Utilization of prawn waste: isolation of chitin and its conversion to chitosan

process is described for the preparation of chitosan from prawn waste. The process involves extraction of protein using 0.5% sodium hydroxide solution, bleaching the protein free mass with bleach liquor containing 0.3-0.5% available chlorine followed by demineralisation with 1.25 N hydrochloric acid in the cold and deacetylation using 1:1 (w/w) sodium hydroxide solution at 100°C for 2 hours.

Evidence of gene conversion in the evolutionary process of the codon 41/42 (-CTTT) mutation causing beta-thalassemia in southern China

The 4-bp deletion (-CTTT) at codon 41/42 (CD41/42) of the human beta-globin gene represents one of the most common beta-thalassemia mutations in East Asia and Southeast Asia, which is historically afflicted with endemic malaria, thus hypothetically evolvi

A preliminary study on the evaluation of casein, shrimp meal, squid meal and spirulina as protein sources of Penaeus monodon (Fabricius) postlarvae

P. monodon postlarvae were fed with fresh brown mussel (Modiolus metcalfei ) meat, and artificial diets containing casein, shrimp (Metapenaeus ensis ) meal, squid (Loligo ) meal, and Spirulina as protein sources at a rate of 20% of their biomass per day for a period of 10 days. No statistical difference was found among the weight gains of shrimp fed on various experimental diets. However, shrimp fed squid meal diet had highest weight gain followed by shrimp meal, fresh brown mussel meat, casein and Spirulina . Shrimp fed squid meal diet had a significantly better feed conversion and those receiving other experimental diets. Poorest fed conversion was observed in shrimp fed Spirulina . The protein efficiency ratio was statistically highest for the squid meal diet, with the lowest value again for Spirulina diets. Survival rate was significantly highest for shrimp fed the shrimp meal diet. No statistical differences were found among shrimp fed other experimental diets. Appropriate data are tabulated.

Solid loss and weight gain in prawns during storage in ice

Loss of solids from and gain in weight of meat of whole prawn and prawn meat stored in ice has been studied to explain the mechanism of solid loss. Two stages are identified in this phenomenon. In the first stage water is absorbed without loss of solids resulting in a maximum increase in weight. In the second stage both solids and water are lost resulting in gradual decrease in weight from the maximum reached but not reaching the original weight. It is inferred that whole prawns stored in ice up to two days give the maximum peeled yield without loss of nutrients and at the same time making the peeling process easier.

Effect of chitin and prawn shell on the growth of albino rat

The effect of addition of pure chitin from prawn shell, deproteinised prawn shell, demineralized prawn shell and dry prawn shell in casein based control diet on albino rats was studied. The diets contained 0.5% chitin and 10% protein. The results obtained in the studies show that the weight gain and feed conversion were maximum in the control diet. While addition of pure chitin slightly brought down the weight gain, addition of deproteinsed prawn shell have the minimum weight gain showing that presence of minerals adversely affects both feed consumption and weight gain in the case of albino rats. Although it was reported that addition of pure chitin at 0.5% in the commercial feed of broiler chicken gave increased weight, in the case of albino rats the weight gain was slightly reduced compared to control diet.

Effects of dietary supplementation of commercial human probiotic and antibiotic on the growth rate and content of intestinal microflora in ornamental fishes

The effects of dietary supplementation of commercial human probiotic, Lactobacil and antibiotic, oxytetracycline on the growth, survival, disease resistance and content of intestinal microflora in two ornamental fishes, viz., goldfish, Carassius auratus and swordtail, Xiphophorus helleri were studied. The total wet weight gain, food conversion ratio and specific growth rate of C. auratus did not vary significantly (p>0.05) among treatments. While in X. helleri, significant differences existed in the total wet weight gain, survival, food conversion ratio and specific growth rate among treatment groups (p<0.05). The counts of antibiotic resistant bacteria in fish gut increased with days of culture in all the treatments and the increase was more in antibiotic fed fishes. A reduction in the development of antibiotic resistance among the bacterial flora of fish gut was noticed in probiotic fed groups of C auratus and X. helleri. The results of the present study revealed that the effects of human probiotic on the growth, survival and disease resistance of ornamental fishes are variable and difficult to reproduce the similar effect on different species.

Dietary protein and energy interations: an approach to optimizing dietary protein to energy ratio in walking catfish, Clarias batrachus

An 8 weeks feeding trial was conducted in a static indoor rearing system to investigate protein to energy ratio (PIE ratio) in walking catfish Clarias batrachus. Six fishmeal based diets of two protein levels (25 and 35%), each with three lipid levels (5, 10 and 15%) resulted in P/E ratios ranging from 13.57 to 21.97 mg protein kJˉ¹ gross energy (GE) were fed to 50 fish in triplicate. Fish were fed 6% of their body weight three times per day adjusted fortnightly. Significantly higher (p<0.05) growth rates in terms of weight gain, % weight gain and specific growth rate (SGR) were evident in fish fed with higher protein diet. The highest growth rate was found by fish fed 35% protein, 17.06 kJˉ¹GE with a P/E ratio of 20.55 mg protein kJˉ¹GE. Significantly better (p<0.05) feed conversion ratio (FCR) was also evident in fish fed with higher protein diet and best FCR was found by fish fed 35% protein, 10% lipid, 17.06 kJˉ¹GE with a P/E ratio of 20.55 mg protein kJˉ¹GE. Significantly indifferent (p>0.05) values of protein utilisation were found in between the both (higher and lower) protein diets. Higher lipid deposition (p<0.05) in whole body was observed with increasing dietary lipid level at each protein diet and as higher (p<0.05) for the lower protein diets. The study reveals that C. batrachus performed best the diet containing 35%, 17.06 kJ gˉ¹ and 20.55 mg protein kJ gˉ¹ GE protein, gross energy and P/E ratio respectively.

Suitable stocking density of tilapia in an aquaponic system

An aquaponic system was studied through the integrated culture of mono-sex GIFT and two types of vegetables viz. morning glory, Ipomoea reptans and taro, Colocasia esculenta in a recirculating system for 15 weeks. Tilapia fry of uniform size of 0.76 g were released in three treatments (stocking densities): 106 fish/m³ (T1), 142 fish/m³ (T2) and 177 fish/m³ (T3) to assess the effect of stocking density on the growth performance of fish. Fish were fed with a commercial feed containing 25% protein. Weight gain (g) of tilapia ranged from 19.41 to 32.67 g and was inversely related with stocking density. Percent weight gain varied between 2553.99 and 4298.68% and was significantly different among the treatments. SGR ranged from 3.09 to 3.59% per day and varied significantly. FCR varied from 2.19 to 2.69 and had a positive correlation with stocking density. The highest survival rate (%) was achieved in T1 (99%) followed by T2 (98%) and T3 (96%). Production of fish ranged from 3.43 to 3.52 kg/m³ and was inversely related with stocking density. The present study demonstrated that 106 fish/m³ was the best stocking density in terms of growth, food conversion ratio, survival and production for tilapia culture in the aquaponic system.

Effects of stocking density on growth and production of GIFT (Oreochromis niloticus)

The study was carried out to assess the effects of stocking density on growth and production of GIFT for a period of 100 days. Three stocking densities were used 150, 200 and 250 fish/decimal; designated as treatment T1, T2 and T3 respectively having two replicates for each. Commercial pellet feeds were fed at the rate of 30% body weight up to first 10 days and then gradually it was readjusted to 22%, 18%, 15%, 12%, 10%, 8%, 6%, 5% and 4% respectively after every 10 days interval. The result showed that the fish in the treatment T1 stocked with the lowest stocking density (150 fish/dec) resulted in best individual weight gain (148.65g) followed by those in treatment T2 and T3 respectively. The specific growth rates (SGR) at every 10 days were ranged from 6.59 to 1.11 in different treatments during the experimental period. The food conversion ratio (FCR) values ranged between 1.82 to 2.03 with treatment T1 showing the lowest FCR. The survival rate ranged between 84 to 92%. Treatment T1 and treatment T2 showed significantly higher survival than Treatment T3. The fish production rate in treatment T1, T2 and T3 were 18.58, 23.87 and 26.78 kg/decimal respectively.

Merging effects of vitamin E and C on biological factors, blood characteristics and resistance against thermal stress in rainbow trout (Onchorhyncus mykiss)

This study was conducted to assay the effects of different levels of dietary vitamins C and E on growth indices and survival and resistance against thermal stress of rainbow trout (Oncorhynchus mykiss) in pond culture of Marzan abad from December 2011 to February 2011. Seven diets were supplemented. 300 fish with the average weight of 17 g were introduced to ponds for 60 days. The results showed that the highest and the lowest weight gain were in fish fed with diet containing 50 mg/kg vitamin C and E and 0 mg/kg vitamin C and E(control) , respectively. The highest and the lowest Feed Conversion Ratio (FCR) were measured in control and diet 50 mg/kg vitamin C and E. There is a significant difference in their treatments (P<0.05). Also, the lowest and highest amount of Weight Gain (WG) were observed in (E) treatment with 165.04% and 117.5% in control, the highest and lowest Specific Growth Rate (SGR), Protein Efficiency Ratio (PER), Condition Factor (CF) was found in control and treatment 50 mg/kg vitamin C and E, respectively(P<0.05). In conclusion vitamin C and E have an important role in enhancement of growth performance and feed efficiency of rainbow trout.The highest red blood cells were found in combined treatments and which the vitamin C was added.The highest RBC were found in E treatment(1.1×104 /mm3) and the lowest one in control (P˂0.05). Counting white blood cells also confirmed highest quantity in combined treatments with (69.83×104/mm3) and the lowest one (28.83×104 /mm3) in control. In conclusion these vitamins have a significant role in blood characteristics. Meantime, the resistance against termal stress was measured at the end of 60 days by facing fishes into 5 centigrade warmer water so consentration of Cortisol and Glucose measured for this reason.The lowest cortisol amount was measured in E treatment with 188.74 ng/ml and the highest was found in control(P<0.05). There was a significant difference in blood glucose consentration of fishes in F treatment with (78.66 mg/dl) and control with 136 mg/dl as a highest one(P<0.05).

Effect of diets containing various protein and energy levels on some growth parameters, survival and the production of Astacus leptodactylus in different salinities

A factorial experiment was conducted for 60 days to determine of the response of Narrow clawed crayfish Astacus leptodactylus (average weight of 17±2.3 g) to diets containing various protein and energy levels. Nine diets containing three levels of protein (30, 35 and 40 %) and three levels of energy (300,370 and 450 kcal/100g) were formulated and prepared in this trial. Each diet also was used in two levels of salinity include 0 (fresh water) and 12 ppt(Caspian sea water). So this study was conducted with 18 treatments and triplicates random group of 5 crayfish per each 110-litre tank. Weight Gain, Feed conversion ratio (FCR), Protein Efficiency Ratio (PER), Net Protein Utilization (NPU), Daily Food Consumption (DFC), Survival (SVR) and body composition of tail-muscle meat of animal were determined. Comparing the growth parameters in response to interaction between protein, energy and salinity levels demonstrated that all growth parameters have difference between them significantly (p<0.05). Comparing between survival in fresh and Caspian Sea water showed difference significantly. Compare the body composition results indicate the greatest amount of protein absorption in diet number 2(30/370) on fresh water condition. Results from this study indicate that narrow clawed crayfish can be fed a practical diet containing 30% protein and 370 Kcal/100g on non-salinity water which is the optimize CP percentage for their producer’s profits.

Impact of mangrove conversion

The article presents the impact of mangrove conversion on fisheries and on coastal areas. The mangrove areas which serve as nursery grounds for important species of fish and crustaceans are also rich feeding ground for many species from various trophic levels. Thus, the destruction of mangroves could affect the availability of fry and broodstock and, consequently, aquaculture production and fisheries. While in coastal areas, the destruction of mangroves increased the risk of coastal erosion from storm surges and winds, accelerates the erosion of riverbanks, exposes acid sulfate soils, leading to poor production and mass mortality of stocks, and affects the freshwater supply through salt intrusion upstream among others.