Media and methods for the cryopreservation of European eel (Anguilla anguilla) sperm

Different media and protocols were assayed for European eel sperm cryopreservation.     

Nutritional efficiency of feed-restricted F1 Holstein/Zebu cows in early lactation

Tropical Animal Health and Production - The quantitative feed restriction of lactating cows has been used in intensive production systems as a strategy to reduce production costs. However, the...     

Effects of boron excess in nutrient solution on growth,mineral nutrition,and physiological parameters of Jatropha curcas seedlings

Jatropha curcas L. has recently attracted the attention of the international research community due to its potential as a biodiesel crop. In addition, its high resistance to drought and salinity is well known. Under arid and semiarid conditions, boron (B) concentrations in irrigation water can be higher than desired when water from industry, urban areas, or desalination is used. However, the growth and physiological responses of J. curcas plants to B excess in the irrigation water are unknown. Therefore, a greenhouse experiment was conducted to study the effects of B excess in the nutrient solution (0.25, 2, 4.5, and 7 mg L^–1 B, applied as H₃BO₃) on plant growth, mineral concentration in the different plant tissues, photosynthesis, water relations, chlorophyll fluorescence, chlorophyll concentration (as SPAD values), and composition of carbohydrates. Plant growth decreased with increasing B concentration in the nutrient solution; growth reduction was higher for roots than for leaves or stems. The B concentration increased in all plant tissues, in the following order: leaf > root > stem. These data indicate that the roots of J. curcas are more sensitive to B toxicity than the leaves and that B has restricted mobility inside these plants, accumulating mainly in the basal and middle leaves via the transpiration stream. Increasing B concentration in leaves decreased the A_CO2 and the stomatal conductance, but the leaf water parameters were not affected. The data for chlorophyll concentration and chlorophyll fluorescence indicated that nonstomatal factors were involved in the A_CO2 decline, whereas decreases in the parameters of PSII photochemistry due to B toxicity suggest that there was structural damage in chloroplasts. There was also a general tendency for a decrease in nonstructural carbohydrates in all plant tissues, possibly due to the decline in A_CO2. With excess B, the concentrations of K and Mg increased in leaves due to a decrease in the growth, while a typical antagonistic effect between B and P was evident from the P concentration decrease in leaves. In summary, J. curcas should be considered a B‐sensitive plant, as a leaf B concentration of 1.2 mg (g dw)^–1 caused a growth decline of approximately 30%.     

Leishmania (Leishmania) chagasi is not vertically transmitted in dogs.

The most frequent and most important mode of human or canine visceral leishmaniasis (CVL) transmission is through the bite of infected sand flies. This study investigates Leishmania (Leishmania) chagasi vertical transmission in offspring of naturally infected dogs. Thus 63 puppies from 18 female dogs with CVL were used. Parasite presence was evaluated through parasitologic and histopathologic examination of lymphatic organs, as well as polymerase chain reaction (PCR) on samples from adults (milk, uterus, placenta, spleen, liver and bone marrow) and offspring (spleen, liver, lymph nodes and bone marrow). PCR sensitivity and specificity were calculated using a microscope as the gold standard on samples of bone marrow, spleen and liver. Specificity was 100% for all organs and sensitivity was 100% for bone marrow, 71.4% for spleen and 66.6% for liver. Bone marrow smears (n = 63), histopathology and imprint of spleen (n = 25), liver (n = 25) and lymph nodes (n = 25) were performed to evaluate congenital transmission in the 63 offspring. PCR was done on 92 samples collected from 56 of the offspring. No test performed on the offspring was positive. It was not possible to confirm vertical transmission of CVL (95% confidence interval for the observed prevalence), despite positive PCR in the placenta of seropositive adults.     

Genetic mapping of a major gene delaying blooming time in almond

The objective of this study was to determine the genetic basis of late blooming in almond. Molecular markers were used to study the Late bloom gene (Lb), responsible for a delay of blooming time, in an F₁ segregating population of 134 plants. Using a qualitative approach, the Lb gene was located on linkage group 4 of the almond map, flanked by markers AG6 and FG3. The quantitative analysis confirmed the presence of a major gene on linkage group 4, which explained at least 79% of the phenotypic variation. On average, the plants with the Lb allele bloomed 15 days later and the Lb allele showed dominant gene action. In addition, three RAPD markers associated with the Lb gene were identified by bulked segregant analysis. One was placed at 5.4 cM from Lb and could be used as a diagnostic marker for flowering time.     

Effect of salinity on growth,mineral composition,and water relations of grafted tomato plants

A greenhouse experiment was designed in order to evaluate growth, water relations, and nutrient concentrations of grafted and ungrafted tomato plants grown under varying levels of salinity (0, 30, or 60 mM NaCl). Two cultivars, ‘Fanny’ and ‘Goldmar’, were grafted onto AR‐9704, using the cleft‐grafting method. Growth of grafted ‘Fanny’ plants was higher than that of ungrafted plants. Growth of ‘Goldmar’ plants was not affected by salinity treatments or grafting, but it was slower than for ‘Fanny’. Leaf turgor showed no significant differences between grafted and ungrafted plants or between salinity levels. The stomatal conductance (G_s) was higher for grafted than for ungrafted plants, and salinity decreased it significantly and progressively in both grafted and ungrafted plants and in both varieties. The concentrations of Na⁺ and Cl^– were significantly higher in ungrafted than in grafted ‘Fanny’ plants. ‘Fanny’ was more tolerant when grafted, probably due to reduced accumulation of Na⁺ and/or Cl^– in the shoot.     

The effect of crude fibre on apparent digestibility and digestible energy content of extruded dog foods

The apparent digestibility of nutrients and energy of 38 commercial dry extruded dog foods was measured using six adult (2 to 3 year-old) female Beagles. Diets contained [in g/kg dry matter (DM)]: 164–360 crude protein (CP); 79–261 ether extracts (EE); 8–33 crude fibre (CF) and 318–585 nitrogen free extracts (NFE). Apparent energy digestibility ranged from 77.3 to 91.6%, and was closely related to CF content ( r =–0.85), yielding the resultant equation: GED (%)=94.00 – 4.04 × CF (% DM). The estimation of digestible energy content of foods from digestibility coefficients predicted from the above equation and gross energy measured or estimated from the Weende fractions, provides a more accurate prediction of experimental values than the Atwater approach followed by the National Research Council and the Association of American Feed Control Officials.     

Poor Prediction Value of Sperm Head Morphometry for Fertility and Litter Size in Rabbit

This study was conducted to investigate the predictive capacity of fertility and litter size of sperm head morphometric measurements when the ejaculates fulfilled the minimum requirements commonly used in artificial insemination (AI). Semen samples from 11 rabbits (77 ejaculates) were evaluated for sperm motility, abnormal spermatozoa and sperm head morphometry using computer automated sperm analysis system. Morphometric dimensions for length, width, area and perimeter were analysed. Only ejaculates with more than 70% of motility rate and <15% of abnormal sperm were used for AI. A total of 1031 individual AI were performed in commercial rabbitries. Our results showed significant differences among animals for all sperm head measurements. The mean values for fertility and litter size obtained were 68.4 ± 0.01% and 9.3 ± 0.1% respectively. To assess the predictive value of morphometric dimensions in fertility, a logistic regression analysis was applied. Moreover, multiple linear regression analyses were used to examine the relationship between litter size and sperm head morphometric parameters. Logistic regression analysis rendered a significant model between fertility and area and perimeter, explaining the 0.65% variation. Multiple linear regression analysis rendered a significant model between litter size and width, area and perimeter that explained the 1.3% variation. By conclusion, the sperm head morphometric parameters assay showed low potential to predict fertility and litter size when the ejaculates fulfilled the minimum requirements commonly used in AI (motility and abnormal spermatozoa) in rabbit.