Pig meat quality from entire males

This paper constitutes an updated review of the production and meat quality aspects of rearing entire male pigs. Since a major obstacle in rearing entire males is the incidence of boar taint, possible methods for detection are also summarised. Safe and fast methods for detection of boar taint would be valuable in avoiding complaints from consumers. Pig meat quality is determined by many aspects, among which odour and taste are the most important attributes. Odour may be negatively affected by the presence of a pheromonal steroid, androstenone, and a fermentation product of l-tryptophan, skatole. Male pigs are surgically castrated in many countries to minimise the risk of accumulation of high levels of androstenone and skatole. Raising entire male pigs is more profitable because they have superior production characteristics and improved meat quality due to leaner carcasses and higher protein content, as compared to castrated pigs. Furthermore, surgical castration is negative from an animal welfare point of view. In most studies, no differences in sensory quality have been found between lean meat from entire male pigs with low levels of androstenone and skatole and pork from castrates and females. The question that remains is: which substances are responsible for boar taint besides androstenone and skatole and whether they need to be considered? The threshold values used for androstenone and skatole might also be too high for highly sensitive persons. Recent research shows that a human odorant receptor, ORD7D4, is involved in sensitivity to androstenone. If the ORD7D4 genotypes of consumer and expert panels are known, this might facilitate consumer studies in the future. There is still a great need for rapid on/at-line detection methods in abattoirs for identifying carcasses with unacceptable levels of boar taint compounds. Several emerging rapid technologies with a potential for boar taint detection have been investigated. They represent various measurement principles such as chemical sensor arrays (electronic noses), mass-spectrometry fingerprinting, ultra-fast gas chromatography, gas-phase spectrometry and biosensors. An industrial detection method should allow 100% correct classification of both acceptable and not-acceptable samples with regard to boar taint sorting criteria. There are, however, still too high a percentage of false negatives ranging from 5% to 20%. In addition, these methods do not yet seem to fulfil the industrial specifications with regard to cost efficiency, simplicity and analysis time. There is still no dedicated measurement technology available for on/at-line detection of boar-tainted carcasses that measures both androstenone and skatole.     

An evolutionary perspective of the origin of males from unisexual ancestral females

正The urge to understand the cause and evolution of sex both scientifically and philosophically is the result of the development of human civilization and a fascination regarding the existing phenomenon of sexual reproduction.Theories regarding the evolution of sex have been developed by many scientists such as Aristotle,Charles Darwin,August Weismann,Hermann Henking,Nettie Stevens,John Maynard Smith,the Charlesworths,Sarah P.Otto,and A.S.Kondrashov(Maynard Smith,1978;Kondrashov,1993;Bachtrog et al.,2014).Many theories tried to provide reasons behind the maintenance of sex,but a sequence in the     

Females benefit from mating with different males in the scorpionfly Panorpa cognata

The adaptive significance of female polyandry has become a recurrentsubject of recent theoretical and empirical research. It hasbeen argued that in addition to direct benefits, such as nuptialgifts or an adequate sperm supply, females may gain geneticbenefits from mating with different males. Females of the scorpionflyPanorpa cognata mate with several males during their lifetime.In an experiment designed to rule out any direct nutritionalbenefit of multiple matings, I found that polyandrous femalesthat mated with two different males achieved a significantlyhigher egg-hatching success than monandrous females that matedtwice with the same male. However, individual males did nottrigger the same response in different females as the egg-hatchingsuccess of different females that mated with one and same maledid not correlate. The results, thus, do not conform to predictionsfrom hypotheses assuming that genetic benefits of polyandryare influenced by the intrinsic genetic quality of males. Theresults are, however, consistent with the genetic incompatibilityhypothesis. Nevertheless, substances from different males transferredduring copulation may synergistically affect zygote viability.Furthermore, I discuss why paternity studies can only explicitlytest the genetic incompatibility hypothesis if there are a prioriexpectations of female-male genome compatibilities.     

Dwarf males

Dwarf males are often found in species with sedentary females, where they typically cohabit in varying degrees of intimacy. This is short of true parasitism because, in return for room and board, males provide the benefit of sperm. Sexual selection rarely seems to be an option to explain male dwarfing, whereas natural selection often can.     

Cryptic female choice favours sperm from major histocompatibility complex-dissimilar males

Cryptic female choice may enable polyandrous females to avoid inbreeding or bias offspring variability at key loci after mating. However, the role of these genetic benefits in cryptic female choice remains poorly understood. Female red junglefowl, Gallus gallus, bias sperm use in favour of unrelated males. Here, we experimentally investigate whether this bias is driven by relatedness per se, or by similarity at the major histocompatibility complex (MHC), genes central to vertebrate acquired immunity, where polymorphism is critical to an individual''s ability to combat pathogens. Through experimentally controlled natural matings, we confirm that selection against related males'' sperm occurs within the female reproductive tract but demonstrate that this is more accurately predicted by MHC similarity: controlling for relatedness per se, more sperm reached the eggs when partners were MHC-dissimilar. Importantly, this effect appeared largely owing to similarity at a single MHC locus (class I minor). Further, the effect of MHC similarity was lost following artificial insemination, suggesting that male phenotypic cues might be required for females to select sperm differentially. These results indicate that postmating mechanisms that reduce inbreeding may do so as a consequence of more specific strategies of cryptic female choice promoting MHC diversity in offspring.     

Guarding males protect females from predation in a wild insect

Males frequently remain in close proximity to their mate immediately postcopulation. This behavior has generally been interpreted as a guarding tactic designed to reduce the likelihood that a rival male can rapidly displace the ejaculate of the guarding male [1, 2]. Such attempts by males to control their mates represent a potential source of conflict [3-5], but guarding behaviors in species where it is difficult for males to control their mates suggest that conflict is not inevitable [6, 7]. We employed a network of infrared video cameras to study a wild population of individually marked and genotyped field crickets (Gryllus campestris). Lone females or males suffer similar rates of predation, but when a pair is attacked, the male allows the female priority access to their burrow, and in doing so dramatically increases his probability of being killed. In compensation for this increased predation risk, paired males mate more frequently and father more of the female's offspring. By staying with a male, females increase the sperm contribution of preferred males as well as reducing their predation risk. In contrast to conclusions based on previous lab studies, our field study suggests that mate guarding can evolve in a context of cooperation rather than conflict between the sexes.     

Drosophila dosage compensation: males are from Mars, females are from Venus

Dosage compensation of X-linked genes is a phenomenon of concerted, chromosome-wide regulation of gene expression underpinned by sustained and tightly regulated histone modifications and chromatin remodeling, coupled with constrains of nuclear architecture. This elaborate process allows the accomplishment of regulated expression of genes on the single male X chromosome to levels comparable to those expressed from the two X chromosomes in females. The ribonucleoprotein Male Specific Lethal (MSL) complex is enriched on the male X chromosome and is intricately involved in this process in Drosophila melanogaster. In this review we discuss the recent advances that highlight the complexity lying behind regulation of gene expression by just two-fold.     

Non-polar extracts of serum from males contain covert radioimmunoassayable testosterone

Non-polar extracts of sera from human males contain immunoreactive testosterone in a form that is released by mild alkaline hydrolysis. The non-polar derivative shows no immunoreactivity with testosterone antibody prior to hydrolysis. Hydrolyzed non-polar serum extracts from ten adult male volunteers contained 2.0 +/- 0.8 (SD) ng/mL of testosterone. Neither non-polar serum extracts of normal females nor a water blank substituted for non-polar extract of serum yields any immunoreactive testosterone after alkaline hydrolysis. Testosterone palmitate hydrolyzed alone or after addition to non-polar extract of serum yields the expected quantities of radioimmunoassayable testosterone. Previously described conjugates of testosterone are polar and are neither extractable by petroleum ether nor hydrolyzable by alkali. These observations suggest that fatty acid esters of testosterone may be present in serum of human males.     

Sexually selected nest-building--Pomatoschistus minutus males build smaller nest-openings in the presence of sneaker males

Both natural selection and sexual selection may act on nest-building. We tested experimentally how different regimes of egg-predation and male-male competition influence nest-building before mating, using the marine fish sand goby, Pomatoschistus minutus. Males with sneaker males present built the smallest nest-openings, smaller than males held alone or with Pomatoschistus microps males (which may predate eggs and compete over nest-sites but not compete over fertilizations). Males with visual access to other nest-building males tended also to build smaller openings than males held alone or with P. microps. Males with egg-predators present built nests with openings not differing significantly from any other treatment. Our results indicate that the small nest-openings found in the sneaker male treatment are sexually selected through protection against sneaking or by female choice. Across treatments, time span before a male started to build his nest also explained variation in nest-opening width; males starting late built larger nest-openings.     

Exoskeleton anomalies in taiga tick males from populations of the Asian part of Russia

Variation of the exoskeleton is described for 2630 males of the taiga tick Ixodes persulcatus Schulze, 1930 collected by flagging from vegetation in the Far Eastern, Siberian, and Ural Federal Districts of Russia. Two types of conscutum anomalies were found to be prevalent in all the samples. Exoskeleton anomalies were less frequently recorded in the Far Eastern Federal District than in the Siberian and Ural Federal Districts: 6.5 ± 1.05, 29.7 ± 1.03, and 25.8 ± 3.93%, respectively. The observed phenotypic variation seems to be unrelated to anthropogenic impact. In the meridional direction, the taiga tick samples with different frequencies of exoskeleton anomalies correspond to two races of the species.     

The physique of young males in east Africa from the biosocial point of view

The aim of this study is to show the correlation between the physique of Africans from Kenya, Tanzania, Sudan and the conditions of their biosocial environment. All the young men examined were from Kenya (N=423), Tanzania (N= 153) and Sudan (N=154) aged 18 to 30. Based on the taken measurements (height, weight, sitting height, physiognomic leg length and chest, waist, hip, left thigh and left arm circumferences) the following indices were calculated: Body Mass Index (BMI), Rohrer's index and skelic index. The birth date, the number of children per ménage (in family), and the birth sequence of the examined subject were inquired. The measurement results were elaborated (worked out) statistically in accordance with commonly accepted standards. All the information contained in the collected material within the analysed countries was compared. On the basis of the measured traits and calculated indices it was found that the morphological constitution of the men from Sudan differed. Typical for this group are the largest stature length and the lowest weight and waist measurements. Kenyans are similar to Tanzanians, although the latter have higher weight, hip and thigh measurements and lower chest circumference. The characteristics of the examined Africans' morphological structure were analysed in comparison with the data available in literature and relating to the number of children in family, population density, illiteracy and the growth of income and of the HIV/AIDS problem.     

The occurrence of reactive oxygen species in the semen of males from infertile couples

The aim of this pilot study was to establish a reactive oxygen species (ROS) evaluation method as a step in the routine diagnosis of men from infertile couples, which attend the Centre of Assisted Reproduction at the Teaching Hospital in Olomouc. Standard semen analyses were performed manually according to WHO guidelines. The number of peroxidase-positive leukocytes in the semen was determined using the Endtz test. The levels of ROS were estimated by chemiluminescence assay using luminol (5-amino-2,3 dihydro-1,4 phthalazinedione) as a probe. The semen samples were collected from 68 patients. Normospermia was found in 15 patients (22.1 %). The semen samples of 3 normospermic patients were classified as ROS-positive. Elevated ROS production was recorded in all subgroups of patients irrespective of any pathology found. We confirmed that spermatozoa might be the source of ROS as well as the seminal leukocytes. Apart from the leukocytes, sperm cells with residual cytoplasm and immature spermatozoa are considered to be a major source of ROS. Thus it is suggested that sperm morphology abnormalities should be evaluated more carefully.     

Characteristics of associated microflora of ejaculate from males with gonococcal infections

Species composition and biological properties of aerobic and anaerobic microflora from an ejaculate from males with acute and chronic gonococcal infection and from healthy men were studied. Patients with gonococcal infection were shown to present quantitative and qualitative changes in microbiocenosis of the reproductive tract. Patients with acute gonorrhea displayed decreased species diversity in contrast to healthy persons, while different species of associated with gonococci microbes with high persistent potential, were cultured in patients suffering from a chronic form of infection. The role of revealed pathological biocenosis patterns in developing chronic infection as well as postgonorrheal gonococci-free urethritis is discussed.     

The sodium-22 influx in erythrocytes from black males and females

In order to establish a standard for sodium influx in erythrocytes for the black population, 22Na+ uptake was measured in 29 normotensive black volunteers. Nineteen males and 10 females during the follicular phase of the menstrual cycle were studied utilizing the procedure of Gambhir et al. (1). In the males, cell concentrations ranging from 0.64 to 2.0 X 10(9)/ml showed an influx of 0.42 to 1.34% of the total 22Na+ added, and in the females, using the same erythrocyte concentrations, the 22Na+ influx ranged from 0.37 to 1.1%; these differences were not significant. Intraassay variation of the 22Na+ data was 4.8%. Interassay variations have been explained elsewhere (1). These data provided a range of observed values for 22Na+ uptake in erythrocytes from a subpopulation of normotensive black males and females for comparison with hypertensive patients.     

Proportion of males with lower fertility spermatozoa estimated from heterospermic insemination

This study was designed to evaluate the proportion of males with spermatozoa detectably less fertile than the spermatozoa from other males. Previously unpublished and published data from heterospermic trials involving insemination with equal numbers of spermatozoa and resulting in at least 11 offspring from each pair of males were analyzed. The proportion of pairs in which the males sired equivalent numbers of offspring were 0.42, 0.18, 0.33 and 0.09 for trials with fresh boar semen, liquid-stored boar semen, frozen bull semen and fresh rabbit semen, respectively. The calculated proportion of males with less fertile spermatozoa were 0.36, 0.57, 0.42 and 0.70, respectively. Although these differences in fertility would not be apparent in some management systems, a high proportion of ejaculates had spermatozoa that were detectably less fertile.