Anti-inflammatory activities of cucurbitacin E isolated from Citrullus lanatus var. citroides: role of reactive nitrogen species and cyclooxygenase enzyme inhibition

The in vivo and in vitro mechanistic anti-inflammatory actions of cucurbitacin E (CE) (Citrullus lanatus var. citroides) were examined. The results showed that LPS/INF-γ increased NO production in RAW264.7 macrophages, whereas L-NAME and CE curtailed it. CE did not reveal any cytotoxicity on RAW264.7 and WRL-68 cells. CE inhibited both COX enzymes with more selectivity toward COX-2. Intraperitoneal injection of CE significantly suppressed carrageenan-induced rat's paw edema. ORAC and FRAP assays showed that CE is not a potent ROS scavenger. It could be concluded that CE is potentially useful in treating inflammation through the inhibition of COX and RNS but not ROS.     

Dietary folic acid requirement determined for grass shrimp, Penaeus monodon

A feeding trial was conducted to determine the dietary folic acid requirement of juvenile grass shrimp, Penaeus monodon. Purified basal diets were formulated using vitamin-free casein as the protein source. Graded levels (0, 1, 2, 5, 10, 15, 30, and 60 mg folic acid/kg diet) of folic acid were added to the basal diet, resulting in eight dietary treatments in the experiment. Each diet was fed to three replicate groups of shrimp initially averaging 0.79±0.01 g for 8 weeks. Shrimp fed diets supplemented with 2 mg folic acid/kg diet had greater (P<0.05) weight gain and hepatopancreatic folic acid concentrations than shrimp fed the unsupplemented control diet. Feed efficiency (FE) was highest in shrimp fed the diets supplemented with 2 mg folic acid/kg diet, followed by the groups fed 1 mg/kg, then the control group. Hepatosomatic index (HSI) was highest in shrimp fed the control diet, followed by 1 mg folic acid/kg and lowest in shrimp fed diets supplemented with 2 mg folic acid/kg. Weight gain percentage, hepatopancreatic folic acid concentration and hepatosomatic index of the shrimp analyzed by broken-line regression indicated that the adequate dietary folic acid concentration in growing P. monodon is 1.9–2.1 mg/kg diet.     

Dietary potassium requirement of juvenile grass shrimp Penaeus monodon

ABSTRACT: A feeding trial was conducted to estimate the minimal dietary potassium (K) requirement for juvenile grass shrimp Penaeus monodon . Purified diets with seven levels (0, 0.3, 0.6, 0.9, 1.2, 1.5, 2.0 g/100 g) of supplemental potassium were fed to P. monodon (mean initial weight 0.75 ± 0.01 g) for 8 weeks. Each diet was fed to three replicate groups of shrimp. The rearing water contained 360 mg/L potassium. Weight gain and protein efficiency ratio (PER) of shrimp improved as dietary potassium supplementation level increased up to 1.5 g K/100 g diet and thereafter declined significantly ( P < 0.05). Feed efficiency (FE) of shrimp also showed a similar trend. However, whole body K concentration of the shrimp kept an increasing trend up to 2.0 g K/100 g diet. Analysis of the weight gain (percent) and PER of the shrimp by polynomial regression indicate that the minimal dietary potassium requirement in growing P. monodon is approximately 1.2 g/100 g.     

Effect of supplemental dietary chromium and vanadium on the utilization of different carbohydrates in tilapia, Oreochromis niloticus×O. aureus

Diets containing 40% glucose or starch with either 2 ppm chromium (Cr), 2 ppm vanadium (V) or without either supplement were fed to tilapia, Oreochromis niloticus×O. aureus, to investigate the effect of Cr and V on carbohydrate utilization. Each diet was fed to three aquaria with 18 fish/aquarium in a recirculating, filtered rearing system for 8 weeks. Results indicated that weight gain, protein and energy deposition were significantly (P<0.05) higher in fish fed the starch diet than in those fed the glucose diet. Chromium supplementation significantly increased the weight gain, energy deposition and liver glycogen content in fish fed the glucose diet. Delayed plasma glucose plateau and significantly higher body lipid content were observed in fish fed the glucose diet with Cr than in those without the Cr supplementation.     

Seasonal variations of chemical constituents in the muscle and viscera of small abalone fed different diets

SUMMARY: The seasonal changes in levels of chemical constituents in the muscle and viscera of small abalone Haliotis diversicolor fed gracilar and an artificial diet were investigated. Muscle yields were higher in winter and spring. In October specimens, total adenosine 5'-triphosphate (ATP)-related compounds (ARC), total free amino acids (FAA), and glycogen in both muscle and viscera decreased markedly. The artificial diet fed to small abalone had much higher glycogen in the muscle than those fed on gracilar, and showed a great seasonal change. Total amounts of ARC in the muscles were higher through March to July, while those in the viscera were maximal in January. Taurine, arginine, glycine, glutamic acid, and alanine were the major FAA in both tissues, accounting for 81–94% of the total FAA. Total amounts of FAA in the muscles were higher in the samples collected from winter and early spring than in other seasons. Glycine, glutamic acid, and adenosine monophosphate might be the most important taste components related to the palatability of small abalone. Their total amounts in the muscles of the two specimens were considerably high in December to March. This finding suggested that small abalone produced in winter and early spring might be more palatable.     

The influence of carboxymethylcellulose on growth, digestion, gastric emptying time and body composition of tilapia

Carboxymethylcellulose (CMC) was incorporated into each of two experimental diets at one of four levels (2, 6, 10 and 14%). Each of the eight diets was fed to male tilapia hybrids (Oreochromis niloticus × O. aureus) for 9 weeks. The experiment was conducted in a closed, filtered and recirculated rearing system. The fish were fed the appropriate diets at a rate of 3% of body weight per day, 2 times a day, 6 days a week. The water temperature was maintained at 26°C. Tilapia fed diets containing, 6, 10 and 14% CMC showed significantly poorer (P<0.05) feed conversion rates than fish fed diets containing 2% CMC. The dry matter digestion coefficients of the diets did not differ significantly but generally declined as CMC level increased. Gastric emptying times decreased as the level of inclusion of CMC in the diets increased. Crude protein content and ash content of fish were similar in all dietary groups. Fish fed diets containing 6, 10 and 14% CMC had significantly lower (P<0.05) lipid content than fish fed diets with 2% CMC.     

Renal threshold for urinary glucose excretion by tilapia in response to orally administered carbohydrates and injected glucose

Two experiments, oral carbohydrate administration (Experiment 1) and vein glucose injection (Experiment 2), were conducted to gain more insight into the ability of hybrid tilapia, Oreochromis niloticus × O. aureus, to utilize different carbohydrates and to establish the kidney threshold for urinary glucose excretion. In Experiment 1, both glucose and starch were administered orally after the tilapia were fasted for 24 h. Plasma and urine were sampled from the fish at selected time intervals from 1 to 24 h thereafter. Higher (p<0.05) plasma and urine glucose concentrations were found in fish fed on glucose than in fish fed on starch. The concentration of plasma glucose of tilapia peaked at 3 h (25.45 mM for glucose; 8.24 mM for starch) after the oral ingestion of both carbohydrates. Maximum urinary glucose concentrations (48 mM for glucose; 10 mM for starch) in fish fed glucose and starch were at 3 and 4 h post administration. In Experiment 2, five concentrations (0, 0.08, 0.12, 0.16 and 0.24 g glucose ml^–1) of glucose solution were injected into the caudal vein of the tilapia. Urine were sampled from the fish at 30-min time intervals from 0 to 6 h after the injection. Blood was sampled at 1 h after the injection. Higher urinary glucose concentrations were observed in fish injected with 0.12 g glucose ml^–1. When the urinary glucose concentrations in fish injected with the various glucose concentrations were plotted against the plasma glucose concentrations of the fish 1 h after injection, the kidney threshold for urinary glucose excretion in tilapia appeared to be about 6 mM.     

Seasonal variations of free amino acids and nucleotide-related compounds in the muscle of cultured Taiwanese puffer Takifugu rubripes

SUMMARY: Seasonal variation in the level of extractive nitrogenous components was investigated in the muscle of puffer Takifugu rubripes cultured in two different areas of Taiwan. There were no seasonal and regional variations in the proximate composition of the fish. Of the free amino acids (FAA) in the muscle of puffer, the predominant one was taurine, followed by glycine, lysine, and alanine. Among nucleotide-related compounds, inosine monophosphate (IMP) and guanosine monophosphate (GMP) were the most prominent compounds. The total nucleotide-related compounds in the muscle of puffer were higher in July and November than those in the other months. The level of total taste-active components including glycine, alanine, arginine, GMP, IMP, and adenosine 5'-monophosphate was much higher in the muscle of puffer collected from July to January. Therefore, the puffer is probably more palatable in these periods.