Characteristics Of Progeny Research Articles

Inherited anoxia tolerance and growth performance can result in enhanced invasiveness in hybrid fish.

Northern hemisphere freshwater ecosystems are projected to experience significant warming and shortening of winter duration in this century. This change coupled with depletion of oxygen (hypoxia) will result in a shift toward fish species with higher optimal temperatures for growth and reproduction that can mitigate hypoxic stress. Here, we tested the assumption that reproduction between two distant species, i.e. anoxic-intolerant common carp (Cyprinus carpio) and anoxic-tolerant goldfish (Carassius auratus), results in the expression of genes responsible for ethanol synthesis (alcohol dehydrogenase and pyruvate dehydrogenase subunit E1β2). The expression of this ethanol-producing pyruvate decarboxylase pathway may transform the biochemical characteristics of progeny into anoxic-tolerant hybrids, expanding their suitable environmental range and potentially increasing invasiveness. Concurrently, a genetic strategy for improving fish tolerance to oxygen-depleted environments will be a valuable physiological trait in fish culture. Differential quantification of gene expression by analyzing mRNA revealed that, compared with koi×koi, koi female×goldfish male (F1 hybrid) possessed the pyruvate dehydrogenase subunit E1β2 gene construct, which was expressed at significantly greater levels in red muscle. The potential of this hybrid to both survive in extreme anoxic conditions and grow at elevated water temperatures would likely contribute to their ecological success.

Formation, Transmission, and Dynamic Evolution of a Multidrug-Resistant Chromosomally Integrated Plasmid in Salmonella Spp.

IncHI2 plasmids, possessing high flexibility and genetic plasticity, play a vital role in the acquisition and transmission of resistance determinants. Polymorphic mobile genetic elements (MGEs) generated by a chromosomally integrated IncHI2 plasmid in an individual Salmonella isolate have not yet been detected, and the mechanisms of the formation, excision, and dynamic evolution of a multidrug-resistant chromosomally integrated plasmid (MRCP) have remained obscure. Herein, we identified a 260-kb blaCTX–M–55-qnrS1-bearing IncHI2 plasmid within a Salmonella Muenster strain. Plenty of heterogeneous MGEs (new Escherichia coli chromosomally integrated plasmid or circular plasmids with different profiles) were yielded when this MRCP was conjugated into E. coli J53 with a transfer frequency of 10–4–10–5 transconjugants per donor. A bioinformatic analysis indicated that replicative transposition and homologous recombination of IS26 elements were particularly active, and the truncated Tn1721 also played a vital role in the formation of MRCP offspring. More importantly, when released from the chromosome, MRCP could capture and co-transfer adjacent chromosomal segments to form larger plasmid progeny than itself. Stability and growth kinetics assays showed that the biological characteristics of MRCP progeny were differentiated. This study provides an insight into a flexible existence of MRCP. The conversion between vertical and horizontal transmission endowed MRCP with genetic stability as a chromosomal coding structure and transferability as extra-chromosomal elements. This alternation may accelerate the acquisition and persistence of antibiotic resistance of clinical pathogens and enhance their ability to respond to adverse environments, which poses a great challenge to the traditional antibiotic treatment.

Maternal Serotonin: Shaping Developmental Patterns and Behavioral Strategy on Progeny in Molluscs

Serotonin is a well-known neurotransmitter and neurohormone regulating mood, sleep, feeding, and learning in high organisms. Serotonin also affects the embryonic events related to neurogenesis and maturation of hormonal systems, the underlying organism adaptation to a changing environment. Such serotonin-based mother-to-embryo signaling is realized via direct interactions in case of internal fertilization and embryonic development inside the mother body. However, the possibility of such signaling is less obvious in organisms with the ancestral type of embryogenesis and embryo development within the egg, outside the mother body. Our data, based on the investigation of freshwater gastropod molluscs (LymnaeaandHelisoma), demonstrated a correlation between seasonal variations of serotonin content within the female reproductive system, and developmental patterns and the behavioral characteristics of progeny. The direct action of serotonin via posttranslational protein modification—serotonylation—during early development, as well as classical receptor-mediated effects, underlies such serotonin-modulated developmental changes. In the present paper, I will shortly overview our results on freshwater molluscs and parallel the experimental data with the living strategy of these species occupying almost all Holarctic regions.

Impact of genetic potential for residual feed intake and diet fed during early- to mid-gestation in beef heifers on carcass characteristics and meat quality attributes of their castrated male offspring

Carcass attributes of steers were examined for influences of selection for residual feed intake (RFI), and exposure to different levels of prenatal nutrition. Heifers characterized for RFI corrected for backfat were mated to bulls with genetic potential for either High-RFI or Low-RFI, such that the progeny were expected to be H/H or L/L RFI (sire/dam). Pregnant heifers were assigned to a low diet (Ldiet; 0.40 kg/d ADG), or moderate diet (Mdiet; 0.57 kg/d ADG), from 30 to 150 days of gestation, after which all heifers were managed similarly. Steer offspring (n = 23) were also managed similarly until slaughter. Dressing percentage of steers from H-RFI dams/sires exposed to Ldiet during gestation was lower than all other groups (P = 0.02). Marbling was greater for steers from H-RFI parents, as was fat content of longissimus thoracis et lumborum and triceps brachii (P ≤ 0.02). Results suggest that parental selection for RFI and prenatal maternal diet can influence carcass characteristics of progeny.

The Influence of Maternal Dietary Intake During Mid-Gestation on Growth, Feedlot Performance, miRNA and mRNA Expression, and Carcass and Meat Quality of Resultant Offspring

This research analyzed how maternal plane of nutrition during mid-gestation impacts growth, blood metabolites, expression of microRNA and messenger RNA in skeletal muscle, feedlot performance, and carcass characteristics of progeny. Thirty-two cows were bred to the same Angus sire and fed to either maintain a body condition score (BCS) of 5.0 to 5.5 (maintenance [MAIN]; n = 15) or to lose 1 BCS (restriction [REST]; n = 17) over an 84-d period of mid-gestation. Following the second trimester, all cows were co-mingled and fed at maintenance for the remainder of gestation. Following the 84-d treatment period, REST cows had a lower (P < 0.01) BCS than MAIN cows. At the end of the third trimester, there was no difference (P = 0.78) in BCS between the treatment groups. There was no difference (P > 0.10) between offspring in birthweight, weaning weight, average daily gain, feed efficiency, dry matter intake, carcass yield, steak quality, or in circulating levels of glucose, cortisol, insulin, or insulin-like growth factor-1. REST offspring expressed more (P < 0.05) miR-133a, miR-133b, miR-181d, miR-214, miR-424 and miR-486 at weaning than MAIN offspring. At harvest, REST offspring expressed more (P < 0.05) miR-133a and less (P < 0.01) miR-486 than MAIN offspring. REST steaks were perceived as more tender (P = 0.05) by a trained sensory panel. These results indicate that maternal nutrient restriction during mid-gestation resulting in a loss of 1 BCS has an effect on microRNA expression in the skeletal muscle but does not alter postnatal growth potential, carcass quality, or end product quality of the offspring. This suggests that moderate restriction in maternal nutrition during the second trimester, which results in a drop in BCS that can be recovered during the third trimester, should not cause alarm for producers when considering future offspring performance.

71 Effects of timing of supplementation during late gestation in Bos indicus-influenced beef cows on post-weaning growth, immunity, and carcass characteristics of steer progeny

Abstract This study evaluated the growth, immunity, and carcass characteristics of beef steers born to cows offered dried distillers grains (DDG) at different timing during late gestation. Approximately 84 d before calving (d 0), 84 mature Brangus cows were stratified by BW and BCS (422 ± 42 kg; 5.0 ± 0.14) and allocated into 1 of 6 bahiagrass pastures (14 cows/pasture). Treatments were randomly assigned to pastures: 1) no prepartum supplementation (CON); 2) 1 kg/d DDG from d 0 to 84 (LATE84); or 3) 2 kg/d from d 0 to 42 (LATE42). Calves were weaned at 261 ± 23 d of age. At weaning, 38 steers were vaccinated against bovine viral diarrhea virus (BVDV-1) and parainfluenza-3 (PI-3) and transported to a feedlot facility. Steers were penned according to cow prepartum pasture distribution and fed a similar diet until slaughter (d 587). Data were analyzed as complete randomized design using MIXED procedure of SAS, pasture as the experimental unit, treatment as fixed effect, and pasture(treatment) and steer(pasture) as random effects. Steer feedlot BW, ADG, DMI, and G:F did not differ (P ≥ 0.12) among treatments. Plasma haptoglobin concentrations were greater (P ≤ 0.03) for LATE42 and LATE84 vs. CON steers 2 d after feedlot entry. Plasma cortisol and seroconversion for BVDV-1 and PI-3 did not differ (P ≥ 0.15) among treatments. The percentage of carcasses grading Choice did not differ (P = 0.13), but carcasses grading low Choice were greater (P = 0.03) for CON vs. LATE42, with LATE84 being intermediate (91, 40, and 58%, respectively). Thus, prepartum dried distillers grain supplementation to B. indicus-influenced cows did not enhance feedlot growth but had subtle positive impacts on carcass quality and innate immunity in steer progeny. In addition, timing of dried distillers grain supplementation (last 84 d vs. first 42 d of late gestation) did not impact steer post-weaning feedlot performance and carcass quality.

190 Winter vs. year-round supplementation of mature beef cows on feedlot performance and carcass characteristics of steer progeny

Abstract This study evaluated the effects of year-round supplementation of molasses/urea or wheat middlings-based range cubes to mature cows on subsequent feedlot growth, immunity, and carcass characteristics of their steer progeny. On d 0, 82 mature Brangus cows were stratified by BW and BCS (433 ± 47 kg; 4.6 ± 0.77) and randomly allocated into 1 of 6 bahiagrass pastures (13–14 cows/pasture). Treatments were randomly assigned to 2 pastures/treatment and consisted of supplementation with molasses/urea during winter (MOL-W), or year-round supplementation with molasses/urea (MOL-Y) or range cubes (CUB-Y). Supplements were isocaloric and isonitrogenous (75% TDN, 20% CP; DM basis) and offered at a total yearly supplement DM amount of 272 kg/cow. On d 423, all calves were weaned, and 33 steers were randomly selected for the feedlot phase. Steers were penned based on cow prepartum pasture distribution and managed similarly until slaughter (d 661). Data were analyzed as complete randomized design using MIXED procedure of SAS, pasture as the experimental unit, treatment as fixed effect, and pasture(treatment) and steer(pasture) as random effects. Dry matter intake did not differ (P ≥ 0.70), but MOL-Y and MOL-W steers had greater (P = 0.05) overall ADG vs. CUB-Y steers. Plasma haptoglobin concentrations tended (P = 0.06) to be greater for CUB-Y vs. MOL-W, and intermediate for MOL-Y. Serum titers against bovine viral diarrhea virus-1 and parainfluenza-3, hot carcass weight, REA, and YG did not differ (P ≥ 0.16) among treatments, but back fat thickness was greater (P = 0.03) for MOL-W vs. MOL-Y and CUB-Y. The percentage of carcasses grading Choice did not differ (P = 0.35) among treatments, but more carcasses tended (P = 0.08) to grade low Choice for MOL-W vs. CUB-Y and MOL-Y. Therefore, providing molasses/urea supplementation to mature beef cows during winter only or year-round increased steer post-weaning feedlot performance and carcass quality compared to steers born from cows offered year-round supplementation with range cubes.

Supplementation of rangeland primiparous Bos indicus x Bos taurus beef heifers during lactation. 1. Effects on dam milk production and liveweight, bull calf growth, live carcass characteristics and metabolic hormone concentrations

The practice of feeding replacement-breeding bulls on high energy diets after weaning to meet liveweight (LW) and carcass expectations between 18 and 24 months of age negatively affects reproductive potential. This experiment reports upon the effects of an alternative management strategy aimed at improving calfhood nutrition in rangeland-reared bulls to enhance LW and live carcass characteristics at 2 years. Following artificial insemination (AI cohort; n = 26), or natural mating, subsequent to the addition of bulls at 39 d post-AI (NM cohort; n = 36), primiparous Santa Gertrudis heifers grazing rangeland pastures with bull calf progeny were allocated at parturition to receive either nil supplement (control; CON) or provided with unrestricted access to a pelleted vegetable protein meal-based supplement containing 35% CP (SUPP) until weaning at 199 ± (SD) 26 d. The mean estimated pellet consumption by SUPP heifers during lactation was 2.6 ± (SEM) 0.5 kg DM daily. Grazing diet quality measurements indicated nutritional restriction of CON heifers until at least 115 d of lactation. This was confirmed by lower blood urea nitrogen concentrations at 88 d (P < 0.001) and greater mean NEFA (P < 0.001) concentrations. Rainfall during mid-lactation subsequently improved grazing diet quality; thus the CON heifers experienced moderate nutritional restriction across lactation, but sufficient to reduce milk yield by 1.6 kg/d (P < 0.001) and maternal LW at weaning by 18.4 kg (P < 0.001). Bulls reared by SUPP heifers were 17.5 kg heavier at weaning (P = 0.001) and had elevated IGF-I and leptin concentrations between 4 and 4.5 months of age (P < 0.05). Effects on metabolic hormones during calfhood were cohort specific, with greater concentrations of IGF-I confined to AISUPP bulls and NMSUPP bulls demonstrating greater concentrations of leptin. Bulls were amalgamated at weaning and grazed common pastures without supplementation until the experiment concluded at 675 d. Pre-weaning plane of nutrition did not affect the LW, carcass fat depth, IGF-I or leptin concentrations of bulls after weaning. Mean eye muscle area (EMA) was greater in SUPP compared to CON bulls (68.5 ± 0.9 cm2vs 65.2 ± 0.9 cm2; P < 0.05) and AISUPP bulls tended to have greater EMA (P = 0.06) than AICON bulls from 495 d of age. Thus when primiparous heifers experience moderate nutritional restriction during lactation, supplementation may have persistent effects upon increasing carcass muscle characteristics of bull progeny.

Effect of including n-3/ n-6 fatty acid feed sources in diet on fertility and hatchability of broiler breeders and post-hatch performance and carcass parameters of progeny.

ObjectiveThe present trial was conducted to determine the influence of different dietary fatty acid (omega-3 and omega-6) sources on reproductive performance of female broiler breeders and growth performance and carcass traits of their progeny.MethodsTwo hundred and twenty, 25 weeks old Ross-308 male (20) and female (200) broiler breeders were used in the experiment for the period of 6 weeks. All birds were randomly divided into four dietary treatments (containing 2% soybean oil, 2% sunflower oil, 2% flaxseed oil, and 2% fish oil) each with five replicates of one male and ten females. Throughout this experiment hatching performance of broiler breeders, progeny growth performance and carcass parameters were recorded.ResultsThe results showed that the inclusion of different fatty acid sources in female broiler breeders diet had no significant effects (p>0.05) on number of fertile eggs, post-hatch mortality, and fertility rate. The soybean oil supplemented group had significantly (p<0.05) higher late embryonic mortality compared to other three treatments.ConclusionIt was concluded that inclusion of 2% of different sources of omega-3 and omega-6 fatty acids (especially 2% flax seed oil) in broiler breeders’ diet can reduce late embryonic mortality. The other reproductive characteristics of parents and growth and carcass characteristics of progeny remained unaltered by dietary sources of omega-3 and omega-6 fatty acids.

Influence of maternal protein restriction in primiparous heifers during mid- and/or late-gestation on meat quality and fatty acid profile of progeny

The objective of this study was to evaluate the influence of metabolizable protein (MP) restriction in mid- and/or late-gestation on meat quality characteristics of progeny. Heifers were assigned to 2 levels of dietary protein (control [CON], 102% of MP requirements; or restricted [RES], 80% of MP requirements) at 2 stages of gestation (mid-gestation [MID] and late-gestation [LATE]) in a Balaam's Design crossover treatment structure resulting in 4 treatment combinations (CON-CON, CON-RES, RES-CON, RES-RES). A carryover effect of MID MP treatment on LATE CON indicated CON-CON steaks were more tender (P < .001) than RES CON. Mid-gestation restriction resulted in progeny with increased (P < .05) carcass water, soft tissue moisture, and decreased soft tissue fat percentage compared with progeny from dams receiving MID CON. Reduced maternal MP also differentially influenced the fatty acid profiles of progeny. Results suggest it is possible for progeny to overcome a moderate gestational MP restriction with minimal impacts on carcass composition or meat characteristics.

Optimized graded screen array configuration for particle size distribution of radon progeny in standard chamber

Particle size distribution of radon progeny is one of the most important parameters and it needs to be measured accurately. Graded screen array measurement is the most frequently used method for analyzing the characteristics of radon progeny but it needs optimization due to its complex configuration. In this paper, collection efficiency of a single screen and the number of screen array were applied for optimization and simplification of the graded screen array configuration by a series of experimental measurements, theoretical calculations, and standard comparison research methods. When optimized in this way, an experiment was designed for radon progeny particle size distribution in a customized radon chamber. The experiment results indicated that the activity median diameter in unattached mode was 0.81 nm and 287.32 nm in attached mode, which were similar to the results obtained by other researchers. The results prove that the method can satisfy the requirements of graded screen array measurement.

Radiobiological characteristics of descendant progeny of fish and amphibian cells that survive the initial ionizing radiation dose

PurposeTo evaluate the development of delayed lethal mutations, the production of medium borne lethal bystander signals, and the acquirement of radiosensitive or radioresistant traits in distant descendant progeny of fish and amphibian cells surviving ionizing radiation Materials and methodsAmerican eel brain endothelial cells (eelB) and African clawed frog epithelial cells (A6) were initially irradiated with gamma rays at 0.5 Gy or 2 Gy. Ionizing radiation (IR)-surviving cells were grown for 27 population doublings (PDs) for eelB and 43 PDs for A6. Reproductive cell death as quantified by clonogenic survival assays was used to determine the development of delayed lethal mutations, the production of medium borne lethal bystander signals, and the acquirement of radiosensitive or radioresistant traits in the progeny survivors. ResultsOnly medium borne bystander signals produced by 2-Gy-irradiated eelB progeny survivors at 12 PDs could reduce the clonogenic survival of the bystander reporter cells. IR-induced delayed lethal mutations occurred in irradiated eelB cells at 15–18 PDs; however, subsequently propagated progeny cells retained normal replicative abilities. No IR-induced delayed lethal mutations developed in progeny of irradiated A6 cells at up to 43 PDs. eelB progeny survivors did not develop new radiosensitive or radioresistant traits while A6 progeny survivors acquired a new radiosensitive characteristic. ConclusionThis study enriches the current literature on the radiobiological characteristics of distant surviving progeny of irradiated fish and amphibian cells and highlights cell-type/species-dependent differential responses to IR. This study is the first to examine the potential transgenerational effects of progenitor irradiation in amphibian cells.

0018 Impact of maternal protein restriction in first-calf heifers during mid- to late- gestation on gene expression, feedlot performance, and carcass characteristics of progeny

0018 Impact of maternal protein restriction in first-calf heifers during mid- to late- gestation on gene expression, feedlot performance, and carcass characteristics of progeny

Influence of prepartum dietary energy on beef cow performance and calf growth and carcass characteristics

Objectives were to evaluate the effects of prepartum dietary energy intake on cow performance as well as performance and carcass characteristics of subsequent progeny. Spring-calving, mature cows (n=106 total) were blocked by BW and allotted to 1 of 2 treatments: ground hay and dried distillers grains plus solubles (REQ: TDN=61.8%, CP=11.0%, fat=2.1%), or corn bran and ground cornstalks (HE: TDN=70.3%, CP=10.0%, fat=5.7%). Treatments were limit-fed as isonitrogenous rations with REQ and HE providing 100% and 125% of TDN requirements, respectively, and were fed from 83±10d prepartum to calving. All cows were fed a common diet postpartum. Cow BW and BCS were recorded at the beginning of the feeding period, 24h post-calving, and at breeding. Milk production was estimated via the weigh–suckle–weigh technique 65±9 and 120±9d postpartum. Calf BW was measured at birth and at weaning (120±9d of age). Calves (n=86) were fed a common feedlot diet beginning 2d after weaning, and individual feed intake was monitored using GrowSafe. Progeny were slaughtered in 3 groups at an average 12th rib fat thickness of 1.3cm. From initiation of experiment to breeding, cow BW change was greater (P<0.01) and BCS change tended to be greater (P=0.09) for HE relative to REQ cows. Birth BW was greater (P=0.02) for calves born to cows fed HE with no increase (P=0.30) in percentage of unassisted births. There were no effects (P≥0.27) of treatment on calving date, milk production, or subsequent pregnancy rate. Calf weaning BW, initial feedlot BW, final BW, and days on feed were not affected (P≥0.20) by treatment. Feedlot DMI, ADG, and G:F were not different (P≥0.35). There was no effect (P≥0.27) of treatment on progeny morbidity. Although progeny born to HE dams tended (P=0.10) to have greater marbling scores at weaning, there was no effect (P≥0.60) of treatment on carcass marbling score or other carcass traits. Feeding cows 125% of TDN requirement during late gestation increased cow BW change and progeny birth body weight. Feeding cows 125% of TDN requirement during late gestation had no effect on pregnancy rate or progeny performance.

Influence of late gestation drylot rations differing in protein degradability and fat content on beef cow and subsequent calf performance.

Spring-calving, mature cows ( = 191 total) and their progeny were used to evaluate the effects of late gestation drylot rations differing in RUP and fat content on cow performance as well as performance and carcass characteristics of subsequent progeny. Cows were blocked by BW and anticipated calving date and assigned to 16 pens. Pens were randomly allotted to 1 of 2 treatments: limit-fed corn coproducts and ground cornstalks (COP; TDN = 64.4%, CP = 11.1%, RDP = 60.2% of CP, and fat = 5.1%) or limit-fed ground mixed, cool-season grass hay (HY; TDN = 55.7%, CP = 9.5%, RDP = 86.0% of CP, and fat = 2.3%). Treatments were limit fed as isocaloric, isonitrogenous rations from 88 ± 11 d prepartum to calving. All cows were fed a common diet postpartum. Cow BW and BCS were collected at the beginning of the feeding period, within 48 h after calving, and at breeding. Calf BW was collected at birth and at 64 ± 11 and 124 ± 11 d of age. Milk production was determined using the weigh-suckle-weigh technique at 64 ± 11 and 124 ± 11 d postpartum. At 124 ± 11 d of age, steers ( = 68) and nonreplacement heifer calves ( = 25) were weaned and placed on a common feedlot diet with individual feed intake monitored using GrowSafe. Feedlot calves were slaughtered at a commercial facility 35 ± 10 d after a minimum ultrasound 12-rib fat thickness estimation of 0.9 cm. After calving, cow BW was greater ( < 0.01) and BCS was greater ( < 0.01) for cows fed COP than for cows fed HY. Calf birth BW was greater ( = 0.04) for those born to cows fed COP with no difference ( = 0.43) in percentage of unassisted births across treatment. Cows fed HY were lighter ( < 0.01) at breeding with lower BCS ( = 0.03); nevertheless, overall pregnancy rate was not different ( = 0.80). No differences ( ≥ 0.22) in milk production were detected. For feedlot progeny, initial feedlot BW, final BW, and days on feed were not different ( ≥ 0.23), and as a result, no difference ( = 0.21) in feedlot ADG was detected. Feedlot DMI and G:F were not different ( ≥ 0.19) across treatments. Feedlot calf health was monitored with no differences ( ≥ 0.68) in morbidity and mortality observed. No differences ( ≥ 0.27) were detected for HCW, LM area, backfat, marbling score, yield grade, or KPH. Increased dietary RUP and fat content during late gestation increased cow BW and BCS but did not alter milk production, subsequent reproduction, or subsequent calf performance or carcass characteristics.

Techniques to alleviate nuisance alarms observed by PCMs following 222Rn-progeny deposition on clothing.

This paper presents technically-based techniques to deal with nuisance personnel contamination monitor (PCM) alarms. The techniques derive from the fundamental physical characteristics of radon progeny. Some PCM alarms, although valid alarms and not actually "false," could be due to nuisance naturally-occurring radionuclides (i.e., radon progeny). Based on certain observed characteristics of the radon progeny, several prompt techniques are discussed that could either remediate or at least mitigate the problem of nuisance alarms. Examples are provided which demonstrate the effective use of the techniques.

Characteristics of Progeny Obtained from the Cross between Geraniums (Pelargonium^|^times;hortorum) and Wild Species in Section Ciconium, Including Heat Tolerance and Odor of Leaves

Characteristics of Progeny Obtained from the Cross between Geraniums (Pelargonium^|^times;hortorum) and Wild Species in Section Ciconium, Including Heat Tolerance and Odor of Leaves

Genetic characterization of the progeny of a pair of the tetraploid silver crucian carp Carassius auratus langsdorfii

Silver crucian carp Carassius auratus langsdorfii comprises a diploid-polyploid complex in wild Japanese populations. Bisexually reproducing diploids are sympatrically distributed with gynogenetically developing triploids and tetraploids. Triploid and tetraploid males are very rare among Japanese silver crucian carp due to their gynogenetic reproduction. We examined the genetic characteristics of progeny that arose in a tank by natural spawning of a tetraploid silver crucian carp pair. The ploidy status of 120 samples randomly collected from these progeny was determined to be tetraploid by DNA content flow cytometry. DNA fingerprints from a random amplified polymorphic DNA assay indicated that almost all the progeny examined had genotypes identical to the maternal tetraploid female with no paternally derived fragments. Selected specimens’ cytogenetic analyses revealed that the progeny examined had tetraploid chromosome numbers, categorized into 40 metacentric, 80 submetacentric, and 80 subtelocentric or telocentric chromosomes, which were arranged into quartets and six supernumerary microchromosomes. Fluorescence in situ hybridization signals were detected in four homologous chromosomes in all analyzed metaphases prepared from diploid goldfish specimens. Contrary, tetraploid silver crucian carp gave eight rDNA signals. These results suggest that gynogenetic development in eggs spawned by tetraploid females should be triggered by tetraploid males’ homospecific sperm.

Importance of average litter weight and individual birth weight for early postnatal performance and myofiber characteristics of progeny

Recent evidence suggests that different patterns of prenatal survival causing different levels of intrauterine crowding are occurring in prolific sows bearing litters with 10–15 piglets born, resulting in marked differences in average litter birth weight. Because early intrauterine crowding of embryos is known to have negative effects on prenatal development, the objective of the study was to compare litter characteristics, as well as histomorphometrical and molecular traits of myofibers of selected offspring born from litters of high (H: >1.7kg) and low (L: <1.3kg) average birth weight. The selected newborn littermates were either two females representing the intermediate (HI: 1.73kg) and low (HL: 1.41kg) birth weight from H-litters or two females representing the intermediate (LI: 1.26kg) and high (LH: 1.55kg) birth weight from L-litters. These piglets were sacrificed the day of birth and the longissimus (LM) and semitendinosus (ST) muscles were collected. The average birth weight of the selected HI and LI piglets differed (P<0.05) whereas that of the HL and LH piglets was similar. From birth to weaning, H-offspring grew faster (P<0.05), which was associated with greater (P<0.05) body weight loss of H-compared with L-sows during lactation, where their feed intake did not differ. In LI offspring, brain proportion of birth weight and brain to ST ratio was greater (P<0.05) than in HI but similar between LH and HL progenies. Expressed per mm2, the dark portion of the ST of HI piglets had fewer (P<0.05) primary but similar secondary myofiber numbers compared to LI progeny. Nevertheless, due to the larger ST, total myofiber number was greater in HI and LH than LI piglets. In the LM, myofiber characteristics were similar across birth weight classes, except for the greater (P<0.10) secondary to primary myofiber ratio in HL than LH offspring. In the ST, but not in the LM, the expression of the myoblast differentiation factor 1 was greater (P<0.05) in LH than HL offspring. No birth weight class differences occurred in myosin heavy chain isoform distribution in the LM. In conclusion, female progenies falling in the mid-weight range of the L-litters, but not their heavier littermates, carried some negative phenotypic traits normally associated with intrauterine growth restriction, such as greater brain to ST ratio and impaired myofiber hyperplasia.

Biological Characteristics ofTrichospilus diatraeae(Hymenoptera: Eulophidae) are Influenced by the Number of Females Exposed Per Pupa ofTenebrio molitor(Coleoptera: Tenebrionidae)

Different numbers of parasitoid females confined with a host can variously affect the number, sex ratio and other characteristics of the parasitoid's progeny. The objective of this study was to elucidate the effects of various ratios of Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) females to pupae of one its hosts, Tenebrio molitor L. (Coleoptera: Tenebrionidae), primarily on the number of this parasitoid's progeny and their sex ratio. Both the parasitoid and the host used in this study were taken from cultures reared in the laboratory by standard methods. In order to minimize the effects of variations in host weight, 24 h-old T. molitor pupae weighing between 0.110 and 0.140 g were held as a single individuals in glass tubes (2.5 cm Ø × 14 cm L) with 48 h-old T. diatraeae females for 72 h to allow parasitization. After this period, female wasps were removed and the host pupa were transferred, one per glass tube, to a climate-controlled room at 25 ± 2 °C, 70 ± 10% RH and 12:12 h L:D. The experimental design was completely randomized with six treatments (parasitoid-host ratios) and 12 replicates per treatment. The ratios of T. diatraeae females per host used were: 1:1, 7:1, 14:1, 21:1, 28:1 and 32:1. The percentage parasitism of T. diatraeae on T. molitor pupae was 33.33, 82.00 and 83.33% at ratios of 1:1, 7:1 and 14:1, respectively, and 100% at all other ratios. The emergence of T. diatraeae adults from parasitized pupae was 75% at a parasitoid-host ratio of 1:1 and 100% at ratios of 21:1, 28:1 and 32:1. The duration of the parasitoid's life cycle ranged from 21.00 ± 2.22 to 24.00 ± 2.00 days at parasitoid-host ratios of 32:1 and 1:1, respectively. The number of T. diatraeae progeny per T. molitor pupa was highest at a ratio of 21:1 (246.50 ± 50.18). The proportion of T. diatraeae females in the offspring decreased as the parasitoid-host ratio increased, varying between 0.82 ± 0.06 and 0.97 ± 0.01. A parasitoid-host ratio of 21:1 T. diatraeae females per T. molitor pupa is considered the most adequate and appropriate for mass-rearing of this parasitoid. Tenebrio molitor appears to be a suitable alternate host for efficient mass-rearing of T. diatraeae for biological control of lepidopteran pests. At the parasitoid-host ratio of 21:1, each T. molitor pupa supported the production of 246.5 parsitoids of which 88% were females, i.e., 216.9 females and 29.6 males; each T. diatraeae female produced 9.55 ± 0.48 female progeny, and the developmental time from egg to adult was 20.4 days.