Evaluación de oligosacáridos de manano (MOS) en dietas balanceadas para juveniles de pejelagarto (Atractosteus tropicus)

Background: Prebiotics are polysaccharides that cannot be digested by the host; however, they generate benefits by stimulating the activity of beneficial microorganisms in the digestive system, which can maximize weight gain, feed conversion, and stimulate the immune response. Mannan oligosaccharides (MOS) have been evaluated in several fish species of commercial importance. Goals: Determine inclusion effects of diffe­rent MOS levels in balanced diets for juveniles of Atractosteus tropicus on the growth, productive parameters, survival, somatic indexes, and activity of digestive enzymes. Methods: Six experimental diets including MOS (0.0, 0.2, 0.4, 0.6, and 0.8%) and a trout control diet (DC) were designed, manufactured, and evaluated in triplicate during 62 days. A hundred and eighty juveniles (5.11 ± 0.08 g) were distributed in a recirculation system with 18 tanks of 70 L with a flow of 10 L min-1. Results: The 0.2% MOS diet produced the highest va­lues in weight gained (WG), specific growth rate (SGR), and protein efficiency rate (PER) and the lowest value in feed conversion rate (FCR). Survival in all treatments was greater than 96%. The hepatosomatic index was higher for the 0.4% treatment, while the viscerosomatic index was higher for the 0.4% and 0.6% treatments. All the enzymatic activities (acid protease, alkaline protease, trypsin, chymotrypsin, leucine aminopeptidase, carboxypeptidases, lipases, α-amylase, acid phosphatases, and alkaline phosphatases) showed significant differences by the inclusion of MOS in the diet. Conclusions: Supplementation of 0.2% MOS in diets for juveniles of A. tropicus, generates benefits in growth and productive performance. The inclusion of MOS in diets for juveniles of A. tropicus modifies somatic indices and the activity of digestive enzymes of juveniles.Antecedentes. Los prebióticos, son ingrediente no digerible que benefician al huésped, estimulando selectivamente el crecimiento y la actividad de bacterias benéficas en el sistema digestivo. La eliminación de las colonizaciones bacterianas, estimula la respuesta inmune, maximiza la ganancia de peso, la conversión alimenticia y mejora la resistencia a enfermedades y al estrés. En este contexto, el Manano oligosacárido (MOS) ha sido empleado en varias especies de importancia comercial. Objetivo. Es así que se pretende determinar el efecto de los diferentes niveles de MOS en dietas balanceadas para juveniles de A. tropicus. Métodos. Se diseñó un experimento simple completamente aleatorizado con seis tratamientos, los cuales se evaluaron por triplicado, empleando diferentes porcentajes de MOS (0, 0.2, 0.4, 0.6 y 0.8%) y una dieta control de trucha (DCo). Se seleccionaron 180 juveniles (5.11 ± 0.08 g), que se distribuyeron en un sistema de recirculación. Resultados. La supervivencia en todos los tratamientos fue del 100%, mientras que la dieta 0.2% MOS presentó los valores más altos en crecimiento promedio diario (AWD), tasa de eficiencia proteínica (PER), ganancia en peso (DWR) y tasa específica de crecimiento (SGR), además se presentaron las mayores actividades enzimáticas digestivas (proteasa ácida, proteasa alcalina, tripsina, quimotripsina, leucina aminopeptidasa, y ?-amilasa). Conclusiones.  La suplementación con 0.2% de MOS en dietas para juveniles de pejelagarto, puede ser considerada como un suplemento dietético beneficioso para mejorar el crecimiento y la capacidad digestiva de los juveniles de A. tropicus

Larval Development in Tropical Gar (Atractosteus tropicus) Is Dependent on the Embryonic Thermal Regime: Ecological Implications under a Climate Change Context

This article belongs to the Special Issue Current Advances and Challenges in Fisheries and Aquaculture Science: Feature Papers for the New Journey of Fishes[EN] In ectotherm species, environmental temperature plays a key role in development, growth, and survival. Thus, determining how temperature affects fish populations is of utmost importance to accurately predict the risk of climate change over fisheries and aquaculture, critical to warrant nutrition and food security in the coming years. Here, the potential effects of abnormal thermal regimes (24, 28 and 32 °C; TR24, TR28, and TR32, respectively) exclusively applied during embryogenesis in tropical gar (Atractosteus tropicus) has been explored to decipher the potential consequences on hatching and growth from fertilization to 16 days post-fertilization (dpf), while effects on skeletal development and body morphology were explored at fertilization and 16 dpf. Egg incubation at higher temperatures induced an early hatching and mouth opening. A higher hatching rate was obtained in eggs incubated at 28 °C when compared to those at 24 °C. No differences were found in fish survival at 16 dpf, with values ranging from 84.89 to 88.86%, but increased wet body weight and standard length were found in larvae from TR24 and TR32 groups. Thermal regime during embryogenesis also altered the rate at which the skeletal development occurs. Larvae from the TR32 group showed an advanced skeletal development, with a higher development of cartilaginous structures at hatching but reduced at 16 dpf when compared with the TR24 and TR28 groups. Furthermore, this advanced skeletal development seemed to determine the fish body morphology. Based on biometric measures, a principal component analysis showed how along development, larvae from each thermal regime were clustered together, but with each population remaining clearly separated from each other. The current study shows how changes in temperature may induce craniofacial and morphological alterations in fish during early stages and contribute to understanding the possible effects of global warming in early development of fish and its ecological implicationsSIThis work was partially funded by “Study of the digestive physiology in larvae and juveniles of tropical gar (Atractosteus tropicus) based on histological, biochemical and molecular techniques” project (Ref. CB-2016-01-282765) from the National Council for Science and Technology (CONACyT) of Mexico. I.F. acknowledges the funding from the MICIU and the European Social Fund, “The European Social Fund invests in your future” through the Ramón y Cajal (Ref. RYC2018-025337-I) contract from the Plan Estatal de Investigación Científica y Técnica e Innovación 2017–2020Authors also thanks the support from the RED LARVAplus “Estrategias de desarrollo y mejora de la producción de larvas de peces en Iberoamérica” (117RT0521) funded by the Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (CYTED

EFFECT OF STOCKING DENSITY ON PRODUCTIVE PERFORMANCE OF JUVENILE OF THE BLACKSTRIPE CICHLID Vieja fenestrata (CICHLIFORMES: CICHLIDAE)

Background: Native fish species are a developing alternative for sustainable aquaculture worldwide and in Mexico, the southern region is leading the efforts in freshwater species. Objective: To assess the effect of different stocking densities on the productive performance of native fish juveniles of blackstripe cichlid (Vieja fenestrata). Methodology: A one-factor randomized experimental design was used, evaluating in triplicate four stocking densities, 0.5 (L), 2 (M), 4 (H) and 6 (S) juvenile L-1. The experiment lasted 30 days. Wet weight and total length were registered every 15 days and growth performance indices were obtained. Results: Growth and survival were superior (P<0.05) for densities L and M. However, the M density showed a higher (P<0.05) growth rate, weight gain, and condition factor. Implications: The stocking density showed an apparent effect on the growth and survival of juveniles of the blackstripe cichlid, with the M density showing the best results; however, a cost-benefit assessment is required before starting production of this tropical native species. Conclusion: Our results suggest that a territorial and/or food competition was probably responsible for the survival and growth obtained. Although more studies are required, it appears that Vieja fenestrata showed the typical patrons of behaviour of another most famous cichlids, as Nile tilapia, with high levels of aggression that depend on stoking density

Potential bioavailability of protein and lipids in feed ingredients for the three-spot cichlid Amphilophus trimaculatus: An in vitro assessment

For the commercial culture of the three-spot cichlid (Amphilophus trimaculatus), it is important to have available a set of protein and lipid ingredients suitable for feed manufacturing, which allow to optimize the culture at affordable costs. The in vitro digestibility was evaluated with pH-stat technique, using stomach and intestine multi-enzymatic extracts from A. trimaculatus juveniles. The digestion of protein ingredients was taken place both in acid and in alkaline conditions, quantifying the total of free amino acids at the end of the hydrolysis, whereas the digestion of lipid ingredients was taken place only in alkaline conditions. The digestive enzymes of this species showed a better affinity to raw materials of animal origin such as beef meal, fish meal and premium chicken meal, which presented better digestibility. The best lipid ingredient that could be used is the fish oil. However, it is possible to use ingredients from the plant sources, such as soy or cereals, and vegetable oils such as olive, corn or soy oil. It is necessary to complement this study in vitro with the digestibility analysis in vivo, in order to determine the inclusion percentages in feeds and costs and therefore to develop an efficient feed formulation for the aquaculture of A. trimaculatus.Fil: Toledo Solís, Francisco J.. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Martínez García, Rafael. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Díaz, Manuel. Universidad de Almería; EspañaFil: Peña Marín, Emyr Saul. Consejo Nacional de Ciencia y Tecnología; México. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Di Yorio, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Vissio, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Álvarez González, Carlos Alfonso. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Saenz de Rodrigáñez, Miguel. Universidad de Granada; Españ

Fructooligosaccharide supplementation in diets for tropical gar (Atractosteus tropicus) juvenile: Effects on morphophysiology and intestinal barrier function

Supplementary fructooligosaccharides (FOS) were evaluated on growth, survival, gut morphology, digestive enzyme activity and expression of intestinal barrier genes in tropical gar (Atractosteus tropicus). Four treatments were designed to include FOS (5, 10, 15 and 20 g/Kg) and were compared with a control (0 g/Kg) and the current commercial trout diet. Ten fish were stocked (0.25 ± 0.01 g and 4.2 ± 0.4 cm total length) per experimental unit by triplicate in a 45-day experiment. Fish fed with 5 and 10 g/Kg of FOS had the highest average weight and total average length. Fish fed 5 g/Kg FOS showed the best growth indexes (absolute weight gain: 2.16; specific growth rate: 4.96; and feed conversion rate: 1.23) and survival (96.66%) and also had the highest acid protease, chymotrypsin and leucine aminopeptidase activities. Fish fed 5 g/Kg FOS had a high absorption area and accumulation of lipids in the liver. Finally, relative overexpression of occluding (occ), nucleotide-binding oligomerization domain-2 (nod2) and mucin 2 (muc2) was detected in fish fed 10 and 15 g/Kg FOS. The supplementation between 5 and 10 g/Kg FOS in diets for A. tropicus juveniles could be beneficial for growth, digestive enzyme activities, gut morphology and intestinal barrier function.Fil: Sepúlveda Quiroz, Cesar Antonio. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Peña Marín, Emyr Saul. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Pérez Morales, Alfredo. Universidad de Colima; MéxicoFil: Martínez García, Rafael. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Alvarez Villagomez, Carina Shianya. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Maytorena Verdugo, Claudia Ivette. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Camarillo Coop, Susana. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Vissio, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Pérez Sirkin, Daniela Irina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Tovar Ramírez, Dariel. Centro de Investigaciones Biologicas del Noroeste; MéxicoFil: Galaviz, Mario. Universidad Autónoma de Baja California Sur; MéxicoFil: Álvarez González, Carlos Alfonso. Universidad Juárez Autónoma de Tabasco; Méxic

Dietary live yeast (Debaryomyces hansenii) provides no advantages in tropical gar, Atractosteus tropicus (Actinopterygii: Lepisosteiformes: Lepisosteidae), juvenile aquaculture

Tropical gar, Atractosteus tropicus Gill, 1863, is an ancient freshwater fish that is commercially cultivated in southern Mexico. Currently, there is a specific diet for its culture; however, the addition of probiotics has not been investigated. The objective of this study was to evaluate the supplementation of live yeast Debaryomyces hansenii for A. tropicus juveniles on growth, productive parameters, survival, somatic index, digestive enzyme activity, and immune system gene expressions (interleukin 10, il-10, Transforming growth factor β1, tgf-β1, and β2 microglobulin, b2m). Three experimental diets increased the dose of live yeast (0.5, 1.0, and 1.5%; 1014, 1015, and 1016 CFU g diet–1, respectively) and a control diet (CD; without yeast) were designed. Daily weight gain and specific growth rate were higher in fish fed with CD and 0.5% D. hansenii. High activities of trypsin, chymotrypsin LAP, and α-amylase, as well as overexpression of il-10 in the spleen, were detected in fish feed 0.5% D. hansenii. The inclusion of D. hansenii had no positive effect on aquaculture for A. tropicus, lower doses should be tested to optimize the diet

Changes in digestive enzyme activities during the early ontogeny of the South American cichlid (Cichlasoma dimerus)

Cichlasoma dimerus is a neotropical cichlid that has been used as a biological model for neuroendocrinology studies. However, its culture is problematic in terms of larval feeding to allow having enough fry quantity and quality. Larviculture requires full knowledge about the digestive system and nutrition; therefore, this study was intended to assess the digestive enzymes' changes at different ages during the early ontogeny. Acid protease activity was detectable from the first day after hatching (dah), increasing to its maximum peaks on 9 dah. In contrast, alkaline proteases had low activity in the first days of life but reached their maximum activity on 17 dah. Chymotrypsin, L-aminopeptidase, and carboxypeptidase A activities increased at 6 dah, while trypsin activity was first detected on 13 dah and reached its maximum activity on 17 dah. Lipase and α-amylase activity were detectable at low levels in the first days of life, but the activity fluctuated and reaching its maximum activity at 21 dah. Alkaline phosphatase continued to oscillate and had two maximum activity peaks, the first at 6 dah and the second at 19 dah. Zymograms of alkaline proteases on day 6 dah six revealed four activity bands with molecular weights from 16.1 to 77.7 kDa. On 13 dah, two more activity bands of 24.4 and 121.9 kDa were detected, having a total of six proteases. The enzymatic activity analyzes indicate the digestive system shows the low activity of some enzymes in the first days after hatching, registering significant increases on 6 dah and the maximum peaks of activities around at 17 dah. Therefore, we recommend replacing live food with dry feed and only providing dry feed after day 17 dah.Fil: Toledo Solís, Francisco Javier. Universidad de Almería; España. Consejo Nacional de Ciencia y Tecnología; MéxicoFil: Hilerio Ruiz, Andrea Guadalupe. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Delgadin, Tomás Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Pérez Sirkin, Daniela Irina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Di Yorio, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Vissio, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Peña Marín, Emyr Saul. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Martínez García, Rafael. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Maytorena Verdugo, Claudia Ivette. Universidad Juárez Autónoma de Tabasco; MéxicoFil: Alvarez González, Carlos Alfonso. Universidad Juárez Autónoma de Tabasco; MéxicoFil: de Rodrigáñez, Miguel Ángel Sáenz. Universidad de Granada; Españ

Incorporation of Fructooligosaccharides in Diets Influence Growth Performance, Digestive Enzyme Activity, and Expression of Intestinal Barrier Function Genes in Tropical Gar (<i>Atractosteus tropicus</i>) Larvae

This study was conducted to investigate the effects of dietary fructooligosaccharides (FOS) on the growth, survival rate, digestive enzyms activity, and the expression of intestinal barrier function genes in tropical gar (Atractosteus tropicus) larvae. A total of 960 larvae (0.030 ± 0.006 g) were fed three diets supplemented with increasing FOS concentrations (2.5, 5, and 7.5 g kg−1) and a control diet for 15 days. Results revealed that a 7.5 g kg−1 FOS supplementation improved weight gain, specific growth rate, and survival rate (p −1 FOS supplementation increased alkaline protease and amylase activities and induced an upregulation of the claudin-17 gene expression (p −1 FOS induced the upregulation of mucin 2 (muc-2), and the tight junction genes zo-2 and claudin-3 (p −1 FOS promoted the downregulation of the claudin-15 gene expression (p il-8 expression. We can conclude that 7.5 g kg−1 FOS supplementation improves growth performance, survival rate, and digestive capacity, and could contribute to the reinforcement of the intestinal barrier function of Tropical gar larvae