Revista Peruana de Investigación Agropecuaria

Duckweed (Lemna minor): a potential alternative protein input for animal feed

Ronaldo Francesco Zevallos-Contreras, Walter Rolando Oscanoa-Condor — Thu, 10 Oct 2024 00:00:00 -0500

Duckweed (Lemna minor) emerges as an innovative ingredient in animal feed, offering a vegetable protein source that can complement or replace conventional protein sources such as soybean cake and fishmeal. Therefore, worldwide research has been carried out on its use in food. By its nutritional composition, this plant is characterized by its high protein, amino acid and fibrous profile, varying between 30 and 45% protein, in addition to its low fat and carbohydrate content, which is directly influenced by the environment where it is grown and the nutrients present in the water with the use or not of organic fertilizers, being also a very friendly and low-cost alternative, provided that the minimum accumulation of heavy metals and anti-nutritional components is controlled, thus obtaining a safe input for humans, animals and the environment. This review mainly addresses the nutritional composition of duckweed (Lemna minor) and its effects in feeding some monogastric species.

Reproductive biology of Hypophthalmus edentatus (Pimelodidae) and Brycon amazonicus (Bryconidae) in the Putumayo basin, Loreto region, Peru

Thu, 10 Oct 2024 00:00:00 -0500

Fishing is one of the main economic activities in the Putumayo River, despite the little biological information generated on the exploited species. The objective was to characterize the reproductive biology of Hypophthalmus edentatus and Brycon amazonicus in the middle basin of the Putumayo River (Loreto-Peru). A total of 192 specimens of H. edentatus were captured, with an average length and weight of 34,35 cm and 175,9 g, respectively, and 152 specimens of B. amazonicus, with an average length and weight of 30,73 and 175,9 ± 40,6 g, respectively. These specimens were collected between November 2020 and October 2021 in the fishing port and the municipal market of El Estrecho and through exploratory fishing. The size at first sexual maturity (L50) of H. edentatus was 26,5 and 28,3 cm standard length (SL) and maximum gonadosomatic index (GIS) of 1,6% and 0,6% for females and males, respectively. For B. amazonicus, the L50 was 25,1 cm and 24,8 cm LE and maximum IGS of 6,9% and 1,09% E for females and males, respectively. For both species, the average sex ratio was 2:1 (females: males). Based on these results, it is recommended to implement effective strategies for the conservation of both species.

Prediction of soil fertility using machine learning in Alto Amazonas province, Peru

Thu, 10 Oct 2024 00:00:00 -0500

The objective of the work was to predict soil fertility in the province of Alto Amazonas with the use of satellite images and machine learning techniques. The study was in the province of Alto Amazonas in Peru. Soil sampling was carried out in all the provinces, totalling 100 samples. Afterwards, soil physical (texture) and chemical analyses were performed. Satellite images were obtained from USGS, and vegetation indexes were calculated based on these images. Finally, descriptive analysis and machine learning modelling using 06 algorithms (GLM, CUBIST, KKNN, SVM, Random Forest and NN) were used and selected based on their R2 and rmse. In this work, we observed that most soils in the province have low pH, P, Mg, K and high acidity. We also managed to achieve good predictions for pH, Ca, Mg and CEC, and we observed that the most successful algorithm was Random Forest. Nevertheless, for Al, CUBIST performed better. This is one of the first works using machine learning to predict soil fertility in the Peruvian Amazon, and we hope it may serve as a base for future projects.

Development of an energy drink based on cocoa and guayusa

Thu, 10 Oct 2024 00:00:00 -0500

The research focused on the development of energy drinks using cocoa powder (Theobroma cacao L), guayusa (Ilex guayusa), powdered panela as a natural sweetener, and water. An experimental approach was employed, and three treatments were developed. Guayusa leaves, cocoa and powdered panela were used. As part of the experimental design, variable amounts of cocoa (20%, 30%, 27%) and guayusa (35%, 25%, 28%) were tested while keeping the amounts of panela and water constant. A sensory evaluation using a 4-level hedonic scale determined the most accepted product. Statistical analysis of the results indicated that treatment 2 achieved the best averages, with a mean score of 3.47 for color, 3.57 for texture, 3.23 for flavor, and 3.60 for aroma. Additionally, physicochemical analyses were conducted, showing pH and soluble solids values of 5.5 and 22°C. Microbiological tests, according to the INEN 2411:2017 standard, indicated the absence of mesophilic aerobes, coliforms, molds, and yeasts, and a bromatological analysis revealed a caffeine content of 230 mg/l, indicating that the beverage meets the basic caffeine requirement for energy drinks.

Freshwater shrimp diversity (Crustacea: Palaemonidae) in tributaries of the upper basin of the Itaya River, Loreto, Peru

Thu, 10 Oct 2024 00:00:00 -0500

Freshwater shrimp are essential organisms for the proper functioning of aquatic ecosystems. However, little is currently known about their diversity and abundance in Amazonian water bodies. Thus, the present study aimed to conduct a preliminary survey of the diversity and abundance of shrimp species from the family Palaemonidae in two tributaries of the upper Itaya River basin, Loreto, Peru. A total of 40 samples were collected between October and November 2018 in the tributaries Huanganaico and Pumayucu of the upper Itaya River. A total of 60 individuals were recorded belonging to the species Macrobrachium brasiliense, which was the most abundant (85% occurrence, n = 52 individuals), and M. amazonicum (15% occurrence, n = 9 individuals). Monthly abundance indicated fluctuations in individuals during the sampled months, and biological indices showed low levels of alpha diversity. In conclusion, there is low species diversity of shrimp in the upper Itaya River basin, with M. brasiliense being the most abundant species during the capture period. These results contribute to the understanding of freshwater shrimp diversity in the Itaya River basin for management and conservation purposes.