Effect of salinity on food consumption and growth of juvenile Nile tilapia (Oreochromi niloticus L.)

The effect of salinity (0, lO and 20%o, water temperature 28 ± l oC) on food consumption and growth of juvenile Nile tilapia, Oreochromis niloticus L. (9.94 ± 0.15 g) were investigated by feeding group of 20 fish at 2% body weight day. Individual food consumption was measured using X-radiography. There were no significant differences in growth or white muscle protein concentrations among groups. During feed deprivation, weight loss was similar for fish held at O%o and 10 %o salinity, but after 7 days over 50% of the fish maintained at 20%o salinity developed lesions covering 5-25% of the body. No significant relationships were observed between individual specific growth rates and food consumption rates within the groups. The fish in all salinity groups showed a negative correlation between specific growth rate and food conversion ratio. The coefficient of variation for wet weight specific food consumption and the mean share of meal for each fish were used as a measure of social hierarchy strength. A negative correlation was observed between coefficient of variation in food consumption and mean share of meal. The social hierarchy structure was similar in all salinities; 25% of the fish were dominant (18.29% above an equal share of meal) and 30% were subordinate (16.19% below an equal share of meal) and the remainder 45% fish fed theoretical share of meal (MSM, 5.26%).

Food and feeding habit of chapila (Gudusia chapra)

Abundance of diatom (Bacillariophyceae) in the plankton population and the dietary role of it in chapila (Gudusia chapra) in pond were studied. A total of 25 genera of phytoplankton belonging to Bacillariophyceae (7), Chlorophyceae (11), Cyanophyceae (5) and Euglenophyceae (2) and 9 genera of zooplankton belonging to Crustacea (3) and Rotifera (6) were recorded from the water. Among the phytoplankton, highest abundance of Chlorophyceae was observed, and Bacillariophyceae, Cyanophyceae and Euglenophyceae ranked the second, third and fourth position in the planktonic population, respectively. Among the zooplankton, Rotifera was recorded as the most dominant group and Crustacea as the least one. From the gut content analysis, 4 groups of phytoplankton consisting of 33 genera of plankton were identified and recoded [sic] of which 25 belonging to phytoplankton and 8 belonging to zooplankton. This study reveals that the Chlorophyceae and Cyanophyceae were the most dominant food items of chapila. Bacillariophyceae (diatom) and Euglenophyceae were less important and Crustacea and Rotifera were the least important in the diet of Chapila. The present investigation showed that chapila appeared to be a plankton feeder with a preference for phytoplankton to zooplankton. Electivity analysis showed that the fish avoided zooplankton and strongly selected phytoplankton. In the gut contents of fish, Chlorophyceae was positively and Bacillariophyceae (diatom) was negatively selected throughout the experimental period, in the pond water.

Food of two size-groups of the catfish Mystus giulio (Hamilton-Buchanan) in Vemblai canal, Vypeen Island

The stomach contents of two length-groups of the catfish Mystus gulio collected from Vemblai Canal in Vypeen Island (Kochi) were examined by frequency of occurrence and points methods. Analyses using standard indices proved difference in diet composition between the two size-groups.

Quality assessment of rotating and solar tunnel dried marine fish product

Studies were conducted to evaluate the quality aspects of marine dried fish i.e. silver jew fish (Johnius argentatus), Bombay duck (Harpodon nehereus) and ribbon fish (Trichiums haumela) products produced in rotating and solar tunnel dryers. On the basis of organoleptic characteristics such as colour, odour, texture, broken pieces, insect infestation and overall quality, four member panels of experts evaluated the quality of the dried products obtained from both rotating and solar tunnel dryers and all the products were found in acceptable quality. Reconstitutions properties of samples were in the range of 51.05 to 98.75% for the dried fish produced in rotating dryer, while 24.64 to 76.76% for dried fish produced in solar tunnel dryer. The highest reconstitution rate was found in dried silver jew fish and lowest in ribbon fish produced in rotating dryer. On the other hand, the highest reconstitution was observed in dried silver jew fish and lowest in dried Bombay duck produced in solar tunnel dryer. Proximate composition such as moisture, crude protein, lipid and ash content of the dried fish muscles produced in rotating dryer ranged from 16.36% to 19.1%, 62.35% to 67.37%, 6.37% to 10.75% and 7.00% to 8.05%, respectively and in solar tunnel dried fish products, they were in the range of 14.05% to 19.71%,57.64% to 69. 21%,6.92% to 15.40%and 7.69% to 8.80 %, respectively. The TVBN values of dried fish products obtained from rotating dryer were in the range of 15.02 to 19.05 mg/100g, while in solar tunnel dried fish products, the values were in the range of 15.46 to 19.21 mg/100g. The results of the studies indicated that dried fish produced from both rotating and solar tunnel drier were acceptable quality in terms of organoleptic and food quality aspects.

Nutritional quality of some food fish

The proximate compositions and amino acid make-up of silver jew fish (Johnius argentatus), Indian halibut (Psettodes erumei), grey mullet (Mugil cephalus) and pearl spot (Etroplus suratensis) are reported. Calorific values of these fishes have been calculated from their proximate compositions and their amino acid make-up compared with the available data for beef and egg. From the study, pearl spot is adjudged to be the most nutritive among the fishes studied, followed by Indian halibut, grey mullet and silver jew fish.

Studies on the suitability of producing value-added products from silver carp, Hypophthalmichthys molitrix

Silver carp, Hypophthalmichthys molitrix is contributing significantly to the total production of fish through aquaculture in Bangladesh. However, its low market price has become a serious concern to the fish farmers. The suitability of silver carp mince for the production of various value-added products (VAPs) - surimi, fish sausage, fish burger and fish stick was studied during April-September 2000 to ensure more appropriate and profitable utilization of silver carp. Surimi/frozen mince block was produced by washing the silver carp mince with 0.1% NaCl for 7-8 min (4-5 min agitation and 3-4 min settling). A two-step heating schedule for incubation at 50°C for 2 h and cooking at 95°C for 30 min gave high textured good quality consumer product. With the addition of cryoprotectants, surimi could be kept frozen for 5 months without loosing [sic] much of its textural and sensory qualities. Mince-mix and a batter with different ingredients and spices were formulated to produce fish burger using potato smash as the binding agent. Fish flake-mix and a batter with different ingredients and spices were formulated to prepare fish stick using both potato starch and potato smash as filler ingredients. Unwashed and washed frozen mince block or fresh flesh of silver carp was used to prepare fish sausage by heating at 100°C for 1 h after incubating at 50°C for 2 h. A spice-mix formulated with various local spices at the rate of 1.0-1.2% gave good texture and flavor to the sausage. A good-appeared sausage-pink color was developed by combining three food-grade colors of asthaxanthin. Products prepared with potato starch, potato smash and rice smash had an acceptable bacterial load in refrigeration (5°C) for up to 8 days and in room temperature (28°C) for up to 3 days. No coliform bacteria were found in the products prepared.

Food and feeding habits of Saurida Tumbil (Block, 1795) off Mumbai waters

The present investigation suggests that Saurida tumbil (Bloch, 1795) is carnivorous and predacious feeding mainly on fishes followed by crustaceans and molluscs. Cannibalism has been observed in the species. Young ones of this species were observed to feed on small fish and Acetes spp., while adults feed on a variety of food. However, fish seems to be the preferred food item. Monthly gastro-somatic index in males indicates poor feeding in the month of february and maximum during august and september. In females, monthly gastro-somatic index indicate poor feeding in december and maximum during january and march. Sex wise study of feeding intensity did not reveal significant difference in males and females.

Nutritional evaluation of an indigenous low cost protein food

A study of supplementary feeding was conducted on children with a protein food (edible fish powder in the form of 'chutney') for 35 days and the effect assessed periodically. The most noticeable effect was gain in weight and mid arm circumference in children. 35% children showed a weight gain of 1 kg, 27% 0.5 kg, 21% 1.5 kg and 2.5% 2.5 kg. 48% children registered an increase in their mid-arm circumference by 0.5 cm, 16% 1 cm and 2.5% 1.5 cm. 10% children did not gain weight. However, these children had intercurrent infections like measles, whooping cough and asthma.

On the importance of Mesopodopsis zeylanica (Crustacea, Mysidacea) as food of fish.

This investigation was aimed at ascertaining the actual consumers of Mesopodopsis zeylanica, to assess its importance in the trophic relationship within the habitat.

Phospholipids of five Indian food fishes

The phospholipids of five Indian food fishes (sardine, pomfret, mackerel, anchovies and thrissocles) were fractionated quantitatively using column and thin layer chromatographic techniques and the results reported in this communication.

Sequential analysis for testing quality standard of fish ham and sausage

Fish sausages are finely ground fish flesh, either of a single species or mixed, homogenised with starch, sugar, fat, spices and preservatives, generally filled in cylindrical synthetic or natural casings and pasteurised. Similar products containing small pieces of quality fish and lard are termed "fish ham". They are highly relished products in Japan, annual consumption exceeding 2 lakh tones. Preliminary studies have shown that they can catch a lucrative market in our country. However, being a pasteurised product which is often consumed as such without any further cooking, strict quality control measures have to be enforced so as to avoid food poisoning hazards. Besides physical characteristics like absence of damages, pin-holes, curliness and air pockets as well as jelly strength, texture and flavour, chemical characteristics like pH and acid values, moisture, carbohydrate and fat contents and volatile bases have to be assessed. A very important test that has to be carried out along with the above, before passing a lot for free distribution is the bacteriological examination to avoid the presence of pathogenic organisms.

The free alpha amino acid nitrogen contents of some common food fishes of Kakinada region, Andhra Pradesh

The moisture and free alpha amino nitrogen contents of some important food fishes and shell fishes of Kakinada region have been studied. Crustaceans and molluscs contain free alpha amino acids in quantities several times higher than all other aquatic animals examined in this study. Their probable role in the physiological activities of these animals has been discussed.

The food and feeding habit of Penaeus monodon Fabricius collected from Makato River, Aklan, Philippines

The food of Penaeus monodon collected from Makato R., from Sept 1977 to Jan 1978 is described with preliminary observations on its feeding habit and rate of foregut clearance. Feeding behaviour appears to be associated with the tidal phase. Foregut clearance rate is rapid, with 95% of food transported from the foregut 4 h after feeding. Frequency of occurrence and proportion of total food of various foregut contents are shown, as are dry weight, percentage mineral, organic and crude protein nitrogen from individual and pooled samples of gut contents, and foregut index in P. monodon collected during different phases of one tidal cycle.

The use of decapsulated brine shrimp eggs as food for shrimp larvae

Decapsulated cysts of Artemia salina were experimentally fed to the larvae of Penaeus monodon, Metapenaeus ensis, M. endeavouri and Macrobrachium rosenbergii and were found to be comparable to freshly hatched brine shrimp nauplii.

Preserved algae as food for Penaeus monodon larvae

Uni-algal cultures of C. calcitrans, S. costatum, T. chui and Isochrysis sp. obtained from the laboratory were harvested. The harvest, preserved by either freezing or sun-drying, was fed to the larvae of P. monodon . Among the test algal species, Chaetoceros and Tetraselmis were used in larval feeding trials with frozen food while Chaetoceros, Tetraselmis and Isochrysis species were utilized in feeding experiments with sun-dried algae. Their relative effects on larval survival and development were assessed. Results showed that, except the alum-flocculated cells, both frozen Chaetoceros and Tetraselmis can support survival at the zoea stage. Best survival of 68% was atained with dried Chaetoceros followed by Tetraselmis at 44%. Dried Isochrysis did not perform as well, a significantly low survival of only 25% was obtained.