Yolk Composition Research Articles

Evaluation of equine semen frozen in extenders free of animal proteins

Various countries are reticent regarding importation of semen that contains egg-yolk, limiting its commercialization. Egg-yolk composition is complex, varying with the diet of the chicken and egg-yolk granules are similar in size to sperm, interfering with analysis. Therefore, development of a chemically defined cryopreservation extender that maintains seminal parameters is relevant. Twelve ejaculates from 4 stallions of proven fertility (n= 4; r=3) were diluted in one of 5 extenders: 1) EDTA-glucose with 11% lactose, Equex, 20% egg-yolk and 5% dimethylformamide (EY); 2) casein salt and cyclodextrin cholesterol extender (CE); 3) CE with 3% dimethylformamide (CE-3); 4) OptiXcell (OP); 5) BioXcell (BIO). Cryopreservation was carried out in a Cryogen, Neovet automatic freezing machine: -0.5°C/minute to 5°C, 180 minutes equilibration, then -5°C/minute to -20°C and -20°C/minute to -100°C, then plunging in N2. Thawing was carried out at 37°C for 1 minute and sperm kinematic parameters (CASA, AndroVision, Minitube), viability and acrosome status (FITC-PNA-PI stain), membrane lipoperoxidation (BODIPY stain) and DNA fragmentation (SCD) were evaluated. Data were analyzed using ANOVA or Friedman test and results are reported as mean ± SD. Higher (P<0.05) percentages of total and progressively motile sperm were observed in samplescryopreserved in EY (29.25 ± 11 and 21.17 ± 10), CE-3 (30.4 ± 15 and 22 ± 12) and OP (23.1 ± 14 and 15.5 ± 10) compared to those in CE (4.75 ± 3 and 1.58 ± 2) and BIO (8 ± 4 and 3.25 ± 3). Straight-line, curvilinear and average-path velocity parameters, amplitude of lateral head and beat-cross frequency were significantly higher in samples frozen with EY, CE-3 and OP compared to CE and BIO media. Straight-line and average-path velocities were also significantly higher in OP compared to EY medium. Live acrosome-intact sperm were significantly higher in EY (45 ± 14) compared to the rest of the extenders; with CE-3 (25 ± 10) being significantly higher than CE (8 ± 5), OP (9 ± 5) and BIO (13 ± 5). Live, non-peroxidized sperm were significantly higher in EY (47 ± 15) compared to the other extenders; with CE-3 (29 ± 15) being significantly higher than CE (14±10), OP (21 ± 15) and BIO (23 ± 14). No significant differences were observed in the percentages of sperm with intact DNA in any of the extenders: EY (95 ± 4); CE (95 ± 2); CE-3 (93 ± 8); OP (94 ± 7) and BIO (94 ± 5). To conclude, the casein salt and cyclodextrin cholesterol extender with 3% dimethylformamide, without egg-yolk could be a suitable alternative for extenders with animal proteins. Further studies are ongoing to evaluate in vivo fertility of ejaculates cryopreserved in this extender.

Integration of LC-MS-Based and GC-MS-Based Metabolic Profiling to Reveal the Effects of Domestication and Boiling on the Composition of Duck Egg Yolks.

Egg yolks contain abundant lipids, proteins, and minerals that provide not only essential nutrients for embryonic development but also cheap sources of nutrients for consumers worldwide. Previous composition analyses of egg yolks primarily focused on nutrients such as lipids and minerals. However, few studies have reported the effects of domestication and heating on yolk composition and characteristics. The objective of this study was to investigate the impact of domestication and boiling on the metabolite contents of egg yolks via untargeted metabolomics using GC-MS and LC-MS. In this study, eggs were collected from Fenghua teals, captive mallards, and Shaoxing ducks. Twelve duck eggs (half raw and half cooked) were randomly selected from each variety, and the egg yolks were separated for metabolic profiling. The analysis identified 1205 compounds in the egg yolks. Domestication generated more differential metabolites than boiling, which indicated that the changes in the metabolome of duck egg yolk caused by domestication were greater than those caused by boiling. In a comparative analysis of domestic and mallard ducks, 48 overlapping differential metabolites were discovered. Among them, nine metabolites were upregulated in domesticated ducks, including monoolein, emodin, daidzein, genistein, and glycitein, which may be involved in lipid metabolism; some of them may also act as phytoestrogens (flavonoids). Another 39 metabolites, including imethylethanolamine, harmalan, mannitol, nornicotine, linoleic acid, diphenylamine, proline betaine, alloxanthin, and resolvin d1, were downregulated by domestication and were linked to immunity, anti-inflammatory, antibacterial, and antioxidant properties. Furthermore, four overlapping differential metabolites that included amino acids and dipeptides were discovered in paired comparisons of the raw and boiled samples. Our findings provided new insights into the molecular response of duck domestication and supported the use of metabolomics to examine the impact of boiling on the composition of egg yolks.

Effects of Dietary Rapeseed (Brassica napus), Hemp (Cannabis sativa) and Camelina (Camelina sativa) Seed Cakes Supplementation on Yolk and Albumen Colour and Nutritional Value of Yolk Lipids in Estonian Quail Eggs.

The aim of this study was to investigate the effects of supplementing commercial diets with rapeseed, hempseed and camelina seed cakes on the yolk and albumen colour and nutritional value of yolk lipids in Estonian quail eggs. A total of 585 eggs were used to evaluate egg weight, yolk and albumen pH and colour, proximate yolk composition, cholesterol content and fatty acid composition in the yolk lipids of three Estonian quail groups each fed a diet supplemented with 10% rapeseed, hemp or camelina seed cakes. The higher (p &lt; 0.01 and p &lt; 0.05, respectively) lightness (L*) of the yolk was detected in the group of quail fed the diet supplemented with rapeseed and camelina cakes compared to the hempseed addition. Meanwhile, the albumen lightness in the rapeseed group was higher (p &lt; 0.01) in comparison to the camelina group. A lower (p &lt; 0.001) yolk negative a* value was estimated in the hemp group than in the groups fed rapeseed and camelina seed cake supplements, while the rapeseed group demonstrated lower (p &lt; 0.001) albumen yellowness (b*) and colour saturation (C) in comparison to the other groups. The highest and lowest proportions of total saturated (SFAs)and monounsaturated (MUFAs) fatty acids, respectively, were found in the yolk lipids of quails fed a mixture supplemented by hemp cake. A higher (p &lt; 0.05) proportion of polyunsaturated fatty acids (PUFAs) was only found in the hemp group compared to the camelina group. The highest and lowest (p &lt; 0.001) n-6/n-3 PUFA ratios were found in the yolk lipids of quail receiving mixtures supplemented with rapeseed and camelina cakes, respectively. The yolk of the quail from the rapeseed group showed more favourable lower and higher (p &lt; 0.01 and p &lt; 0.05, respectively) atherogenic index (AI) and hypocholesterolemic/hypercholesterolemic (h/H) ratio compared to the hemp and camelina groups. The lower yolk cholesterol content was found in the eggs of the quail fed the diet supplemented with rapeseed cake compared to the eggs of the quail which were fed the diets containing more n-3 PUFAs from the addition of hemp and camelina cakes (p &lt; 0.05 and p &lt; 0.01, respectively).

Influence of free fatty acid content and degree of fat saturation in laying hen diets on egg quality, yolk fatty acid profile, and cholesterol content

The aim of the present study was to evaluate the effect of dietary free fatty acid (FFA) content and the degree of saturation on egg quality, yolk fatty acid (FA) profile, and yolk cholesterol content. For a 15-wk period, a total of 144 laying hens (19-wk-old) were randomly assigned to 8 treatments arranged in a 2×4 factorial design, with 2 sources of crude oil (soybean oil and palm oil) and 4 levels of FFA (10, 20, 30, and 45%). The dietary treatments were achieved by progressively substituting the original oils with equivalent amounts of their corresponding acid oils (soybean acid oil and palm fatty acid distillate, respectively). No differences in ADFI or egg mass were found. However, dietary FFA reduced egg production (linear, P < 0.05) and increased the feed conversion ratio (linear, P < 0.05). Higher levels of FFA in soybean diets resulted in higher egg weight with higher albumen and yolk weights (linear, P < 0.01). Palm diets presented higher yolk:albumen ratio than soybean diets (P < 0.001), but the effect of FFA did not follow a linear trend. Hens fed soybean diets laid eggs with higher Haugh units (HU) than palm diets (P < 0.001), although increasing the dietary FFA% reduced the HU values in both (linear, P < 0.001). Palm diets enhanced shell quality with greater resistance to breakage, and higher dry matter and ash content than soybean diets (P < 0.05). No differences in egg chemical composition and yolk cholesterol content were found (P > 0.05). The saturation degree had a significant effect on all the analyzed yolk FA (P < 0.001) except for arachidonic acid (C20:4 n-6), whereas increasing the FFA content did not affect to a great extent. These results show that varying dietary FFA level did not affect egg quality and yolk composition as much as the dietary fat source did, supporting the use of acid oils and fatty acid distillates as fat ingredients for feed.

Nutrient sources differ in the fertilised eggs of two divergent broiler lines selected for meat ultimate pH

The pHu+ and pHu− lines, which were selected based on the ultimate pH (pHu) of the breast muscle, represent a unique model to study the genetic and physiological controls of muscle energy store in relation with meat quality in chicken. Indeed, pHu+ and pHu− chicks show differences in protein and energy metabolism soon after hatching, associated with a different ability to use energy sources in the muscle. The present study aimed to assess the extent to which the nutritional environment of the embryo might contribute to the metabolic differences observed between the two lines at hatching. Just before incubation (E0), the egg yolk of pHu+ exhibited a higher lipid percentage compared to the pHu− line (32.9% vs. 27.7%). Although 1H-NMR spectroscopy showed clear changes in egg yolk composition between E0 and E10, there was no line effect. In contrast, 1H-NMR analysis performed on amniotic fluid at embryonic day 10 (E10) clearly discriminated the two lines. The amniotic fluid of pHu+ was richer in leucine, isoleucine, 2-oxoisocaproate, citrate and glucose, while choline and inosine were more abundant in the pHu− line. Our results highlight quantitative and qualitative differences in metabolites and nutrients potentially available to developing embryos, which could contribute to metabolic and developmental differences observed after hatching between the pHu+ and pHu− lines.

The Effect of L-Glutamine on Basal Albumen and Yolk Indices, and Albumen Amino Acids Composition

Simple SummaryAt present, with increased consumers’ focus on eating healthy, it is expected that egg protein content and amino acids profile are among the components of eggs that play critical roles in egg selection. Thus, this research investigated the effect dietary L-glutamine supplementation has on basal albumen and yolk indices as well as albumen protein amino acid profile. The study shows a potential role of L-glutamine supplementation for enhancing nutritional values of eggs by the decrease of albumen lipid content and the change of amino acid profile.The current study tested the hypothesis that 1.0% dietary inclusion of L-glutamine (Gln), an non-essential amino acid that influences protein synthesis, can improve internal egg quality, including amino acids profile. Thirty-week-old Bovans Brown laying hens in their middle laying period were assigned to one of the two experimental groups (12 replicate cages, 2 hens/cage) with Gln in the form of alpha-ketoglutarate (10 g/kg) or without Gln inclusion. The experimental period lasted for 30 wks, from the 31st to the 60th week of age of hens, when eggs were collected and selected egg quality indices were determined. Gln supplementation had no effect on albumen and egg yolk share, albumen and yolk basal indices and composition, including yolk cholesterol content. However, Gln decreased the lipid content of the egg albumen (p < 0.001), and influenced albumen amino acid profile, increasing content of asparagine (p < 0.05), phenylalanine (p < 0.05), proline (p < 0.001), tryptophan (p < 0.01), and tyrosine (p < 0.05). In conclusion, the study shows a potential role of Gln supplementation for enhancing nutritional values of eggs by lower lipid content and higher amino acid profile.

Knock out of a major vitellogenin receptor gene with eight ligand binding repeats in medaka (Oryzias latipes) using the CRISPR/Cas9 system

Recent studies of vitellogenesis engendered a novel model of teleost yolk formation in which multiple yolk precursors, vitellogenins (Vtgs), and their receptors (Vtgrs) interact to ensure proper yolk composition for embryonic development and larval growth. As a step toward verification of this concept, we examined the role of one candidate Vtgr, termed low-density lipoprotein receptor relative with eight ligand-binding repeat (Lr8), in the medaka, a representative teleost and established laboratory model. A homozygous lr8 knock out (lr8-KO) medaka was produced to perform reverse-genetic functional analyses. In ovaries of wild type (WT) medaka, Western blotting detected a putative Lr8 protein band at ~130 kDa, while immunohistochemistry detected the putative Lr8 signal at the periphery of the oocyte underneath the zona radiata. These signals disappeared in ovaries of the lr8-KO group. Offspring of lr8-KO medaka exhibited decreased survival rate compared to WT fish, but KO of lr8 was not 100% lethal. There was no significant difference in total yolk protein content or size of eggs between WT and lr8-KO fish. However, LC-MS/MS analyses revealed a remarkable decrease in the relative abundance of yolk proteins derived from VtgAb in lr8-KO eggs, in conjunction with a compensatory increase in proteins derived from VtgAa1. These findings strongly support the conclusion that Lr8 is an important receptor for VtgAb in medaka. The disruption of proper yolk composition by lr8-KO is possibly one cause of the low offspring survival.

Age-related changes in egg yolk composition between conventional and organic table eggs

The aim of this study was to investigate fatty acids, fat-soluble vitamins, malondialdehyde and cholesterol in conventional and organic eggs obtained from hens of different ages (30 and 60 weeks). A total of 360 egg yolks were used in this study. Polyunsaturated fatty acid, omega-3, and omega-6 levels were higher in the organic eggs from the 30-week-old hens. The monounsaturated fatty acid level was higher in the conventional eggs but was the same between the two age groups. Cholesterol and vitamin A levels were not influenced by either the rearing system or the age of the hens. The malondialdehyde, vitamin D2, and vitamin K2 were higher in the organic eggs; however, vitamin E was higher in the conventional eggs. The results showed that the rearing system and age, as well as the diet, had an impact on the composition of the egg. Total levels of polyunsaturated fatty acid, omega-3, and omega-6 are higher in organic eggs produced by younger hens.

(Metal yolk)/(porous ceria shell) nanostructures for high-performance plasmonic photocatalysis under visible light

We describe a route to the preparation of (metal yolk)/(porous ceria shell) nanostructures through the heterogeneous growth of ceria on porous metal nanoparticles followed by the calcination-induced shrinkage of the nanoparticles. The approach allows for the control of the ceria shell thickness, the metal yolk composition and size, which is difficult to realize through common templating approaches. The yolk/shell nanostructures with monometallic Pt and bimetallic PtAg yolks featuring plasmon-induced broadband light absorption in the visible region are rationally designed and constructed. The superior photocatalytic activities of the obtained nanostructures are demonstrated by the selective oxidation of benzyl alcohol under visible light. The excellent activities are ascribed to the synergistic effects of the metal yolk and the ceria shell on the light absorption, electron-hole separation and efficient mass transfer. Our synthesis of the (metal yolk)/(porous ceria shell) nanostructures points out a way to the creation of sophisticated heteronanostructures for high-performance photocatalysis.

Fatty acids profile and oxidative stability of eggs from laying hens fed diets containing hemp seed or hempseed cake

High levels of polyunsaturated fatty acids (PUFAs) are desirable in eggs for its nutritional quality, but render them vulnerable to oxidation. The aim of this trial was to assess the effects of dietary intake of hemp (seeds or cake) on the fatty acid (FA) profile and oxidative stability of eggs. The control diet (C), which was composed of corn, soybean meal and sunflower oil (2.5%), was compared with two experimental diets that were designed to replace sunflower oil with fat from hemp seed (HS diet) or hempseed cake (HC diet). One hundred and twenty Tetra-SL LL laying hens (24-week old) were used in a 10-week trial. Each treatment was replicated five times with eight birds each. Average hen-day egg production was not affected by feeding either the HS or the HC diet. The α-linolenic acid (ALA) concentration in eggs was increased by substituting the HS- or HC-based diets fed to the hens with dietary ALA. Similar deposition profiles were exhibited by eicosapentaenoic acid (EPA) and docosahexaenoic acids (DHA) in yolks in response to increasing the dietary ALA supply. The HS group showed a greater concentration of egg yolk ALA and EPA than the HC group, which had a higher concentration of linoleic acid (LA). These alterations in yolk composition resulted in n−6 : n−3 FA ratio values as low as 2.98 and 4.15 for HS and HC, respectively, compared to 11.07 for the control diet. The atherogenicity index and cholesterol level were not affected by hemp (seed or cake) inclusion, while the thrombogenicity index decreased when compared to the control diet. On days 0, 15 and 30 of storage (4 °C), two eggs were selected randomly from each replicate (totalling 10 eggs per treatment) and analyzed. The PUFAs were not affected by storage. An exception occurred in the HC group, in which eggs had lower n-6 FA content. Egg storage for 30 d led to a reduction in egg α-tocopherol and an increase of malondialdehyde (MDA) concentration, an indicator of lipid peroxidation. The HS treatment resulted in the lowest MDA (0.22 mg MDA/kg yolk for fresh eggs and 0.35 mg for eggs in 30-day storage). The study demonstrates that the level and type of PUFAs, level of α-tocopherol and duration of egg storage significantly affected the oxidative stability of eggs. The results obtained suggest that the inclusion of hemp seed appears to be more effective in maintaining the oxidative stability of egg lipids than hempseed cake. Keywords: egg enrichment, α-tocopherol, malondialdehyde, omega-3, storage time

Oogenesis and Egg Quality in Finfish: Yolk Formation and Other Factors Influencing Female Fertility

Egg quality in fishes has been a topic of research in aquaculture and fisheries for decades as it represents an important life history trait and is critical for captive propagation and successful recruitment. A major factor influencing egg quality is proper yolk formation, as most fishes are oviparous and the developing offspring are entirely dependent on stored egg yolk for nutritional sustenance. These maternally derived nutrients consist of proteins, carbohydrates, lipids, vitamins, minerals, and ions that are transported from the liver to the ovary by lipoprotein particles including vitellogenins. The yolk composition may be influenced by broodstock diet, husbandry, and other intrinsic and extrinsic conditions. In addition, a number of other maternal factors that may influence egg quality also are stored in eggs, such as gene transcripts, that direct early embryonic development. Dysfunctional regulation of gene or protein expression may lead to poor quality eggs and failure to thrive within hours of fertilization. These gene transcripts may provide important markers as their expression levels may be used to screen broodstock for potential spawning success. In addition to such intrinsic factors, stress may lead to ovarian atresia or reproductive failure and can impact fish behavior, fecundity, and ovulation rate. Finally, postovulatory aging may occur when eggs become overripe and the fish fails to spawn in a timely fashion, leading to low fertility, often encountered during manual strip spawning of fish.

Effect of marine by-product meals on hen egg production parameters, yolk lipid composition and sensory quality.

The effect of including 5% marine by-product meals in feeds of laying hens on egg production, composition and sensory characteristics was tested. Marine by-product meals were prepared using two methods: (i) cooking (100°C/10min) followed by drying (60°C/24hr) or (ii) grinding followed by drying. The raw materials used for meal production were scallop or squid viscera, shrimp heads or whole mackerel. A total of 108 laying hens were allocated to nine diet treatments; one control diet (corn and soya bean based) and eight experimental diets, containing 95% of the control feed and 5% of the experimental meal for three weeks. Daily intake was higher in hens fed the dried mackerel and cooked shrimp meals. All the experimental treatments showed significantly higher concentration of n-3 HUFA in yolk reserves and phospholipids compared to the control (0.12-0.13g per 100g), especially those with scallop or squid prepared by both methods (0.53-0.95g per 100g). Scallop, squid and shrimp meal inclusion in the feed produced eggs with more astaxanthin (0.22mg per 100g) while this carotenoid was absent in the control and mackerel treatments. Visual evaluation of raw yolk colour increased with the inclusion of marine by-product meals with higher values in hens fed shrimp heads (13), followed by scallop viscera (11), squid viscera (9), and with similar values for mackerel and control (4). The taste, aroma, texture and colour of cooked eggs from different treatments were not statically different when evaluated by a panel of 60 untrained people. These results suggest that meals from marine by-products are a better alternative for improving egg yolk composition by increasing n-3 HUFA when compared to fishmeal as they also increase astaxanthin and yolk pigmentation without affecting egg sensory characteristics.

Differences in egg nutrient availability and embryo development in white layer breeder genotypes

Because of consumers' preferences and also due to changes in production systems, the importance of pure breeds has increased again. There are a lot of differences among breeds which have been studied extensively, however, the differences during the incubation period are not yet fully known. Therefore, the present study was conducted to evaluate the composition of the egg parts, absorption of nutrients, and development of embryos from different genotypes. A total of 354 fresh hatching eggs were obtained from one hybrid (Lohman White, LW) and two pure breeds (Denizli and Gerze). Hatching eggs from each genotype were examined on the day of setting for egg analysis and then at the beginning of the embryonic d 19 (E19) and embryonic d 21 (E21) for egg, embryo, jejunum, and tibia analysis. On d 21 of incubation, the healthy chicks were removed and weighed. Egg weight, shell thickness, percentages of albumen, and some parameters of albumen composition (dry matter, water, ash, protein, energy, Na, Ca, K, and Mg) were higher in fresh eggs obtained from LW hens. Furthermore, the relative yolk sac and embryo weight, some yolk parameters (dry matter, water, protein, fat, and energy) and some shell parameters (dry matter, ash, Na, Ca, and K) were also higher in eggs obtained from LW hens during incubation. However, tibia deformation and villus width were lower in LW embryos than the other genotypes. Relative chick weights were 68.9, 72.0, and 68.0% in LW, Denizli, and Gerze genotypes, respectively. During incubation, differences in all examined parameters were significant except thickness and weight of shell, tibia deformation, and crypt depth. Yolk sac weight, some yolk composition parameters, K level in the shell, Cu level in the tibia, and villus height were also affected by genotype and period interaction. Based on these results, LW was found advantageous in terms of egg composition, however, regarding villus development and tibia deformation in embryos during incubation, pure breeds showed better results.

Differences in egg nutrient availability and embryo development in white layer breeder genotypes.

ABSTRACT Because of consumers’ preferences and also due to changes in production systems, the importance of pure breeds has increased again. There are a lot of differences among breeds which have been studied extensively, however, the differences during the incubation period are not yet fully known. Therefore, the present study was conducted to evaluate the composition of the egg parts, absorption of nutrients, and development of embryos from different genotypes. A total of 354 fresh hatching eggs were obtained from one hybrid (Lohman White, LW) and two pure breeds (Denizli and Gerze). Hatching eggs from each genotype were examined on the day of setting for egg analysis and then at the beginning of the embryonic d 19 (E19) and embryonic d 21 (E21) for egg, embryo, jejunum, and tibia analysis. On d 21 of incubation, the healthy chicks were removed and weighed. Egg weight, shell thickness, percentages of albumen, and some parameters of albumen composition (dry matter, water, ash, protein, energy, Na, Ca, K, and Mg) were higher in fresh eggs obtained from LW hens. Furthermore, the relative yolk sac and embryo weight, some yolk parameters (dry matter, water, protein, fat, and energy) and some shell parameters (dry matter, ash, Na, Ca, and K) were also higher in eggs obtained from LW hens during incubation. However, tibia deformation and villus width were lower in LW embryos than the other genotypes. Relative chick weights were 68.9, 72.0, and 68.0% in LW, Denizli, and Gerze genotypes, respectively. During incubation, differences in all examined parameters were significant except thickness and weight of shell, tibia deformation, and crypt depth. Yolk sac weight, some yolk composition parameters, K level in the shell, Cu level in the tibia, and villus height were also affected by genotype and period interaction. Based on these results, LW was found advantageous in terms of egg composition, however, regarding villus development and tibia deformation in embryos during incubation, pure breeds showed better results.

Effects of Soy Lecithin Extender on Dog Sperm Cryopreservation

ABSTRACTSemen cryopreservation is an essential biotechnology in canine reproduction and during the cryopreservation process commonly egg yolk are used. The discrepancy in the egg yolk composition and the potential risk of disease dissemination are obstacles for semen exportation and use. Therefore, studies aiming to substitute egg yolk are extremely important. In this context, soy lecithin contains a low-density lipoprotein fraction, is an interesting alternative. Thus, the objective of this study was to compare extenders based on soy lecithin (several concentrations and forms) with egg yolk during the cryopreservation process of dog sperm. For this purpose, we used twelve dogs. Semen was evaluated at different time points (after refrigeration, glycerolization, and thawing), by motility analysis (CASA) and functional tests (e.g., membrane integrity—eosin/nigrosin, acrosome integrity—fast green/Bengal rose, mitochondrial activity—3’3 diaminobenzidine, Chromatin susceptibility to acid-induced denaturation—SCSA, and susceptibility to oxidative stress—thiobarbituric acid reactive substances). The results indicated that egg yolk and lower concentrations of lecithin had similar effects on mitochondrial activity and motility. Thus, soy lecithin is a potentially viable alternative to egg yolk for the cryopreservation of dog semen.

Developmental programming: a new frontier for the poultry industry?

Increasing evidence that the maternal environment influences the programming of developing embryos and fetuses through epigenetic mechanisms has significant potential application in the broiler industry. The broiler breeder hen is subjected to restricted-feeding regimes to maximise egg quantity and quality, but the genetically high-intake potential of these birds makes this regime a stressful one. We propose that this stress is signalled to the developing embryo via changes in yolk composition as an evolutionary adaptation to changing environments, and that exposure to high levels of corticosteroids in ovo is associated with developmental reprogramming, which has effects on the behaviour, health and growth of the progeny. The present paper describes some preliminary results from a series of trials designed to elucidate the relationship between breeder hen diet and egg composition, and the growth, behaviour and immune function of the progeny. We conclude that manipulation of the breeder hen diet is an untapped opportunity to maintain the competitiveness of the chicken meat industry and further, that achieving improved productivity by this means may be compatible with improved animal welfare outcomes for the hen and her progeny.

Liposome-based semen extender is suitable alternative to egg yolk-based extender for cryopreservation of buffalo (Bubalus bubalis) semen

Demand for alternative of egg yolk in freezing extenders have increased in recent years due to variability in egg yolk composition, risk of microbial contamination and presence of steroid hormones. The alternative to egg yolk-based extender (EY) can be soya lecithin-based extender (SL) and liposome-based extender (LP). However, the efficacy of SL is still a matter of debate. Few studies have been performed on the effect of LP but to date evaluation of buffalo semen cryopreserved in LP has not been studied. Therefore, this study was designed to compare SL and LP with conventional EY for evaluation of post-thaw quality of buffalo semen. Results showed that total, progressive and rapid sperm motility were found significantly higher (P<0.05) in LP among these extenders. In vitro assessment of post-thaw sperm longevity has also resulted in better maintenance of sperm kinetics and motility in LP in comparison to other extenders. Furthermore, sperm cryopreserved in LP travelled significantly more (P<0.05) distance in cervical mucus as compared to SL and EY. Therefore, it can be concluded that the LP is more efficient than SL and EY for the cryopreservation of buffalo semen.

Influence of mate preference and laying order on maternal allocation in a monogamous parrot species with extreme hatching asynchrony

It is well established that in many avian species, prenatal maternal resource allocation varies both between and within clutches and may affect offspring fitness. Differential allocation of maternal resources, in terms of egg weight and yolk composition, may therefore allow the female to adjust brood reduction and to fine-tune reproductive investment in accordance with the expected fitness returns. The adaptive value of such maternal resource allocation is thought to be context-dependent as well as species-specific. We investigated the effects of female preference for her mate on the allocation of prenatal maternal resources in the budgerigar, Melopsittacus undulatus, a monogamous species of parrot that shows an extreme hatching asynchrony. We assessed mate preferences in a two-way preference test and allowed females two breeding rounds: one with the preferred and one with the non-preferred partner. We found no effect of preference on either latency to lay or clutch size, but females mated with the preferred partner laid eggs that contained significantly more yolk. Their eggs also contained significantly more androstenedione but not testosterone. Our results suggest that in this species, female preference may influence maternal resource allocation, and that the functional roles of each androgen in the yolk should be considered separately. In addition, we found a significant effect of laying order on egg and yolk weight as well as on yolk testosterone and androstenedione levels. These measures, however, did not change linearly with the laying order and render it unlikely that female budgerigars compensate for the extreme hatching asynchrony by adjusting within-clutch allocation of prenatal maternal resources.

Egg quality and yolk lipid composition of laying hens fed diets containing cashew nut meal

The objective of this study was to assess the effect of the addition of cashew nuts meal (0, 5, 10, 15, 20, and 25%) to laying hen diets on egg quality and yolk composition. The variables studied were: egg weight, specific gravity, Haugh Units, percentages of shell, albumen, and yolk, moisture, total solids, total lipids, fatty acids profile, and yolk cholesterol. The addition of up to 25% of cashew nuts meal to hen diets did not affect egg quality and freshness, moisture and total solids content. However, an increase in total lipid content and a decrease in yolk pigmentation was observed. Oleic acid level increased in the yolk, whereas palmitic, stearic, and linoleic acid levels decreased. The addition of cashew nuts meal increased the monounsaturated/saturated fatty acid ratio in the yolk and reduced the cholesterol content. Therefore, the use of cashew nuts meal in laying hen diets favorably modifies the fatty acid composition of egg yolk and contributes to a better acceptance of this food by consumers since it also reduces yolk cholesterol levels.

Egg quality and yolk lipid composition of laying hens fed diets containing cashew nut meal

The objective of this study was to assess the effect of the addition of cashew nuts meal (0, 5, 10, 15, 20, and 25%) to laying hen diets on egg quality and yolk composition. The variables studied were: egg weight, specific gravity, Haugh Units, percentages of shell, albumen, and yolk, moisture, total solids, total lipids, fatty acids profile, and yolk cholesterol. The addition of up to 25% of cashew nuts meal to hen diets did not affect egg quality and freshness, moisture and total solids content. However, an increase in total lipid content and a decrease in yolk pigmentation was observed. Oleic acid level increased in the yolk, whereas palmitic, stearic, and linoleic acid levels decreased. The addition of cashew nuts meal increased the monounsaturated/saturated fatty acid ratio in the yolk and reduced the cholesterol content. Therefore, the use of cashew nuts meal in laying hen diets favorably modifies the fatty acid composition of egg yolk and contributes to a better acceptance of this food by consumers since it also reduces yolk cholesterol levels.