Browsing by Autor "Erick Loayza"

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A Comprehensive Analysis of the Nutritional Value, Antioxidant Potential and Fatty Acid Composition of Lucuma (Pouteria lucuma) Fruit, Grown in the High-Altitude Valleys of Bolivia.
(National Institutes of Health, 2025) Solan Glez; Cristhian Carrasco; Olof Böök; Grover Castañeta; Erick Loayza; J. Mauricio Peñarrieta; Teodora Popova; Franco M Cabrerizo; Leslie Tejeda
The lucuma tree (Pouteria lucuma), native to South America, is gaining attention for its unique nutritional profile and potential health benefits. This study aimed to analyze the nutritional composition, antioxidant capacity, and fatty acid profile of lucuma fruit from a high-altitude valley in Bolivia. The proximate analysis revealed high levels of carbohydrates (41.7%), dietary fibre (2.4%), and protein (6.9%). Antioxidant assays identified significant amounts of polyphenols, flavonoids, and carotenoids, known for their antioxidant and anti-inflammatory properties. The fruit's fatty acid profile showed a healthy omega-6:omega-3 ratio of 0.21. These results highlight lucuma's potential as a functional food and support further research into its health benefits.
Detailed whole‐body nutrient analysis identifies differences in feeding ecology between related fish species: The case of Orestias native Andean killifish in Lake Titicaca
(Wiley, 2023) Erick Loayza; Arturo Muñoz‐Saravia; Marleen De Troch; W.H. Hendriks; Geert Janssens
Body nutrient profiles in ecological studies allow for relating the nutritional status of consumers and their effects on the movement and retention of elements in ecosystems, as well as reflecting feeding conditions and habitat quality. This study compared the detailed whole-body nutrient composition (macronutrients, minerals, fatty acids and amino acids) of two omnivorous natives Orestias killifish from Lake Titicaca (Orestias agassizii and Orestias luteus, Valenciennes), the largest lake in the Andes, as an indirect tool to understand differences in their feeding ecology. Although both species are usually described as omnivorous fish, both have amphipods (Hyalella spp) as their main food source. Our results showed that both killifish had a comparable macronutrient composition, and the mineral concentrations of Mg, P and Ca (reflecting bony structures) differed between them. Many of the saturated fatty acids were significantly lower in O. luteus, and O. agassizii had higher concentrations of cis-vaccenic acid (18:1n11 (cis)), supporting the idea of a higher algal contribution to the diet of this fish. The lower histidine and higher taurine concentrations in O. agassizii compared with O. luteus (independent of body size) may reflect its ubiquitous behaviour and plasticity. This study shows how whole-body nutrient analysis can identify differences in feeding ecology and feeding behaviour between related species.
Dietary patterns and sympatry in Lake Titicaca (Bolivia): the role of seasonality in niche overlap between native Andean killifish
(Springer Science+Business Media, 2025) Erick Loayza; Arturo Muñoz‐Saravia; Julio Pinto; Carla Ibañez; Marc Pouilly; Geert Janssens
Ecomorphological variations of Orestias sp. (gr agassizii, Cyprinodontiformes, Cyprinodontidae) from Eastern slope of the Andes
(2021) Erick Loayza; Débora Alvestegui; Kelvin Herbas; Carla Ibañez; Claudia Zepita; Guido Miranda
Evidence of microplastics in water and commercial fish from a high-altitude mountain lake (Lake Titicaca)
(PeerJ, Inc., 2022) Erick Loayza; Amaya C. Trigoso Barrientos; Geert Janssens
Microplastic pollution is a widespread environmental concern. Like other anthropogenic pollutants, microplastics can reach aquatic ecosystems through rivers and interact with the aquatic biota. For instance, Lake Titicaca (between Bolivia and Peru), one of the great ancient lakes in South America (3,809 m a.s.l.), shows a pollution problem, particularly in the southern shallow basin (Lago Menor) in Bolivia. Nevertheless, our knowledge of the presence of microplastics and their interaction with the biota of Lake Titicaca is limited. Therefore, this study evaluated the presence of microplastics in the stomach content of the four fish species targeted by local fisheries in Lago Menor of Lake Titicaca (Orestias luteus, Orestias agassizii, Trichomycterus dispar, and Odonthestes bonariensis; N = 1,283), and looked for relationships with trophic guilds or fishing areas. Additionally, surface water was analyzed to evaluate the presence of microplastics in the water. The evaluation of microplastics was carried out by visual observations. We observed that the frequency of microplastic ingestion was low in all species (<5%). Conversely, microplastic was present in the water, with the highest quantity at the southern part of Lago Menor (103 ± 20 particles per L), without differences in the microplastic number between sites. Most microplastics counted in stomach contents were fibers, whereas water samples mainly contained fragments. Our results point to microplastic pollution in Lago Menor of Lake Titicaca. However, we could not determine the pollution rate due to considerable methodological limitations. Further research will be needed to robustly detect microplastics in Lake Titicaca and their impact on the fish species in the lake.
First Hydroacoustic Assessment Of Fish Abundance And Distribution In The Shallow Sub-Basin Of Lake Titicaca
(2020) Erick Loayza; Arnaud Bertrand
For the last two decades, a rapid eutrophication process impacts Lake Titicaca, the largest tropical freshwater lake in South America and the main highest Great Lake. This is especially notorious in the Bolivian sector of its shallow Lago Menor sub-basin. Lago Menor is deteriorated by the combination of multiple contaminations (domestic, industrial and mining) from untreated wastewater discharged from the urban area of El Alto, indiscriminate overfishing, and climate change. These threats particularly affect the native Andean killifish genus Orestias, the ecology and dynamics of which require in-depth studies with non-invasive techniques.
Influence of Sunlight Exposure and Traditional Dehydration on Chemical and Nutritional Properties of Oxalis tuberosa (oca) Tubers
(Springer Science+Business Media, 2025) Grover Castañeta; Daniela Miranda-Flores; Atma‐Sol Bustos; Rocío García; Erick Loayza; Cristhian Carrasco; Leslie Tejeda; Franco M. Cabrerizo; J. Mauricio Peñarrieta
Monitoring native killifish in the La Paz metrópolis by citizen scientists: advantages and opportunities
(2022) Erick Loayza; Guido Miranda; Guido Miranda-Chumacero
The Metropolitan Region of La Paz (MRDLP) in Bolivia has grown with minimal planning, leading to major changes to the natural habitat. Currently, citizen science is becoming an important contributor of information on the biodiversity of urban areas. This study presents novel records of native Andean killifish (Orestias spp.) in the MRDLP obtained from the iNaturalist website, expanding its distribution and highlighting the important role of citizen participation as a tool to expand biodiversity knowledge and monitoring of ecosystems sensitive to climate change.
Nutritional distinction of Bolivian Quinoa Real compared to global varieties
(Nature Portfolio, 2026) J. Mauricio Peñarrieta; Erick Loayza; Javier A. Linares-Pastén
Quinoa is globally recognised for its nutritional value, and its production has recently expanded worldwide. However, Quinoa Real (Royal Quinoa), a landrace group grown exclusively in the Intersalar zone of Bolivia, stands out for its grain quality and adaptation to extreme environments, such as high altitude, high salinity, intense UV radiation, aridity, and temperature fluctuations. This study compares the nutritional composition of 13 well-established commercial quinoa samples from 9 countries, including Quinoa Real white, red, and black. Analyses covered granulometry, proximate composition, fatty acid and amino acid profiles, vitamins, and minerals. Multivariate analyses (PCA and nMDS) revealed clear compositional distinctions for Quinoa Real, including higher levels of dietary fibre, ash, phytosterols, and essential minerals. It also exhibits a more favourable fatty-acid profile, higher levels of several vitamins, and a well-balanced essential amino acid profile. These results show that Quinoa Real is not only a nutritional outlier but also a valuable agrobiodiversity resource with implications for food security, functional foods, and sustainable production in the face of global dietary and environmental challenges.
Seasonal and depth variations in diet composition and dietary overlap between three native killifish of an emblematic tropical-mountain lake: Lake Titicaca (Bolivia)
(2019) Erick Loayza
ABSTRACT Lake Titicaca (∼3800 m a.s.l.), an emblematic tropical-mountain ecosystem is the major source of fish for people on the Altiplano. The Andean killifish genus Orestias , represent an important resource for local fisheries in Lake Titicaca. It has been suggested that exist an effect of segregation in the Lake Titicaca in order to avoid competition for food resource between native fish species, due most of Orestias species share the littoral habitat, which is now also share with introduced species. Such scenario increases the pressure for food resource. Here I examined the gut content of O. luteus, O. agassizii and O. mulleri (Cuvier & Valenciennes, 1846) from a bay of Lake Titicaca during rainy (April) and dry season (July) with the predominance method, frequency of occurrence and numerical percentage to describe the diet and dietary overlap between these native fish. I also applied a PERMANOVA test in order to determine diet variations related to depth and seasonally, as well as the Levins and Pianka’s index to test diet breadth and dietary overlap respectively. 396 gut contents were evaluated, identifying a high frequency of amphipods and molluscs in the three Orestias native species. Diet breadth revelled a selectivity for a few preys and the composition of the diets was influenced mainly by depth, followed by seasonality (PERMANOVA, P = <0.05). Dietary overlapping between O. luteus and O. agassizii was evidenced in the rainy season. During the dry season, the three species undergone dietary overlapping. This study provided a detail knowledge on the diet variations of native species in Lake Titicaca, especially for Orestias mulleri , a little-known species. Here I also discussed the importance of the amphipods as a food resource in Lake Titicaca not only for fish community, but for the food web in general. The seasonal and depth diet variations here discussed are relevant for fisheries management and conservation and could be used to guide aquaculture development in Lake Titicaca.
Variaciones ecomorfológicas de Orestias sp. (gr agassizii, Cyprinodontiformes, Cyprinodontidae) de la Vertiente Oriental de los Andes
(2021) Erick Loayza; Débora Alvestegui; Kelvin Herbas; Carla Ibañez; Claudia Zepita; Guido Miranda