delphacidae)

The biology of the Turkish Metadelphax propinqua population was investigated in Finland. The egg closely resembles that of other delphacids, and the five nymphal instars are distinguished by the characteristics of the legs. The adults were macropters, brachypters orintermediary form. At 22°C the duration of the egg stage was 12 d, that of the nymphal stage 19 d, and that of the female stage 51 d. The average number of eggs was 1112 per female. In the trials the planthoppers oviposited 3.3.-3.5 eggs per group in the sheath or blade of the leaf.