Tilapia Body Research Articles

Productive Performance and Serum Biochemical Parameters of Nile Tilapia Fingerlings Fed on Different Dietary Carbohydrate: Protein Ratios with Biotin Supplementation

The current experiment evaluated the effects of different dietary carbohydrate: protein ratios (CHO: CP ratio) without or with biotin supplementation on the growth performance, body composition, serum biochemical parameters and intestinal morphology in Nile tilapia. Fingerlings were assigned to 6 treatments arranged as following; Group 1 (G1) fed the basal diet (BD) with a medium CHO: CP ratio (47:32); G2 with high CHO: CP ratio (57:21); G3 with low CHO: CP ratio (36:42); while G4, G5 and G6 had the same previous experimental design of the first 3 groups but with biotin supplementation (0.06 mg/kg diet). The growth performance was only assessed for the first 6 weeks, then the experiment continued to 4 months and ended by sampling for other parameters determined. Fish feeding on high CHO: CP ratio (57:21) significantly reduced the fish body weight, gain and feed intake (FI) (P ≤ 0.05), while improved the feed efficiency compared to the medium and low ratios. Biotin addition to the high or the medium ratios containing diets resulted in lower growth, increased FI and deteriorated the feed efficiency when compared to their control groups without biotin addition (P≤ 0.05). Different dietary CHO: CP ratios significantly altered tilapia body composition of nutrients (moisture, EE, and ash), serum parameters (glucose, triglyceride, LDL and VLDL) and the liver function enzymes (GPT and GOT) (P≤ 0.05). The relative mRNA expression of GHR and IGF was significantly upregulated in fish fed on the low and the high ratios containing diets respectively. In conclusion, feeding of the early fingerling of tilapia on the high CHO: CP ratio during the first 6 weeks of life resulted in lower growth, however, it showed a protein sparing effect. Supplementation of biotin (extra over the diet) was not recommended as it showed adverse effects on tilapia growth especially during the first periods of life, however it showed some beneficial effects on alleviating the high-dietary carbohydrate-induced effects. Feeding on medium CHO: CP ratio (47:32) or low ratio (36:42) would be recommended during the fry and early fingerling stage of tilapia while the high ratio (57:21) would be beneficial in the diet of late fingerlings or adult tilapia.

Comparative effects of exotic Raanan and local feeds on growth performances of Nile tilapia (Oreochromis niloticus) reared in engineered multi-constructed ponds for efficient water use

Purpose: Growth performance of 30 randomly sampled tilapias were examined fortnightly for 12 weeks.
 Research methodology: Growth of male Oreochromis niloticus in two-by-two Completely Randomized Block Design (CRBD) with four treatments [New Water with Raanan (NWR), New Water with Local feed (NWL), Old Water with Local feed (OWL) and Old Water with Raanan (OWR)] was monitored in four ponds measuring 360 m2 each. Pond Temperature, pH, Dissolved Oxygen were assessed using the multi parameter-probe. Fish total body weights and lengths were measured using electronic scale and 30 cm rule.
 Results: Temperatures ranged from 26.2 °C (OWR) < 26.4 °C (OWL) < 26.5 °C (NWR) < 26.8 °C (NWL). Highest mean pH of 6.7 was recorded in NWR compared to the lowest (6.1) in NWL. Dissolved oxygen was 3.0 mg/l for all treatments, except in OWR (3.7 mg/l). There were significant differences among entire physicochemical parameters (p < 0.05). The NWR produced highest tilapia body weights (88.3 g) followed by OWL (47.9 g), NWL (47.1 g) and OWR (44.0 g). Final fish body lengths were in order of OWR (9.1 cm) < OWL (9.2 cm) < NWL (9.7 cm) < NWR (12.1 cm) respectively with significant variations. Raanan cultured tilapia grew better than the local feed comprised of energy sources.
 Limitations: Null hypothesis failed to confirm significant differences in fish growths (p < 0.05).
 Contribution: Use of old water is recommended in absence of fresh, if pond is completely drained/limed to eliminate leeches, tilapia eggs, fry which may infest introduced fingerlings.

Exploring the morphological dynamics of Nile tilapia (Oreochromis niloticus Linn. 1758) in Victoria Nile as depicted from geometric morphometrics

BackgroundVarious anthropogenic activities continue to threaten the fish biodiversity of the East African water bodies such as the Victoria Nile. Although the Victoria Nile is a significant source of livelihood for human populations, the biology and ecology of Nile tilapia in this ecosystem remain understudied with little or no information on the morphology of the fish given varying and immense anthropogenic activities. Here, we use geometric morphometrics to examine the morphology/shape variations of Nile tilapia populations in Victoria Nile to gain insights into their current ecological state.ResultsOur results indicate unexpectedly smaller Nile tilapia body weights in Victoria Nile than in L. Victoria. Despite this, nearly all the populations displayed a relative condition factor (Kn) of greater ≥1 suggesting a healthy stock. However, two populations, LMF and VN_Bukeeka demonstrated Kn values of less than one (< 1). We also report that some Upper and Lower Victoria Nile populations display morphological similarities. Apart from L. Albert, Nile tilapia populations from Lakes Victoria and Kyoga are morphologically divergent from the riverine ones. We note that Nile tilapia from Nalubale Dam Reservoir is morphologically distinct from the close neighbouring Victoria Nile populations which are likely allied to the influence of the Nalubale Hydroelectric power dam as a barrier.ConclusionNile tilapia’s morphological variation appears to be influenced by various anthropogenic disturbances notably, overfishing, hydroelectric power dams, and fish translocational history in Uganda. Management should enforce regulatory frameworks to avert human-mediated activities as these are likely to compromise the sustainability of the fisheries. Further studies are required to follow these populations with molecular genetics and environmental data to gain a deeper understanding of the fish species for informed sustainable management and conservation options.

Accurate Segmentation of Tilapia Fish Body Parts Based on Deeplabv3+ for Advancing Phenotyping Applications

As an important economic fish resource, germplasm resources and phenotypic measurements of tilapia are of great importance in the direction of culture and genetic improvement. Furthermore, accurate identification and precise localization of tilapia body parts are crucial for enabling key technologies such as automated capture and precise cutting. However, there are some problems in the semantic segmentation of tilapia fish, including the accuracy of target edge segmentation and the ambiguity in segmenting small targets. To improve the accuracy of semantic segmentation of tilapia parts in real farming environments, an improved Deeplabv3+ network model method is proposed for implementing tilapia part segmentation to facilitate phenotypic measurements on tilapia in this paper. The CBAM module is embedded in the encoder, which can improve the accurate identification and localization of tilapia parts by adaptively adjusting the channel weights and spatial weights and better focus on the key features and spatial connections of tilapia body parts. Furthermore, the decoding part of the Deeplabv3+ model is optimized by using SENet, which greatly increases the segmentation accuracy of the network by establishing the interdependence between channels while suppressing useless features. Finally, model performance is tested and compared with the original network and other methods on the tilapia part segmentation dataset. The experimental results show that the segmentation performance of the improved network is better than other networks, such as PSPNet and U-Net, and the IoU values in the head, fins, trunk, and tail of the fish body are 9.78, 2.27, 6.27, and 6.58 percentage points higher than those of the Deeplabv3+ network, respectively. The results validate the effectiveness of our approach in solving the above problems encountered in the semantic segmentation of tilapia parts.

Food Safety Level Assessment on Heavy Metals (As, Cd, Li, Ni, Pb, Ti) Concentration in Tilapia Fish (&lt;i&gt;Oreochromis&lt;/i&gt; sp.) from Sleman and Bantul Yogyakarta

Research on Concentration of Heavy Metals (As, Cd, Li, Ni, Pb, Ti) in tilapia fish (Oreochromis sp.) from Sleman and Bantul and The Food Safety Level was studied. The aims of this research were to determine heavy metals concentration in tilapia fish, discover the correlations between metal and morphometric factors in tilapia fish, and determine food safety level intake of tilapia fish to be consumed per week. Determining metal concentrations in tilapia fish were using ICP-MS instrument, which the samples were dried using freeze dryer and destructed using microwave digester. The concentrations obtained were utilized to determine correlations between metal and morphometric factors, and measure Maximum Weekly Intake, Maximum Tolerable Intake, and food safety level intake per week. Based on research, the results showed metal accumulation in tilapia fish (Oreochromis sp.) from the largest to the smallest value for Bantul area was Ti, As, Ni, Pb, Li, Cd and for Sleman was Ti, As, Ni, Pb, Cd, Li. Concentration of As metal shows higher content than the threshold limit standards. Heavy metal accumulation was found in tilapia body that has positive and negative correlations between As metal and morphometrics in tilapia fish. Based on the measurement, food safety level intake tilapia fish for one adult is 1096 fish/week.

Development and evaluation of Nile tilapia (Oreochromis niloticus) body composition models

Mathematical models can be used as an alternative to conventional analytical methods (AOAC), allowing to indirectly estimate the body composition of fish without, in some cases, being necessary to sacrifice animals. To develop models with high predictive capacity, in addition of having access to representative data, it is important to use calibration methods that minimize the estimation of the generalization error.In this work, Nile tilapia whole-body composition data were collected from 138 scientific publications, covering fish from 0.01 g to 1470 g. Predictive models were obtained for each body component using different combinations of models and calibration methods. The different combinations were evaluated through cross-validation approaches in order to select the models with the best predictive capacity. Such models were compared against other published Nile tilapia body composition models, using an independent validation dataset.The results show that model predictions are greatly affected by the type of model, calibration method and amount of calibration data available. Models calibrated under the assumption of multiplicative error had better predictive capacity than those calibrated assuming additive error, which indicates that, in this particular case, performing regression on log-transformed data, even for isometric models, is advantageous. From the models tested, the ones with the best predictive capacity are the allometric model (al_mu; calibrated assuming multiplicative error) and a robust hybrid model (hyb_rob; ensemble of isometric and allometric models, calibrated assuming multiplicative error using a robust regression method), with both having good prediction capacity when compared with models published by other authors.Although the results obtained support the hypothesis that Nile tilapia body composition is essentially allometric, isometric models can also potentially be used without much performance loss, if they are calibrated assuming multiplicative error (i.e., using log-transformed data).

Dietary supplementation of Nile tilapia (Oreochromis niloticus) with β-glucan and/or Bacillus coagulans: Synergistic impacts on performance, immune responses, redox status and expression of some related genes.

A 14-week feeding study was conducted to assess the effects of feed supplementation with prebiotics β-glucan (BG group) and/or probiotics Bacillus coagulans (BC group) on O. niloticus growth performance, body analysis, intestinal structure, immunological response, and antioxidant status. The fish were equally divided into six groups, as follows: the fish group fed an un-supplemented diet served as a control group; the other fish groups were fed supplemented diets with 0.1 g β-glucan kg−1; 1 g Bacillus coagulans kg−1; 2 g B. coagulans kg−1; 0.1 g β-glucan combined with 1 g B. coagulans kg−1; 0.1 g β-glucan combined with 2 g B. coagulans kg−1. The findings revealed that supplementing B. coagulans and the β-glucan mixture improved growth performance and feed efficiency parameters (RGR and SGR) more than the other groups. The fish flesh analysis revealed increased crude protein and dry matter content and lower lipid and ash levels in the BG and BC supplemented groups than in the Control group. On the other hand, β-glucan and B. coagulans supplementation significantly boosted antioxidant activity and immunological responses in serum as determined by CAT, MDA, lysozyme, and phagocytic activity. Dietary β-glucan and B. coagulans supplementation remarkedly enhanced anterior intestine villus histomorphometry characteristics. Furthermore, B. coagulans, alone or in combination with β-glucan, could reduce HSP70 and IL-1β gene expression while increasing IL-8 and GH gene expression. According to the findings, B. coagulans and/or BG increased growth performance by increasing gut health and morphology. Furthermore, β-glucan and B. coagulans supplementation enhanced Tilapia's body composition, immunological responses, and antioxidant status.

HEMATOLOGIC ANALYSIS OF TILAPIA (Oreochromis niloticus) ON ECTOPARASITE INFECTION OF THE FLOATING NET CAGES IN RAWA PENING

Hematological analysis of plasma proteins by testing for hemoglobin, erythrocytes, and leukocytes against ectoparasite infection in cages was carried out by taking samples of fish with consumption sizes of 15-20 cm. The aim of this study was to find out the amount of exposure to ectoparasites internally in the body of tilapia based on blood protein hematology test. Analysis of the data used is analysis of variance (ANOVA) with the aim of knowing the effect of sampling and the parameters tested. The results showed that the presence of infection identified normal hemoglobin levels of 7.438 g/dL, erythrocytes were quite low at 1.5605 x1012/L, this is the nutritional factor given to tilapia and leukocytes were still in normal condition, namely 61.985x109/L. The ectoparasites found were Streptococcus sp, Lernaea sp, Aeromonas sp, and Trichodina sp. The effect of the value of plasma protein content in blood for hemoglobin and leukocytes is still in normal condition, but erythrocytes are below the normal point so that from internal factors of tilapia disease, hematological blood plasma protein affects tilapia disease, especially on erythrocyte variables that affect fish anemia to mass death. This is in accordance with the situation in the field where tilapia in the KJA (Floating Net Cage) experienced sudden and mass death in a short period of time even though previously routine controls had been carried out by cage cultivators. When fish experience stress, fish blood glucose levels will increase while fish blood plasma total protein levels decrease.

Generation of ornamental Nile tilapia with distinct gray and black body color pattern by csf1ra mutation

Nile tilapia (Oreochromis niloticus) is an important species in aquaculture and an excellent model fish for studying teleost color patterns. Colony-stimulating factor 1 receptor a (csf1ra) is critical for xanthophores development and body color formation in zebrafish and guppy. In this study, we established csf1ra mutant lines with two different targets by CRISPR/Cas9 in Nile tilapia. Unlike the wild type fish (WT) with vertical bars, the homozygous mutants showed two different color patterns, either uniformly gray (GT) or gray with black tail (BT). Compared with WT, the mutants had fewer melanophores, a few xanthophores and no erythrophores. Increased numbers of melanophores were observed in the tail of BT mutants. However, the establishment of early embryonic pigment cell precursors and the appearance of melanophores on the body were independent of csf1ra. In contrast, the appearance of xanthophores on the body and the formation of the vertical bar pattern dependent on the late metamorphic melanophores required csf1ra. The deletion of xanthophores and erythrophores caused by csf1ra mutation changed the body color pattern of Nile tilapia. These results demonstrated that csf1ra activity is essential for the development of erythrophores, late developing xanthophores and late metamorphic melanophores. These mutants provided good models for analyzing the genetic basis of tilapia body color pattern formation. Our study may help deepen the understanding of the formation of fish body color pattern, especially for cichlids with vertical bars. In addition, the mutants might be developed as ornamental fish (BT) or new strains for aquaculture.

Aurantiochytrium sp. Meal Improved Body Fatty Acid Profile and Morphophysiology in Nile Tilapia Reared at Low Temperature

Aurantiochytrium sp. is a heterotrophic microorganism that produces docosahexaenoic acid (DHA), thus being considered as a possible replacement for fish oil in aquafeeds. We investigated the effect of Aurantiochytrium sp. meal (AM) dietary levels (0, 5, 10, 20, and 40 g kg−1) on Nile tilapia body and hepatopancreas fatty acid (FA) profile, body FA retention, somatic indices, and morphophysiological changes in the intestine and hepatopancreas, after feeding Nile tilapia juveniles (average initial weight 8.47 g) for 87 days at 22 °C. The 10AM diet was compared to a control diet containing cod liver oil (CLO), since their DHA concentration was similar. Within fish fed diets containing increasing levels of AM, there was a linear increase in n-3 FA content, especially DHA, which varied in the body (0.02 to 0.41 g 100 g−1) and hepatopancreas (0.15 to 1.05 g 100 g−1). The morphology of the intestines and hepatopancreas was positively affected in AM-fed fish. Fish fed 10AM showed less accumulation of n-3 FAs in the body and hepatopancreas when compared to fish fed CLO. Therefore, AM is an adequate substitute for fish oil in winter diets for Nile tilapia, with the supplementation of 40AM promoting the best results regarding intestine and hepatopancreas morphophysiology.

Identifying geographically differentiated features of Ethopian Nile tilapia (Oreochromis niloticus) morphology with machine learning.

Visual characteristics are among the most important features for characterizing the phenotype of biological organisms. Color and geometric properties define population phenotype and allow assessing diversity and adaptation to environmental conditions. To analyze geometric properties classical morphometrics relies on biologically relevant landmarks which are manually assigned to digital images. Assigning landmarks is tedious and error prone. Predefined landmarks may in addition miss out on information which is not obvious to the human eye. The machine learning (ML) community has recently proposed new data analysis methods which by uncovering subtle features in images obtain excellent predictive accuracy. Scientific credibility demands however that results are interpretable and hence to mitigate the black-box nature of ML methods. To overcome the black-box nature of ML we apply complementary methods and investigate internal representations with saliency maps to reliably identify location specific characteristics in images of Nile tilapia populations. Analyzing fish images which were sampled from six Ethiopian lakes reveals that deep learning improves on a conventional morphometric analysis in predictive performance. A critical assessment of established saliency maps with a novel significance test reveals however that the improvement is aided by artifacts which have no biological interpretation. More interpretable results are obtained by a Bayesian approach which allows us to identify genuine Nile tilapia body features which differ in dependence of the animals habitat. We find that automatically inferred Nile tilapia body features corroborate and expand the results of a landmark based analysis that the anterior dorsum, the fish belly, the posterior dorsal region and the caudal fin show signs of adaptation to the fish habitat. We may thus conclude that Nile tilapia show habitat specific morphotypes and that a ML analysis allows inferring novel biological knowledge in a reproducible manner.

Effects of different levels of vitamin B6 in tank water on the Nile tilapia (Oreochromis niloticus): growth performance, blood biochemical parameters, intestine and liver histology, and intestinal enzyme activity.

According to the importance of vitamin B6 (pyridoxine) as a water-soluble vitamin on the physiological conditions of aquatic animals, the present study aimed to investigate effects of different concentrations of this vitamin in recycle system culture water on the Nile tilapia (Oreochromis niloticus). Treatments including 0 (control), 10, 20, 30, and 40mgL-1 vitamin B6 were adjusted in triplicate recirculating systems. Each of the experimental tanks (100L) was stocked 15 fingerling Nile tilapia during 60-day experimental period. According to the findings, weight gain in treatments of 30 and 40mgL-1 pyridoxine was significantly higher than the other treatments while blood cortisol hormone in the treatment of 40mgL-1 was significantly highest among the treatments. In addition, mid-intestine trypsin activity in the treatment of 40mgL-1 was significantly higher than the other treatments. The histological analysis of the intestine showed that the number of mucus-secreting cells significantly decreased in treatments of 30 and 40mgL-1. Our findings here suggest that pyridoxine can possibly be absorbed by the Nile tilapia's body through culture water and it seems 20-30mgL-1 pyridoxine in the culture water is the optimal concentration for the Nile tilapia juveniles in recycle system culture.

Effect of Dietary Phytobiotics Supplementation On Growth, Serum Biochemical And Chemical Composition Of Nile Tilapia (Oreochromis Niloticus).

A Factorial experiment (2 × 2) was designed to investigate the effect of dietary phytobiotics (onion and thyme powder) and their interaction on growth, feed utilization, serum biochemical and chemical composition of whole Nile tilapia. Four experimental diets were fourmulated; Diet 1 without addition, Diet 2 containing 5.0 g kg-1 onion powder, Diet 3 containing 5.0 g kg-1 thyme powder, Diet 4 containing 5 g onion powder + 5 g thyme powder kg-1 diet. Each treatment group was assigned randomly in duplicate groups of 25 fish (4.51 ± 0.01 g/fish) in 8 plastic tanks for 84 days. The highest values of FBW, WG and SGR (%), PPV, FR and ER were recorded in Diet 4 but, the highest value of PER was obtained by fish fed diet Diet 2 supplemented with 5 g kg-1 diet onion. The best value of FCR was obtained in groups Diet 4. ALT and AST activites were significantly decresed by addition of onion and thyme powder (5 g kg-1 diet). Whereas, the lowest total protein, globulin and albumin values were estimated by fish fed on Diet 1. Supplementation of onion and thyme powder (5 g kg-1 diet) in the diets of Nile tilapia significantly effected on CP of whole – body of tilapia.

Deep Learning image segmentation for extraction of fish body measurements and prediction of body weight and carcass traits in Nile tilapia

Individual measurement of traits of interest is extremely important in aquaculture, both for production systems and for breeding programs. Most of the current methods are based on manual measurements, which are laborious and stressful to the animals. Therefore, the development of fast, precise and indirect measurement methods for traits such as body weight (BW) and carcass weight (CW) is of great interest. An appealing way to take noninvasive measurements is through computer vision. Hence, the objectives in the current work were to: (1) devise a computer vision system (CVS) for autonomous measurement of Nile tilapia body area (A), length, height, and eccentricity, and (2) develop linear models for prediction of fish BW, CW, and carcass yield (CY). Images from 1653 fish were taken at the same time as their BW and CW were measured. A set of 822 images had pixels labeled into three classes: background, fish fins, and A. This labeled dataset was then used for training of Deep Learning Networks for automatic segmentation of the images into those pixel classes. In a subsequent step, the segmentations obtained from the best network were used for extraction of A, length, height, and eccentricity. These variables were then used as covariates in linear models for prediction of BW, CW, and CY. A network with an input image of 0.2 times the original size and four encoder/decoder layers achieved the best results for intersection over union on the test set of 99, 90 and 64 percent for background, fish body and fin areas, respectively. The overall best predictive model included A and its square as predictor variables and achieved R2 of 0.96 and 0.95 for fish BW and CW, respectively. Overall, the devised CVS was able to correctly differentiate fish body from background and fins, and the extracted area of the fish body could be successfully used for prediction of body and carcass weights.

Utilization of Telang Leaf Meal as Antioxidant Source in Feed of Tilapia (Oreochromis niloticus)

Aims: This study aimed to determine the effective percentage of telang leaf meal on feed to increase antioxidant levels in tilapia liver feed.&#x0D; Study Design: A total of 12 aquariums with sizes 60 x 40 x 40 cm3and volume 96 L prepared and filled with 30 L water. Heater was installed and the temperature was raised slowly until it reached 34℃. Feed in the form of a mixture of telang leaf flour and commercial feed was given 3 times a day according to treatment and with the provisions of 3% of body weight of fish per day. Analysis of antioxidant levels was analyzed from the content of the superoxide dismutase enzyme as an antioxidant bioindicator in the body of the fish.&#x0D; Place and Duration of Study: The cultivation was carried out at Ciparanje Hatchery and Fisheries Area, Faculty of Fisheries and Marine Science, Universitas Padjadjaran and Dismutase Superoxide Level Analysis was carried out at the Central Laboratory of Universitas Padjadjaran in June and July 2019.&#x0D; Methodology: This research was carried out by giving high temperatures as a source of stress, for 40 days. Tilapia were given a mixture of telang leaf meal as a source of anti-oxidants. At the end of research, Test liver fish taken superoxide dismutase levels were observed and analyzed descriptively. Daily growth and survival rate of fish were analysed using F test at 5% level, and if there were significant differences, Duncan's test was performed.&#x0D; Results: By giving heat stress continuously for 40 days the result is obtained the highest average superoxide dismutase level in treatment B (telang leaf meal 5%) as much -0.92 inhibition and lowest in treatment D (telang leaf meal 15%). A decrease in SOD levels identifies a decrease in antioxidant activity in the body of Tilapia. Daily growth rate obtained showed no significant difference. The fish will continue to grow but not as rapidly, because tilapia utilize protein up to 40% of commercial feed used to repair cells damaged during stressful periods and as a source of energy. Survival of fish decreases with increasing concentration of telang leaf flour, where the feed given has been mixed and resulted in the fish's response to the feed decreases, consequently not only the fish adapted to the environment, fish also adapt to new types of feed.&#x0D; Conclusion: Based on the results of research that has been done then conclusions can be drawn that the addition of telang leaf mealup to 15% in commercial feed by giving heat stress since the beginning of the culture period does not provide an effect of increasing antioxidant levels.

PSII-6 Deep Learning image segmentation for extraction of body measurements and prediction of body weight in Nile tilapia

Abstract Individual measurement of traits of interest is of great importance for breeding and management decisions in animal production systems. However, measurements are often taken manually, which is laborious and also stressful for the animals. Therefore, the development of fast, precise and indirect measurement methods is paramount. An appealing way for such a task is through computer vision systems (CVS). Hence, the objectives of the current work were: 1) Devise a CVS for autonomous measurement of Nile tilapia body area, length, height, and eccentricity; and 2) Evaluation of linear models for prediction of body weight (BW). The pixels of 822 RGB images of live fish were labeled into background, fish fins or body using the “MTurk” crowdsourcing service. This dataset was then split into training (60% of data) and testing sets for the development of Deep Learning Networks for image segmentation into the three pixel categories. The networks differed in input image size (10 to 40% of original size) and number of encoder/decoder layer stacks (1 to 5). An independent dataset with 831 images was used for validation of the linear predictive models. The results for intersection over union (IoU) show that a network with input of 20% of the original size and 4 encoder/decoder stacks achieved the best results, with IoU on the test dataset of 99, 90 and 64% for background, fish body and fin, respectively (Figure 1). Predicted segmentation from this network on randomly selected images is shown in Figure 2. From the linear models evaluated, the one considering only area as input showed predicted R2 of 0.92 for fish BW (Table 1). In conclusion, the devised CVS was able to correctly separate fish body from background and fins, and a linear model using fish body area as input provided good predictive quality of Nile tilapia BW.

Evaluation of growth and fatty acid profile of Nile tilapia (Oreochromis niloticus) fed with Schizochytrium sp.

The objective of this study was to evaluate growth, body chemical composition and lipid profile of Nile tilapia juvenile fed with Schizochytrium sp. Two hundred and forty Nile tilapia (Oreochromis niloticus) juvenile (1.33 ± 0.11 g) were distributed in 20 aquariums, at the density of 12 fish per aquarium. The juvenile were fed with five levels of Schizochytrium sp.: Control (0 g/kg of Schizochytrium sp. in feed); AS10 (10 g/kg of Schizochytrium sp. in feed); AS20 (20 g/kg of Schizochytrium sp. in feed); AS30 (30 g/kg of Schizochytrium sp. in feed) and AS40 (40 g/kg of Schizochytrium sp. in feed). The inclusion of Schizochytrium sp. increase the body weight, weight gain, final biomass and biomass gain of tilapia juvenile. The body crude protein of tilapia was increased after addition of microalgae. Juvenile lipid profile also was influenced when fed with 40 g of Schizochytrium sp. per kg and have it levels of omega-3 and docosahexaenoic acid (DHA) increased, and omega 6:3 ratio decreased. Tilapia juvenile fed with Schizochytrium sp. per kg have better growth, omega-3 and DHA levels rising in the body, being a considerable source of fatty acids for human nutrition. Levels above 20 g of Schizochytrium sp. per kg in the feed favour the increase of protein in Nile tilapia body.

Determination of sulfamonomethoxine in tilapia (Oreochromis niloticus × Oreochromis mossambicus) by liquid chromatography-tandem mass spectrometry and its application pharmacokinetics study

A precise and reliable analytical method to measure trace levels of sulfamonomethoxine (SMM) and N4-acetyl metabolite in tilapia samples using liquid chromatography-tandem mass spectrometry was developed. Optimized chromatographic separation was performed on C18 reversed-phase columns using gradient elution with methanol and 5 mmol/L of an ammonium acetate aqueous solution (adjusted to pH 3.5 using formic acid). This study investigated the pharmacokinetic properties and tissue distribution of SMM and its major metabolite N4-acetyl sulfamonomethoxine (AC-SMM) in tilapia after a single dose of 100 mg kg−1 body weight of orally administered SMM. Blood and tissues were collected between 0.5 and 192 h with 14 total sampling time points. SMM was rapidly absorbed, and extensively distributed in the bile and liver through systemic circulation. Enterohepatic circulation of SMM was observed in the tilapia body. Acetylation percentages were 45% (blood), 90% (liver), 62% (kidney), 98% (bile), and 52% (muscle). High concentrations of AC-SMM accumulated in the tilapia bile. At 192 h, AC-SMM concentration in the bile remained at 4710 μg kg−1. The ke value of AC-SMM (0.015 h−1) in the blood was lower than that of SMM (0.032 h−1). This study demonstrated effective residue monitoring and determined the pharmacokinetic properties of SMM and AC-SMM in tilapia.

Trophic transfer of Cd from duckweed (Lemna minor L.) to tilapia (Oreochromis mossambicus).

The transfer of the toxic heavy metal Cd from duckweed (Lemna minor L.) to the freshwater fish tilapia (Oreochromis mossambicus) was investigated. Concentrations of Cd in different chemical forms in duckweed and in different tissues (gut, edible muscle, and remnants or residual) of tilapia (i.e., ethanol-extractable fraction [FE ], HCl-extractable fraction [FHCl ], and residual fraction [FR ]) were quantified, and the bioaccumulation factors (BAFs) of Cd in the tilapia body were calculated. Simple linear regression analysis was used to unravel the correlation and accumulation mechanisms of Cd along the short food chain. Our results showed that with increasing exposure concentrations of Cd (0-50 μM for duckweed and 0-10 μM for tilapia), the total, FE (Fe,d )-, FHCl (Fh,d )-, and FR (Fr,d )-Cd concentrations in duckweed and different tissues of tilapia increased progressively. The Cd sources (aqueous or dietary) influenced the BAF for Cd accumulation in the whole body of tilapia. Furthermore, regression analyses yielded significant positive correlations (R2 > 0.96) between the Cd concentration in duckweed and in both the 3 parts and the whole body of tilapia. This finding suggests that Cd transfer from duckweed to tilapia can be quantitatively evaluated when tilapia is exposed only to duckweed. In addition, the linear regression between Cd accumulation in whole tilapia and Fe,d -, Fh,d -, and Fr,d -Cd showed that particularly the correlation with Fe,d -Cd is statistically significant (p < 0.001). The accumulated Cd concentrations and chemical forms in tilapia tissues also positively correlated with Cd sources (solution or duckweed). Compared with waterborne exposure only, duckweed especially increased the accumulation of Cd in the gut of tilapia. Taken together, our findings support a strong dependence of Cd accumulation and transfer from duckweed to tilapia on its chemical forms, especially on Fe,d -Cd. This knowledge may expedite more accurate risk assessment of heavy metals through aquatic food chain ecosystems. Environ Toxicol Chem 2018;37:1367-1377. © 2018 SETAC.

Efeito do fotoperíodo sobre a composição do filé de juvenis de tilápia do Nilo

Com este estudo objetivou-se avaliar o efeito do fotoperíodo sobre a composição centesimal de filés de juvenis de tilápia do Nilo. Utilizou-se um delineamento inteiramente casualizado com cinco tratamentos (0L:24E; 6L:18E; 12L:12E; 18L:6E; 24L:0E) e quatro repetições. Foram utilizados 160 alevinos de tilápia, distribuídos em 20 aquários (20L) em sistema de recirculação, temperatura controlada em 27 ºC e densidade de oito peixes por aquário. Os peixes foram alimentados duas vezes ao dia, com ração comercial extrusada contendo 40% de proteína bruta. Ao final de 75 dias, amostras do filé foram coletadas e armazenadas em freezer (-80 ºC) para posteriores análises da composição bromatológica. Não houve efeito dos diferentes fotoperíodos sobre a umidade e cinzas do filé (P&gt;0,05). Por outro lado, os peixes sob fotoperíodo de 18L:6E apresentaram maior quantidade de proteína e retenção desta no filé, assim como menor quantidade de gordura e retenção de lipídeo (P&lt;0,05). Portanto, pode-se concluir que o fotoperíodo pode alterar a composição corporal de alevinos de tilápia do Nilo, sendo que e o fotoperíodo de 18L:6E contribui para o aumento da concentração de proteína bruta e uma menor deposição de gordura no filé.