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252 results on '"Vega-Villasante, Fernando"'

26. Optimization of Classical Lipase Activity Assays for Fish Digestive Tract Samples.

Author

Nolasco-Soria, Héctor, Alvarez-González, Carlos Alfonso, Tovar-Ramírez, Dariel, González-Bacerio, Jorge, del Monte-Martínez, Alberto, and Vega-Villasante, Fernando

Subjects
BILE salts, FISH physiology, ALIMENTARY canal, ABSORPTION coefficients, BIOCHEMICAL substrates, LIPASES
Abstract

Fish possess lipases from embryonic development to adulthood. Lipase activity methods vary and significantly differ in terms of the concentration of the substrate used, bile salt, Ca2+, temperature, pH, and type of lipase units, which limits comparative studies. The three most-used substrates are p-nitrophenyl (p-NP), β-naphthyl (β-N) derivates, and emulsified natural oils. These were selected to be redesigned in this study to measure lipase activity under temperature, pH, ion, and bile salt conditions closer to fish physiology, using the appropriate molar absorption coefficient to calculate the lipase units. Cynoscion parvipinnis (CP), Seriola rivoliana (SR), Centropomus viridis (CV), Elop affinis (EA), and Canthidermis maculate (CM) pyloric caeca-intestine extracts were studied. Sodium taurocholate showed the highest activity for intestinal lipases, and the fatty acid length in the substrates changed the lipase hydrolysis rate. The highest lipase activity was obtained with p-NP butyrate and p-NP caprylate in four fish species. Lipase activity was highly activated with Ca2+ (4–7 mM). The β-N absorption spectrum indicates a plateau between 534 and 554 nm for fish lipases. Salmon oil was identified as the most digestible lipid in the four fish species using the in vitro digestibility assay. The lipase zymogram showed an apparent size of 46.3 kDa for CP, 40.2 kDa for SR, 46.2 kDa for CM, 106.6 kDa for EA, and 58.3, 84.6, and 162.1 kDa for CV. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Biochemical Composition of Eggs, Larvae and Tissues of Macrobrachium tenellum Females Fed Diets with Different Lipid and Protein Levels.

Author

Peña-Almaraz, Omar Alejandro, Vargas-Ceballos, Manuel Alejandro, Cortés-Jacinto, Edilmar, and Vega-Villasante, Fernando

Subjects
GONADS, MACROBRACHIUM, DIET, NUTRITIONAL requirements, LARVAE, LIPIDS, PROTEINS
Abstract

One way to approach the nutritional requirements of native shrimp, necessary to consolidate their culture, is to know their biochemical composition. The effect of feeding two levels of lipids (4 and 12% L) and four levels of proteins (30, 35, 40 and 45% P) in M. tenellum females was evaluated with respect to the biochemical composition of their eggs (EG), larvae (LR), gonad (GO) and hepatopancreas (HP). Total protein (TP), total carbohydrate (TC) and total lipid (TL) were estimated. In EG, L and P levels influence TP and TL; TP increases in diets higher than P35. In LR, there are no differences (p > 0.05) in TP and in TL, only diets L4P40 and L12P30 were different (p < 0.05). In GO, there is no trend in TP differences; in TC there was variation in the range of the data and TL was higher in L4P30 and L4P35. In HP, the diets with L4 obtained the highest TP values (p < 0.05); the L12 diets were higher in TL (p < 0.05). In general, diets with an inclusion of L12 showed the highest TP, TC and TL means, within this lipid level the P30 diet stood out; therefore, it is recommended to use a diet with L12P30 in the formulation of balanced feed for the species. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Population structure and abundance of the amphidromous prawn Macrobrachium tenellum (Smith, 1871) (Decapoda: Caridea: Palaemonidae) in the lower basin of Ameca River, western Mexico, before anthropogenic modifications.

Author

Vargas-Ceballos, Manuel A, Wehrtmann, Ingo S, López-Uriarte, Ernesto, Vega-Villasante, Fernando, Peña-Almaraz, Omar A, Espinosa-Magaña, Alí F, and García-Guerrero, Marcelo U

Subjects
MACROBRACHIUM, DECAPODA, SHRIMPS, WATERSHEDS, ANTHROPOGENIC effects on nature
Abstract

The population of the freshwater prawn Macrobrachium tenellum (Smith, 1871) in four sites in the lower part of the coastal plain of the Ameca River, Mexico is analyzed before drastic anthropogenic modifications of the riverbed occurred. Of the 7,100 individuals of M. tenellum collected between February 2015 and January 2016, 45.7% of which were females (3,250), 4.3% ovigerous females (309), 39.3% males (2,79), and 10.6% undifferentiated (750). Males were significantly larger and heavier than females. In general, the largest individuals were collected at the most distant sites from the coastline (Colomo and San Juan), whereas the smallest ones were captured near the river mouth. The sex ratio (males:females 1:1.3) deviated from the expected 1:1. The length-weight relationship of females, males, and the population in general indicated a negative allometric growth for all three groups. The results of our research may serve as a reference point for future investigations assessing the impact of anthropogenic changes on M. tenellum populations. [ABSTRACT FROM AUTHOR]

Published
2024
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