Publications by authors named "Margarida Maria Barros"

5 Publications

  • Page 1 of 1

Ascorbic Acid Supplementation Improves Skeletal Muscle Growth in Pacu () Juveniles: In Vivo and In Vitro Studies.

Int J Mol Sci 2021 Mar 15;22(6). Epub 2021 Mar 15.

Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, UNESP, Botucatu 18618-689, São Paulo, Brazil.

In fish, fasting leads to loss of muscle mass. This condition triggers oxidative stress, and therefore, antioxidants can be an alternative to muscle recovery. We investigated the effects of antioxidant ascorbic acid (AA) on the morphology, antioxidant enzyme activity, and gene expression in the skeletal muscle of pacu () following fasting, using in vitro and in vivo strategies. Isolated muscle cells of the pacu were subjected to 72 h of nutrient restriction, followed by 24 h of incubation with nutrients or nutrients and AA (200 µM). Fish were fasted for 15 days, followed by 6 h and 15 and 30 days of refeeding with 100, 200, and 400 mg/kg of AA supplementation. AA addition increased cell diameter and the expression of anabolic and cell proliferation genes in vitro. In vivo, 400 mg/kg of AA increased anabolic and proliferative genes expression at 6 h of refeeding, the fiber diameter and the expression of genes related to cell proliferation at 15 days, and the expression of catabolic and oxidative metabolism genes at 30 days. Catalase activity remained low in the higher supplementation group. In conclusion, AA directly affected the isolated muscle cells, and the higher AA supplementation positively influenced muscle growth after fasting.
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http://dx.doi.org/10.3390/ijms22062995DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7998472PMC
March 2021

The combination of resveratrol and exercise enhances muscle growth characteristics in pacu (Piaractus mesopotamicus).

Comp Biochem Physiol A Mol Integr Physiol 2019 09 8;235:46-55. Epub 2019 May 8.

Department of Morphology, Institute of Bioscience, Sao Paulo State University, UNESP, Botucatu, SP, Brazil; Aquaculture Center, CAUNESP, Sao Paulo State University, UNESP, Jaboticabal, SP, Brazil. Electronic address:

Pacu is a tropical fish with important value to aquaculture. During cellular metabolism, reactive oxygen species (ROS) are produced, which can influence muscle growth. Resveratrol is an effective antioxidant that scavenges ROS and can modulate physical performance preventing oxidative stress. We investigated the effects of resveratrol and exercise on pacu muscle growth characteristics. Four groups were used: fish fed with control diet /without exercise (C); fish fed with control diet/subjected to exercise (CE); fish fed resveratrol-supplemented diet/without exercise (R); and fish fed resveratrol-supplemented diet/subjected to exercise (RE). At 30 days, the RE group presented a significant increase in body weight, fewer muscle fibers in the 20-40 μm and more fibers in the >60 μm diameter class compared to the C group. At day 7, catalase activity decreased in CE and RE groups. Superoxide dismutase activity decreased only in the CE group. Myod and mtor gene expression was higher in R and RE and igf-1 was up-regulated in the RE group. Murf1a level decreased in CE, R, and RE, while sdha expression was higher in the RE group. We suggest that resveratrol in combination with exercise was beneficial for muscle growth and metabolism, increasing the expression levels of genes related to muscle anabolism and oxidative metabolism, besides the decrease of catabolic gene expression. Notably, all of these changes occurred together with muscle hypertrophy and increased body weight. Our results show a positive application for resveratrol in association with exercise as a strategy to improve the growth performance of juvenile pacus.
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http://dx.doi.org/10.1016/j.cbpa.2019.05.002DOI Listing
September 2019

Novel inexpensive fungi proteases: Production by solid state fermentation and characterization.

Food Chem 2016 May 17;198:119-24. Epub 2015 Nov 17.

Laboratory of Bioprocess, Department of Chemistry and Biochemistry, IB, UNESP, Botucatu, SP, Brazil. Electronic address:

A comparative study was carried out for proteases production using agroindustrial residues as substrate for solid state fermentation (SSF) of several fungal strains. High protease production was observed for most of the microorganisms studied, as well as very different biochemical characteristics, including activities at specific temperatures and a wide range of pH values. The enzymes produced were very different regarding optimum pH and they showed stability at 50 °C. Aspergillus oryzae showed stability at all pH values studied. Penicillium roquefortii and Aspergillus flavipes presented optimum activity at temperatures of 50 °C and 90 °C, respectively. Lyophilized protease from A. oryzae reached 1251.60 U/g and yield of 155010.66 U/kg of substrate. Therefore, the substrate as well as the microorganism strain can modify the biochemical character of the enzyme produced. The high protease activity and stability established plus the low cost of substrates, make these fungal proteases potential alternatives for the biotechnological industry.
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http://dx.doi.org/10.1016/j.foodchem.2015.11.089DOI Listing
May 2016

Non-specific immune parameters and physiological response of Nile tilapia fed β-glucan and vitamin C for different periods and submitted to stress and bacterial challenge.

Fish Shellfish Immunol 2014 Aug 14;39(2):188-95. Epub 2014 May 14.

UNESP, Univ. Estadual Paulista, FMVZ, AquaNutri, Botucatu, SP, Brazil.

This study attempts to describe the effects of different administration periods of dietary β-glucan and Vit C on the non-specific immune response, physiological parameters and disease resistance of Nile tilapia against Aeromonas hydrophila infection. Therefore, a feeding trial (288 fish) was conducted to determine the best administration period (7, 15, 30 and 45 days) for a Nile tilapia diet supplemented with 0.1% β-glucan and 600 mg Vit C/kg diet. After the administration period, three different groups of 96 fish were exposed to one of the following three stresses: cold-induced stress, transport-induced stress, and A. hydrophila challenge. Hematological, biochemical and immunological responses were analyzed before and/or after stress. Cold-induced stress increased cortisol levels and reduced the leukocyte count in fish fed the test diet for seven days compared with the other periods. After transport-induced stress, fish fed the test diet for seven days required more hours to return to the baseline levels of cortisol and neutrophils. Moreover, independently of the administration period, fish needed 24 h for leukocyte and glucose levels to return to the initial values. The lowest survival after bacterial infection was observed in fish test diet for seven days. Based on fish hematological and biochemical responses, diet supplemented with 0.1% of β-glucan and 600 mg of Vit C/kg fed for at least 15 days is recommended for Nile tilapia especially when fish are likely to encounter transport-induced stress, and this stress was more severe than cold-induced stress or bacterial challenge.
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http://dx.doi.org/10.1016/j.fsi.2014.05.004DOI Listing
August 2014

Determination of chromium by GFAAS in slurries of fish feces to estimate the apparent digestibility of nutrients in feed used in pisciculture.

Talanta 2006 Jun 14;69(4):1025-30. Epub 2006 Feb 14.

Faculdade de Medicina Veterinária e Zootecnia, Programa de Pós-Graduação em Zootecnia, Bolsista CAPES, Departamento de Melhoramento e Nutrição Animal, UNESP, Caixa Postal 560, 18618-000 Botucatu, SP, Brazil.

This paper presents a simple, fast and sensitive method to determine chromic oxide (used as a biological marker of fish feed) in samples of fish feces by GFAAS through the direct introduction of slurries of the samples into the spectrometer's graphite tube. The standard samples of feces and of fish feed containing 0.10-1.00mgkg(-1) of Cr(2)O(3) were pre-frozen for 1min in liquid nitrogen and then ground a cryogenic mill for 2min, which reduced the samples' grain size to less than 60mum. The standard slurries were prepared by mixing 20mg of standard samples of fish feed or feces with 1mL of a solution containing 0.05% (v/v) of Triton X-100 and 0.50% (v/v) of suprapure HNO(3) directly in the spectrometer's automatic sampling glass. The final concentrations of Cr(2)O(3) present in the standard slurries were 2, 4, 8, 16 and 20mugL(-1). After sonicating the mixture for 20s, 10muL of standard slurries were injected into the graphite tube, whose internal wall was lined with a metallic palladium film that acted as a permanent chemical modifier. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (2%, m/v of feces or feed devoid of minerals) were 0.81 and 2.70mugL(-1) of Cr(2)O(3) for the standard feces slurries, 0.84 and 2.83mugL(-1) of Cr(2)O(3) for the standard feed slurries. The proposed method was applied in studies of nutrient digestibility of different fish feeds and its results proved compatible with the results obtained from samples pre-mineralized by acid digestion.
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http://dx.doi.org/10.1016/j.talanta.2005.12.008DOI Listing
June 2006
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