Nile Tilapia Skin Research Articles

Coliform bacteria in San Pedro Lake, western Mexico.

Urbanization, livestock activities, and rainfall are factors that contribute to the contamination of inland water. This study aimed to determine the spatial and temporal variability of total coliforms (TCs) and fecal coliforms (FCs) in the surface water of San Pedro Lake as well as the gills and skin of Nile tilapia (Oreochromis niloticus) cultivated in the lake. The study consisted of seasonal sampling during an annual cycle. Using the multiple-tube fermentation technique, we quantified the microbial load of TCs in the lake and fish. The median of the TC and FC groups in surface water showed differences during the seasonal cycle, in which a significant correlation was observed between rainfall and bacterial load in the lake surface water. There was a significant seasonal difference between FCs and TCs in the gills as well as in skin FCs. Anthropogenic activities in the watershed combined with rainfall influence the bacterial load of San Pedro Lake. However, the water quality is still classified as excellent and uncontaminated according to Mexican regulations with lower FC values acceptable for higher FC values. In addition, the bacterial load in tilapia from San Pedro Lake does not pose a risk to human health. PRACTITIONER POINTS: Watershed livestock activities combined with rainfall increase fecal matter pollution in specific areas of the lake. San Pedro Lake displays satisfactory quality for aquatic life. The median fecal coliform population in lake fish (gills and skin) differs by season.

Biocomposite based on nanoscale calcium phosphate and collagen from Nile tilapia (Oreochromis niloticus) skin: Properties and morphological features

This work proposes the synthesis of biocomposites with nanoscale calcium phosphate (nCaP) and collagen (extracted from fish skin), aiming at a possible application as artificial bone graft. Biocomposite micrographs show needle-shaped and aggregated CaP nanoparticles, with undefined orientation on the surface of the collagen matrix. In addition, the obtained nCaP-Collagen biocomposite had a composition of 6.5% water, 53.9% collagen and 39.6% nCaP, exhibiting similar characteristics to natural bones in mineralization stage, such as: calcium (Ca) / potassium (P) ratio of 1.54, featuring a non-stoichiometric hydroxyapatite (Ca/P < 1.67, which corresponds to biological hydroxyapatite); low crystallinity (ICr = 0.34); and elasticity modulus (32.1 ± 4.0 MPa) close to the internal compartment of human bone. Thus, the nCaP-Collagen has suitable physical and morphological characteristics for potential application as artificial bone graft.

Supplementation of cryodiluent media with seaweed or Nile tilapia skin sulfated polysaccharides for freezing of Colossoma macropomum (Characiformes: Serrasalmidae) semen

Tambaqui, Colossoma macropomum, is an ideal fish for cultivation in captivity and it is valued in the consumer market. Studies on various aspects of aquaculture, including semen freezing, have been conducted. Despite its many benefits, cryopreservation damages the samples. Thus, to refine the existing protocols, products with antioxidant properties can be added, such as sulfated polysaccharides. This study evaluated the effect of adding sulfated polysaccharides from seaweed (green: Caulerpa cupressoides; red: Acanthophora muscoides and Solieria filiformis) and Nile tilapia skin into the tambaqui semen freezing medium. The resulting polysaccharidic samples were diluted and added to the cryopreservation medium. The semen was then collected, pooled, and subsequently frozen. The pools were diluted and frozen in solutions containing powdered coconut water (ACP-104) and 10% dimethyl sulfoxide (DMSO), and were supplemented with different polysaccharide concentrations (100, 250, 500, or 1000 μg/mL) from seaweed or Nile tilapia skin. Semen cryopreserved in an un-supplemented solution was used as control. After 45 days, the samples were thawed by immersion in a water bath (45 °C/8 s) and the membrane integrity, the morphology and, the sperm motility kinetics were evaluated. There were no differences in sperm kinetics for any of the analyzed parameters that could be linked to the polysaccharide source that was used. For membrane integrity, semen supplemented with sulfated polysaccharides from Nile tilapia skin showed better results (76.3 ± 1.9%) compared to treatments supplemented with A. muscoides (65.0 ± 1.8%), C. cupressoides (66.1 ± 1.7%), or S. filiformis (68.8 ± 1.0%), but there was no difference compared to the control (73.6 ± 2.9%). For morphology, the best results were observed in semen supplemented with C. cupressoides (86.7 ± 0.8%) and S. filiformis (87.7 ± 1.0%) polysaccharides at 100 μg/mL. For the mean path velocity (VAP), semen treated with 250 μg/mL of polysaccharides was significantly faster for A. muscoides (21.1 ± 2.4 μm/s) compared to S. filiformis (15.8 ± 1.7 μm/s). However, at 1000 μg/mL, these two red algae shown to be more efficient than the green algae. In C. cupressoides, 1000 μg/mL of polysaccharides showed lower velocity (13.8 ± 1.5 μm/s) than the other concentrations. In S. filiformis, 100 μg/mL and 1000 μg/mL of polysaccharides did not differ and presented higher VAP than 250 μg/mL and 500 μg/mL. Therefore, the addition of sulfated polysaccharides extracted from aquatic sources to ACP-104 and 10% DMSO solution is safe and has a potential of applicability on C. macropomum semen cryopreservation.

Kinetic modeling of the alkaline deproteinization of Nile-tilapia skin for the production of collagen

A new phenomenological model, based on a second order dissolution kinetics, was developed for the alkaline removal of non-collagenous protein (NCP) from the skin of Nile tilapia (SNT). This model allows estimating the liquid concentration of NCP in terms of temperature, skin size, NaOH concentration and time. This model was fitted with 135 experiments averaging a R2 of 0.99. The root-mean-square deviation and the mean-absolute-percentage error of the model were 0.0041 and 3.15%, respectively. The Arrhenius-activation energy was 15–122 kJ mol−1. Multi-objective optimization led to the highest NCP extraction (NCPE) of 24.3% and to the lowest loss of collagen (LC) of 1.3%, with R2 coefficients of 0.98 and 0.92, respectively. Ultimately, SNT deproteinized under optimal conditions was subjected to acid extraction and purification. FTIR and SEM analyses indicated that the product was a Type I collagen that could be used in the pharmaceutical industry.

Exploring candidate genes in a major QTL region associated with salinity tolerance in the skin of Nile tilapia based on transcriptomic analysis

Salinity is recognized to be a major environment factor that influences cellular hemostasis and functions in Tilapia. Previously, we identified a major quantitative trait locus (QTL) that associated with salinity tolerance at chrLG18 in tilapia. However, the causative functional genes within the QTL interval and their underlying molecular mechanisms in salinity tolerance remain unclear. In this study, we investigated the skin transcriptomic responses of the Nile tilapia GIFT line in response to three and a half months of salinity challenge with a concentration of 0, 17 and 27 ppt respectively, using RNA-seq. We detected 61, 1303 and 87 differentially expressed genes (DEGs) in three groups of comparison (ppt 0vs17, ppt 0vs27 and ppt 17vs27, respectively). These DEGs were mainly enriched in 5 pathway categories: apoptosis, cell junction, signal transduction, endocytosis and energy metabolism (p < .01). Colocalization of QTL intervals with the gene expression data revealed that three DEGs, nmrk2, ptprf and arhgef18a, were located within the major QTL region. In a red tilapia family, three SNPs in the gene ptprf were found significantly correlated with salinity tolerance. Our findings provide a DEG dataset for further identifying functional genes of salinity tolerance within the major QTL interval.

Successive digestion of tilapia collagen by serine proteinase and proline specific endopeptidase to produce novel angiotensin I-converting enzyme inhibitory peptides

Serine proteinase, purified from the hepatopancreas of Pacific white shrimp (Litopenaeus vannamei), was used to hydrolyze acid solubilized collagen (ASC) isolated from Nile tilapia (Oreochromis sp.) skin to produce angiotensin I-converting enzyme (ACE) inhibitory peptides (ACEIPs). A series of column chromatography assays were used to separate the ACEIPs. A peptide, NPARTCR, was isolated as it exhibited high ACE inhibition potential. Further digestion of this peptide by a proline specific endopeptidase (PSEP), produced a pentapeptide ARTCR with ACE inhibitory activity (IC50) of 77.0 μmol/L. Both NPARTCR and ARTCR inhibited ACE in a non-competitive manner. An in vivo study in rats demonstrated that ARTCR has ACE inhibitory activity via lowering systolic blood pressure in spontaneously hypertensive rats (SHRs). These results suggest that processing by-products from shrimp and tilapia are ideal raw materials for the production of serine proteinase and collagen, respectively. Serine proteinase and collagen are both ideal raw materials that can be used to derive ACE inhibitory active peptides against hypertension.

Male-to-Female Gender-Affirming Surgery Using Nile Tilapia Fish Skin as a Biocompatible Graft

Insufficient penile skin is common during vaginoplasty for male-to-female transition. This issue may be compensated by a scrotal skin flap, with the drawback of hair growth [1]. In recent studies, Nile tilapia skin was successfully used for the surgical management of Mayer-Rokitansky-Küster-Hauser syndrome [2,3] and vaginal stenosis [4,5]. This study aims to describe a novel technique for primary vaginoplasty in male-to-female gender-affirming surgery using Nile tilapia skin as a biocompatible graft to ensure adequate vaginal depth. Stepwise demonstration of the procedure with narrated video footage. Transgender health clinic. A 29-year-old patient with gender dysphoria was referred to our office because of a desire for gender-affirming surgery. A physical examination revealed normal male genitalia with a 14-cm-long penis. Before surgery, approval from the institutional review board and written permission from the patient were obtained. After orchiectomy, penile disassembly, perineal dissection, and urethroplasty were performed, and a hollow Nile tilapia skin mold was prepared and sutured to the distal edge of the remaining penile skin. This structure was inverted, covering the newly created canal. The neocavity was then filled with a handmade inflatable vaginal mold, held in place by sutures in the labia majora. Finally, labiaplasty and clitoroplasty were conducted. After 7 days, the inflatable mold was removed, and the use of progressively larger dilators was initiated. After 3 weeks, a neovagina that was 16 cm long and able to accommodate the width of 2 fingers was detected. At that time, the Nile tilapia skin was completely reabsorbed into the neovaginal mucosa. There were no complications in the early postsurgical period. Nile tilapia skin, a safe, low-cost, and easy-to-use biocompatible material, may be an alternative option to scrotal skin grafts for neovaginal augmentation in primary vaginoplasty for male-to-female gender transition. However, further studies are needed to confirm this assertive.

Optimization of the collagen extraction from Nile tilapia skin (Oreochromis niloticus) and its hydrogel with hyaluronic acid

Nile tilapia skin, an abundant waste from fish processing, can be used for collagen extraction, which has a high aggregated value for biomedical applications. Collagen extraction was conducted under different reaction conditions (time, temperature, and concentration of acetic acid) in order to optimize the yield without compromising the integrity of the collagen. Temperature and time were responsible for increased yield. The extraction at 4 and 20 °C produced the acid-solubilized collagen (ASC) with the intact triple helix and was analysed by Fourier-transform infrared spectroscopy (FT-IR) and circular dichroism (CD). The optimized ASC (which used 0.35 mol/L of acetic acid at 20 °C) was consumed to obtain for the first-time fish-based hydrogels with hyaluronic acid (HA) crosslinked with 1-ethyl-3-(3-dimethylaminopropryl carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The hydrogel was characterized by FT-IR, rheology, swelling, and scanning electron microscopy (SEM), confirming that cross-linking was accomplished. It possesses a robust organized network, swells 255 % in PBS and bears interconnected pores with a diameter in the range of 10−100 μm. Until now, col-HA hydrogels crosslinked with EDC/NHS have not been reported in literature with collagen from Nile Tilapia skin. Fish collagen can be a better option than those from land-based animals (cow and pig).

The effect of fishwort (Houttuynia cordata) on skin mucosal, serum immunities, and growth performance of Nile tilapia

The present study addressed the possible effects of fishwort (Houttuynia cordata) powder (FWP) on Nile tilapia's skin mucus parameter, serum immune response, and growth performance. Three hundred twenty tilapia fingerlings (average weight of 39.06 ± 0.16 g) were divided into four treatments and fed four levels of FWP; 0, 5, 10, and 20 g kg−1 for 72 days. Completed randomised design of the four replications was applied and revealed that fish fed FWP significantly improved skin mucus lysozyme activity (SMLA). The highest value (P < 0.05) was recorded in fish fed 10 g kg−1 FWP. However, no significant difference in SMLA was observed by feeding the fish 5 and 20 g kg−1 FWP. Significant (P < 0.05) enhanced skin mucus peroxidase activity (SMPA) was observed in fish fed 10 g kg−1 FWP, but no significant difference in SMPA was detected between FWP supplemented diets (5 and 20 g kg−1 FWP) and the control group. Regarding serum immunity, dietary administration of FWP showed significantly (P < 0.05) improved serum lysozyme, peroxidase, alternative complement (ACH50), and phagocytosis vs. the control. The highest values of serum immunity (P < 0.05) were recorded in fish fed 10 g kg−1 FWP. However, no significance in respiratory burst activity was observed. Similarly, no significant difference in growth performance, feed conversion ratio, and survival rate was observed in fish fed FWP compared to the control. In summary, diets supplemented with FWP (10 g kg−1) increased the serum and mucosal immunity; however, no FWP supplementations had effects on Nile tilapia growth and survival rate.

Comprehensive assessment of Nile tilapia skin collagen sponges as hemostatic dressings.

Nile tilapia skin collagen sponge was fabricated by lyophilization and cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide in the presence of N-hydroxysuccinimide (EDC/NHS). The physicochemical properties were examined. The EDC/NHS cross-linked collagen sponge presented an enhanced water absorption capacity. In addition, biocompatibility and hemostatic efficiency were evaluated by acute systemic toxicity assay, dermal irritation test, intradermal reaction test, sensitization test, cytotoxicity, blood clotting assay in vitro, and liver and femoral artery hemorrhage models in vivo. Results showed that the produced collagen sponges before and after EDC/NHS cross-linking had excellent biocompatibility. Furthermore, EDC/NHS cross-linking promoted fibroblast cells viability and proliferation reflected by the MTT reduction assay. Meanwhile, EDC/NHS cross-linked collagen sponge exhibited the best blood clotting ability and hemostatic efficiency in rat femoral artery hemorrhage model in comparison with non-crosslinked and commercial collagen sponges. Our results demonstrated that the fabricated collagen sponges could be used as perfect hemostatic dressings.

Characterization of gelatins from Nile tilapia skins preserved by freezing and salting

After Nile tilapia skin was preserved using the methods of freezing and dry salting, characteristics of skin gelatin were evaluated with regard to yield, rheological features and physical and chemical properties. Preservation was performed after filleting, at which time skins were either frozen (-18°C) for 7 days or salted (25°C) for 7 days. Although no differences (p &gt; 0.05) were observed with respect to humidity, protein, lipid, ash and calcium levels, gelatin from salted skins had a higher concentration of iron relative to frozen skins. Further, twenty-three fatty acids were detected in salted skins compared with merely three found in skin derived gelatin. Of amino acids found, glycine, alanine, proline and arginine were the most abundant. Hydroxyproline abundance in salted and frozen skin gelatin were 8.76% and 8.71%, respectively. In addition, salted skin gelatins had a greater accumulation of saturated fatty acids and lower rates of monounsaturated fatty acids. Salted skin gelatin had the highest yield (18g × 100g-1), gel strength (200 g) and viscosity (19.02mPas) when compared to the yield (17g × 100g-1), gel strength (12.7g) and viscosity (9.16 mPas) of frozen skins. Results show that gelatin from dry salted skin had the best yield and also had relatively better rheological properties, more iron, and better coloration relative to gelatin obtained from frozen skins of Nile tilapia.

Tilapia fish skin as a new biologic graft for neovaginoplasty in Mayer-Rokitansky-Kuster-Hauser syndrome: a video case report

To describe a McIndoe procedure technique for surgical management of Mayer-Rokitansky-Kuster-Hauser syndrome with the use of Nile tilapia skin as a scaffold for the proliferation of new vaginal epithelium. Surgical video article. Local Institutional Review Board approval and written permission from the patient were obtained. There were no conflicts of interest. University hospital. A 17-year-old woman who presented at our gynecology department with the complaint of primary amenorrhea. At physical examination, she had a phenotypically normal vulva with no vaginal canal. Magnetic resonance imaging of the abdomen and pelvis revealed normal ovaries and absence of uterus and vaginal canal. No other congenital malformations were found. Karyotype was 46,XX. The McIndoe procedure involved only a vaginal approach. Labia minora were separated, and a transverse midline incision of 3cm was made. The vesicorectal space was progressively dissected. Blunt dissection was performed initially with digital separation of tissues. The neovagina was then inspected with the introduction of a vaginal speculum, allowing for review of hemostasis. Blunt dissection was continued with the aid of the speculum, to reach the appropriate vaginal dimensions. Subsequently, a vaginal acrylic mold covered with two pieces of processed and sterilized tilapia fish skin was inserted and accommodated into the newly created cavity. The external side of the tilapia skin, which maintained its grayish coloration after the removal of the scales, stayed in contact with the acrylic mold, while the white internal side of the tilapia skin, which was previously attached to the fish's muscle, stayed in contact with the walls of the neocavity. The mold was held in position by four multifilament polyglactin 1.0 sutures in the labia majora, thus preventing expulsion. Anatomic data, such as measurement of the final canal length, and histomorphologic analysis, 180days after surgery. The patient remained on bed rest for 9days, after which the tilapia fish skin had been partially reabsorbed. After this time, the acrylic mold was removed. A larger plastic mold was then inserted and the patient was advised to wear it day and night for the first postoperative month. The vaginal mold had to be worn each night until normal sexual intercourse was possible. The final canal length 180days after surgery was between 8 and 9cm. For the histopathologic analysis, fragments of the lateral vaginal wall were removed 180days after surgery and showed the presence of stratified squamous epithelium with five cell layers, ectasic blood vessels, and occasional desquamated epithelial cells. The procedure described offered this patient an anatomic and functional neovagina by means of a simple, safe, easy, effective, quick, and minimally invasive procedure. Limitations include the experimental nature of this study, based on a single case report with no long-term outcome results. The tilapia fish skin is a low-cost and widely available biomaterial.

First report of Trichodinella and new geographical records of trichodinids in Nile tilapia (Oreochromis niloticus) farmed in Brazil.

Massive occurrence of trichodinids is frequently accompanied by serious disease in fish farms. In this study, trichodinid species from the gills and skin of Nile tilapia (Oreochromis niloticus) farmed in the central-western region of Brazil (state of Goiás) were morphologically characterized. Dried slides were prepared from the parasites and were impregnated with silver nitrate (2%). Morphometric characteristics were determined and schematic drawings of the denticles were made using photomicrographs produced from the slides. Seven species of trichodinid ectoparasites (Protozoa: Ciliophora: Trichodinidae) were found parasitizing the gills: four of the genus Trichodina Ehrenberg, 1838; one of Tripartiella Lom, 1959; one of Paratrichodina Lom, 1963; and one of Trichodinella Ṧrámek-Huṧek, 1953. On the body surface, three specimens of the genus Trichodina were identified. This study presents new geographical records of trichodinids in Brazil, thus confirming that Trichodina centrostrigeata, Trichodina compacta, Trichodina heterodentata, Paratrichodina africana and Tripartiella orthodens are widely distributed worldwide. Additionally, the first record of the genus Trichodinella in Brazil is presented.

Physicochemical and Biocompatibility Properties of Type I Collagen from the Skin of Nile Tilapia (Oreochromis niloticus) for Biomedical Applications.

The aim of this study is to investigate the physicochemical properties, biosafety, and biocompatibility of the collagen extract from the skin of Nile tilapia, and evaluate its use as a potential material for biomedical applications. Two extraction methods were used to obtain acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from tilapia skin. Amino acid composition, FTIR, and SDS-PAGE results showed that ASC and PSC were type I collagen. The molecular form of ASC and PSC is (α1)2α2. The FTIR spectra of ASC and PSC were similar, and the characteristic peaks corresponding to amide A, amide B, amide I, amide II, and amide III were 3323 cm−1, 2931 cm−1, 1677 cm−1, 1546 cm−1, and 1242 cm−1, respectively. Denaturation temperatures (Td) were 36.1 °C and 34.4 °C, respectively. SEM images showed the loose and porous structure of collagen, indicting its physical foundation for use in applications of biomedical materials. Negative results were obtained in an endotoxin test. Proliferation rates of osteoblastic (MC3T3E1) cells and fibroblast (L929) cells from mouse and human umbilical vein endothelial cells (HUVEC) were increased in the collagen-treated group compared with the controls. Furthermore, the acute systemic toxicity test showed no acute systemic toxicity of the ASC and PSC collagen sponges. These findings indicated that the collagen from Nile tilapia skin is highly biocompatible in nature and could be used as a suitable biomedical material.

Nile tilapia skin xenograft versus silver-based hydrofiber dressing in the treatment of second-degree burns in adults

Nile tilapia skin xenograft versus silver-based hydrofiber dressing in the treatment of second-degree burns in adults

Effect of tannic acid as crosslinking agent on fish skin gelatin-silver nanocomposite film

Abstract Gelatin was obtained from the Nile tilapia skin and used to prepare and stabilize silver nanoparticles (AgNPs) at a pH of 11.0. The properties gelatin-AgNP and gelatin-AgNP films with tannic acid (TA) were evaluated. TA is a non-toxic cross-linker agent and was add to enhance the mechanical properties of the gelatin-AgNPs nanocomposite. The films were studied by UV–vis and infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), mechanical analysis (tensile strength and elongation at break), water vapor permeability, solubility, scanning electron microscopy and antimicrobial activities (tested against two pathogens: S. aureus (gram-positive) and E. coli (gram-negative)). The gelatin films containing 5.0 wt% of TA, 0.2 wt% of AgNPs and 20 wt% of glycerol exhibited high mechanical strength, low water barrier, and antimicrobial activity against both pathogens. The presence of TA in gelatin-AgNPs nanocomposite was essential to promote these properties. Therefore, films with TA presented greater possibility to be used as food packaging.

Fish Skin Gelatin Hydrolysate Production by Ginger Powder Induces Glutathione Synthesis To Prevent Hydrogen Peroxide Induced Intestinal Oxidative Stress via the Pept1-p62-Nrf2 Cascade.

Gelatin hydrolysate was reported to contain large amounts of biologically active peptides with excellent antioxidant properties. However, its inducement of antioxidant response within cells and the underlying molecular mechanism are far from clear. Here, gelatin from Nile tilapia skin was hydrolyzed by ginger protease to produce antioxidant hydrolysate, and three fish skin gelatin hydrolysate fractions (FSGHFs) were obtained by ultrafiltration. Fractionation of the hydrolysate increased the free radical scavenging capacity of the FSGHFs, particularly FSGHF3, which showed the lowest molecular weight (below 1000 Da). Furthermore, FSGHF3 treatment prior to H2O2 exposure increased cell viability and membrane integrity in IPEC-J2 cells. H2O2-induced ROS production and epithelial barrier damage were suppressed by FSGHF3 pretreatment. FSGHF3 stimulated the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2), along with increases in the mRNA and protein expression of catalytic and modulatory subunits of γ-glutamylcysteine ligase as well as in the level of glutathione. Silencing of Nrf2 or p62 (an upstream regulator of Nrf2) suppressed FSGHF3-induced Nrf2 activation and its protection against H2O2-induced oxidative stress. Moreover, oligopeptides in FSGHF3 may mediate the cytoprotective effect against oxidative stress, which was confirmed by the result that FSGHF3 failed to inhibit the ROS production in H2O2-exposed cells with the knockdown of Pept1 (an oligopeptide transporter). Therefore, FSGHF3 can induce glutathione synthesis and prevent oxidative stress through the Pept1-p62-Nrf2 cascade and thus may be a functional food for gastrointestinal dysfunction.

Effect of oral administration of collagen hydrolysates from Nile tilapia on the chronologically aged skin

The oral ingestion of collagen hydrolysates (CHs) seems popular nowadays, but there has been little report on the chronological aging of skin so far. A CHs (average molecular weight = 624.72 Da) was prepared from the skin of Nile tilapia by simulated gastrointestinal digestion in this study. It exhibited high yield (97.04%), digestibility (98.12%) and antioxidant activity towards 1,1-diphenyl-2-picrylhydrazyl radical (half maximal inhibitory concentration, IC50 = 2.57 mg/mL) and linoleic acid peroxidation (IC50 = 0.36 mg/mL). The safety (4.07 g/kg bw·d) was also confirmed through the feeding of 9-month-old mice for 180 days. More importantly, the visual appearance, histological structure and matrix homeostasis of mice skin were remarkably improved. Furthermore, oxidative stress was alleviated by enhancing the activities of antioxidant enzymes, which was an important reason for the improvement of skin properties. These suggested its potential to be exploited into new functional foods with the effect against chronological aging of skin.

The Quality of Edible Film Made from Nile Tilapia (Oreochromis niloticus) Skin Gelatin with Addition of Different Type Seaweed Hydrocolloid

The functional properties of fish skin’s gelatin lower than mammals, hence the gelatin proteins needed a polysaccharides hydrocolloids to form a continuous and more cohesive network of edible film. Polysaccharides hydrocolloid (carrageenan, agar and alginate) containing phenol compounds was oxidized to be converted into quinone and it was expected to act as a cross linking agent. The purpose of this study was to determine the characteristics (thickness, tensile strength, elongation, solubility and water vapour transmition rate) of edible film made from nile tilapia skin gelatin by adding different type polyssacharide hydrocolloid. Edible film was made by mixture of gelatin 5 g and addition of carrageenan (C1), agar (C2), alginate (C3) concentration ; 0,5% (v/w), all the materials were poured into 100 ml destilled water that containing 10% glycerol (w/w). The solution was then heated on a hot plate stirer at 40°C for 30 min and dehydrated in a oven at 50°C. All data were analysed using ANAVA. Based on the result it can be seen that the addition of oxidized polisacarides hydrocolloid have a significant effect on tensile strength (TS), water vapor transmision rate, solubility and elongation at break properties, but did not in thickness. Edible film gelatin with the addition of alginate has better characteristics viewed by tensile strength (23.05 Kgf/cm2), water vapor transmission rate (0.61 gram/m2/hour) and thickness (0.16 mm) than carrageenan and agar.

Study of tensiometric properties, microbiological and collagen content in nile tilapia skin submitted to different sterilization methods.

Tissue bioengineering development is a global concern and different materials are studied and created to be safe, effective and with low cost. Nile Tilapia skin had shown its biological potential as covers for the burn wound. This study evaluates the tilapia skin histological, collagen properties and tensiometric resistance, after treatment by different sterilization methods. Tilapia skin samples were submitted to two sterilization processes: (1) chemical, which consisted in two 2% chlorhexidin baths, followed by sequential baths in increasing glycerol concentrations; and (2) radiation, when glycerolized skin samples were submitted to gamma radiation at 25, 30 and 50kGy. Microscopic analyzes were performed through Haematoxylin-eosin and Picrosirius Red under polarized light. For tensiometric analysis, traction tests were performed. Glycerol treated skin presented a discrete collagen fibers disorganization within the deep dermis, while irradiated skin did not show any additional change. Throughout the steps of chemical sterilization, there was a higher proportion of collagen with red/yellow birefringence (type I) in the skin samples up to the first bath in chlorhexidin, when compared to samples after the first two glycerol baths (P<0.005). However, there was no difference in relation to total collagen between groups. In irradiated skin, there was a larger total collagen preservation when using until 30kGy (P<0.005). Tensiometric evaluation did not show significant differences in relation to maximum load in the groups studied. We concluded that chemical and radiation (25 and 30kGy) are efficient methods to sterilize Nile Tilapia skin without altering its microscopic or tensiometric characteristics.