Differences In Egg Production Research Articles

Effects of crowding and photoperiod on wing morph and egg production in Eobiana engelhardti subtropica (Orthoptera: Tettigoniidae)

Eobiana engelhardti subtropica (formerly Metrioptera hime) is wing-dimorphic. The long-winged (LW) morph was clearly induced by crowding during the nymphal stages. Short-winged (SW) females produced eggs more intensively in an earlier period than did LW females. This difference in egg production between the two wing morphs seems to be associated with different patterns of increase in body weight after adult emergence. The body weight of SW females rapidly increased and reached its peak at about the time when oviposition started. On the other hand, the increase in body weight of LW females was slow, although it continued even after the start of oviposition. These findings suggest that the SW morph is adapted to sedentary life and rapid reproduction and that the LW morph tends to migrate before or during reproduction. However, in both the morphs, reproductive traits (pre-oviposition period, egg-laying period, number of eggs laid, and longevity) were to some extent flexible and could be modified by photoperiodic conditions.

Replacement of limestone with calcite prill derived from underground water in diets for molted layer hens

Two hundred and forty, approximately 100-week-old molted Hyline Grey layer birds were used to compare the efficacy of calcite (CaCO3) prill (derived from an underground water lime treatment process for the removal of hardness; hereafter referred to as 'calcite prill') or limestone ('control') added as supplementary sources of calcium (Ca) to layer diets. One hundred and twenty birds were allocated to each diet. The 120 birds derived from 8 pens, with each pen comprising 5 cages each of 3 birds (15 birds per pen). The 2 diets were formulated to provide equal amounts of nutrients and vitamins and minerals, with the calcite prill and limestone added to each diet at 70�g/kg. Diets were offered on an ad libitum basis for 5 weeks. Measurements of bird performance, egg production, and egg quality were determined on a weekly basis. There were no statistical differences (P > 0.05) between the 2 diets in any of the indices measured over the experimental period. The average hen day percent was 73.2% and 69.5% for calcite-prill-fed birds and control birds, respectively. The lack of differences in egg production, egg weights, and egg quality seen between birds fed calcite prill and those fed limestone suggests that the Ca in calcite prill has a bioavailability at least equal to that for Ca from limestone. In this regard, calcite prill would appear to be a suitable alternative to limestone in diets for layer birds of this age.

Ambient temperature and the egg laying characteristics of laying fowl

Laying hens have physiological responses that affect their productive performance when given different ambient temperatures. The objectives of this study were, first, to quantitatively describe the relationship between different constant environmental temperatures and egg production characteristics of laying hens by a statistical analysis and assessment of the published literature. Second, to compare the effect of different cycling environmental temperatures on the egg production characteristics of laying hens. Twenty-nine experiments were selected that had compared different constant temperatures and that included 21°C within their range. Differences in egg production were expressed as a proportion of the treatment group given 21°C within that experiment. An exponential curve with the addition of a linear trend gave the best (P<0.001) description of egg numbers, weight and mass, feed intakes and egg composition variables. There was a linear decrease (P<0.001) in measures of shell strength with increasing temperature. A second statistical analysis compared eight published experiments that had described the egg laying responses of laying hens kept in daily fluctuating temperatures and had been compared to a treatment group kept at 21°C within the same experiment. The results indicated that the egg laying responses of the hens were best predicted by computing the mean of the predicted responses to each of the temperatures that occurred during the day. However, information on the low temperature, the proportion of the day at the low temperature and the amplitude of the temperature cycle were required to give a precise prediction of the egg laying responses.

Dietary levels of chia: Influence on hen weight, egg production and sensory quality, for two strains of hens

1. Laying hens, 225 white and 225 brown, were fed for 90 d to compare a control diet with diets containing 70, 140, 210 and 280 g/kg chia ( Salvia hispanica L.) seed. 2. Hen weight was not significantly affected by diet; however, manure production was less for the hens fed on chia. 3. Egg weight and production, yolk weight, and yolk percentage were determined at d 0, 30, 43, 58, 72 and 90. 4. A sensory evaluation was conducted on eggs produced during the last week of the trial. 5. No significant differences in egg production were found among treatments for the brown hens. 6. With the 280 g/kg chia diet, the white hens produced fewer and lighter eggs than did the hens fed on the control diet. 7. No significant differences were detected in yolk weight until d 90. 8. On this date the yolks produced by the white hens fed on the 70 g/kg chia diet were significantly lighter in weight, whereas the brown hens produced significantly heavier yolks, compared with the hens fed on the control diet. 9. Yolk weight as a percentage of egg weight was lower for white hens throughout the trial except on d 58 with the 140 g/kg chia diet. Significant differences, however, were detected only with the 70 g/ kg chia diet on d 90 and with the 210 g/kg chia die on d 58, 72 and 90. 10. No significant differences in taste preference or flavour were found among any of the chia treatments and the control.

Effects of Housing Type and Breeding System on the Reproductive Capacity of the Red-Legged Partridge (Alectoris rufa)

Current methods of intensive breeding of the red-legged partridge (Alectoris rufa) are based on “industrial” laying practices, including removal and artificial incubation of eggs. These procedures can alter the reproductive behavior and physiology of the birds and, therefore, may not be suitable for use in breeding programs designed to increase wild populations. This study aimed to determine the effects of intensive housing and breeding methods on the laying capacity and reproductive behavior of the red-legged partridge. In Experiment 1, 70 pairs from a commercial game farm were randomly allocated into three treatment groups and placed in differing designs of breeding cages: 8 m2 cages with solid sides (n = 30), 4 m2 cages with solid sides (n = 30), and 4 m2 cages with mesh sides (n = 10). The number of eggs laid was recorded each week. In Experiment 2, 30 pairs, placed in 30 closed 8 m2 cages, were used. Fifteen pairs were birds reared under the intensive system used on game farms, and the other 15 pairs were birds adopted by pairs of foster parents when they were less than 48 h old. The total number of eggs laid during the reproductive period was recorded.In Experiment 1, egg production was greater in pairs housed in 8 m2 cages. There were no differences in egg production between birds housed in closed or open 4 m2 cages. In Experiment 2, the rearing method did not affect egg production. In both experiments, regardless of rearing history or cage type, the numbers of eggs laid were considerably higher than published figures for wild red-legged partridges. This fact, together with the absence of incubation by 100% of the females, indicates the considerable physiological and behavioral modifications that red-legged partridges have undergone due to domestication.

Effect of Supplementation of Two Different Sources of Phytase on Egg Production Parameters in Laying Hens and Nutrient Digestiblity

Hens were fed corn-soybean meal diets containing 0.35, 0.25, 0.15, or 0.10% nonphytate phosphorus (NPP) (40 to 60 wk). Phytases A and B were added at 0.25, 0.15, and 0.10% at 250 to 300 units of phytase (FTU)/kg feed in a 3 × 3 factorial; 0.35% was a control diet. Treatments were replicated with eight cages per treatment (five hens per cage) in a randomized complete block design. Phytase supplementation had a significant effect on several production parameters: feed intake, feed conversion, and egg mass. Results showed nonsignificant effects (P < 0.06) on feed intake when hens were supplemented with phytase A or B and consumed more feed compared to the basal diet at 0.10% NPP. The feed conversion of birds fed 0.10% NPP without phytase was the least efficient compared to the other nine treatments (P < 0.05). Egg mass was significantly greater for hens supplemented with phytases A and B than for hens fed the basal diet at low (0.10%) NPP (P < 0.05). There were no significant differences in egg production, egg weight, specific gravity, Haugh units, wet shell, or dry yolk percentages. Dry shell percentage was higher among basal diets at 0.15 and 0.25% NPP in contrast to phytase, whereas albumen and dry yolk percentages were significantly higher for diets with phytase than for the basal diet at 0.10% NPP. Bone ash percentage was uncharacteristically high in hens fed 0.10% NPP without phytase; however, mortality was 22% in this group. Phytase supplementation improved Ca and P digestibilities to varying degrees. Supplementation of phytase in normal, corn-soybean meal diets improved feed intake, feed conversion, and egg mass and elicited a response in shell quality and egg components at the low (0.10%) NPP.

Reproductive effects and duckling survivability following chronic dosing with tungsten-iron and tungsten-polymer shot in adult game-farm mallards.

Tungsten-iron and tungsten-polymer shot were given conditional approval for waterfowl hunting by the U.S. Fish and Wildlife Service based partly on the results of a 30-day acute toxicity trial utilizing mallards (Anas platyrhynchos). Final approval of the two tungsten-containing shot was contingent on the results of a 150-day study that assessed the health and reproductive effects of tungsten-iron and tungsten-polymer shot in adult mallards. Reproductive data are presented in this paper. Sixteen male and 16 female adult mallards were dosed orally with eight #4 steel shot (control), eight #4 tungsten-iron shot, or eight #4 tungsten-polymer shot on days 0, 30, 60, 90, and 120 of a 150-day trial (26 January 1998 to 25 June 1998). Reproductive performance was assessed during the last 90 days (day 61 to day 150) of the trial. There were no significant differences in egg production and fertility and hatchability of eggs from tungsten-iron- and tungsten-polymer-dosed ducks compared to control ducks. There was no evidence of differences in percent survivability and body weight of ducklings from tungsten-iron and tungsten-polymer mallards compared to ducklings from control ducks. Tungsten-iron or tungsten-polymer shot repeatedly administered to adult mallards during the 150 day trial did not adversely affect reproduction or their offspring.

Stem Cells and Their Progeny Respond to Nutritional Changes during Drosophila Oogenesis

Understanding how stem-cell proliferation is controlled to maintain adult tissues is of fundamental importance. Drosophila oogenesis provides an attractive system to study this issue since cell production in the ovary depends on small populations of observable germ-line and somatic stem cells. By controlling the amount of protein-rich nutrients in the diet, we established conditions under which the rate of egg production varied 60-fold. Using a cell-lineage labeling system, we found that both germ-line and somatic stem cells, as well as their progeny, adjust their proliferation rates in response to nutrition. However, the number of active stem cells does not appear to change. Proliferation rates varied fourfold; the remaining 15-fold difference in egg production resulted from different frequencies of cell death at two precise developmental points: (1) the region 2a/2b transition within the germarium, and (2) stage 8 egg chambers that are entering vitellogenesis. To initiate a genetic analysis of these changes in cell proliferation and apoptosis, we show that ovarian cells require an intact insulin pathway to fully upregulate their rate of cycling in response to a protein-rich diet and to enter vitellogenesis.

A Comparison of Performance and Energy Intake of Commercial Layers Based on Body Weight or Egg Weight

Laying hens were sorted into slight, medium, and heavy groups at 25 wk based on either body weight (BW) or egg weight (EW). They remained in these groups for a 10-wk experimental period. There was no difference in egg production among the three groups. Egg weights, feed consumption (FC), and energy intake increased as the 25-wk BW or EW increased.

A STUDY OF EGG PRODUCTION IN THREE SPECIES OF WOLF SPIDERS (ARANEAE, LYCOSIDAE), PARDOSA AMENTATA,P. PALUSTRIS, AND P. PULLATA IN THE FIELD

Egg production by three species of Pardosa was studied over a 3-year period in a grassland, a fallow field, and a meadow in Northumberland (England).Differences in egg production were found to be related to the size of the female spiders and habitat structures. Influence of localities and egg production in subsequent years are discussed.

Preliminary results of the effect of dietary energy and protein levels on the production of male breeding Ostriches

Main effects only are presented, as no significant interactions were observed. The starting mass of the birds did not differ significantly between dietary treatments. The end mass for the 7.5 MJ energy level and 10% protein level differed significantly (P ≤ 0.05) from that of the 8.5 MJ and 9.5 MJ energy and 12% protein level. The egg production results show a significant difference (P < 0.05) between the lowest energy level of 7.5 MJ and that of the 8.5 MJ and 9.5 MJ level. There was no significant difference in egg-production between energy levels 8.5 MJ and 9.5 MJ or between the different protein levels. A significant difference (P < 0.05) was found in chicken production between energy levels 7.5 MJ, 8.5 MJ and that of energy level 9.5 MJ. The different levels of protein had no effect on the egg-production or chicken production. Neither the energy levels nor the protein levels of the diets had any significant effect on infertile eggs, embryonic deaths or live chicks hatched.

Effect of Acorus calamus (L.) (Araceae) essential oil vapours from various origins on Callosobruchus phaseoli (Gyllenhal) (Coleoptera: Bruchidae)

The toxic effects of vapours of essential oils of Acorus calamus (L.) rhizomes obtained from three countries on the adults and eggs of Callosobruchus phaseoli (Gyllenhal) reared on seeds of Lablab purpureus (Medik.) were studied. All oils were toxic to adults and eggs depending on exposure period and dose. Indian oil showed a strong latent effect, while an acute effect was more dominant in the Yugoslavian oil, followed by Russian oil. Significant reduction of oviposition was found in Yugoslavian and Russian oil vapours at 5 and 10 μl oil per 400 ml jar after 24 h exposure. Longer exposure periods increased the differences in egg production of treated and untreated insects. The fertility of the treated females was little affected. Newly-laid eggs were more susceptible than older ones, Indian oil vapours were the most effective.

New monochromatic light source for laying hens

Artificial illumination is an important factor in the management of layers. In this study, a new monochromatic light system was developed for egg layers. Prelaying pullets (Lohmann) were marked and housed in nine light and temperature control rooms (15 battery cages, 3 hens per cage; n = 45), divided into three light treatments: 0.1 and 0.01 W/m2 light intensity using light emitting diode (LED) lamps and 0.1 W/m2 using mini-fluorescent bulbs (PL) (control). In each of the LED rooms, three wavelengths were tested: 560 (n = 9), 660 (n = 9), 880 (n = 6), and 660 intermitted lighting (15 min light 45 min dark, 660IN) (n = 9). Birds were exposed to 12 h light and 12 h of darkness using PL lamps. At 21 wk of age, the light period was increased to 12.75 h by using 5.5 h of LED lamps and 7.25 of PL light source for Groups 1 and 2, the third group received 12.75 h of PL light. Until 28 wk of age, light hours increased by 0.5 h/w using LED light for Groups 1 and 2 and PL source for the third group, reaching 16 h of light at 28 wk of age. Egg production and feed consumption were recorded daily; egg components were recorded weekly for 10 mo. A significant reduction in egg production was observed in all 880nm groups; no differences in egg production and quality were found in the other groups. Feed consumption was significantly lower by 7% in all 0.01 W/m2 groups. We suggest that an important reduction in rearing costs of laying hens may be obtained by using this system.

Growth of Juveniles and Egg Production of Mummichogs Fed Different Diets in the Laboratory

Abstract This study was designed to evaluate the effectiveness of six diets to promote growth, survival, and egg production in juvenile mummichogs Fundulus heteroclitus reared in the laboratory. Fish were fed one of six diets—nauplii of brine shrimp Artemia sp. (24 h posthatch), frozen brine shrimp, BioTrainer, Salomon Moist, TetraMin, or Canadian Moist—for 33 weeks. The instantaneous growth rate in mummichogs changed significantly (analysis of variance, P < 0.05) between diet treatment and over time. TetraMin and Canadian Moist produced the lowest growth overall. Survival was high for fish fed brine shrimp nauplii, frozen brine shrimp, BioTrainer, and TetraMin. There were no significant differences in egg production on the basis of total female weight. Brine shrimp nauplii, frozen brine shrimp, BioTrainer, and Salomon Moist promoted the best growth; brine shrimp nauplii, frozen brine shrimp, BioTrainer, and TetraMin promoted the best survival. Fish size rather than diet affected total egg production. Processed diets high in animal protein that contained added flavor enhancement promoted better growth in juvenile mummichogs than diets made of plant and animal products.

Reproduction and polychlorinated biphenyls in Fundulus heteroclitus (Linnaeus) from new bedford harbor, massachusetts, USA

AbstractThis investigation evaluated polychlorinated biphenyl (PCB) accumulation, survival, and reproduction in Fundulus heteroclitus from four stations along a gradient of increasing sediment contamination from West Island in Buzzards Bay, Massachusetts, USA, to the most contaminated area of the New Bedford Harbor, Massachusetts, USA, Superfund site. Fish collected during their natural spawning season were held in the laboratory for 5 weeks. Liver concentrations of non‐ortho‐ and mono‐ortho‐PCBs averaged 0.461, 9.48, 20.8, and 29.3 μg/g dry weight, with dioxin toxic equivalent concentrations (TEQs) of 0.006, 0.132, 0.543, and 1.56 ng/g; differences among stations were statistically significant. Females from two stations within the Superfund site had significantly greater mortality (30 and 23%) compared to those within West Island (0%), and growth was reduced. Progeny of fish from the most contaminated station exhibited significantly reduced survival (49%) and greater incidence of spinal abnormalities (26%) compared to those from West Island (70% survival, 7% spinal abnormalities). No differences in egg production or food consumption were observed. A significant residue‐effect relationship was found between TEQs of liver PCBs and female mortality, consistent with that determined previously from laboratory exposures and validating TEQ as an effects indicator. Embryo and larval survival were inversely related to maternal liver TEQ.

Nutrition and the regulation of egg production in the Calanoid copepod Acartia tonsa

The nutritional composition of the copepod diet is determined by the feeding response, often through complex interactions with the food environment. On the time scales at which studies of copepod feeding and egg production are typically conducted (hours to weeks), variations in the nutritional composition of the food supply may be responsible for considerable variability in egg production. A substantive portion of this variability can be accounted for when the nutritional composition of the diet is known. In a laboratory study in which we measured the amino and fatty acids in the diet of Acartia tonsa in six “food environments,” we detected differences in egg production that were apparently associated with amino acid deficiency, differences in the proportions and types of fatty acids in the diet, and differences in the kinds of food organisms taken from a mixture and in the effort required to capture a ration. Egg production varied systematically with the concentrations of 3 fatty acids (of 18 present in the diet) and 4 amino acids (of 16 present) in the diet.

A Life Table for the fresh water mollusc Bithynia tentaculata (L.)

Bithynia can be collected in fairly large numbers and may be measured by weighing. Probability paper can be used to separate year groups. Bithynia can be cultured in the laboratory. Year groups can be isolated to study differences in egg production. This data together with data from probability paper analysis can be used to construct a life table. The development of embryonic snails can be studied while still in the egg case. The analyses are sufficient to enable a general picture of the life cycle to be gathered with regard to the interaction of egg production versus gain in biomass. The method could be applied to other species of freshwater mollusc.

Effects on white Leghorn hens of constant exposure to ultraviolet light from insect traps

Constant exposure of Hy-Line W-36 White Leghorn hens to ultraviolet light from insect traps resulted in no significant differences in egg production, fertility, hatchability of fertile eggs, or total hatchability. Also, there were no apparent effects on the eyes of the birds. Results were the same when either blacklight or blacklight blue tubes were used. The need for additional testing of light traps for nuisance fly control in commercial caged layer houses is discussed.

The Effect of L-Lysine Intake on Egg Component Yield and Composition in Laying Hens

Currently, 24% of the total U.S. egg supply is consumed as liquid egg product (LEP). In addition to egg weight and size, the commercial value of LEP is a function of percentage solids. The influence of L-Lys on LEP, the texture profile analysis of heat formed albumen and yolk gel plugs, and yolk emulsion separations was examined in two experiments. In Experiment 1, 108 layer hens (42 wk of age) were fed three sorghum-soybean diets with Lys levels ranging from 677 to 1613 mg per hen per d (mg/HD). In Experiment 2, 108 layer hens (23 wk of age) were fed four sorghum diets with Lys levels ranging from 638 to 1165 mg/HD.In Experiment 1, Lys intake of 1,613 compared to 677 mg/HD significantly increased albumen weight, solids, and protein and egg weight. There were no significant differences in egg production, feed consumption, or yolk weight, protein, and solids. In Experiment 2, Lys intake of 1,165 mg/HD resulted in significantly lower feed consumption, nutrient intake, and egg production. Lysine intake of 1,062 compared to 638 mg/HD resulted in significantly greater albumen solids, protein, and hardness, and egg production. Lysine intake of 828 compared to 638 mg/HD resulted in significant increases in yolk weight, protein, hardness, and emulsion separations. Lysine intakes of 1,062 mg/HD resulted in most yolk parameters returning to levels observed at 638 mg/HD. There were no significant differences in egg weight or yolk solids. This increased understanding of the influence of L-Lys on LEP parameters offers economic benefit to liquid egg producers.

Influence of Trichoderma viride Enzyme Complex on Nutrient Utilization and Performance of Laying Hens in Diets With and Without Antibiotic Supplementation

The experiment was designed to test possible interactions of an enzyme complex (product from Trichoderma viride) and a feed antibiotic (flavophospholipol) in a barley diet on metabolism variables and egg production performance of Warren Brown laying hens. The basal diet contained 40% winter barley (French cultivar “Express”, six-row). The four treatments were as follows: O, control (without supplement); E, enzyme complex, 600 ppm; A, flavophospholipol, 10 ppm; EA, enzyme complex, 600 ppm and flavophospholipol, 10 ppm. The enzyme complex contained the following main activities: cellulase (10,500 U/g), endo-β-(l:3)(l:4)-glucanase (24,000 U/g), and xylanase (32,000 U/g). The enzyme positively influenced AME content of the feed, organic matter (OM) utilization, and neutral detergent fiber (NDF) degradability (P ≤ 0.01). When supplemented alone, the antibiotic had no influence on energy and nutrient utilization. No significant differences in egg production due to dietary treatments were observed.A significant enzyme by antibiotic interaction for AME (P ≤ 0.01) and OM utilization (P ≤ 0.001) as well as NDF degradability (P ≤ 0.01) indicated a reduced enzyme effect in the diet containing antibiotic. Negative enzyme by antibiotic interaction for energy utilization in laying hens suggested that the positive response to dietary enzyme supplementation in the mature laying hen (Treatment O vs E) was to great extent mediated by the activity of intestinal microbes.