Domestication strategies for the endangered catfish species Pseudopimelodus mangurus Valenciennes, 1835 (Siluriformes: Pseudopimelodidae)

Wild fish domestication can be considered a strategic approach to endangered species conservation, supporting studies and reducing economic and environmental costs. Three of the most important strategies in the domestication processes of fish are the adaptation of wild fish to captivity, the reproduction of the adapted fish and the production and maintenance of the young individuals. That being said, the present study is divided in three experiments: the 1st aimed to adapt wild Pseudopimelodus mangurus to captivity environment using different feeding approaches and a prophylactic strategie; the 2nd aimed to reproduce the adapted individuals from the 1st experiment; and the 3rd aimed to train the P. mangurus juveniles to accept commercial diets. The 1st and 2nd experiments were successful at the maintenance and artificial reproduction of P. mangurus kept in tanks between the reproductive seasons. The results suggest that the reproductive performance of animals kept in captivity (initial relative fertility-IRF = 609.25 ± 36.6 eggs/g) was similar (p > 0,05) to the performance found in wild individuals (IRF = 679.21 ± 45.66 eggs/g). Feed training of P. mangurus juveniles (3rd experiment) was also conducted, evaluating three feeding treatments with different concentrations of bovine heart and ration. At the end of the experiment, the treatment containing half bovine heart and half commercial feeding resulted in the highest values of weight gain (0.10 ± 0.16 g), specific growth rate (0.37 ± 0.11 mm), length (47.78 ± 2.35 mm) and growth (2.15 ± 2.27 mm), suggesting reasonable acceptability to artificial diets in the cultivation of this species. As conclusion, the present study contributes with the development of techniques for the domestication of fresh water fish species with commercial value or andangered of extinction, showing the domestication and reproduction of wild P. mangurus in captivity. However, more studies have to be conducted in order to improve the acceptance of artificial feeding by juveniles and to increase their survival rate.

A mitochondrial genetic divergence proxy predicts the reproductive compatibility of mammalian hybrids

Numerous pairs of evolutionarily divergent mammalian species have been shown to produce hybrid offspring. In some cases, F 1 hybrids are able to produce F 2 s through matings with F 1 s. In other instances, the hybrids are only able to produce offspring themselves through backcrosses with a parent species owing to unisexual sterility (Haldane's Rule). Here, we explicitly tested whether genetic distance, computed from mitochondrial and nuclear genes, can be used as a proxy to predict the relative fertility of the hybrid offspring resulting from matings between species of terrestrial mammals. We assessed the proxy's predictive power using a well-characterized felid hybrid system, and applied it to modern and ancient hominins. Our results revealed a small overlap in mitochondrial genetic distance values that distinguish species pairs whose calculated distances fall within two categories: those whose hybrid offspring follow Haldane's Rule, and those whose hybrid F 1 offspring can produce F 2 s. The strong correlation between genetic distance and hybrid fertility demonstrated here suggests that this proxy can be employed to predict whether the hybrid offspring of two mammalian species will follow Haldane's Rule.

Fishery-exteriors characteristics of the brooders of brown trout, rainbow trout and brook trout

This study aims to determine the reproductive indices of three types of salmon fish: brown trout (Salmo trutta morfa fario Linnaeus (1758), rainbow trout (Oncorhynchus mykiss Walbaum, 1792) and brook trout (Salvelinus fontinalis Mitchill, 1814) in aquaculture. For this purpose, 10 females and 10 males of each species were selected on an analogous basis and the main fishery-exteriors and reproductive characteristics were identified. The researching of relative fertility permit to establish that this indicator in brook trout females was 18.36% higher compared to rainbow trout, however, by 7.5% lower compared to the brown trout. It was found that brook trout eggs had less weight and size in comparison with other studied species. In particular, the weight and diameter of the eggs were 2.89 and 9.7% respectively lower than of rainbow trout, as well as 8.1 and 3.44% respectively lower compared to the brown trout. When studying the quantity of ejaculate, it was found that on average, brook trout males had 16.95% less of ejaculates compared to rainbow trout males, but 79.6% more than of brown trout males. When comparing the main indices of the brooders body of the studied species, it was found that the condition factor of the brook trout and rainbow trout females was quite high at 1.55–1.57, the brown trout one was 1.35, and the profile index respectively was 3.5, 3.52 and 4.0. The males' condition factor of brook trout, rainbow trout and brown trout was respectively 1.64, 1.52 and 1.35. Fishery-exteriors indicators met the requirements of brooders species and age specificity norms of the studied fish species.

PARAMETERS OF THE FECUNDITY OF AMPHIPOD CRUSTACEAN ALIEN SPECIES (CRUSTACEA, AMPHIPODA) FROM WATERCOURSES OF BELARUS

For the first time for water bodies of Belarus, based on studies (2008–2015), the main fertility parameters for eight alien species of amphipods were established . The minimum sizes of individuals for which identification of sex and the size of sexual maturation is possible are presented. The ranges of the body length of the egg-bearing females and the average sizes of the breeding individuals were determinate. The sizes and number of eggs are given at three stages of development for females of different age groups. Absolute and relative fertility were revealed. It is established that the number of eggs in the brood bag correlates with the size and weight of the female; the dependences of fecundity on the length and weight of the female were calculated. The theoretical possible number of litters in the period of reproduction of animals in the conditions of the obtained range was determined. The obtained results differed insignificantly with the literature data from regions with similar climatic conditions, that was determined mainly by various ecological conditions.

Fertility and Reproductive Pathways of Triploid Flowering Pears (Pyrus sp.)

Flowering pears are popular landscape plants due to a combination of desirable traits including broad adaptability, pest resistance, and attractive ornamental features. However, in some areas, flowering pears readily reseed and naturalize. Considering the value and utility of these trees, the development of infertile cultivars would be desirable. Breeding of triploid plants is one of the approaches that has been successfully used to develop seedless cultivars of many crops. The objective of this study was to evaluate female fertility and reproductive pathways of triploid flowering pear hybrids. Female fertility was characterized by evaluating fruit set, seeds per fruit, seed germination, seedlings per flower, and percent relative fertility [(seedlings per flower for triploid/seedlings per flower for diploid control) × 100]. Flow cytometry was used to determine relative genome sizes and ploidy levels of female parents, seedlings, and seeds (both embryo and endosperm) and to make inferences regarding reproductive pathways. Mean holoploid genome sizes were confirmed for the diploid [1.25 ± 0.05 (se) pg] and triploid [1.88 ± 0.12 (se) pg] female parents. Relative female fertility was significantly reduced in triploids, but varied considerably among accessions and ranged from 0.0% to 33.6%. Of the 13 triploids used in this study, five accessions had a relative fertility of <2%. One accession had no measurable female fertility. Cytometric analysis of seeds and seedlings from triploid maternal parents showed that they were predominantly abnormal aneuploids, which typically results in seedlings with reduced fitness and fertility. Fertilization with unreduced gametes, apomixis, and pseudogamy were documented in triploid-derived embryos/offspring, but were relatively uncommon. The considerable reduction in female fertility of some triploid selections, coupled with the limited production of primarily aneuploid progeny, provides desirable options for new infertile flowering pears to prevent or reduce reseeding and naturalizing.

Fertility in Germany before and after the 2011 Census: Still no Trend Reversal in Sight

The population projections by the German Federal Statistical Office show a likely decrease in the number of births in the 2020s. This development will be the result of a declining number of prospective mothers combined with an assumed continued low fertility rate. Given the available empirical findings prior to the 2011 census, there was no indication that a possible distinct rise in the fertility rate in the next decade would compensate for the declining number of potential mothers. However, the 2011 census led to revisions in the population size, age structure and consequently in relative fertility measures such as period and cohort fertility rates.The objective of this article is to quantify the effects of the 2011 census on these fertility statistics and to check the validity of previous findings for fertility trends on the census-adjusted data basis. A special focus is laid on analyses of the cohort fertility and the consequences of ever-later entry into motherhood on the completed fertility and on parity distribution. Using numerous findings, we will show that a continuous rise in the completed fertility in the coming two decades cannot be realised without a reversal of fertility behaviour. A greater increase in fertility from the age of 30 onwards would be necessary to offset the decrease in fertility for ages under 30 – a trend which intensified with cohort 1974 – and thereby stabilise the total cohort fertility rate at a relatively low level between 1.5 and 1.6 births per woman. A rise and subsequent stabilisation of the total cohort fertility rate at the level of at least 1.6 births per woman would, additionally, necessitate a trend reversal in the development of childlessness and distinct changes in birth timing.

58 OVARIAN DOWN-REGULATION WITH ORAL PROGESTIN FOR FIXED-TIME LAPAROSCOPIC OVIDUCTAL ARTIFICIAL INSEMINATION WITH FRESHLY COLLECTED AND FROZEN–THAWED SPERMATOZOA IN DOMESTIC CATS

Laparoscopic oviductal AI (LO-AI) with low numbers of freshly collected or frozen-thawed spermatozoa has resulted in high pregnancy success (50–70%) in domestic cats. However, proper timing of AI depends on identifying anestrual, non-luteal queens before exogenous gonadotropin injection, confounding AI scheduling and limiting applicability with felids housed at distant institutions. Recent research (Stewart et al. 2012 Biol. Reprod. 87, 1–11) has shown that daily oral progestin treatment is effective for down-regulating ovarian activity in cats and allowing synchronized stimulation with exogenous gonadotropins. Our study objectives were to (1) assess the effect of oral progestin treatment on pregnancy success following LO-AI in domestic cats and (2) compare relative fertility following LO-AI of each female with low numbers of freshly collected versus frozen-thawed spermatozoa. Young (<2 years old), nulliparous domestic cats were assigned to either control (Con; n = 8) or oral progestin (OP; n = 7) treatment groups. Con females were monitored daily for behavioural oestrus and blood samples from anestrual females assessed for progesterone concentration to confirm non-luteal status before exogenous gonadotropin treatment [100 IU of eCG followed 85 h later with 1000 IU of porcine LH (pLH)]. Oral progestin females were fed altrenogest (Regu-Mate; 0.088 mg kg–1 of body weight) mixed in moist cat food for 38 consecutive days and then treated with exogenous gonadotropins 6 days after altrenogest cessation. At 31 to 33 h post-pLH treatment, each female was inseminated via laparoscopy in 1 oviduct with freshly collected sperm (motile) from 1 male and frozen-thawed sperm (motile; frozen in a soy lecithin-based cryomedium) from a second male. Ultrasonography was conducted approximately Day 21 post-AI for pregnancy diagnosis. Pregnant females were spayed immediately and recovered fetuses assessed for paternity using short tandem repeat molecular marker analysis to determine relative fertility of fresh versus frozen semen. All females ovulated following gonadotropin treatment, averaging ( ± standard error of the mean) 20.6 ± 1.7 corpora lutea per queen. Most [12/15 (80%)] females conceived following LO-AI, producing an average of 8.1 ± 1.4 implantations and 5.9 ± 1.2 fetuses per pregnancy. There was no difference (P > 0.05) between Con and OP cats in pregnancy success [Con: 6/8 (75%); OP: 6/7 (86%)] or in mean implantation number (Con: 6.0 ± 1.8; OP: 10.2 ± 2.0) or fetal number (Con: 4.3 ± 1.6; OP: 7.5 ± 1.6) in pregnant cats. Paternity assessment revealed that freshly collected and frozen-thawed spermatozoa were equally effective (P > 0.05) in producing pregnancies (fresh: 11/15 (73%); frozen: 10/15 (67%)], with no difference (P > 0.05) in total fetal numbers [fresh: 37/69 (54%); frozen: 32/69 (46%)]. These results indicate that oral progestin treatment may be used to down-regulate ovarian function in felids for fixed-time AI without compromising fertility in vivo, and that LO-AI with low numbers of cat sperm frozen in a soy lecithin medium may produce high pregnancy percentages and normal litter sizes.