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Protein retention assessment of four levels of poultry by-product substitution of fishmeal in rainbow trout (Oncorhynchus mykiss) diets using stable isotopes of nitrogen (δ15N) as natural tracers

DANIEL BADILLO ZAPATA (2014, [Artículo])

This is second part from an experiment where the nitrogen retention of poultry by-product meal (PBM) compared to fishmeal (FM) was evaluated using traditional indices. Here a quantitative method using stable isotope ratios of nitrogen (δ15N values) as natural tracers of nitrogen incorporation into fish biomass is assessed. Juvenile rainbow trout (Oncorhynchus mykiss) were fed for 80 days on isotopically distinct diets in which 0, 33, 66 and 100% of FM as main protein source was replaced by PBM. The diets were isonitrogenous, isolipidic and similar in gross energy content. Fish in all treatments reached isotopic equilibrium by the end of the experiment. Two-source isotope mixing models that incorporated the isotopic composition of FM and PBM as well as that of formulated feeds, empirically derived trophic discrimination factors and the isotopic composition of fish that had reached isotopic equilibrium to the diets were used to obtain a quantitative estimate of the retention of each source of nitrogen. Fish fed the diets with 33 and 66% replacement of FM by PBM retained poultry by-product meal roughly in proportion to its level of inclusion in the diets, whereas no differences were detected in the protein efficiency ratio. Coupled with the similar biomass gain of fishes fed the different diets, our results support the inclusion of PBM as replacement for fishmeal in aquaculture feeds. A re-feeding experiment in which all fish were fed a diet of 100% FM for 28 days indicated isotopic turnover occurred very fast, providing further support for the potential of isotopic ratios as tracers of the retention of specific protein sources into fish tissues. Stable isotope analysis is a useful tool for studies that seek to obtain quantitative estimates of the retention of different protein sources. © 2014 Badillo et al.

nitrogen 15, nitrogen, protein intake, animal behavior, animal experiment, animal food, animal tissue, aquaculture, Article, biomass, controlled study, energy metabolism, food composition, juvenile animal, nonhuman, poultry by product meal, protein a CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA

Do marine reserves increase prey for California sea lions and Pacific harbor seals?

ALEJANDRO ARIAS DEL RAZO (2019, [Artículo])

Community marine reserves are geographical areas closed to fishing activities, implemented and enforced by the same fishermen that fish around them. Their main objective is to recover commercial stocks of fish and invertebrates. While marine reserves have proven successful in many parts of the world, their success near important marine predator colonies, such as the California sea lion (Zalophus californianus) and the Pacific harbor seal (Phoca vitulina richardii), is yet to be analyzed. In response to the concerns expressed by local fishermen about the impact of the presence of pinnipeds on their communities’ marine reserves, we conducted underwater surveys around four islands in the Pacific west of the Baja California Peninsula: two without reserves (Todos Santos and San Roque); one with a recently established reserve (San Jeronimo); and, a fourth with reserves established eight years ago (Natividad). All these islands are subject to similar rates of exploitation by fishing cooperatives with exclusive rights. We estimated fish biomass and biodiversity in the seas around the islands, applying filters for potential California sea lion and harbor seal prey using known species from the literature. Generalized linear mixed models revealed that the age of the reserve has a significant positive effect on fish biomass, while the site (inside or outside of the reserve) did not, with a similar result found for the biomass of the prey of the California sea lion. Fish biodiversity was also higher around Natividad Island, while invertebrate biodiversity was higher around San Roque. These findings indicate that marine reserves increase overall fish diversity and biomass, despite the presence of top predators, even increasing the numbers of their potential prey. Community marine reserves may help to improve the resilience of marine mammals to climate-driven phenomena and maintain a healthy marine ecosystem for the benefit of both pinnipeds and fishermen. © 2019 Arias-Del-Razo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Article, biodiversity, biomass, climate change, ecosystem resilience, environmental exploitation, fish stock, fishing, marine environment, marine invertebrate, nonhuman, Phoca vitulina, Pinnipedia, prey searching, Zalophus californianus, animal, biom BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) BIOLOGÍA ANIMAL (ZOOLOGÍA)

Climate change and the northern elephant seal (Mirounga angustirostris) population in Baja California, Mexico

M. Concepción García-Aguilar (2018, [Artículo])

The Earth0s climate is warming, especially in the mid- and high latitudes of the Northern Hemisphere. The northern elephant seal (Mirounga angustirostris) breeds and haul-outs on islands and the mainland of Baja California, Mexico, and California, U.S.A. At the beginning of the 21st century, numbers of elephant seals in California are increasing, but the status of Baja California populations is unknown, and some data suggest they may be decreasing. We hypothesize that the elephant seal population of Baja California is experiencing a decline because the animals are not migrating as far south due to warming sea and air temperatures. Here we assessed population trends of the Baja California population, and climate change in the region. The numbers of northern elephant seals in Baja California colonies have been decreasing since the 1990s, and both the surface waters off Baja California and the local air temperatures have warmed during the last three decades. We propose that declining population sizes may be attributable to decreased migration towards the southern portions of the range in response to the observed temperature increases. Further research is needed to confirm our hypothesis; however, if true, it would imply that elephant seal colonies of Baja California and California are not demographically isolated which would pose challenges to environmental and management policies between Mexico and the United States. © 2018 García-Aguilar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

air temperature, article, Baja California, climate change, human, Mirounga angustirostris, nonhuman, population size, warming, animal, ecosystem, environmental protection, Mexico, Phocidae, population density, population migration, temperature, Anima CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA

Behavior of private retailers in a regulated input market: An empirical analysis of the fertilizer subsidy policy in Nepal

Shriniwas Gautam Dyutiman Choudhary Dil Bahadur Rahut (2022, [Artículo])

The private sector in Nepal participates in the regulated import and distribution of three types of subsidized fertilizer. However, almost 55% of the agrovets (family-owned microenterprises) that retail agricultural inputs do not comply. Many farmers rely on the fertilizer purchased through these agrovets, including subsidized ones. There is no private sector importer of the three types of fertilizer covered by the subsidy program, which indicates that the agrovets either acquire these through leakage in the government distribution system or through illegal cross-border trade from India, both of which are considered legal noncompliance. We discern the determinants for this noncompliant behavior of agrovets using logistic regression. The results from logistic regression suggest that the agrovets that are more likely to comply are registered, have membership in business associations, and have a higher number of competitors. Those with diversified business portfolios and covering a greater number of districts are less likely to comply. Key informants, consisting of both public and private sector stakeholders, were solicited for their views on solving this noncompliant behavior. The private sector unanimously asserts the need for deregulation of fertilizer imports and the participation of agrovets in the distribution of the subsidized fertilizer. In contrast, the public sector is skeptical of the ability and trustworthiness of the private sector in the import and distribution of quality fertilizer. We propose a middle ground to mitigate private sector noncompliance and suggest a policy revisit to increase the fertilizer supply and distribution efficiency.

Fertilizer Subsidy Policy Input Retailers CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA FERTILIZERS POLICIES MARKET REGULATIONS

Spatiotemporal analysis of rainfall and temperature variability and trends for climate resilient maize farming system in major agroecology zones of northwest Ethiopia

Kindie Tesfaye Dereje Ademe Enyew Adgo (2023, [Artículo])

Spatiotemporal studies of the annual and seasonal climate variability and trend on an agroecological spatial scale for establishing a climate-resilient maize farming system have not yet been conducted in Ethiopia. The study was carried out in three major agroecological zones in northwest Ethiopia using climate data from 1987 to 2018. The coefficient of variation (CV), precipitation concertation index (PCI), and rainfall anomaly index (RAI) were used to analyze the variability of rainfall. The Mann-Kendall test and Sen’s slope estimator were also applied to estimate trends and slopes of changes in rainfall and temperature. High-significance warming trends in the maximum and minimum temperatures were shown in the highland and lowland agroecology zones, respectively. Rainfall has also demonstrated a maximum declining trend throughout the keremt season in the highland agroecology zone. However, rainfall distribution has become more unpredictable in the Bega and Belg seasons. Climate-resilient maize agronomic activities have been determined by analyzing the onset and cessation dates and the length of the growth period (LGP). The rainy season begins between May 8 and June 3 and finishes between October 26 and November 16. The length of the growth period (LGP) during the rainy season ranges from 94 to 229 days.

Climate Trends Spatiotemporal Analysis Agroecology Zone CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AGROECOLOGY CLIMATE CLIMATE VARIABILITY MAIZE

Transformation and innovation of knowledge in the construction and sustainable function of housing at the headwaters of San Juan Chamula.

Alejandra Trujillo Miguel Sánchez Álvarez (2022, [Artículo, Artículo])

SUMMARY

 

San Juan Chamula, Chiapas, is one of the most representative cultures of the native peoples of Mexico. The municipal seat is made up of three main neighborhoods: San Juan, San Sebastián and San Pedro. In ancient times, the architectural design of the houses was made of materials such as straw, adobe, bajareque and others of organic origin, which were part of the natural environment of the inhabitants. Thus, houses were built based on the use of natural elements available to the inhabitants as a result of the use of primary sector activity.

 

From the Chamula worldview housing has played functions for rest and shelter, therefore it was considered as a sacred place. When building one, ceremonies and offerings were carried out to appease any disgust of the guardians of Mother Earth, as they considered that nature had life, and to avoid any misfortune among the members of the family. For this, it was necessary to offer music, songs, and special dishes to feed the house and the Earth, so there would be harmony and well-being. Today, that worldview has been disrupted by the presence of multiple religions and other factors.

 

Chamula housing has gone through different stages of transition, from 1990 onwards, it was made of materials such as bricks, blocks and cement. With international migration and the arrival of young Chamula in the United States, changes in the building styles and function of housing are observed, as well as a loss of Chamula-type architectural knowledge, so that traditional architectural knowledge remains only with the elderly. Nowadays, Chamula masons and house builders opt for a foreign architectural design like California, thus changing their cultural identity, their way of life and their relationship with nature.

 

Keywords: traditional architecture, migration, architectural change.

traditional architecture migration architectural change arquitectura tradicional cambio arquitectónico chamula migración vivienda CIENCIAS SOCIALES CIENCIAS SOCIALES

User manual: How to use Agvisely to generate climate service advisories for livestock in Bangladesh

T.S Amjath-Babu Timothy Joseph Krupnik (2023, [Libro])

The Agvisely digital service for livestock integrates location-specific meteorological forecasts generated by the Bangladesh Meteorological Department (BMD) with species specific biological thresholds for weather variables (Temperature, rainfall, and temperature-humidity index (THI). When a biological threshold is to be breached in next five days' forecast, the system automatically generates location-specific management advice for livestock farmers. Advisories are based on a decision tree developed by the Bangladesh Livestock Research Institute (BLRI) and CIMMYT. Agvisely is a smart phone app and web-based service developed by the International Maize and Wheat Improvement Center (CIMMYT) CIMMYT with the support of USAID, securing the Food Systems of Asian Mega- Deltas (AMD) for Climate and Livelihood Resilience and the Transforming Agrifood Systems in South Asia (TAFSSA) initiatives in collaboration with Bangladesh Dept. of Agricultural Extension (DAE) and Bangladesh Meteorological Department (BMD).

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CLIMATE SERVICES LIVESTOCK DIGITAL TECHNOLOGY