Identification of differential broodstock contribution affecting genetic variability in hatchery stocks of Atlantic salmon (Salmo salar)     

Jose L. Horreo  Gonzalo Machado-Schiaffino  Andrew Griffiths  Dylan Bright  Jamie Stevens  Eva Garcia-Vazquez   《Aquaculture (Amsterdam, Netherlands)》2008,280(1-4):89-93

Supportive breeding of Atlantic salmon (Salmo salar) is commonly employed to maintain numbers of fish where the species has become locally endangered. Increasingly, one of the main aims of population management is the preservation of natural genetic diversity. If the stocks employed in supportive breeding exhibit reduced variation they can alter the natural pattern of genetic variation observed in wild populations. In northern Spain, wild adult salmon are caught every year from local rivers and artificially crossed in order to create supportive stocks. The offspring are hatchery reared until the juvenile stage, then released into the same river where their parents were caught. In the current study, our findings demonstrate that although adult broodstock exhibit a pattern of variation similar to the wild populations, variability at microsatellite loci was drastically reduced in the juveniles released into one of three rivers analyzed. The contribution of broodstock to this juvenile stock was examined by pedigree analysis. A restricted number of females contributing to the hatchery stock was identified as the main cause of loss in genetic variation, possibly due to overmaturity of some multi-sea-winter females. We suggest that better monitoring and control of parental contribution will help in solving the problem of loss of genetic diversity in hatchery populations.  相似文献   

Intrinsic phytase in hybrid rye increases the digestibility of phosphorus in corn and soybean meal in diets fed to growing pigs     

Joan L Archs Toledo  Su A Lee  Molly L McGhee  Gonzalo G Mateos  Hans H Stein 《Journal of animal science》2020,98(10)

An experiment was conducted to test the hypothesis that inclusion of hybrid rye in diets containing corn and soybean meal (SBM) without or with microbial phytase improves the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P because of the intrinsic phytase activity in hybrid rye. Forty-eight growing barrows (initial body weight: 39.5 ± 7.7 kg) were allotted to six diets. A basal diet containing corn and SBM; a rye-based diet; and a diet containing corn, SBM, and rye were formulated. Each diet was formulated without and with microbial phytase (500 units/kg of diet) for a total of six diets. Fecal samples were collected for 4 d following a 5-d adaptation period according to the marker-to-marker procedure. Results indicated that no interactions between diets and concentration of phytase were observed for any of the response criteria measured. The ATTD and STTD of P and the ATTD of Ca differed (P < 0.05) among diets, but regardless of diet, the concentration of P in feces was reduced (P < 0.05) by adding microbial phytase to the diets. As a consequence, microbial phytase increased (P < 0.05) ATTD and STTD of P, and the ATTD of Ca was also increased (P < 0.05) by the use of microbial phytase. Measured values for the ATTD and STTD of P in the diets containing corn, SBM, and hybrid rye without or with phytase were greater (P < 0.05) than values that were predicted based on the ATTD and STTD of P for the corn–SBM and the hybrid rye diet. The observation that STTD predicted from the individual ingredients underestimated the STTD of P in the mixed diet indicates that the intrinsic phytase in hybrid rye resulted in increased digestibility of the P in the corn and SBM included in the corn–SBM–hybrid rye diet. In conclusion, microbial phytase increased the ATTD and STTD of P and the ATTD of Ca regardless of feed ingredients used in diets fed to pigs. In addition, the intrinsic phytase from hybrid rye increased the ATTD and STTD of P in corn and SBM.  相似文献   

Intrauterine therapy with ozone reduces subclinical endometritis and improves reproductive performance in postpartum dairy cows managed in pasture-based systems     

Escandón  Byron M.  Espinoza  Juan S.  Perea  Fernando P.  Quito  Fernando  Ochoa  Rafael  López  Gonzalo E.  Galarza  Diego A.  Garzón  Juan Pablo 《Tropical animal health and production》2020,52(5):2523-2528

Tropical Animal Health and Production - New postpartum strategies have been developed in dairy cows to ameliorate uterine health and reproductive performance, especially the first service...  相似文献   

Visual quality: An examination of a South American Mediterranean landscape,Andean foothills east of Santiago (Chile)     

Gonzalo De La Fuente De Val  Hermann Mühlhauser S. 《Urban Forestry & Urban Greening》2014,13(2):261-271

This study assessed landscape visual quality in a sector of Andean foothills, east of Santiago, Chile. Sample photographs were taken in four dominant native landscape types that were systematically selected on the basis of four categories of vegetation density. Visitors (n = 180) were randomly sampled from among the residents of Santiago. The results showed that native vegetation has a positive impact on visual quality. Sclerophyllous shrublands and ravines (associated with semi-arid forests) are rated higher than savannahs of “espinales” and shrublands with succulent plants (associated with semi-arid grassland with shrubs). Findings also indicate that landscape scenes with high-vegetation density have a positive effect on visual quality, while those with a low density have a negative one. The key is the amount of visual access, which also increases people's perceptions of safety and orientation. Finally, results showed that information variables are associated with people's visual appreciation. Two preference factors were found to be consistent with the model of spatial information of Kaplan and Kaplan (1989). The implications of the results for the enhancement of public consensus in the planning and management of the Andean foothills, east of Santiago, are also discussed.  相似文献   

The pond network: can structural connectivity reflect on (amphibian) biodiversity patterns?     

Raquel Ribeiro  Miguel A. Carretero  Neftalí Sillero  Gonzalo Alarcos  Manuel Ortiz-Santaliestra  Miguel Lizana  Gustavo A. Llorente 《Landscape Ecology》2011,26(5):673-682

Landscape connectivity is a very recurrent theme in landscape ecology as it is considered pivotal for the long term conservation of any organism’s populations. Nevertheless, this complex concept is still surrounded by uncertainty and confusion, largely due to the separation between structural and functional connectivity. Amphibians are the most threatened vertebrates around the globe, in Europe mostly due to habitat alteration, and to their particular life cycle. Pond breeding amphibians are considered to be organised in metapopulations, enhancing the importance of landscape connectivity in this group of animals. We sampled the amphibian species present in two pond groups in Central Western Spain. We applied the graph theory framework to these two pond networks in order to determine the importance of each pond for the entire network connectivity. We related the pond importance for connectivity with the species richness present in each pond. We tested if connectivity (partially) determined the presence of the amphibian species sampled using logistic regression. The results show that the structural connectivity of the pond network impacts on the amphibian species richness pattern and that the importance of the pond for the connectivity of the network is an important factor for the presence of some species. Our results, hence, attest the importance of (structural) landscape connectivity determining the pattern of amphibian (functional) colonization in discrete ponds.  相似文献   

Effects of thinning intensity on radial growth patterns and temperature sensitivity in <Emphasis Type="Italic">Pinus canariensis</Emphasis> afforestations on Tenerife Island,Spain     

Gonzalo Pérez-de-Lis  Ignacio García-González  Vicente Rozas  José Ramón Arévalo 《Annals of Forest Science》2011,68(6):1093-1104

• Context   

The suitability of thinning to prevent forest growth decline as a result of global warming has not been tested extensively in Macaronesian Canary pine (Pinus canariensis Sweet ex Spreng.).  相似文献   

Picrocrocin kinetics in aqueous saffron spice extracts (Crocus sativus L.) upon thermal treatment     

Sánchez AM  Carmona M  Jarén-Galán M  Mosquera MI  Alonso GL 《Journal of agricultural and food chemistry》2011,59(1):249-255

The kinetics of picrocrocin degradation in aqueous extracts of saffron upon thermal treatment from 5 to 70 °C have been studied, together with the degradation of purified picrocrocin in water at 100 °C. The best fits to experimental data were found for a second-order kinetics model. Picrocrocin showed high stability with half-life periods (t(1/2)) ranging from >3400 h at 5 °C in saffron extracts to 9 h in the experiments with purified picrocrocin at 100 °C. In saffron extracts, the evolution of the rate constant (k) with temperature showed maximum values at 35 °C, and filtration of the extracts contributed to picrocrocin stability. In the case of purified picrocrocin, the generation of safranal in the first 5 h (yield up to 7.4%) was confirmed. Spectrometric parameters used in saffron quality control (E(1cm)(1%) 257 nm and ΔΕ(pic)) were not appropriate for documenting the evolution of picrocrocin.  相似文献   

Water retention and field soil water states in a vertisol under Long-Term direct drill and conventional tillage     

Karl Vanderlinden  Yakov Pachepsky  Aura Pedrera-Parrilla  Gonzalo Martinez  Antonio Espejo-Pérez  Francisco Perea  Juan Giráldez 《European Journal of Soil Science》2021,72(2):667-678

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Soil profile distribution of total C content and natural abundance of 13C in two volcanic soils subjected to crop residue burning versus crop residue retention     

Erick Zagal  Cristina Muñoz  Soledad Espinoza  Jorge Campos 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):263-272

Abstract

Soil organic carbon (SOC) plays a key role in crop productivity and soil quality. Conservation agriculture has a positive effect on SOC accumulation in the surface soil horizons, but little information is available regarding the effect of the removal of crop residues by burning. This study aimed to assess the impact of different types of crop residue management practices on the total C distribution and natural abundance of ¹³C (‰, δ¹³C). Two volcanic soils, located in the Mediterranean temperate zone of Southern Chile, were studied: an Ultisol (Collipulli Series, CPL) and an Andisol (Santa Bárbara Series, SBA). Both soils had been cultivated under direct-drilling and a typical annual crop rotation system for a long period of time. Two different types of crop residue management practices were imposed in both soils: (i) crop residue burning (CPL-B; SBA-B) and (ii) crop residue retention over the soil (CPL-R; SBA-R), corresponding to treatments B and R, respectively. Soil profile distribution of the C content and natural abundance of ¹³C were analysed for bulk soils (down to 100 cm depth) and three particle-size fractions of the soils (down to 20 cm of soil depth): (a) ≤ 53 µm, (b) 53-212 µm and (c) ≥ 212 µm. It was found that the effect of crop residue management can be observed in the variations of C content and δ¹³C in the soil profile in both volcanic soils. Crop residue burning (B treatment) increased the C content in bulk soil and the particle-size fractions. On the other hand, soil organic matter of crop residue retention (R treatment) showed higher natural abundance of ¹³C (δ¹³C) compared with residue burning (B treatment) in the two volcanic soils. R treatment enriched the particle-size fractions (except ≥ 212 µm fraction of CPL soil) with ¹³C. Factors that could account for these findings are also discussed here.  相似文献   

Scarring patterns of whale sharks,Rhincodon typus,at a provisioning site in the Philippines     

Luke Penketh  Anna Schleimer  Jessica Labaja  Sally Snow  Alessandro Ponzo  Gonzalo Araujo 《水产资源保护:海洋与淡水生态系统》2021,31(1):99-111

1. Shark-based tourism continues to be a rapidly growing industry, and thus understanding the impacts of such activities is essential to mitigate the potential negative effects on the target species. The consequences of provisioning on whale sharks (Rhincodon typus) are not fully understood, although changes to the local environment, ecology, behaviour, and site visitation patterns have been highlighted. Here, the scarring patterns of whale sharks were investigated at a provisioning site in Oslob, Cebu, Philippines, as an indicator of the physical impacts of tourism activities on individual sharks. Photographic identification was used to attribute scars to individual animals (n = 152) between March 31, 2012 and January 31, 2015.
2. Scars were categorized by type and body location, and were compared with non-provisioned aggregations in Australia, Mozambique, and Seychelles. Oslob whale sharks were more scarred than other studied populations, with 94.7% (n = 144) having at least one scar, and with 90.8% (n = 138) having more than one scar. Scarring incidence was found to be significantly higher in sharks that regularly visited the provisioning site, and analysis of scarring over time in highly resident sharks showed that all individuals gained scars through periods of consistent re-sightings. A significantly higher incidence of minor scar types was found, most commonly on the dorsal side of the animal, probably resulting from sustained proximity to boats and ropes throughout the provisioning activities. The consequences of interactions with propeller boats were observed, despite a ban on their use in the provisioning site, highlighting the risk to the species beyond the study site.
3. We recommend the strict enforcement of a minimum distance between boats and sharks, a zero-contact policy during interactions, the expansion of the provisioning site, and the implementation of a no-boat-access zone around the perimeter of the provisioning site to mitigate potential collisions.

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