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91.
Helgason A Pálsson S Gudbjartsson DF Kristjánsson T Stefánsson K 《Science (New York, N.Y.)》2008,319(5864):813-816
Previous studies have reported that related human couples tend to produce more children than unrelated couples but have been unable to determine whether this difference is biological or stems from socioeconomic variables. Our results, drawn from all known couples of the Icelandic population born between 1800 and 1965, show a significant positive association between kinship and fertility, with the greatest reproductive success observed for couples related at the level of third and fourth cousins. Owing to the relative socioeconomic homogeneity of Icelanders, and the observation of highly significant differences in the fertility of couples separated by very fine intervals of kinship, we conclude that this association is likely to have a biological basis. 相似文献
92.
The effect of prebiotic xylooligosaccharides (XOS) on the growth performance and digestive enzyme activities of the allogynogenetic
crucian carp, Carassius auratus gibelio, was investigated. XOS was added to fish basal semi-purified diets at three concentrations by dry feed weight: diet 1, 50 mg kg−1; diet 2, 100 mg kg−1; diet 3, 200 mg kg−1, respectively. Twelve aquaria (n = 20) with three replicates for each treatment group (diets 1–3) and control treated without XOS were used. Weights of all
collected carp from each aquarium were determined at the initial phase and at the end of the experiment, and the carp survival
was also determined by counting the individuals in each aquarium. After 45 days, there were significant differences (P < 0.05) in the relative gain rate (RGR), and daily weight gain (DWG) of diets 1–3 were compared with the control. However,
the survival rate was not affected (P > 0.05) by the dietary treatments. For enzymatic analysis, dissection produced a crude mixture of intestine and hepatopancreas
of each segment to measure. The protease activity in the intestine and hepatopancreas content of fish in diet 2 (487.37 ± 20.58 U g−1 and 20.52 ± 1.93 U g−1) were significantly different (P < 0.05) from that in the control (428.13 ± 23.26 U g−1 and 12.81 ± 1.52 U g−1) and diet 3 (428.00 ± 23.78 U g−1 and 14.04 ± 1.59 U g−1). Amylase activity in the intestine was significantly higher for diet 2 compared to diet 1 and the control. As for amylase
in the hepatopancreas, assays showed higher activity in diet 2 (P < 0.05) compared to the rest. 相似文献
93.
Within the framework of a larger project aimed to assess the potential of second generation hybrid striped bass for German
aquaculture the genotypic segregation of five microsatellite loci was analysed in two progeny lots (n = 74 and 76, respectively). There was no consistent correlation between microsatellite genotypes and phenotypic category
(white bass, hybrid, or striped bass). None of the individuals expressed neither only white bass nor only striped bass genotypes
at all five loci. On the other hand, only hybrid genotypes at all five loci were detected in three individuals of lot 1 and
four individuals of lot 2. Single loci tests for conformity of microsatellite genotypic segregation with Mendelian rules revealed
significant deviations (P < 0.05) in four cases for lot 1 and in three cases for lot 2. If pooled over all five loci, both lots displayed highly significant
deviations (P < 0.01) with an excess of hybrid genotypes and a deficiency of white bass genotypes. It is concluded that stabilizing selection
performed on hybrid genotypes might be a suitable approach for practical aquaculture in Europe if the goal is to become independent
of first generation hybrid fry supply and/or if establishing domesticated brood stocks of both parental species is impossible.
However, more detailed studies on the characteristics and performance of multiple hybrid generations are needed. 相似文献
94.
Pine wilt disease: a short review of worldwide research 总被引:1,自引:0,他引:1
This article summarizes the results of the research papers presented at the International Symposium on pine wilt disease (IUFRO Working Party Meeting 4.04.03) held in July 2009, at Nanjing, China. The general topics covered were on pine wilt disease (PWD), its causal organism, the pinewood nematode (PWN) Bursaphelenchus xylophilus, plus other PWN-associated microorganisms that play a significant role in PWD such as bacteria (e.g. Pseudomonas fluorescens). Most of the papers that are reviewed are based on work on PWD-PWN in East Asia and Russia. Specific topics covered include: 1) the fundamental conceptions of PWD development, 2) pathogenicity, 3) host-parasite relationships including the histopathology of diseased conifers and the role of toxins from bacteria-nematode ecto-symbionts, 4) PWN life cycle and transmission, 5) B. xylophilus dissemination models, 6) associations (with other nematodes), 7) diagnostics, 8) quarantine and control of the PWN and 9) biocontrol of the PWN. 相似文献
95.
96.
Kahori Arita Kiyoshi Isowa Takashi Ishikawa Hideo Aoki Hiromi Ohta 《Fisheries Science》2012,78(3):625-630
The post-thaw motility and fertility of Japanese pearl oyster sperm show large variances, even among sperm samples obtained
from the same individuals. This study aimed to clarify the factors that cause such differences. Spermatozoa were diluted 50
times with diluent comprising 10 % methanol, 18 % fetal bovine serum, and 72 % seawater, and dispensed into 0.25 ml straws.
A total of 59 straws were cooled, one by one, at 11 different heights from the surface of liquid nitrogen (LN) to −50 °C,
and then immediately immersed in LN. After thawing the straws, the relationships between the cooling rate and the post-thaw
motility and post-thaw fertility of the spermatozoa were examined. Both the post-thaw motility and the post-thaw fertility
showed a sharp peak when the straws were cooled at around −20 °C/min. There was a strong correlation between post-thaw motility
and fertility (P < 0.001). There was a large difference in the cooling rates and the post-thaw motilities and fertilities of the spermatozoa,
even between straws cooled at the same height. These results indicate that the optimum range for the cooling rate of oyster
spermatozoa is quite narrow, and the method of cooling straws at a fixed distance from the LN surface is unsuitable for the
cryopreservation of Japanese pearl oyster spermatozoa. 相似文献
97.
Jordão RS Ribeiro CP Pituco EM Okuda LH Del Fava C Stefano Ed Filho MM Mehnert DU 《Research in veterinary science》2011,91(2):311-315
Bovine Viral Diarrhea Virus (BVDV) is widespread in cattle in Brazil and research shows its large antigenic variability. Available vaccines are produced with virus strains isolated in other countries and may not be effective. In this study, inactivated vaccines containing the Brazilian BVDV-Ib IBSP11 isolate were developed and tested on 6 groups of 10 guinea pigs (Cavia porcellus). Animals in groups A and C received an aqueous vaccine (aluminum hydroxide); B and D groups received an oily vaccine (Montanide ISA50); Group E positive-control animals were given an imported commercial vaccine with BVDV-Ia Singer; Group F animals were sham vaccinated (negative control). Groups A, B and E received two doses, and Groups C and D, three, every 21 days. Twelve blood samples were taken, at 21-day intervals over 231 days, and evaluated for antibody titer through virus-neutralization (VN), using a homologous strain (IBSP11), and a heterologous strain (BVDV-Ia NADL). Most animals, 42 days following the first dose, seroconverted to both strains and, after the second dose, there was a significant increase of titers in all groups. The oily formulation induced greater response after the third administration. This increase was not observed with the aqueous vaccines, regardless of the virus used in the VN. Antibody decline was more rapid in animals that received aqueous vaccines. The results showed the importance of studying the influence of endemic strains of commercial vaccines, to improve the efficacy of BVD vaccination. Use of the endemic strain in vaccine formulation presented promising results, as well as the use of guinea pigs as a laboratory model. 相似文献
98.
María?C.?Mateo-SánchezEmail author Aitor?Gastón Carlos?Ciudad Juan?I.?García-Vi?as Jorge?Cuevas César?López-Leiva Alfredo?Fernández-Landa Nur?Algeet-Abarquero Miguel?Marchamalo Marie-Josée?Fortin Santiago?Saura 《Landscape Ecology》2016,31(6):1261-1276
Context
Multi-scale approaches to habitat modeling have been shown to provide more accurate understanding and predictions of species-habitat associations. It remains however unexplored how spatial and temporal variations in habitat use may affect multi-scale habitat modeling.Objectives
We aimed at assessing how seasonal and temporal differences in species habitat use and distribution impact operational scales, variable influence, habitat suitability spatial patterns, and performance of multi-scale models.Methods
We evaluated the environmental factors driving brown bear habitat relationships in the Cantabrian Range (Spain) based on species presence records (ground observations) for the period 2000–2010, LiDAR data on forest structure, and seasonal estimates of foraging resources. We separately developed multi-scale habitat models for (i) each season (spring, summer, fall and winter) (ii) two sub-periods with different population status: 2000–2004 (with brown bear distribution restricted to the main population nuclei) and 2005–2010 (with expanding bear population and range); and (iii) the entire 2000–2010 period.Results
Scales of effect remained considerably stable across seasonal and temporal variations, but not the influence of certain environmental variables. The predictive ability of multi-scale models was lower in the seasons or periods in which populations used larger areas and a broader variety of environmental conditions. Seasonal estimates of foraging resources, together with LiDAR data, appeared to improve the performance of multi-scale habitat models.Conclusions
We highlight that the understanding of multi-scale behavioral responses of species to spatial patterns that continually shift over time may be essential to unravel habitat relationships and produce reliable estimates of species distributions.99.
Nilnaj Chaitanawisuti Sirusa Kritsanapun Wannanee Santhaweesuk 《Aquaculture International》2011,19(5):865-872
A 120-day feeding trial was conducted to determine growth, feeding efficiency, and biochemical composition of juvenile spotted
babylon Babylonia areolata (initial mean weight of 1.48 ± 0.06 g) fed on conventional trash fish and a formulated moist diet in a flow-through grow-out
system. The snails readily accepted the formulated moist diet and showed good growth and survival during the trial. There
were no significant differences in specific growth rate, feeding efficiency, and survival between the snails fed on trash
fish or the formulated moist diet. At the end of the experiment, biochemical analysis of the snail flesh showed significant
differences in flesh quality, with the snails fed on trash fish having a significantly higher crude protein compared to those
fed on the formulated diet, but there was little difference in crude lipid content. Whole body tissue of snails fed on trash
fish had significantly higher total amino acid, essential amino acid, and non-essential amino acid levels compared to those
fed the formulated diet. This study showed that the formulated moist diet can be readily used for B. areolata growout for maximizing growth, survival, and feeding efficiency; however, further research is needed to improve the flesh
quality particularly amino acid and fatty acid levels before its suitability for B. areolata is assured. 相似文献
100.
Savlík M Fimanová K Szotáková B Lamka J Skálová L 《Research in veterinary science》2006,80(3):267-274
Fenbendazole (FEN) and flubendazole (FLU) are benzimidazole anthelmintics often used in pig management for the control of nematodoses. The in vivo study presented here was designed to test the influence of FLU and FEN on cytochrome P4501A and other cytochrome P450 (CYP) isoforms, UDP-glucuronosyl transferase and several carbonyl reducing enzymes. The results indicated that FEN (in a single therapeutic dose as well as in repeated therapeutic doses) caused significant induction of pig CYP1A, while FLU did not show an inductive effect towards this isoform. Some of the other hepatic and intestinal biotransformation enzymes that were assayed were moderately influenced by FEN or FLU. Strong CYP1A induction following FEN therapy in pigs may negatively affect the efficacy and pharmacokinetics of FEN itself or other simultaneously or consecutively administered drugs. From the perspective of biotransformation enzyme modulation, FLU would appear to be a more convenient anthelmintic therapy of pigs than FEN. 相似文献