Aroldo Botello-León

The valorization of fishery discards represents a key challenge for the sustainability of the maritime sector and the circular economy. This study evaluated the potential of whole European anchovy (Engraulis encrasicolus) from fishery discards as a nutritious and functional ingredient through its transformation into flour and its nutritional, functional, and microbiological characterization. Anchovies were processed by washing, grinding, autoclave sterilization (116 °C, F₀ = 6), drying, and milling to obtain a homogeneous flour. The resulting flour exhibited a high dry matter content (96.87%) and crude protein content (74.03%), together with a nutritionally balanced amino acid profile, with essential amino acids representing 50.59% of the total amino acid content and all indispensable amino acids meeting or exceeding the FAO/WHO/UNU reference amino acid pattern for adults. The flour also contained nutritionally relevant amounts of polyunsaturated fatty acids (4.73%), calcium (2.52%), and phosphorus (2.11%). Histamine concentrations were within acceptable limits, and microbiological analyses confirmed compliance with food safety criteria, with no detection of relevant pathogens. The results indicate that discarded anchovy flour has potential for incorporation into food and feed value chains, promoting the circular economy and the blue economy through a zero-waste-oriented strategy.

Objective. To evaluate the nutritional composition of duckweed (DW) (Lemna minor) and water hyacinth (WH) (Eichhornia crassipes) and its effect on the apparent digestibility of dry matter (%, ADDM), apparent digestibility of crude protein (%, ADCP) and the apparent digestibility of the crude lipid (%, ADCL) in the nutrition of tilapia (Oreochromis niloticus). Material and methods. The DW and WH were used to formulate nine isoproteic (32.47%), isolipidic (5.46%) and isoenergetic (16.45 MJ kg-1) diets, with three replicates and 15 male tilapia (36.36± 1.16 g) per repetition: 0% (T0); 10% (T10); 15% (T15); 20% (T20) and 25% (T25), respectively random. A principal component analysis (PCA) was applied. Results. The crude protein (%) of the WH and the DW, were 21.72% and 27.37% (p˂0.05), respectively. Fish fed with WH and DW, up to 10 and 15% inclusion in the diet, respectively, did not show significant differences (p>0.05) for ADDM. However, for ADCP and ADCL, up to 15 and 20%, respectively, significant differences (p>0.05) were not observed. Conclusions. Water hyacinth and duckweed meals were an alternative vegetable protein source, which can partially replace soybean meal and cornmeal in tilapia diets. The PCA suggests that the control diet, 10% WH, 10-15% DW, showed the best results in terms of the apparent digestibility of the nutrients.

In recent decades, interest has been aroused worldwide in the use of silicon in nutrition; however, information on its effect on nutrition and metabolism of fish is limited. The objective of the research was to evaluate the effect of dietary supplementation with organic silicon on the growth performance, blood biochemistry, digestive enzymes, morphohistology and intestinal microbiota and stress resistance in hybrid Tilapia (Oreochromis mossambicus × Oreochromis niloticus). Methodologically, six levels of organic silicon (DOS) [control (0), 10, 20, 30, 40 and 50 mg·kg⁻¹] were used to feed juvenile fish (initial weight 7.51 ± 0.25 g) grown for eight weeks in 18 aquariums (15 fish/aquarium). The results indicated that growth performance showed differences (p < 0.05) for specific growth rate, feed conversion and survival. Triglycerides, cholesterol and glucose, transaminases and digestive enzymes were significantly influenced by DOS levels. The histological study confirmed that the administered diets did not cause damage and induced significant morphological changes in the proximal intestine. The 16S rRNA gene sequencing analysis of the gut microbiota showed a high diversity and richness of OTU/Chao-1, with Fusobacteria, Proteobacteria, Bacteroidetes and Acidobacteria predominating in the DOS treatments compared to the control (p < 0.05). Induction of hypoxia stress after the feeding period showed a significant relative survival rate of 83.33% in fish fed 50 mg·kg⁻¹. It is concluded that the DOS treatments performed better than the control treatment in most of the variables analysed. DOS had no negative effects on the fish. The results showed that up to 50 mg·kg⁻¹ DOS improved digestive, metabolic and growth performance in hybrid Tilapia.

This study aimed to evaluate the growth performance, feed utilisation, digestive and metabolic enzyme activity, and liver histology in juveniles of hybrid red tilapia (Oreochromis mossambicus × Oreochromis niloticus) fed with the inclusion of chitosan in their diet. Six dietary chitosan levels (0 “control’’, 10, 20, 30, 40, and 50 g kg⁻¹) were used to feed juvenile fish (initial weight 7.50 ± 0.20 g) that were cultured for eight weeks in 18 tanks at a density of 15 fish/tank. The growth performance presented significant differences (p ˂ 0.05) for weight gain, specific growth rate, feed conversion ratio, hepatosomatic index, and survival rate. The digestive and metabolic enzyme activities were significantly (p < 0.05) influenced by the levels of chitosan in the administered diet. Histologically, no damage was found in the liver; however, morphometrically, a significant difference (p < 0.05) was found in the hepatocyte area and sinusoid area. Vacuolisation of hepatocytes was found in treatments with 40 and 50 g kg⁻¹ of chitosan in the diet. Treatments with doses of chitosan showed a better response (p < 0.05) compared to the control treatment in most of the different groups of variables analysed. The result of the principal component analysis suggests that a diet containing 40 g kg⁻¹ of chitosan is optimal for tilapia growth performance.

The aquaculture due to the high cost and continued shortage of animal protein sources, the development of alternative plant protein sources has been one of the main challenges to establish sustainable aquaculture as economically viable. Objective of this investigation was to determine the chemical composition and effect of Tithonia diversifolia on the growth performance, feed efficiency and metabolic biochemistry of juveniles of Oreochromis mossambicus × Oreochromis niloticus. Five treatments were used: 0% (control), 4, 8, 12 and 16% levels of inclusion of T. diversifolia flour in diet to feed juvenile fish cultured in 15 plastic aquariums at a density of 15 fish/aquarium. The assay lasted eight weeks. The T. diversifolia flour was characterized for showing adequate levels of crude protein (21%), with low crude fat (4.5%) levels, neutral detergent fiber levels: 43.03% and acid detergent fiber: 24.40%. The growth performance presented significant differences (p˂0.05), for weight gain, day average weight gain (DAW), length gain, day average length gain (DAL), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER) and feed conversion ratio (FCR). In treatment with 16% of inclusion of T. diversifolia flour, values obtained for weight gain, DAW, SGR, FE and PER (15.88 g, 0.28 g. day-1, 2.03 %, 0.34 g.g-1 and 0.98, respectively), which did not differ with the control treatment, highlighting the benefits of T diversifolia flour. The metabolic biochemistry parameters experienced a decrease with the increase of T. diversifolia in diet, where the highest values of triglycerides, cholesterol, and glucose were for the control treatment (p <0.05), while the protein increased to 4% of the flour. T. diversifolia flour presents an adequate balance of nutrients for its chemical composition and amino acids, without causing negative effects on the growth performance, weight-length relationship, feed efficiency, survival and metabolic biochemistry.

Objetivo. Caracterizar la composición química de intestinos de pollos procesados con harinas vegetales (HV), como fuente alternativa de proteína para la acuicultura. Materiales y métodos. Los intestinos de pollos, molidos, cocidos y desgrasados (IPMCD), se mezclaron de forma individual con harinas vegetales (HV): polvo de arroz (PA), salvado de trigo (ST), harinas de palmiste (HPa), maíz (HM) y soya (HS), en proporciones (p:p): 80:20, 70:30, 60:40, 50:50 y 40:60 (IPMCD:HV), con 20 tratamientos y diseño completamente aleatorizado. Se evaluó materia seca, proteína cruda, lípidos, fibra, cenizas, energía bruta (MJ kg^-1) y costos. Se aplicó análisis de componentes principales (PCA) para verificar la interacción entre proporciones. Resultados. Las mayores proporciones con IPMCD, incrementaron el contenido de proteína y lípidos (pConclusiones. Las proporciones de IPMCD:HV alcanzaron altos niveles de materia seca, que facilitó el proceso de deshidratación. El contenido nutricional y costos de las mezclas, las acredita como posibles alimentos acuícolas, para reemplazar la proteína en las dietas, según la especie, fin productivo y requerimientos del mercado. El PCA con matriz de covarianza, sugiere que los tratamientos IPMCD:HS (80:20), IPMCD:HS (70:30) y IPMCD:HS (60:40) tienen mejores características nutricionales, aunque, IPMCD:HPa (80:20) mostró altos niveles de proteína y fue la más económica.

Objetivo. Determinar la respuesta de los indicadores productivos al incluir palmiste (Elaeis guineensis) en dietas para la nutrición de alevines de tilapia (Oreochromis niloticus). Material y métodos. Se utilizaron 300 machos masculinizados de tilapia (4,89 ± 0,09 g) y se distribuyeron bajo un diseño completamente al azar con tres repeticiones por tratamiento (20 peces por repetición). Se utilizó palmiste para formular cinco dietas isoproteicas (30,64%), isolipídicas (7,38%) e isoenergéticas (11,84 MJ kg^-1 de alimento), control (T0), 5% (T5); 10% (T10); 15% (T15) y 20% (T20) para alimentar durante 60 días. Resultados. Los peces alimentados con los tratamientos T0, T5 y T10, no mostraron diferencias significativas (p> 0.05), pero sí con T15 y T20 en la digestibilidad de los nutrientes, el crecimiento y la composición del cuerpo. La inclusión de palmiste hasta el 20% de la dieta, disminuyó el costo del alimento. Se observó un alto grado de dependencia entre el contenido de fibra detergente neutro (%), la digestibilidad aparente de la materia seca (%) y la digestibilidad aparente de la proteína (%) (R² = 0,732 y R² = 0,774; p Conclusiones. El palmiste se puede usar hasta el 10% en dietas para alevines de tilapia, sin afectar la digestibilidad aparente de los nutrientes, el crecimiento y el contenido nutricional en todo el cuerpo. La inclusión progresiva de palmiste en las dietas, disminuyó el costo del alimento, para un cultivo de tilapia más rentable.

A comparative study of serum biochemical and hematological parameters from Andinoacara rivulatus and Ichthyoelephas humeralis in Los Ríos Province, Ecuador, was carried out. Two of the native species that are the most commercialized in Quevedo, Mocache and Fumisa, were identified; 60 specimens were captured in each area (180 total). A factorial design (3×2) was used: three habitat zones (Fumisa, Quevedo, and Mocache) and two species (A. rivulatus and I. humeralis). Sex, weight, length, serum biochemistry (total protein, albumin, globulin, albumin/globulin ratio, aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium, phosphorus, sodium, magnesium, and potassium), hematological parameters (hemoglobin, hematocrits, erythrocytes, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), total leukocytes, granulocytes leukocytes, and agranulocytes leukocytes) in fishes were determined. There was zone-species interaction for all indicators except MCH and MCHC (P < 0.05). For total proteins, albumins and ALT were for I. humeralis in Fumisa and Mocache zones (2.81, 1.57, and 326.67 g dL-1, respectively). In comparison, A. rivulatus was higher in Fumisa and Quevedo in globulins and the albumins/globulins ratio with 2.28 g dL-1 and 2.14, respectively. Electrolytes were found in low concentrations in the two species. For the hematological parameters, all presented significant differences (P < 0.05) except MCH and MCHC. For I. humeralis, its highest values were presented in hemoglobin with 13.37 g dL-1 in Fumisa, for MCV and total leukocytes (93.11 fL-1 and 8.03×103 μL-1) respectively, in the Mocache area. This study will provide essential tools in monitoring the health status of these fish species in particular and fish species in general.

Objetivo. Evaluar los efectos de la zona de habitad y sexo en la respuesta bioquímica sérica y morfométrica de Ichthyoelephas humeralis en ecosistemas loticos de la provincia Los Ríos, Ecuador. Materiales y métodos. Se identificó una de las especies nativas (I. humeralis) que más se comercializan en los cantones de Quevedo, Mocache y Fumisa de la provincia Los Ríos. Se capturaron 60 ejemplares por cada zona (180 total). Se realizó el sexado y se determinó el peso vivo, la longitud, el grosor de la cabeza, cuerpo y cola; factor de condición y bioquímica sanguínea (glucosa, colesterol y triglicéridos). Resultados. Para los indicadores morfométricos no hubo interacción zona-sexo. Solo existieron diferencias significativas (pConclusiones. Se evidenció el efecto del sexo sobre los indicadores morfométricos, con los mejores resultados para los machos. Mientras que la bioquímica sanguínea mostró variabilidad con respecto a las zonas con los mayores resultados para Quevedo, producto a las fluctuaciones en condiciones naturales del ambiente y la alimentación.