Relationship between inhibition of mevalonate biosynthesis and reduced fertility in laying hens

Influence of the genotype of the hen (Gallus gallus domesticus) on main parameters of egg quality, chemical composition of the eggs under uniform environmental conditions

The objective of this study was to identify and compare the quality characteristics and concentrations of various compounds in eggs from several pure breeds and lines of hens reared under the same environmental conditions and fed a commercial feed. A total of 280 hens aged 52 to 56 wk belonging to 14 different breeds or lines of hens worldwide were included in this study. Their eggs were characterized by wide differences in various egg quality parameters. Breeds and lines of hens with a higher lutein content in eggs were characterized by a lower beta-carotene content (e.g. Hy line brown, Cochin miniature, Ayam Cemani) (P < 0.001). Additionally, vitamin D, cholesterol, and fatty acid contents were also different between eggs, from 1.51 to 1.79 μg/100g; from 14.1 to 15.4 mg/g fat, PUFA from 19.6 to 22.8 g/100g fat, and SFA from 32.8 to 37.8 g/100g fat respectively (P < 0.001). Lysozyme content also exhibited significant variation among breeds, with some showing a 2-fold higher content in eggs compared to others (0.31% - cochin miniature, 0.66% Faverolle) (P < 0.001). Our study demonstrated that intensively selected hen breeds like Hy-line Brown Hybrid had an improved egg quality seen by the increase in many parameters (e.g., egg weight, Haugh unit, Lutein, vitamins D, MUFA) compared to pure breed hens. In conclusion, genetic differences between breeds and lines of hens have a significant impact on the quality of eggs.

Effect of weight and storage time of broiler breeders' eggs on morphology and biochemical features of eggs, embryogenesis, hatchability, and chick quality

The transfer of hatchability results obtained under experimental conditions to the commercial ground with a positive financial effect proves the value and usefulness of these data. On the other hand, finding results on commercial processes of broiler breeders' egg incubation in the literature is challenging. The presented study aimed to determine the effects of egg weight and storage time on the physical, biochemical characteristics of hatching eggs, embryogenesis and hatchability in Ross 308 broiler breeders. On the laying day, the eggs were divided into four weight groups: S - small eggs (57-61 g), M - medium eggs (62-66 g), L - large eggs (67-71 g), and XL - extra-large eggs (72-76 g). The eggs were then stored for 3, 7, 14, and 21 days under controlled conditions. As the egg storage time increased, a decrease in the yolk quality (lower index) was observed. The highest Haugh units were found in eggs from the S and M groups. The cholesterol content of the M, L, and XL groups was lower on days 7, 14, and 21 as compared to that of eggs only stored for 3 days. Egg weight loss during incubation decreased with an increase in the egg weight. An extension of the egg storage time caused an increase in the loss of egg weight. On the 14th and 18th days of hatching, an increase in the eggshell temperature was noted with an increase in the weight of the egg. The eggs stored for 7 days were characterised by the highest shell temperature on each day. The highest hatchability percentage was recorded for the M group. The hatchability rate decreased with the prolongation of the storage time, while the number of crippled chicks after hatching increased. The results confirmed that the increased weight of the eggs and prolonged storage time (14 and 21 days) increased the weight and decreased the length of the newly hatched chicks, respectively. Chicks from the heaviest eggs and those stored for 14 and 21 days showed poor results on the Pasgar score® test. The observations indicate the need to adopt various (of those available) methods to assess the quality of newly hatched chicks in hatcheries in order to produce high-quality broiler chickens. The results also indicate that prolonged egg storing beyond 14 days may affect the thyroid hormone economy during the hatching of chicks, especially in the XL group.

Statins as Targeted "Magical Pills" for the Conservative Treatment of Endometriosis: May Potential Adverse Effects on Female Fertility Represent the "Dark Side of the Same Coin"? A Systematic Review of Literature

The aim of the study was to analyze all the available evidence from both in vitro and in vivo studies regarding the efficacy of statin therapy in the treatment of endometriosis, evaluating the potential efficacy, side effects, and contraindications of their administration in humans. We focused on defining the potential benefits that the administration of statins may have on patients affected by endometriosis and the possible adverse effects of such a therapy on ovarian function and fertility profile. According to our article selection criteria, we included in the review in vitro and in vivo studies performed on human or animal models. The systematic review of literature identified 24 eligible articles, 12 of which reported evidence regarding the effects of statins on endometrial/endometriotic cells and 12 regarding their effects on ovarian function and fertility. All articles seem to emphasize the utility of statin administration in the treatment of endometriosis due to their anti-proliferative/proapoptotic effects, their ability to reduce cell viability and migration, and the inhibition of angiogenesis and anti-inflammatory activities. Regarding the potential adverse effects on gonadal activities, steroidogenesis and fertility function, no conclusive data were collected in human models (excluding women affected by polycystic ovary syndrome in which significant decline of androgen levels was reported after statin treatment), while contrasting results were reported by studies conducted in in vitro and in vivo in animal models. Despite evidence supporting statins as the potential therapeutic agent for a targeted conservative treatment of endometriosis, the uncertainties regarding their impact on gonadal function may not define them as an appropriate therapy for all young fertile women.

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

1. The research was carried out to investigate correlations between breeder age, egg cholesterol content, blood cholesterol level and hatchability of broiler breeders. 2. Egg cholesterol content increased with increased breeder age. The mean yolk cholesterol contents (mg per g yolk) were 10.47+/-0.28, 15.34+/-0.65 and 15.64+/-0.71 mg/g at 28, 45 and 65 weeks of age, respectively. 3. There were positive correlations between yolk weight and yolk cholesterol content (mg/g yolk) (r=01.941; P<0.01) and egg cholesterol content (mg/egg) (r=0.980; P<0.01). 4. Negative correlations were found between egg yolk cholesterol content and hatchability of fertile eggs (r=-0.345; P<0.05), fertility ratio (r=-0.609; P<0.01) and hatchability of total eggs (r=-0.574; P<0.01). 5. The mean blood cholesterol levels were 165.1+/-11.04, 166.5+/-11.97 and 179.5+/-11.33 mg/dl at 28, 45 and 65 weeks of age, respectively.

Effect of red mold rice supplements on serum and egg yolk cholesterol levels of laying hens

Monacolin K is a secondary metabolite of Monascus species and reduces cholesterol levels. This research focuses on the effect of adding red mold rice to hens' diet on cholesterol level in egg yolk and on cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels in serum. Forty-eight Hy-line laying hens of 48 weeks of age were studied by dividing them into four groups. Except for the control group, the feed for three other groups contained 2.0, 5.0, and 8.0% red mold rice (monacolin K concentrations were 0.0145, 0.035, and 0.056%, respectively). The experiment lasted 6 weeks. During this period, egg weight and egg production were recorded every day, and cholesterol, triglyceride, HDL, and LDL in serum were measured weekly as well. The result showed that the cholesterol in eggs produced by experimental groups was lower than that of the control group (0%, 194.14 +/- 8.30; 2%, 167.17 +/- 4.34; 5%, 168.93 +/- 9.38; 8%, 183.02 +/- 7.63 mg/egg; p < 0.05), and the triglyceride (0%, 1494 +/- 178; 2%, 1280 +/- 174; 5%, 1189 +/- 248; 8%, 1381 +/- 218 mg/dL; p < 0.05) and LDL levels (0%, 36.81 +/- 5.53; 2%, 32.25 +/- 7.93; 5%, 30.06 +/- 4.39; 8%, 28.81 +/- 4.16 mg/dL; p < 0.05) were also significantly lowered in the experimental groups. However, the HDL level did not show significant change for either control or experimental groups (0%, 36.06 +/- 3.96; 2%, 36.25 +/- 5.39; 5%, 33.13 +/- 3.68; 8%, 31.44 +/- 4.29 mg/dL; p > 0.05). Besides, the addition of red mold rice also helps to inhibit production of malondialdehyde (MDA) in serum lipid oxidation (0%, 27.42 +/- 0.53; 2%, 25.62 +/- 0.76; 5%, 24.35 +/- 0.59; 8%, 23.63 +/- 0.48 microM; p < 0.05).

Validation of a modified PCR-based method for identifying mutant restricted ovulator chickens: substantiation of genotypic classification by phenotypic traits

Upon photostimulation, restricted ovulator (RO) female chickens exhibit endogenous hyperlipidemia, develop atherosclerotic lesions, and generally fail to lay eggs. This phenotype results from a point mutation in the gene specifying the very low density lipoprotein receptor (VLDLR), whose protein product normally mediates the massive oocytic uptake of egg yolk precursors from the circulation. Taking advantage of the single base change in the mutant VLDLR allele, a PCR-based method for the rapid identification of RO chickens was developed at the Biocenter and University of Vienna, Austria. However, this procedure was incompletely validated because phenotypic data were not obtained and conventional progeny testing of sons and grandsons was not performed. Here, the assay validation was completed by providing plasma lipid concentrations, plasma very low density lipoprotein particle sizes, or egg production records of PCR-genotyped females and their brothers and sires to demonstrate that each bird's phenotypic traits substantiated their genotypic classification. Moreover, several methodological modifications resulted in improved chemical safety, speed, and cost of preparing and analyzing genomic DNA from chicken erythrocytes. Because the ovaries of mutant RO females generally contain numerous vitellogenic follicles in the absence of a functional oocyte plasma membrane VLDLR, the existence of an alternate system for the oocytic uptake of plasma very low density lipoprotein and vitellogenin is suggested, whereas a physiological explanation as to why some, but not all, mutant RO hens are able to ovulate and lay eggs is lacking.

Assessment of reproductive function in mutant restricted ovulator carrier roosters

Two splice variant forms of the chicken very low density lipoprotein receptor (VLDLR) have recently been shown to exist in both male and female chicken gonads. The longer form, containing an O-linked sugar domain, is produced in the somatic cells of the testes and ovaries, whereas the shorter form, which lacks this domain, is expressed in the male and female germ cells. The latter is essential for female reproduction, because a naturally occurring point mutation in the gene encoding the short form of the VLDLR causes its functional absence, resulting in atherosclerosis and a general failure to lay eggs. Thus, the term restricted ovulator (RO) was originally coined to describe females with the mutant gene. In contrast, the roles of the VLDLR gene products in male reproduction have yet to be defined, because only heterozygous RO roosters, which have a mutant allele of the VLDLR gene (short form) on one of their two Z (sex) chromosomes, can be obtained. However, the question of whether two normal alleles of the VLDLR gene are needed for optimal male reproductive performance can be addressed. Here, the reproductive abilities of heterozygous RO roosters were compared to their wild-type siblings. The RO roosters were found to be phenotypically normal, suggesting that only one normal allele for the VLDLR gene is needed for optimal male reproductive performance. Alternately, it is also possible that the one normal allele compensated for the presence of the mutant one in terms of VLDLR gene product production (i.e., a dosage compensation).