The dietary lysine requirement has not been established for finishing Nile tilapia despite being considered the first limiting essential amino acid in many cereal grain ingredients. A feeding trial ...was designed to determine the dietary lysine requirement using 600 fish (274.9±3.3g) distributed into 15, 1.2m3 net cages in a completely randomized design with five treatments and three replicates. Five extruded isoproteic (251.2g of crude protein kg−1) and isoenergetic diets (13.1MJ of digestible energy kg−1) containing 11.1, 12.5, 13.9, 15.1 and 16.4glysinekg−1 were prepared. Fish were hand fed four times a day until apparent satiety. Fish fed 15.1glysinekg−1 exhibited improved final body weight and daily weight gain compared to fish fed 11.1glysinekg−1. Fillet weight and fillet yield of finishing Nile tilapia were significantly affected by dietary lysine levels and optimized at 15.1glysinekg−1 compared to fish fed the other treatments. Whole-body and fillet compositions of fish were unresponsive to dietary lysine levels. Whole-body lysine, tryptophan, alanine, aspartic acid and tyrosine retention was significantly affected by dietary lysine levels. Although the recruitment of new fibers by hyperplasia continues in adult Nile tilapia, the predominance of muscle growth was by hypertrophy as observed in fish from all treatments. Based on second-order regression analysis, the dietary lysine requirement for maximum fillet yield of finishing Nile tilapia was estimated at 14.6gkg−1, corresponding to 5.8% of dietary protein.
First mention of lysine requirements of large Nile tilapia
•Dietary lysine requirement for fillet yield of finishing Nile tilapia is 14.6gkg−1.•Lysine requirement for fillet yield is above growth performance for Nile tilapia.•Lysine affects skeletal muscle recruitment by hyperplasia of finishing Nile tilapia.•Amino acid retention is enhanced in fish fed optimized lysine level.
Background
There is no established management algorithm for portal vein thrombosis (PVT) in cirrhotic patients. The aim of our study was to prospectively evaluate anticoagulation and transjugular ...intrahepatic portosystemic shunt (TIPS) to treat PVT.
Methods
Cirrhotics with non‐malignant PVT were included. Low weight molecular heparin anticoagulation was considered in all; TIPS was indicated if thrombosis progressed or anticoagulation was contraindicated. Patients who were not anticoagulated nor received TIPS served as controls.
Results
Fifty‐six patients (of whom 21 controls) were included. PVT was occlusive in 11/35, with extension to the superior mesenteric or splenic vein in 13/35. In the study group 33 patients were anticoagulated, with a recanalization rate of 36% (12/33) compared with 1/21 among controls. A time interval between appearance of thrombosis and anticoagulation < 6 months predicted chance of repermeation. Thrombus progression occurred in 15/21 non anticoagulated patients and in 5/33 anticoagulated patients (P < 0.001). TIPS was placed in six patients. There were five variceal bleedings and two intestinal venous ischaemia episodes in the control group, compared with one variceal bleeding episode in the study group.
Conclusions
In cirrhotics with PVT, a treatment algorithm using anticoagulation and TIPS achieves a good chance of complete repermeation, reduces portal hypertensive complications, and decreases the rate of thrombosis progression.
This study evaluated the effects of substituting soybean oil (SO) by linseed oil (LO) on growth performance, fatty acid profile and flesh quality in large Nile tilapia, Oreochromis niloticus reared ...under cold suboptimal temperature. Fish (initial weight 1035.4 ± 10.5 g) were used in a completely randomized design with a 2 × 2 factorial arrangement, two oil sources (SO or LO) at two levels (15 or 30 g/kg) and four replicates of 12 fish. The fish were hand‐fed until apparent satiety for seven weeks. The interaction between the oil source led to improved daily weight gain in the fish that were fed LO at 30 g/kg when compared with those on other diets. Fish fed LO exhibited higher fillet yield and n‐3/n‐6 PUFA ratio in the fillet compared with SO. Fish offered oil at 30 g/kg showed enhanced feed conversion ratio and fillet with higher lipids content coupled with decreased hardness than that fed oil at 15 g/kg. Fillet water loss, pH and colour were unaffected by diets. Together, LO at 30 g/kg optimized the growth performance and the n‐3/n‐6 PUFA ratio without showing any adverse effects on fillet quality in large Nile tilapia reared under suboptimal temperature.
Recent studies provide new mechanistic insights that isoleucine (ILE) regulates protein synthesis through genomic approaches. An 8-week feeding trial was performed to determine dietary ILE ...requirement based on growth performance, body composition, amino acid (AA) retention, and mRNA levels of myogenic regulatory factors (MRFs), including myogenic differentiation (MyoD), myogenin (MyoG), and myostatin (Mst) as negative regulatory of myogenesis, and mammalian target of rapamycin (mTOR) genes in fingerling Nile tilapia, Oreochromis niloticus. Fish (n = 288; 2.46 ± 0.10 g; mean ± SD) were randomly distributed into six treatments with four replicate groups of 12 fish. Fish were fed diets with graded levels of analyzed ILE at 9.08 (ILE1), 12.13 (ILE2), 15.11 (ILE3), 18.02 (ILE4), 21.15(ILE5), and 24.06 g kg−1 diet (ILE6). Fish were hand-fed, six times a day, until apparent satiety. At the end of the feeding trial, incremental levels of dietary ILE significantly affected body weight gain (BWG), feed efficiency ratio (FER), protein retention efficiency (PRE), and essential and non-essential AA retention. Also, the relative expression of MyoD and MyoG genes in the white skeletal muscle and mTOR gene in the liver was up-regulated in fish fed diet ILE3 (P > 0.05). Optimal branched-chain amino acid (BCAA) ratio (Ile:Leu:Val) was found at 1:1.3:0.9. Based on one-slope broken line model of BWG, the optimal dietary ILE requirement for fingerling Nile tilapia was estimated at 13.67 g kg−1. The results indicate that appropriate dietary ILE level at 5.0% dietary protein could improve protein synthesis and positively regulates muscle growth-related and mTOR genes in fast-growing Nile tilapia.
•Dietary isoleucine requirement of fast-growing Nile tilapia was estimated at 13.67 g kg−1•Optimal branched-chain amino acid ratio (Ile:Leu:Val) was found at 1:1.17:1.26•Isoleucine up-regulated relative expression of MyoG, MyoD, and mTOR genes
•Dietary tryptophan affects growth, feed conversion ratio and fish uniformity.•Tryptophan is an essential and limiting amino acid in corn-soybean meal diets for Nile tilapia.•Adequate tryptophan ...supplementation improves weight gain and feed efficiency of fish.•Tryptophan supplementation may be considered to avoid antagonism or toxicity.
The objective of this study was to determine the dietary tryptophan (Trp) requirements to optimize growth performance of juvenile Nile tilapia. A hundred and eighty fish (38.2±0.09g) were fed to extruded isonitrogenous (28% crude protein) and isoenergetic (14.5MJ/kg digestible energy) diets, containing graded levels of dietary Trp (1.8, 2.3, 2.7, 3.2, and 3.7g/kg). Fish were hand fed to triplicate groups of 12 fish, three times a day to apparent satiety for 45 days. The relationship between body weight gain, feed conversion ratio, protein efficiency ratio, and fish uniformity against dietary Trp levels could be expressed as a second-order polynomial regression analysis, where the best Trp levels were estimated to be 2.9, 3.1, 3.1, and 2.9g/kg, respectively. No effects of dietary Trp on hepatosomatic index, visceral fat, survival, or body composition were observed. Whole body retentions of arginine, phenylalanine, and lysine were highest in fish fed 3.0, 3.1, and 3.1g/kg Trp, respectively. The dietary Trp requirement of juvenile Nile tilapia was estimated to be 2.9g/kg for maximum weight gain of fish.
Recent research has provided new mechanistic insights that amino acids (AA) coordinate protein synthesis by expressing the evolutionarily conserved target of rapamycin complex 1 (mTORC1) signaling ...pathway genes. An 8-week feeding trial was conducted to evaluate the impacts of experimental diets (420 g kg−1 crude protein; 15 MJ g kg−1) with protein-bound AA (Control), crystalline amino acids (CAA) supplemented at 60 g kg−1 and CAA at 120 g kg−1 on growth performance, AA retention, and mTORC1 signaling pathway (mTOR, mLST8, and Raptor) genes in Nile tilapia, Oreochromis niloticus fingerling (n = 360; 4.3 ± 0.1). At the end of feeding trial, the time-course postprandial plasmatic lysine and methionine were determined by collecting blood samples of fish immediately after feeding and at 60, 120, 240, 480 and 960 min. Each diet was randomly distributed into eight replicates groups of 12 fish and hand-fed, six times a day until apparent satiety for eight weeks. Compared with fish fed CA120 diet, body weight gain (BWG), feed intake (FI), feed efficiency (FE), protein retention efficiency (PRE) and retention of six essential and five non-essential AA parameters were improved in fish fed Control and CA60 diets. Furthermore, fish fed CA60 diet showed significantly lower whole-body lipids and higher crude protein than those fed other diets, whereas humidity and ash were not affected by dietary treatments. Plasmatic lysine and methionine linearly increased in fish fed Control diet. However, time-course plasmatic lysine and methionine were affected along with quadratic effect, and plasmatic lysine and methionine peaked at 461 and 496 min in fish fed CA60 diet, being reduced at 364 and 405 min in fish fed CA120 diet, respectively. The mechanistic insights of well-balanced AA coordinating protein synthesis in fish fed Control and CA60 diets was identified through a similar response on relative gene expression of mLST8 and mTOR genes, but higher than that in fish fed CA120 diet. Overall, this study validated CAA up to 60 g kg−1 without adverse effects on fish growth performance. However, a high CAA level at 120 g kg−1 depressed growth performance and may be considered to produce industrial-scale feeds for precision tilapia feeding.
This study revealed new mechanistic insights that amino acids regulate protein synthesis through genomic approaches by regulating relative gene expression of mTORC1 signaling pathway. The data is relevant to the formulation of well-balanced amino acids precision tilapia feeding.
•Crystalline amino acids (CAA) can successfully be included at 60 g kg−1 in the Nile tilapia diet.•CAA stimulates protein synthesis coupled to lower fat deposition in Nile tilapia.•The mRNA levels of mTOR and Raptor genes are up-regulated by properly CAA supplementation.•CAA would be used as a strategy to improve amino acid balance beyond elaborating eco-friendly diet.
This study aimed to evaluate the growth performance, expression of genes related to the metabolism of sulfur-containing amino acids, and flesh quality of large Nile tilapia (Oreochromis niloticus). ...Fish (n = 120; 1199 ± 46 g) were randomly distributed into four groups and each fish group was hand-fed a basal diet not supplemented (CON) or supplemented with methionine (MET), taurine (TAU), and methionine and taurine (MET+TAU) until apparent satiety for seven weeks. Compared to CON group, the fish group on the MET diet experienced increased in final body weight, protein retention efficiency, and fillet yield by 62.83 g, 9.82%, and 1.31%, respectively (p < 0.05). These results were linked to the down-regulation of cystathionine β-synthase (CBS) and cysteine dioxygenase (CDO) gene controlled by methionine supplementation. Moreover, up-regulation of the adenosylhomocysteine (AHCY) gene in fish offered TAU diet as a metabolic response to methionine deprivation. Furthermore, taurine prevented color deterioration and increased fillet hardness and chewiness attributes as compared to CON group (p < 0.05). Overall, this study indicated a marked effect of dietary methionine on growth performance, particularly fillet yield, and notable synergic effect of methionine and taurine preventing color deterioration and increasing fillet hardness.
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•Methionine enhanced growth, feed efficiency, protein retention, and fillet yield of fish.•Fish fed methionine supplemented diets showed down-regulated expression of CBS and CDO genes.•Taurine addition increased mRNA levels of AHC gene in response to methionine deprivation.•Methionine and taurine in combination effectively prevented color deterioration and enhanced fillet hardness and chewiness.
The effect of graded levels of dietary available phosphorus (AP) on large Nile tilapia (145.87 ± 9.51 g) performance, feed efficiency, body composition and mineral retention in vertebrae was ...evaluated. All male fish were distributed into three replicates in fiberglass aquaria (800 L each; 12 fish per tank) for 87 days and hand fed to pelletized diets three times a day until apparent satiation. Diets with approximately 302 g kg⁻¹ of digestible protein and 15.2 kJ g⁻¹ of digestible energy with graded levels of dibasic phosphate yield AP levels of 2.39, 4.17, 6.12 and 8.91 g kg⁻¹. At the end of the trial, feed intake, hepatosomatic index, fillet yield, whole body moisture and crude protein of fish fed 2.39–8.91 g kg⁻¹ of AP diets were not significantly different. The supplementation of 6.12 and 8.91 g kg⁻¹ of AP resulted in significantly increased weight gain, whole body ash and calcium. Whole body crude lipids significantly decreased with increasing AP from 6.12 to 8.91 g kg⁻¹. However, concentration of zinc in the vertebrae was not affected by dietary treatments. The magnesium contents of the fish vertebrae were lower in fish fed lower dietary AP level. No effects of the dietary AP on apparent digestibility coefficients of energy and nutrients were observed. The study indicated that the dietary AP level of at least 6.12 g kg⁻¹ satisfies the needs for growth performance, body composition and bone mineralization of large Nile tilapia.
