Inheritance of fertility in broiler chickens

Background

The fertility of a chicken''s egg is a trait which depends on both the hen that lays the egg and on her mate. It is also known that fertility of an individual changes over the laying period.

Methods

Longitudinal models including both random genetic and permanent environmental effects of both the female and her male mate were used to model the proportion of fertile eggs in a pedigree broiler population over the ages 29-54 weeks.

Results

Both the male and the female contribute to variation in fertility. Estimates of heritability of weekly records were typically 7% for female and 10% for male contributions to fertility. Repeatability estimates ranged from 24 to 33%, respectively. The estimated genetic variance remained almost constant for both sexes over the laying period and the genetic correlations between different ages were close to 1.0. The permanent environment components increased substantially towards the end of the analyzed period, and correlations between permanent environment effects at different ages declined with increasing age difference The heritability of mean fertility over the whole laying period was estimated at 13% for females and 17% for males. A small positive correlation between genetic effects for male and female fertility was found.

Conclusion

Opportunities to improve fertility in broiler stocks by selection on both sexes exist and should have an impact throughout the laying period.     

Genetic heterogeneity of residual variance in broiler chickens

Aims were to estimate the extent of genetic heterogeneity in environmental variance. Data comprised 99 535 records of 35-day body weights from broiler chickens reared in a controlled environment. Residual variance within dam families was estimated using ASREML, after fitting fixed effects such as genetic groups and hatches, for each of 377 genetically contemporary sires with a large number of progeny (> 100 males or females each). Residual variance was computed separately for male and female offspring, and after correction for sampling, strong evidence for heterogeneity was found, the standard deviation between sires in within variance amounting to 15–18% of its mean. Reanalysis using log-transformed data gave similar results, and elimination of 2–3% of outlier data reduced the heterogeneity but it was still over 10%. The correlation between estimates for males and females was low, however. The correlation between sire effects on progeny mean and residual variance for body weight was small and negative (-0.1). Using a data set bigger than any yet presented and on a trait measurable in both sexes, this study has shown evidence for heterogeneity in the residual variance, which could not be explained by segregation of major genes unless very few determined the trait.     

Binding to syntenin-1 protein defines a new mode of ubiquitin-based interactions regulated by phosphorylation

Syntenin-1 is a PDZ domain-containing adaptor that controls trafficking of transmembrane proteins including those associated with tetraspanin-enriched microdomains. We describe the interaction of syntenin-1 with ubiquitin through a novel binding site spanning the C terminus of ubiquitin, centered on Arg(72), Leu(73), and Arg(74). A conserved LYPSL sequence in the N terminus, as well as the C-terminal region of syntenin-1, are essential for binding to ubiquitin. We present evidence for the regulation of this interaction through syntenin-1 dimerization. We have also established that syntenin-1 is phosphorylated downstream of Ulk1, a serine/threonine kinase that plays a critical role in autophagy and regulates endocytic trafficking. Importantly, Ulk1-dependent phosphorylation of Ser(6) in the LYPSL prevents the interaction of syntenin-1 with ubiquitin. These results define an unprecedented ubiquitin-dependent pathway involving syntenin-1 that is regulated by Ulk1.     

Aflatoxicosis in rabbits: Effectiveness of Egyptian raw bentonite in prevention or diminution the detrimental effects of naturally aflatoxin contaminated diets

Thirty five females and 15 males of New Zealand White mature rabbits about 6 months of age, were assigned to 1–5 dietary treatments (7 does+3 bucks for each): uncontaminated control diet, naturally aflatoxin contaminated diet without or with 1,2 and 3% bentonite. Rabbit fed with the aflatoxin-diet had a decreased (P<0.01 or 0.05) physical semen characteristics of bucks and a reproductive performance traits of does. The values of conception rate (%), gestation length (days), litter size (n) and litter weights (g) at birth and viability (%) of litters of doe rabbits, fed with the aflatoxin-diet, recorded, respectively: 64.5; 31.0; 4.4; 275.0 and 57.1 versus 85.6; 30.3; 7.9; 508.0; and 100 for those fed with the uncontaminated diet. Addition of bentonite to the aflatoxin contaminated diet improved in general the physical semen characteristics of buck and reproductive performance traits of doe rabbits. The results of the study demonstrate that adding 1% of Egyptian raw bentonite to the naturally aflatoxin contaminated rabbit diets can provide an effective, cheap and safe practical technique for preventing the aflatoxicosis in mature rabbits.     

Stem cells of marine invertebrates: Regulation of proliferation and induction of differentiation in vitro

The review surveys own and the literature data on the plasticity of marine invertebrate stem cells. Stem and embryonic cell cultures of marine invertebrates are a novel model system characterized by a high level of physiological and synthetic processes. The production of biologically active substances in vitro may be an alternative to chemical synthesis and aquaculture. The factors involved in determination and maintenance of the pluripotency of marine invertebrate stem cells have been analyzed. The technology of the directed differentiation of marine invertebrate stem cells into certain functionally active cells in vitro embraces the use of different growth factors, various natural and artificial substrates, and unique bioactive compounds from marine invertebrate tissues. To increase the expression levels of regulatory genes, we applied genetically engineered constructions with foreign genes. The regulation of growth and differentiation of marine invertebrate stem cells opens new prospective uses for their application in marine biotechnology and is helpful for research in developmental biology.     

Fibrous framework of human skeletal muscles, fasciae and tendons

By means of scanning and transmissive electron microscopy, the construction of the fibrous framework of the human skeletal muscles, fasciae and tendons has been investigated and its morphofunctional analysis has been performed. The fibrous framework of the endomysium is presented as a complexly organized system of anastomosing fibers of the connective tissue, forming a net-like construction. The fibrous structures of the framework are united into a whole construction by connecting fibers and fibrils. Different types of structural interconnection of collagenous fibers with sarcolemma are revealed. The structure of the fibrous framework both in different muscles and within one muscle has certain peculiarities. The main constructive element of the fascial fibrous framework make large anastomosing collagenous fibers, their architectonics is stabilized by connective fibers and fibrils. The construction of the tendinous fibrous framework is characterized by a pronounced anisotropia of the largest collagenous fibers and a developed network of connective structures both on the surface and inside the collagenous fibers. Structural mechanisms, interconnecting muscles and tendons, are demonstrated. Presence of anastomoses between the fibrils in the composition of the collagenous fibers in the fascia and Achilles tendon are stated. Together with the peculiarities existing, the general principle of the structural organization of the fibrous framework of the muscle system is the net-like constructure dependent on presence of anastomoses and elements of the connective system between the fibrous structures. Depending on the organ's function, the construction of the network acquires certain specific morphological forms.     

Dependence of the fatty acid composition of the lipids in fungi of the genus Penicillium on their natural habitat conditions

The fatty acid composition of lipids was studied in Penicillium fungi growing in different habitats. Saturated fatty acids were represented by lauric, margaric, stearic and palmitic acids (the latter prevailed-- 18%-26%). Unsaturated monoene fatty acids were represented by acids from C16:1 to C18:1, diene and triene fatty acids by linoleic and linolenic acids. The predominance of linoleic acid was not found in all cultures of the genus. Changes in the fatty acid composition of lipids may be attributed to different ecological habitats of the Penicillium genus species.