Growth, osmoregulation and ion accumulation in the coastal halophyte Arthrocnemum indicum under field conditions

Life cycle and population biology of a perennial halophyte Arthrocnemum indicum Willd, was studied from February 1992 to January 1993. During the 12 months, the population was exposed to great variations in soil salinity from 35 to 58 ms/cm2 and soil moisture ranging from flood to drought levels. Seasonal changes in dry weight are directly related to soil salinity stress. When salinity levels become low, the dry matter production increases. A little increase in dry weight from April to July indicates that more negative soil water potentials were limiting plant growth. Proline content increased considerably during the dry season with a corresponding increase in salinity. Water soluble oxalate did not vary much with changes in salinity.

Nutritional and anti-nutritional analyses of Azolla africana Desv. and Spirodela polyrrhiza L. Schleiden as feedstuffs for fish production

The chemical composition of Azolla africana and Spirodela polyrrhiza cultivated in earthen ponds were determined. Crude protein contents of the samples were 28.9~c0.6 and 25.6~c0.2% dry matter for A. africana and S. polyrrhiza respectively. Dry matter, crude fibre and lipid contents of A. africana were higher (P<0.05) than values obtained for S. polyrrhiza. Mineral analyses showed that S. polyrrhiza contained higher levels of Na, S, Ca, Mg and Fe than A. africana. Except for Ca content in S. polyrrhiza, heavy metals (Ni and Zn) accumulation in Azolla were very high. There were no wide differences in the individual amino acid indexes except for methionine. Some anti-nutritional factors were determined. Cyanide, tannin and phytin contents of fresh weed samples were higher than sun-dried samples. A. africana contained more cyanide and tannin than S. polyrrhiza both in fresh and sun-dried forms

Digestibility and nutrient utilization of soybean milk concentrate based diets in Oreochromis niloticus

The digestibility and utilisation of two fresh soybean milk concentrate based diets, two stale soybean milk concentrate based diets and two Fishman based diets serving as control, at optimal (30%) and suboptimal (20%) protein levels were evaluated in Oreochromis niloticus. The diets were as follows: Diet I (control) - fishmeal based diet at 30% crude protein, Diet II (control) Fishman based diet at 20% crude protein, Diet III - fresh soybean milk concentrate based diet at 30% crude protein, Diet IV - fresh soybean milk concentrate based diet at 20%, Diet V - stale soybean milk concentrate based diet at 30% crude protein, Diet VI-stale soybean milk concentrate based diet at 20%. Dry matter digestibility differed not significantly with variation in diets (P:0.05). A significant variation was recorded in the protein, lipid and ash digestibility. Proteins were more digestible at optimum than suboptimum level. Ash digestibility was lowest of all the nutrients. Variations in the utilisation of the diets in terms of weight gain, specific growth rate, food conversion ration, protein efficiency ration and apparent net protein utilization were insignificant (P: 0.05). All diets compared favourably with the standard control diet Diet I. This findings suggest the suitability of stale soybean milk concentrate utilisation as protein supplements in the diets of late fry Oreochromis niloticus

Digestibility and nutrient utilisation of soybean bran-based diets in Nile tilapia Oreochromis niloticus

The digestibility and utilisation of two soybean bran-based diets and two fishmeal-based diets serving as control, at optimal (30%) and suboptimal (20%) protein levels were evaluated in Oreochromis niloticus. These were Diet I (Control)-fishmeal based diet at 30% crude protein, Diet II (Control) - fishmeal based diet at 20% crude protein, Diet III - hydrolysed Soybean Bran based diet at 30% crude protein, Diet IV - hydrolysed Soybean Bran based diet at 20%. Dry matter digestibility differed insignificantly with variation in diets (P<0.05). There was significant variation in the protein (p 20.05), lipid and ash digestibility. Protein was more digestible at optimum level than sub-optimum level, while lipid and ash digestibility did not vary with their inclusion levels. Variation in the utilisation of the diets was significant (P<0.05) except for survival. It was observed that the best diet was Diet 1, closely followed by Diet II with highest values of mean final weight, specific growth rate, protein efficiency ratio and the apparent net protein utilisation. The high digestibility values of Diets III and IV suggests their inclusion in fish diet to spare protein for growth

Study on the biomass yield of Duckweed (Lemna minor) (L.) in hydroponic cultures containing different concentrations of aquaeous extract of chicken manure

The biomass yields of duck week (Lemna minor(L) was monitored in hydroponic media prepared by variously extracting 0.50, 1.00 and 2.00g of dried chicken manure per liter of city water (tap water) supply. The culture media consisting of aqueous extract of the various manure treatments were made up to 12 liters in all cases with tap water as control. Plastic baths of 25 liters capacity with 0.71 super(m2) surface area were used as culture facility. Each bath was stocked at a density of 30g super(m-2) with fresh weed samples (i.e 21.30g/bath). Maximum yields were obtained at all treatment levels and control on day 3 and based on the highest yield of 0.37gm super(-2)d super(-1) (dry matter) obtained at 1.00gL manure treatment which was however not significantly higher (P>0.05) than the 0.36gm super(-2)d super(-1) (dry matter) at 0.05gl super(-1) media manure content, an average manure level of 0.75l super(-1) was selected and used to determine the operational plant density. Thus fresh weights of 30 to 300gm super(-2) was grown in triplicate at 30g intervals for a period of 3 days. A regression equation of Y=2.6720+0.0021x with a corresponding maximum density or operational plant density of 266gm super(-2) and yield of 0.98gm super(-2), d super(-1) (dry matter) were obtained. Further growth trials were carried out at the operational density and manure levels of 0.50, 0.75, 1.00, 1.25, 1.50, 1.75 and 2.00gl super(-1) media manure concentration giving a significantly higher yield (P<0.05) of 17gm super(-2), d super(-1) (dry matter). This yield was however doubled to between 2.21 and 2.24gm super(-2) d super(-1) (equivalent to 7.96 to 8.06mt.ha-1, Yr-1 dry matter on extrapolation) if 25% and 75% respectively of the total weed cover were harvested daily within the experimental period. The role of some dissolved plant nutrients (DPN) were also discussed

Feeding and waste management strategies in the culture of Clarias gariepinus

Nutrient digestibility and amino acid availability were assessed in sharp-toothed catfish, Clarias gariepinus, fingerlings fed diets containing soyabean flour (SF) - Poultry meat meal (PMM) blends (25:75. 50:50, and 75:25) and 0.5 of 1.0%, Cr sub(2)0 sub(3). There was agreement between the pattern of overall protein digestibility and average amino acid availability despite the variability in individual amino acid availability the best dry matter, lipid and protein digestibility coefficients, and amino acid availability values were obtained with diets containing 0.5% Cr sub(2)0 sub(3). Chromic Oxide inclusion level appeared to affect nutrient availability. Increased marker level resulted into decreased nutrient digestibility coefficients. Similarly, these diets generated lower fecal crude protein than those with 1.0% Cr sub(2)0 sub(3). However, the latter group recorded higher protein retention efficiency. Dry mailer and lipid of diets containing more soyabean flour seemed to be more digestible than those of poultry meat meal. Similar trend was observed for the apparent availability of the amino acids. This investigation has indicated that low level of marker was better in digestibility study. Utilization of more SF than PMM in the diets of this catfish was more beneficial and should be encouraged in the feed industries producing catfish diets towards a better feed and waste management strategies in this aquaculture operation

The prospects of duckweed culturing in alleviating poverty in Nigeria

Duckweed is the smallest of all flowering plants and the plant double its mass in less than 2 days under ideal environmental conditions. Dry matter of duckweed contains between 35-45% crude protein. Moreover, the introduction of the plant to feed mill industries as a source of protein and binder supplement for pelleted fish feeds makes it of economic value. Duckweed has great potential if cultivation is encouraged in Nigeria, as this will also provide a good employment opportunity for larger percentage of youth in the riparian communities. The thrust of this paper was to explore the possibility of introducing duckweed farming to the rural populace for alternative sources of income most especially, the fisher folks and other interested farmers

Rhythms of division of some algae in situ and in laboratory culture. [Translation from: Studii Cerc.Biol.(Bot.) 21, 61-65, 1969. ]

The rhythm of division of 9 species belonging to different groups of algae were analysed in situ and in the laboratory. The research which developed in different environmental conditions attempted to establish the capacity for multiplication and assimilation of chlorophyll on the part of the algae under study with a view to placing them in a culture. The results obtained showed that the green multicellular algae (eg. Ulothrix) and the blue algae (eg. Lyngbya, Oscillatoria) are able to produce an appreciable quantity of dry matter, just as the unicellular algae. At the same time it arises that amongst the numerous factors of the environment, temperature plays one of the most important roles in the process of multiplication.

The evolution of body muscle composition of the African catfish (Clarias gariepinus) (Burchell 1822)

Changes in body muscle composition of Clarias gariepinus were studied in fish reared from 1.08 g to 383 g mean body weight in a 201-day culture period. Changes in the amount of protein content, dry matter and ash free dry matter in the muscle tissue can be described as a function of body weight. The percentage of protein content was observed to be higher in bigger fish. Fat content was low throughout the fingerling stage. Specific growth rate decreased significantly at 400 g mean body weight (P<0.05) while feed conversion rate increased. The conclusion, based on the culture conditions in this study, is that the optimal weight for harvesting C. gariepinus is 400 g.

Biochemical composition of the muscle of some freshwater fishes during the pre-maturity phase

Biochemical composition of the muscle of juveniles belonging to 18 different species of freshwater fishes showed that the protein percentage in juveniles was higher than the adults. The fat, on the other hand, was much lower. This suggests that the body fat increases with the onset of maturity. No clear inverse relationship was found between fat and protein in juveniles. Moisture percentage was very high in juveniles. This was probably because of low fat content. In most species the sum of fat and water contents (F + W) was found to be constant. The percentages of ash, calcium and phosphorus were higher in juveniles than those of adults. Dry matter percentage varied inversely with the moisture and in most species carbohydrate was generally low. In juveniles although the calorific value of protein-fraction was high the total calorific value was lower than the adults.

Nutritional value of some small indigenous fish species (SIS) of Bangladesh

Twenty three small indigenous fish species (SIS) in the size range of 3-18 cm were analyzed for proximate composition and minerals (Ca and P) content to evaluate their nutritive value. The moisture content of different species ranged between 71.00 and 81.94%. In general, small sized fishes showed higher moisture content. The muscle protein content among the species varied widely (16.16-22.28%). In general, the muscle protein content of fishes showed higher value than the whole carcass protein content. The carcass lipid content varied between 1.87 and 9.55% and showed an inverse relationship with the moisture content. The gross energy content ranged from 19.51-27.30 KJ/g on dry matter basis. In the present study, the calcium and phosphorus contents ranged between 0.85-3.20% and 1.01-3.29% respectively. The calcium and phosphorus ratio (Ca/P) varied between 0.44 and 2.00. From the nutritional point of view, it shows that the SIS are good source of protein and minerals especially calcium and phosphorus

Survey on the quality of Jaadi available [in] Sri Lankan market

A quality of survey was conducted at the fish curing yards in a northwest coast and the southern coast in Sri Lanka. A total of 40 samples different varieties of fishes were collected from the market and jaadi curing yards and all were evaluated for the quality, fungal and insect infestation. Samples were analyzed for proximate composition chemical, microbiological and sensory quality. Thirty percent of the total analyzed samples of fish were found to be unfit for consumption. Samples collected from Negombo were found to the infected with maggots. Only 42% samples had dry matter above 50%. All the samples showed a protein content above 20%. The highest protein content was 27.92% in hurulla. Over 90% of the samples had TVN at acceptable quality limits (>40). The TBC for 33% of the samples were in the range 104-105/g range, while 48% were in the range of 107-108/g due to contamination of maggots and fungi. The Survey showed jaadi had a high level of protein in its composition. But defects of curing process such on imperfect cleaning inadequate salting resulted in low (Chemical and microbiological) quality of the product.

Influence of nitrogen salts on growth and physiological responses of Rhizophora apiculata Blume in non-aerated water culture

Influence of two different forms of nitrogen on growth and physiological aspects of water-cultured seedlings of Rhizophora apiculata was studied. Of the two forms of nitrogen supplied to the growth medium, ammonium nitrogen was better than nitrate nitrogen by exhibiting increased dry matter production, shoot length, leaf area and also enhanced the contents of carotenoids, chlorophylls and their presence in photosystems and light harvesting protein complex.

Comparison of sensory characteristics and biochemical parameters in commercial frozen prawns

Commercial samples of frozen shrimp of different styles of presentation and size grades were tested for sensory, physical (cooked yield and pH) and biochemical characteristics (moisture, total nitrogen, water extractable nitrogen, nonprotein nitrogen, alpha amino nitrogen, total volatile nitrogen and trimethylamine nitrogen). The test results are compared and correlated. The order of preference of the samples were HL>PUD>P & D. There was significant correlation between sensory score of cooked sample and WEN, NPN and ∞ – NHsub(2)-N values. TVN and TMA-N did not exhibit any correlation with sensory score. It is inferred that in quality measurement of frozen shrimps of commerce the quantity of water soluble components and the total dry matter can be used to support the sensory test results.

Quality assessment of traditional, rotary and solar tunnel dried small indigenous fish species products

Studies on the quality assessments of three traditional, rotary and solar tunnel dried SIS products were conducted. Organoleptic quality of traditional dried SIS products available in the markets was poor compared to those produced in rotary and solar tunnel dryer. Reconstitution of samples were in the range of 54.26% to 75.24%, 69.37% to 83.73% and 55.08% to 80.24% when soaked at 80°C for traditional, rotary and solar tunnel dried products, respectively. The percentage of reconstitution increased with the increase of soaking time and the uptake of water was maximum after 60 min of soaking. The moisture contents of traditional, rotary and solar tunnel dried products were in the range of 26.02% to 27.33%, 16.23% to 22.84% and 13.71% to 19.30%, respectively. The protein contents were in the range of 60.78% to 72.59%, 62.17% to 76.27% and 61.11% to 76.00%, respectively; lipid contents were in the range of 12.26% to 22.60%, 14.00% to 24.71% and 13.92% to 22.39%, respectively and ash contents in the range of 15.11% to 16.59%, 8.32% to 13.51% and 8.71% to 16.45%, respectively on dry matter basis. The TVB-N content of rotary and solar tunnel dried products was low compared to traditional one ranging from 10.64 to 17.52 mg/100g and 14.34 to 15.68 mg/100g, respectively whereas the TVB-N content of traditional samples was in the range of 15.46 to 20.36 mg/100g. The bacterial load of traditional, rotary and solar tunnel dried products were in the range of 1.43x10 super(8) CFU/g to 2.89 x10 super(80 CFU/g, 1.91x10 super(8) CFU/g to 2.84x10 super(8) CFU/g and 1.95x10 super(8) CFU/g to 2.59x10 super(8) CFU/g, respectively. The results of the study indicated that dried fish products from rotary dryer and solar tunnel dryer were found to be of better quality in nutritional and food quality aspects than those of traditional dried products.