Egg Color Research Articles

Thin‐film iridescence in the eggshell of a stick insect (Myronides glaucus)

AbstractColours in nature can be pigmentary, structural or a combination of both. The prevalence, function and nanostructural origin of structural coloration in eggs is largely unknown. Stick and leaf insect eggs display a wide variety of colours, most of which are produced by pigments. The eggs of Myronides glaucus (Phasmida: Lonchodidae; Hennemann, 2021), however, show a clear purple to green iridescence. Here, we use micro‐spectrophotometry, Fourier‐transform infrared reflectance, transmission‐ and scanning electron microscopy, atomic force microscopy, finite‐difference time‐domain optical simulations and experimental approaches to elucidate the mechanism for iridescence in M. glaucus eggshells, which together reveal that iridescence is caused by thin‐film interference by a 200‐ to 450‐nm‐thick outermost layer. These results highlight the diversity of phasmid eggs and the need to study the different mechanisms and functions of structural coloration.

Cultural Perspectives on the Sustainable Use and Added Value of Plant-Based Food Dyes—A Case Study from Bulgaria

Raised personal health awareness and social environmental responsibility put pressure on the agri-food industry to adopt more sustainable ways of production, including the use of more natural ingredients, reducing waste, conservation and the regeneration of resources and energy. Plant-based colorants are ecologically friendly alternatives to artificial food dyes, especially with regards to the current reports on the adverse effects of some of the latter on human health. Various plants are traditionally used by many cultures to obtain vivid food coloration; however, the knowledge and means to produce them becomes less and less accessible to urbanized societies, and affordable organic alternatives are not always available on the market. An online questionnaire was performed to explore the awareness on plant-based dyes and pro-environmental attitudes of Bulgarian customers through the lens of Orthodox Easter eggs dyeing and the obtaining of plant dyes. From a total of 294 adult participants, only 5% reported a strict preference for natural dyes, while more than half of them (54%) were found to use natural and artificial ones concomitantly or switching between both. Of 45 plant taxa used for egg coloration, 12 were most frequently cited with many new additions of imported plants. Most of the used plant-based dyes were common fruits, spices, herbal infusions and even food waste like onion peels and avocado pits that were readily available from home gardens, markets and food shops. Additionally, we made a review of the scientific literature regarding their antioxidant and antimicrobial activity against food spoilage bacteria and foodborne pathogens isolated from eggs. All frequently used taxa were reported to exhibit antibacterial activities against Gram-positive and Gram-negative bacteria and possess antioxidant activity due to the presence of various polyphenols, essential oils and other compounds. Grape and red wine, roselle and stinging nettle are the species with the most diverse antibacterial activity, effective against 15 out of the 16 bacterial species of spoilage and foodbourn microorganisms included in our focus. The antimicrobial activities, however, were found mostly tested against bacterial strains in vitro, and further studies are needed to confirm their potential antibacterial activity when applied to Easter/boiled eggs or other food products. Our findings suggest that traditional cultural practices, as a multifaceted and engaging phenomenon, have the potential to promote environmental responsibility and a healthy lifestyle using both contemporary and traditional knowledge.

Performance, Egg Quality, and Composition in Isa Brown Laying Hens Fed with Different Levels of Desmodium tortuosum Leaf Flour.

The objective of this study was to investigate the effects on laying performance, egg quality traits, color, and composition of supplementing a white corn-based diet with Desmodium tortuosum leaf flour. Three hundred 32-week-old hens were distributed to 30 pens of 10 hens each and allocated to six dietary treatments (five replicates per treatment) for 13 weeks. Two control groups of 50 hens received one of either diet Y, based on yellow corn, or diet W, based on white corn. The other groups received a diet based on white corn supplemented with Desmodium tortuosum leaf flour at 2.5%, 5%, 7.5%, or 10% (diet D). Diet D improved laying performance and yolk color at a reduced feed cost per egg but had no effect on cholesterol content. In conclusion, the inclusion of Desmodium tortuosum leaf flour, in a white corn-based diet, is effective in lowering feed cost, increasing egg production, and improving yolk color.

Impact of High-Dose Supplemental Paprika Extract Feeding on Egg Storage and Biochemical Parameters in Laying Hens.

This study aimed to evaluate the effects of paprika extract supplementation on egg storage and blood biochemical parameters in 63-week-old Rhode Island Red (RIR) and Silky Fowl (SF) hens. The hens were divided into three groups: a control group with a basal diet and two groups receiving the basal diet with paprika extract. The trial lasted 28 days, with egg quality (yolk color and albumen pH) assessed after storing eggs at 25 °C for 21 days. A total of 144 eggs were used in 42 treatments (two breeds, three diets, and seven storage periods) with three eggs examined each (four eggs were used on day 0 and five eggs on day 21). Additionally, the yolk carotenoid content, yolk color, and pH of eggs stored at 4 °C and 25 °C were compared. Results showed that yolk color fan score (YCFS) decreased with storage, and SF had a higher albumen pH than RIR, with both breeds exhibiting an increase in pH over time. HDL cholesterol (HDL-C) levels and the HDL-C to total cholesterol ratio were significantly influenced by breed, diet, and their interaction. The HDL-C level in SF was affected linearly and quadratically by diet, while no such trend was observed in RIR. The study concluded that paprika extract affects egg quality and blood lipid profiles differently in different breeds, highlighting breed-specific responses to dietary supplementation.

Shining a Light on the Specimen Room: Enhancing Global Research on Bird Eggs through Standardized Digital Archives

Bird egg collections in natural history museums are valuable resources for studies such as how birds’ eggs may evolve under different environmental conditions, providing information that is critical in our changing world and of great interest to scientists. However, the millions of bird egg specimens, many collected over 100 years ago, are often not prioritized in digitized archives. To assess the current status of digitized egg specimens, we examined data available on open-source platforms such as iDigBio, based on the Marini et al. (2020) review of egg collections. Millions of bird egg specimens are preserved in museums worldwide, but only about 21% have been digitally cataloged and made accessible on global platforms, mostly from Western countries. While the technology used for extracting features from digital objects has greatly advanced for studying the size, color and spottiness of eggs (e.g., SpotEgg), the digitized specimens may not be formatted to meet the needs for research, thereby limiting their application. For example, among eight museums with digitized collections, images from six include a scale, but only the Yale Peabody Museum also incorporates a color chart with standardized gray patches for calibration (e.g., Calibrite Color Checker). Furthermore, coordinates obtained through georeferencing are essential for studying environmental influences on egg traits. Yet, fewer than half of the specimens (49%) have been georeferenced. Here we demonstrate how properly digitized specimens—using a dark background, adding a scale, and incorporating a standard color chart in the photo—can be utilized to study the evolution of egg color in birds. We urge the adoption of a standard digitization protocol for bird egg collections, the enhancement of georeferencing for the specimens, and the integration of local databases into global platforms to increase accessibility for the scientific community. These procedures should also be implemented at the early stage of the digitization process to maximize the value of digitized specimens.

Ground-nesting birds learn egg appearance to guide background choice for camouflage

Camouflage is vital for the survival of many prey species1,2, including ground-nesting birds3,4,5,6. Egg camouflage via background matching and disruptive coloration (high contrast markings that break up the body outline) is often behaviourally mediated by selecting substrates that enhance egg camouflage1,2,3,4,5,6. However, the mechanisms controlling this behaviour in birds have remained unknown. Several, not mutually exclusive, mechanisms have been suggested to control background choice for egg camouflage7. These include where individual background preferences are genetically linked to egg coloration, enabled through learning egg appearances from previous breeding attempts, or modified by imprinting on visual backgrounds during early life7, Here, using predator vision models, we compared the camouflage of Japanese quail (Coturnix japonica) eggs among females who were allowed to choose one of four coloured substrates on which to lay3. Birds were divided into experienced females who had been given the opportunity to observe the appearance of their eggs, versus naïve females breeding for the first time. Our experiment revealed that breeding experience leads to improved background choices made for egg background matching. However, substrate choice for disruptive coloration appeared genetically determined, as both bird groups chose backgrounds that enhanced egg disruptiveness regardless of experience. These mechanisms underpin behaviours that are likely essential for birds and other animals to optimise camouflage and avoid predation6.

Phylogenetic variations in a novel family of hyperstable apple snail egg proteins: insights into structural stability and functional trends.

The relationship between protein stability and functional evolution is little explored in proteins purified from natural sources. Here, we investigated a novel family of egg proteins (Perivitellin-1, PV1) from Pomacea snails. Their remarkable stability and clade-related functions in most derived clades (Canaliculata and Bridgesii) make them excellent candidates for exploring this issue. To that aim, we studied PV1 (PpaPV1) from the most basal lineage, Flagellata. PpaPV1 displays unparalleled structural and kinetic stability, surpassing PV1s from derived clades, ranking among the most hyperstable proteins documented in nature. Its spectral features contribute to a pale egg coloration, exhibiting a milder glycan binding lectin activity with a narrower specificity than PV1s from the closely related Bridgesii clade. These findings provide evidence for substantial structural and functional changes throughout the genus' PV1 evolution. We observed that structural and kinetic stability decreased in a clade-related fashion and was associated with large variations in defensive traits. For instance, pale PpaPV1 lectin turns potent in the Bridgesii clade, adversely affecting gut morphology, while giving rise to brightly colored PV1s providing eggs with a conspicuous, probably warning signal in the Canaliculata clade. This work provides a comprehensive comparative analysis of PV1s from various apple snail species within a phylogenetic framework, offering insights into the interplay among their structural features, stability profiles and functional roles. More broadly, our work provides one of the first examples from natural evolution showing the crucial link among protein structure, stability and evolution of new functions.

Low evolutionary potential for blue-green egg colouration in a wild bird population.

Exploring the evolutionary architecture of female sexual traits and their potential evolvability is important to understand their possible role as post-mating sexual signals. Egg colouration has been proposed to be one of these post-mating sexual signals, honestly advertising female quality in birds, especially in blue-green laying species. In this study, we used an animal model in a Bayesian framework to estimate the evolvability of multiple descriptors of blue-green egg colouration and egg size in a wild long-term monitored population of spotless starlings (Sturnus unicolor). Our results show low to moderate heritability (h2 = 0.31 - 0.44) for three egg colour descriptors (blue-green chroma, chroma and lightness) and egg size. Using the coefficient of additive genetic variance (CVA) and the evolvability (IA) as proxies of evolutionary potential of all components of this trait, we found low values of CVA for all these variables, suggesting a small evolutionary potential of these phenotypic traits, contrasting to previous results reported in another blue-green egg laying species. Our results indicate a modest raw genetic material of this trait on which sexual selection can act upon and, therefore, a small probability for these traits to respond easily to selection.

The Sensory Characteristics of Eggs Enriched With the fish and Linseed Oil

This research investigates the effect of fish and linseed oils supplemented to the laying hens’ feed on the sensory characteristics of table eggs. The experiment was performed on 480 laying hens of TETRA SL hybrid, which were divided into three groups (K: 5 % of soybean oil, P1: 1.5 % of fish oil and 3.5 % of linseed oil, and P2: 2 % of fish oil and 3% of linseed oil). A sensory analysis of eggs was comprised of an assessment of egg color, smell, taste, and texture and was performed by a panel of tasters (n=52) who administered the triangle test and the hedonic test. The panel determined that there was a significant difference (P<0.05) in taste of eggs between the treatment pairs K: P1 and K: P2 but no significant difference between the treatment pair P1: P2. The most frequently detected difference between the treatment pairs referred to the taste, then to color and smell, and the difference in egg texture between the pairs was not represented that much. An increased amount of fish oil in the hens’ diet increased a sensory perception of egg smell and decreased a sensory perception of taste. The egg taste liking differed significantly between the treatments (P<0.05). Referring to the sensory characteristics of likability of color and odor of eggs, there were no significant differences (P>0.05) determined between the treatments.

Heavy metal pollution exposure affects egg coloration but not male provisioning effort in the pied flycatcher Ficedula hypoleuca

Heavy metal pollution is known to negatively affect numerous traits in birds, including foraging, metabolism, immunity, and reproductive success. In this study, our primary aim was to assess the impact of metal pollution exposure on the visual appearance of the pied flycatcher Ficedula hypoleuca eggs. Specifically, we focused on blue‐green biliverdin‐based coloration, a trait expected to function as a signal of female quality to males. In line with the sexually selected egg coloration (SSEC) hypothesis, which posits that males respond to more intensely colored eggs by increasing their provisioning effort, our second objective was to investigate whether metal pollution exposure affects this specific signaling mechanism and subsequent male behavior. Our results showed that although coloration did not correlate with female quality or male provisioning effort, egg blue‐green coloration decreased in polluted areas compared to non‐polluted control areas. Our analysis of reflectance data revealed that this difference was due to an increased ultraviolet reflectance of eggs from polluted areas, likely caused by changes in eggshell microstructure (e.g. porosity). We therefore propose that metal pollution exposure may compromise crucial color signals of bird eggs. Avian visual modeling indicated that eggs laid by different flycatcher females are generally very similar, making discrimination by males challenging and perhaps impossible especially in dark cavities. Overall, our results suggest that the SSEC hypothesis may lack adaptive relevance for the pied flycatcher in northern Europe, even in environments influenced by anthropogenic activities.

Estimating yolk weight of duck eggs using VIS-NIR Spectroscopy and RGB images and whole egg weights

Duck eggs are widely-consumed food and cooking ingredient. The heavier yolk weight (YW) corresponds to a larger size and greater value. However, there is no non-destructive method available to estimate the weight of the yolk. Accurate weight prediction of duck egg yolks must combine both phenotypic and internal information. In this research, we used Visible-Near Infrared (VIS-NIR) spectroscopy to obtain internal information of duck eggs, and a high-definition camera to capture their phenotypic features. YW was predicted by combiningthe reduced spectral and RGB image information with the whole egg weight. We also investigated the impact of color and thickness of the duck egg on spectral transmittance (ST), as these factors can influence the extent of ST. The results showed that the spectral curves of duck eggs produced two peaks and one valley, which may be caused by the dual-frequency absorption of the C-H group and O-H group, and can be used to symbolize the internal information of duck eggs. The ST was somewhat affected by the color and thickness of the duck eggshell. Before modelling, Principal Component Analysis (PCA) was used to significantly reduce the dimensionality of the RGB image with spectral data. A Partial Least Squares Regression (PLSR) model was utilized to fit all the features. The test set yielded a coefficient of determination (R²) of 0.82 and a Root Mean Squared Error (RMSE) of 1.05 g. After removing the eggshell's color and thickness features, the model showed an R² of 0.79 and an RMSE of 1.11 g. This study demonstrated that the yolk weight of duck eggs can be estimated using VIS-NIR spectroscopy, RGB images and whole egg weight. Furthermore, the effects of shell color and thickness can be neglected.

Enhancing the Quality and Sensory Characteristics of Native Chicken (Gallus gallus) Eggs Using Natural Additives

The study examines the effect of natural egg enhancers on the quality and sensory attributes of native chicken eggs. The research was conducted in Lagangilang, Abra, Philippines, involving 96 native chickens that were fed with different egg enhancers, including pure formulated feed with no additives, commercial egg enhancer, annatto seed powder, turmeric powder, and red-hot pepper powder at 1% level. The results showed that the egg yolk weight, albumen weight, and eggshell thickness were not significantly different among the treatments. However, yolk color was significantly different among the treatments, with annatto seed, turmeric, and red-hot pepper treatments rated as dark yellow having significantly higher yolk color compared to the control and commercial treatments. The study also found that the coloring content agent of egg enhancers, such as annatto seed, turmeric, and red-hot pepper, can improve the yolk color of eggs by providing carotenoids and other antioxidants to the birds. This is important because consumers often prefer eggs with a darker yolk color. The study also evaluates the sensory evaluation of senior high school students, college students, and faculty on native chicken eggs given with egg enhancers. The results indicate that there were no significant differences in appearance, flavor, aroma, aftertaste, and general acceptability among the treatments with a descriptive rating of “like moderately” based on the hedonic scale.

Allantoic Fluid-Based qPCR for Early Onset In Ovo Sexing.

The day-old male chick culling remains a welfare issue in the poultry industry. Several governments have prohibited this practice, pushing hatcheries to seek alternatives. Although different solutions exist for solving this problem, sex determination during the embryo's incubation (in ovo sexing) is considered the most suitable one among the consumers and industry. However, to be industrialized, in ovo sexing technologies must meet several requirements: compatibility with all egg colors and early developmental stages while maintaining a high hatchability rate and accuracy at low cost and high throughput. To meet these requirements, we studied the use of the sexual genes HINTW (female-specific) and DMRT-1 (both sexes) at incubation days 6-9. By utilizing the quantitative polymerase chain reaction in allantoic fluid (AF) samples, our study confirmed female-specific HINTW detection on all days without any significant detrimental effects on embryo development. We achieved 95% sexing accuracy using the HINTW cycle threshold (Ct) alone and 100% accuracy rate when using Δλ values (difference between the HINTW and DMRT-1 Ct). In conclusion, the developed assay can provide information about AF as a sample for in ovo sexing and open new industrial possibilities for faster and cheaper assays.

Breeding biology of the Ochre-breasted pipit (Anthus nattereri), with notes on its conservation in the Upper Rio Grande Grasslands, south-eastern Brazil

ABSTRACT The Ochre-breasted pipit Anthus nattereri is a terrestrial bird restricted to natural grasslands of south-eastern South America. The species is globally Vulnerable to extinction and its natural history is still poorly known. We investigated the breeding biology of Ochre-breasted pipits, commenting on its habitat use and the potential impacts of local grasslands management practices with fire on the species’ conservation. Fieldwork took place mainly between January and December 2016 in the Upper Rio Grande Grasslands, south-eastern Brazil. Five nests of the species were found between September and November, one of them recently destroyed by fire. Nests were cup shaped and placed on the ground, being built with dry grasses, resembling the pattern documented for other species of Anthus. The eggs were covered with brownish spots and dots to a variable extent and the background colour ranged from greyish white to brownish white. The egg colour pattern also fell within the known range of variation for congeneric species, as did the clutch size (two to three eggs) observed in tropical species of Anthus. Ochre-breasted pipits tended to occupy nesting sites with higher and denser grass cover (eg small patches of vegetation that survived the last fire event) when compared to non-nest sites located in adjacent recently burned areas, which potentially suggests a preference for such habitat attributes. Although the Ochre-breasted pipit is relatively common in the study area, the highest temporal incidence of fire coincides with its breeding season, which can directly impact the local population through the burning of nests and the elimination of suitable nesting sites. Thus, it is important to conduct long-term studies to evaluate the impact of different fire regimes on the reproductive performance of Ochre-breasted pipits, thus allowing the design of better ecosystem management practices to guarantee its conservation.

Effects of dietary supplementation of polysaccharide from Agaricus blazei Murr on productive performance, egg quality, blood metabolites, intestinal morphology and microbiota of Korean quail.

This study aimed to investigate the effects of dietary supplementation with Agaricus blazei polysaccharide (ABP) at varying concentrations on the performance, egg quality, blood biochemistry, intestinal morphology, and microflora of quail. The study involved a total of 2,700 Korean quails, which were randomly divided into three groups. The measured variables encompassed productive performance, egg parameters, carcass parameters, serum metabolites, immune response parameters, antioxidative properties, and gut microbiome. The addition of ABP did not have a significant effect on average daily feed intake. However, it was found to increase the average daily egg weight and egg production rate, reduce the feed-egg ratio. There were no significant impacts on egg quality measures such as egg shape index, egg yolk index and color, egg yolk and protein content. However, ABP supplementation significantly increased the Hough unit (p<0.01) and decreased the rate of unqualified eggs (p<0.01). Regarding serum parameters, the inclusion led to an increase in total protein concentration (p<0.05) and a reduction in low-density lipoprotein cholesterol (p<0.05). There were no significant effects observed on immune indicators such as immunoglobulin A (IgA) and IgM. ABP supplementation increased the levels of serum antioxidant indicators, including glutathione peroxidase, total superoxide dismutase (p<0.05), and total antioxidant capacity colorimeter (p<0.05). Furthermore, ABP supplementation significantly elevated the intramuscular fatty acid content in quail meat. Additionally, ABP supplementation demonstrated a significant improvement in the diversity of gut microbiota and induced alterations in the composition of the gut microbiota. The findings of this study indicate that dietary supplementation of ABP enhanced production performance and antioxidant capacity while increasing the levels of polyunsaturated fatty acids in quail muscle.

Dietary inclusion of micelle silymarin enhances egg production, quality, and lowers blood cholesterol in Hy-line brown laying hens.

This study aimed to evaluate the effect of micelle silymarin (MS) supplementation on productive performance, egg quality, and blood biochemical parameters in laying hens. A total of 384 (Hy-Line brown, 28-week-old) laying hens were randomly distributed into one of four dietary treatment groups (eight replicationper treatment; 12 hens per replicate) for a 12-weeklong feeding trial. Hens were fed a basal diet with the addition of 0%, 0.02%, 0.04%, and 0.06% of MS respectively. The results expressed that egg production percentage and egg weight were linearly (p < 0.05) enhanced at Weeks 0-6, 7-12, and 0-12, when 0%, 0.02%, 0.04%, and 0.06% of MS were added to laying hen diets. The feed conversion ratio and feed intake improved (p < 0.05) linearly at Weeks 0-6, 7-12, and 0-12 with increasing levels of MS supplementation in laying hens. The eggshell thickness and eggshell strength were linearly (p < 0.05) improved at weeks 4, 8, and 12 with an MS-supplemented diet. Additionally, eggshell colour, Haugh unit, and albumin height had no significant (p > 0.05) difference throughout the experimental period with different levels of MS-supplemented diet. The yolk colour of eggs showed significant (p < 0.05) differences at weeks 8 and 12 with levels of the MS-supplemented diet. However, at the end of the trial, the blood profile indicated that cholesterol levels decreased (p < 0.05) linearly, and triglyceride levels showed a tendency to decrease (p < 0.10) with MS supplementation. In conclusion, increasing the level of MS addition in the laying hen diet improved the egg production percentage and egg quality, reducing cholesterol levels in Hy-Line brown hens. However, this study indicates that MS can be added to the diet of laying hens up to 0.06% for improved egg production and egg quality.

Effects of replacing Na selenite in laying hen feed with selenized glucose on production performance, egg quality, egg selenium content, microbial population, immunological response, antioxidant enzymes, and fatty acid composition

This study aimed to explore the effects of selenized glucose (SeGlu) and Na selenite supplementation on various aspects of laying hens such as production performance, egg quality, egg Se concentration, microbial population, antioxidant enzymes activity, immunological response, and yolk fatty acid profile. Using a 2 × 2 factorial design, 168 laying hens at 27-wk of age were randomly divided into 4 treatment groups with 7 replications. Se source (Na selenite and SeGlu) and Se level (0.3 and 0.6 mg/kg) were used as treatments. When 0.3 mg SeGlu/kg was compared to 0.3 mg Na selenite/kg, the interaction findings revealed that 0.3 mg SeGlu/kg increased egg production percent and shell ash (P < 0.05). When compared to 0.3 mg Na selenite/kg, dietary supplementation with 0.3 and 0.6 mg SeGlu/kg resulted in an increase in albumen height, Haugh unit, and yolk color of fresh eggs (P < 0.05). SeGlu enhanced albumen height, Haugh unit, shell thickness (P < 0.01), albumen index, yolk share, specific gravity, shell ash (P < 0.05) of fresh eggs and shell thickness (P < 0.05) of stored eggs as compared to Na selenite. The interaction showed that 0.6 mg SeGlu/kg enhanced yolk Se concentration while decreasing malondialdehyde levels in fresh egg yolk (P < 0.05). SeGlu enhanced Se concentration in albumen and glutathione peroxidase activity in plasma (P < 0.05) as compared to Na selenite. 0.6 mg Se/kg increased lactic acid bacteria, antibody response to sheep red blood cells, and lowered ∑n-6 PUFA/ ∑n-3 PUFA ratio (P < 0.05). As a result, adding SeGlu to the feed of laying hens enhanced egg production, egg quality, egg Se concentration, fresh yolk lipid oxidation, and glutathione peroxidase enzyme activity.

Plumage and eggshell colouration covary with the level of sex-specific parental contributions to nest building in birds

Interspecific variation in sex-specific contributions to prenatal parental care, including avian nest building, is becoming increasingly better understood as we amass more information on more species. We examined whether sex-specific nest building contributions covary with the colouration of parents and their eggs in 521 species of Western Palearctic birds. Having colourful plumage and laying colourful eggs are costly because of the deposition of pigments in feathers and eggs and/or forming costly nanostructural substrates in feathers, and so it might be expected that those costs covary with the costs of nest building at the level of individuals and/or across species to produce of a suite of codivergent traits. Using a phylogenetically informed approach, we tested the hypothesis that species in which females alone invest energy building nests exhibit less sexual plumage dichromatism. However, we found comparative support for the opposite of this prediction. We then tested that species in which females alone build nests lay more colourful, and costlier, eggs because the dual costs of building nests and laying colourful eggs can only be borne by higher quality individuals. As expected, we found that species in which females build nests alone or together with males are more likely to lay colourfully pigmented eggs relative to species in which only males build nests. Finally, stochastic character mapping provided evidence of the repeated evolution of female-only nest building. Interspecific sex differences in plumage colouration therefore covary in a complex manner with female pre- (nest building) and post-copulatory (egg production) investment in reproduction.

Use of Cactus Pear Meal in the Feeding of Laying Hens in Semi-Intensive System.

Little information is available in the literature on the use of cactus pear meal (CPM) in poultry diets; therefore, it is important to evaluate diets that provide excellent performance and lower production costs. Our objective was to study the use of Miúda CPM in the diets of laying hens. In the first study, two diets for male and female chicks were used-1: 80% reference diet + 20% Miúda cactus pear meal (CPM) and 2: 80% reference diet + 20% Gigante cactus pear meal (CPM). The variety Miúda provided a better use of metabolizable energy, as well as a greater digestibility coefficient of dry matter, protein, and mineral matter. In the second study, a control diet was compared to three diets with different levels of Miúda CPM for laying hens in the proportions of 3%, 6%, and 9%. No significant differences were found in productive performance. However, there were significant differences in the some parameters egg quality, texture and color profile of the cooked yolk, egg composition, fatty acids and cholesterol in the yolk. It is possible to use 9% Miúda CPM in the diet of laying hens in a semi-intensive system that does not compromise performance and egg quality, and using 3% Miúda CPM provides a higher economic return.

Molluscicidal Activity of Entomopathogenic Fungus, Metarhizium Anisopliae (Hypocreales: Clavicipitaceae) Against Golden Apple Snails, Pomacea Canaliculata (Architaeniglossa: Ampullariidae)

Golden Apple Snails (GAS, Pomacea canaliculata) is known in Malaysia as one of the world's worst invasive pest species, wreaking havoc on paddy fields by lowering rice yield dramatically. Farmers now employ chemical molluscicides to eliminate GAS, but these are expensive and have serious health and environmental consequences. Biological control agent using entomopathogenic fungus is preferred over chemical molluscicides to control GAS because it is non-toxic, environmentally friendly and cost-effective. This study is aimed to investigate the molluscicidal activity of an entomopathogenic fungus, Metarhizium anisopliae towards GAS adults and eggs. M. anisopliae conidia were subsequently produced into four concentrations (3×104, 3×105, 3×106, and 3×107 conidia/mL) and tested against adults and eggs GAS. The median lethal time (LT50) for the concentration of 3×107 took 5 and 3 days to kill 50% of GAS adults and inhibited 50% of eggs from hatching, respectively. Physiological analysis was also conducted on both GAS adults and eggs. The skin of infected individuals became white and opaque, while internal organs such as the pulmonary sac, digestive tract, and hepatopancreas were visibly destroyed. The colour of GAS eggs turned pale after M. anisopliaeinfestation and resulted in non-viable eggs. This research shows that M. anisopliae is an effective biological control agent for GAS and has the potential to be used as a targeted bio-molluscicide for GAS management.