Effect on production and carcass quality characteristics of wether lambs of crossing Blackheaded Mutton,Ile de France and Texel rams with Polish Merino ewes

During the period 1972–1974 investigations were made on 120 wethers fattened semi-intensively to a weight of 45 kg liveweight. These lambs originated from commercial crosses of the Polish Merino with rams of the breeds Blackheaded Mutton (B), Ile de France (IF) and Texel (T) as well as pure Merino (M) in the control group.The use of rams of these meat-producing breeds as compared with Merino gave a better growth rate: an increase in the group IF × M of 6.2%, B × M of 7.8% and T × M of 8.8% respectively. The feed consumption, expressed in starch equivalents per kg of weight, decreased in group IF × M by 11.6%, B × M by 15.1% and T × M by 15.6%, and total digestible protein decreased in the group IF × M by 12.1%, B × M by 16.6% and T × M by 16.9%.Crosses with Blackheaded Mutton and Ile de France rams did not fundamentally change the tissue composition of the lamb carcasses. However, the use of Texel rams resulted in carcasses with a higher lean content and less fat as compared with pure Merino (difference 5.7%) as well as with other crosses (differences 4.2–4.8%).Rams of the meat breeds tested did not greatly influence dressing percentage and carcass yield in terms of bone content and the proportion of valuable cuts; nor were dimensions affected, except for a decrease in length of 2–3.5% compared with Merino.     

Optimization of sperm irradiation protocol for induced gynogenesis in Siberian sturgeon,Acipenser baerii

The great diversity of optimal UV irradiation doses are used for DNA inactivation in fish sperm forcing authors to repeat optimization of irradiation treatment every time. Analysis of sperm UV irradiation protocol for induction of gynogenesis showed the importance of sperm UV light absorption estimations. The UV absorption investigation in Siberian sturgeon sperm showed average extinction coefficient 7.69 × 10^?8 ± 1.04 × 10^?8 cm². It is resulted in high heterogeneity of UV irradiation of undiluted sperm samples. Therefore, it is strongly suggested to specify doses only with defined concentration of spermatozoa; otherwise, the difference in absorbance level between samples can bring a significant error to optimal UV dose estimation. This was confirmed by UV-irradiated sperm motility investigation. Results of motility investigation of UV-irradiated sperm revealed high sensitivity of Siberian sturgeon spermatozoa motion mechanisms to UV irradiation, with complete loss of motility after homogeneous UV irradiation at doses above 2,000 J/m². Partial gynogenesis was conducted using diluted and undiluted sperm. Ploidy level of hatched larvae was estimated by flow cytometry. Percentage of haploid hatched larvae revealed sperm DNA inactivation efficiency. The highest percentage of haploid putative gynogenotes 19.67 ± 4.19 % was obtained at UV irradiation dose 200 J/m² with sperm diluted to 1:4.     

The antioxidant system of sterlet seminal fluid in testes and Wolffian ducts

Oxidative stress is a possible source of spermatozoa function deterioration. Seminal fluid (SF) protects spermatozoa against reactive oxygen species (ROS) attack during development in testes and transit through the reproductive tract. Spermatozoa curvilinear velocity and percent of motile cells as well as changes in thiobarbituric acid-reactive substance (TBARS) content, superoxide dismutase, and catalase activity, and uric acid concentration in SF were evaluated in sterlet sperm collected from testes 24 h after hormone induction of spermiation and from Wolffian ducts at 12, 24, 36, and 60 h after hormone injection (HI). While testicular spermatozoa motility was not initiated in activating medium, Wolffian duct sperm showed low motility at 12 h, significant increase at 24 and 36 h, and decrease at 60 h. Testicular SF was characterized by the highest level of TBARS and activity of studied enzymes compared with SF from Wolffian duct sperm at 24 h post-HI. In fluid from Wolffian duct sperm, a significant increase in TBARS content was shown at 36–60 h post-HI. In contrast to testicular SF, in SF from Wolffian duct sperm, this increase was not counterbalanced by changes in the studied variables of antioxidant system. This may be the source of the observed decrease in spermatozoa motility parameters 60 h post-HI. The results may confirm a dual role of ROS in fish sperm physiology. The data with respect to decrease in sturgeon spermatozoa motility parameters at 60 h post-HI should be taken into account in artificial sturgeon propagation.     

Protective role of antifreeze proteins on sterlet (<Emphasis Type="Italic">Acipenser ruthenus</Emphasis>) sperm during cryopreservation

The loss of sperm quality in sterlet (Acipenser ruthenus) due to freeze-thaw process in cryopreservation was investigated in the present study. Two antifreeze proteins (AFPI or AFPIII) were used at different concentrations of 0.1, 1, 10, and 100 μg/mL. We compared motility, curvilinear velocity, and plasma membrane integrity of fresh, cryopreserved sperm, and sperm cryopreserved in the presence of antifreeze proteins. Fresh sperm (control) had 85?±?4% motility and 160?±?2 μm/s curvilinear velocity, respectively. After cryopreservation, the motility of frozen-thawed sperm without addition of antifreeze proteins significantly decreased (44?±?9%), compared to the control. The highest motility of frozen-thawed sperm was obtained in cryopreserved sperm with addition of 1 μg/mL of AFPIII (58?±?14%). No significant differences were observed in curvilinear velocity between fresh sperm and cryopreserved sperm with/without addition of AFPI or AFPIII. The flow cytometry analysis revealed that fresh sperm contained 94.5?±?6% live cells, while the cryopreserved sperm only contained 26.6?±?14% live cells. Supplementation of antifreeze proteins has significantly improved the percentage of live cells in frozen-thawed sperm, except 0.1 μg/ml of AFPI group. No significant difference in percentage of live cells was detected in the sperm cryopreserved with 10 μg/mL of AFPI or AFPIII, compared to fresh sperm. Thus, addition of antifreeze proteins to cryopreservation medium could be considered to improve the post-thawed sperm quality of sterlet.     

The effects of mechanical fuel reduction treatments on the activity of bark beetles (Coleoptera: Scolytidae) infesting ponderosa pine

Selective logging, fire suppression, forest succession and climatic changes have resulted in high fire hazards over large areas of the western USA. Federal and state hazardous fuel reduction programs have increased accordingly to reduce the risk, extent and severity of these events, particularly in the wildland–urban interface. In this study, we examined the effects of mechanical fuel reduction treatments on the activity of bark beetles in ponderosa pine, Pinus ponderosa Dougl ex. Laws., forests located in Arizona and California, USA. Treatments were applied in both late spring (April–May) and late summer (August–September) and included: (1) thinned biomass chipped and randomly dispersed within each 0.4 ha plot; (2) thinned biomass chipped, randomly dispersed within each plot and raked 2 m from the base of residual trees; (3) thinned biomass lopped-and-scattered (thinned trees cut into 1–2 m lengths) within each plot; (4) an untreated control. The mean percentage of residual trees attacked by bark beetles ranged from 2.0% (untreated control) to 30.2% (plots thinned in spring with all biomass chipped). A three-fold increase in the percentage of trees attacked by bark beetles was observed in chipped versus lopped-and-scattered plots. Bark beetle colonization of residual trees was higher during spring treatments, which corresponded with peak adult beetle flight periods as measured by funnel trap captures. Raking chips away from the base of residual trees did not significantly affect attack rates. Several bark beetle species were present including the roundheaded pine beetle, Dendroctonus adjunctus Blandford (AZ), western pine beetle, D. brevicomis LeConte (AZ and CA), mountain pine beetle, D. ponderosae Hopkins (CA), red turpentine beetle, D. valens LeConte (AZ and CA), Arizona fivespined ips, Ips lecontei Swaine (AZ), California fivespined ips, I. paraconfusus Lanier (CA) and pine engraver, I. pini (Say) (AZ). Dendroctonus valens was the most common bark beetle infesting residual trees. A significant correlation was found between the number of trees chipped per plot and the percentage of residual trees with D. valens attacks. A significantly higher percentage of residual trees was attacked by D. brevicomis in plots that were chipped in spring compared to the untreated control. In lopped-and-scattered treatments, engraver beetles produced substantial broods in logging debris, but few attacks were observed on standing trees. At present, no significant difference in tree mortality exists among treatments. A few trees appeared to have died solely from D. valens attacks, as no other scolytids were observed in the upper bole. In a laboratory study conducted to provide an explanation for the bark beetle responses observed in this study, monoterpene elution rates from chip piles declined sharply over time, but were relatively constant in lopped-and-piled treatments. The quantities of β-pinene, 3-carene, -pinene and myrcene eluting from chips exceeded those from lopped-and-piled slash during each of 15 sample periods. These laboratory results may, in part, explain the bark beetle response observed in chipping treatments. The implications of these results to sustainable forest management are discussed.     

The role of Ca2+ and Na+ membrane transport in brook trout (Salvelinus fontinalis) spermatozoa motility

The role of environmental ion composition and osmolality in Ca²⁺ signaled activation was assessed in spermatozoa of brook trout Salvelinus fontinalis. Milt from ten mature males was obtained by abdominal massage. Spermatozoa motility was evaluated in 0, 100, and 300 mOsm/kg NaCl or sucrose solutions, buffered by 10 mM Tris–HCl pH 8.5. For investigation of spermatozoa reaction to external Ca²⁺ concentration, 2 mM ethylene glycol tetraacetic acid (EGTA) was added to the activation media as a calcium ions chelator. For investigation of the effect of external Na⁺ concentration in conditions of low external Ca²⁺, 100 µM amiloride was added to the EGTA-containing solutions as a Na⁺ transport blocker. Low motility was observed in sucrose (Na⁺ free) solutions containing 2 mM EGTA but not in Na⁺ solutions containing 2 mM EGTA. Addition of amiloride led to significantly increased motility (P < 0.05) compared with sucrose (Na⁺ free) solutions containing 2 mM EGTA. We conclude that Na⁺ transport in Ca²⁺-free solutions plays a regulatory role in brook trout spermatozoa activation. The influence of competitive Na⁺ and Ca²⁺ transport on the control of spermatozoa activation requires further study with respect to its application for improvement of artificial activation and storage media.     

Comparison of Protein Fractions in Seminal Plasma from Multiple Sperm Collections in Sterlet (Acipenser ruthenus)

Seminal plasma of sterlet Acipenser ruthenus was evaluated using comparative proteomics to characterize its protein fractions and to determine any influence of multiple sperm collections on these proteins. An experimental group of fish was used, in which sperm was collected three times at 5 h intervals. Protein fractions of seminal plasma were determined by SDS‐gel electrophoresis (SDS‐PAGE) and two‐dimensional electrophoresis high‐resolution gels (2D). At all stripping times, five protein bands with molecular weights of 93, 53, 48, 33 and 28 kDa were identified using SDS‐PAGE. No significant differences (p > 0.05) in relative mass of protein bands among collections were observed. At the third collection, 20 protein spots were detected from the two‐dimensional gels, compared to 17 found at the first and second collections. Ten protein spots, from the third stripping, were analysed. Screening of these spots by mass spectrometric analysis showed positive results for spot 10. Direct comparison across public databases revealed sequence similarity with two hypothetical proteins, MCAG_00854 and IscW_ISCW011489. Differences in the seminal plasma protein fractions were found at the third stripping compared to the first two. It is hypothesized that these extra proteins after the third collection could be involved in some step of intracellular mechanism which is responsible for regulating of spermatozoa motility. However, protein identification revealed no significant distinction for any protein spot and protein sequences available in public databases. These results highlighted the need for a complete genome sequences for sturgeons.     

Trueness-To-Type and Yield Components of the Banana Hybrid Cultivar FHIA-18 Plants Regenerated Via Somatic Embryogenesis in a Bioreactor

Summary A population of 1,500 plants of the banana hybrid ‘FHIA-18’ (AAAB), regenerated from somatic embryos, which were multiplied in bioreactors, showed similar characteristics to plants propagated from shoot tip cultures both in the acclimatization stage and in field experiments carried out in Cuba. The plants originating from somatic embryos were similar to the plants obtained from shoot tips with respect to plant height, diameter of the pseudostem and number of suckers. Both groups of plants obtained from in vitro cultures were significantly different to the plants obtained from suckers during the flowering period of the mother plants, which was shortened by two months. The greater plant height and diameter of the pseudostem in the plants coming from somatic embryos and shoot tip is due to the effect of in vitro culture, and this was observed in different banana and plantain cultivars. During the second cycle of evaluation, the plants coming from the three propagation methods studied in this work had similar growth habits without significant differences in the majority of the morphological parameters evaluated. These results confirm that the difference obtained during the first cycle between the distinct populations is attributed to temporary changes. The original characteristics of the cultivar were evident from the second cycle of culture. Only 0.13% somaclonal variant was observed in the plants coming from somatic embryogenesis. These percentages are low taking into consideration that other propagated methods accept up to 5% variants in field conditions.     

The couch grass rhizome with Heterobasidion annosum fruiting bodies in afforested post‐agricultural land

The pathogenic fungus Heterobasidion annosum was identified in the rhizome of a couch grass (Elymus repens) using genetic markers. The couch grass grew in the proximity of a Scots pine stand that was visibly affected by the pathogen. The rDNA analysis showed 100% sequence similarity between two H. annosum sequences of ITS1 and ITS2 obtained from fruiting bodies found on the couch grass rhizome and on the stem of the Scots pine. These results indicate a close relationship between the two isolates of H. annosum and that they are derived from a common ancestor. The results show that H. annosum mycelia can infect couch grass rhizomes and subsequently produce fruiting bodies. It also suggests that the known modes of infection of tree roots by this pathogen in coniferous stands should take into account couch grass rhizomes in the dispersal of the disease in afforested post‐agricultural soils.     

Pre-spawning water temperature affects sperm respiration and reactivation parameters in male carps

Concentration, ability to motility, motility during the second activation (reactivation), and endogenous respiration were studied in sperm from two experimental groups of carp males. Group 1 was maintained for 7 days at 15°C (cold water (CW) group), whereas the second group was subjected to a temperature of 20°C (warm water (WW) group) before sperm sampling. Reactivation were achieved after incubation of firstly activated sperm in media with osmotic pressure adjusted up to 300 mOsm*kg⁻¹ by increasing K⁺ concentration. Statistically significant reduction of spermatozoa concentration in CW samples versus WW (from 46.0 ± 12.5 (15°C) to 59.3 ± 7 10⁹ (20°C) spermatozoa /ml) have been observed. The sperm of the CW group required a significantly longer incubation time (37 min) under isotonic conditions to achieve a maximum percentage of potent motility at repeated activation than the WW group (23 min). After activation of sperm motility, an increase of respiration rate up to maximum level has been found, this level remained the same under condition of recovering the potential to repeated activation. During the sperm movement respiration rate, in CW group (6.1 nmolO₂/min/10⁹spermatozoa) and WW (3.9 nmolO₂/min/10⁹spermatozoa), was significant higher compared to nonactivated sperm (2.4 nmolO₂/min/10⁹spermatozoa for CW and 1.1 nmolO₂ /min/10⁹spermatozoa for WW). And keeping males for 7 days at 15°C increase the respiration rate of sperm.