Artificial Pellets Research Articles

Effect of size and shape of artificial pellets on capture success for Octopus tetricus paralarvae

The culture of the paralarvae of merobenthic octopus species generally results in high mortalities with many attempts failing to rear the paralarvae through to juvenile stage. Progress has been made with higher survival for paralarvae cultures, but all successful paralarvae cultures rely heavily on decapod zoeae, which are labour intensive and costly to maintain in many instances. The development of an artificial pellet that is easily captured, can be rapidly consumed and fulfils the nutritional needs of octopus paralarvae would greatly advance octopus paralarvae culture. The aim of this study was to evaluate the effect of shape and size of artificial pellets on feeding behaviour for early Octopus tetricus paralarvae. This study tested the capture success of six different artificial pellets in a crossed experiment for size (i.e., small, medium and large), and shape (i.e., spherical or rectangular). Paralarvae were observed individually for up to 5 min with the number, size, shape and handling time of pellets captured by 2 days post-hatch O. tetricus paralarvae being recorded. A total of 105 out of 250 paralarvae captured one of the six artificial pellets with no difference between the two provided shapes for small and large pellets. In contrast, there was a strong preference for smaller artificial pellets with 57 out of 105 paralarvae capturing the small pellets. The handling times ranged from 1 to 485 s across all sizes and shapes of artificial pellets with shorter mean handling times for rectangular artificial pellets (mean of 13 ± 41 s) compared to spherical artificial pellets (mean of 31 ± 97 s), regardless of size. Overall, handling times were rather short (< 20 s) for the majority of (91%) of paralarvae that captured artificial pellets. The results show that pellet shape is mostly irrelevant to early O. tetricus paralarvae, but size is an important factor that must be considered. Moreover, the short handling times suggest a low palatability of the artificial pellets used in the current study, which will be addressed in future studies.

Reproduction and commercial cultivation of chinese perch &lt;i&gt;Siniperca chuatsi&lt;/i&gt; in conditions of a warm-water farm

A breeding stock of chinese perch was gotten in a warm-water farm located in the southern Far East of Russia, where the experiment is conducted on growing this species up to three years. Combined method of growing in tanks, warm-water fry ponds and cages was used for growing the fingerlings, but two- and three-year old perches were kept in cages only and fed with live and non-living low-value forage fish. There were attempts to train two-year-old perch to feed on wet artificial pellets. By the end of the experiment, three-year-old chinese perches of two size groups had the body weight of 700−880 g with the maximum of 1600 g. Feed costs for the growth of two- and three-year-old fish in the growing seasons were 2.7−3.9 and 5.3−5.6 kg per 1 kg gain, respectively; their survival was 98−100 %. In 2023, the two-year-old perches weighing 0.5−1.1 kg were used for the first time in spawning and their offspring were raised to an average weight of 60 g.

ANALYSIS OF THE CONCENTRATIONS OF ZOOPLANKTON ORGANISMS IN THE PONDS OF THE STATE ENTERPRISE "EXPERIMENTAL FISH FARM "NYVKA" OF THE INSTITUTE OF FISHERIES OF THE NATIONAL ACADEMY OF AGRARIAN SCIENCES OF UKRAINE, TAKING INTO ACCOUNT THE POSSIBILITY OF REARING OF JUVENILES OF THE LARGEMOUTH BASS (MICROPTERUS SALMOIDES)

The period from the largemouth bass larvae hatching to the moment, when fry reaching the size of 25-35 mm, can be attributed to the most critical in the aquaculture of this species. Unlike many other fish species, after switching to external feeding, largemouth bass larvae cannot immediately consume artificial pellets, therefore, the presence of groups of zooplankton organisms of different sizes in rearing ponds is a prerequisite for obtaining a sufficient number of fry and their rapid growth. Besides, a sufficient food base at the initial stages of growing of the largemouth bass fingerlings helps to reduce the degree of cannibalism among fish and increase fish productivity in the future. This article will consider the features of different feeding stages of the largemouth bass fry, the necessary concentrations of zooplankton organisms in the ponds of fish farms during its cultivation, generally accepted world methods of applying mineral and organic fertilizers to stimulate the natural food supply, as well as the results of a study, aimed to make an identification of the average indicators of the development of zooplankton in the ponds of the State enterprise «Experimental Fish Farm «Nyvka» of the Institute of Fisheries of the National Academy of Agrarian Sciences of Ukraine in terms of the possibility of growing of this species in aquaculture reservoirs at the initial stages

SeedborneCercospora beticolaCan Initiate Cercospora Leaf Spot from Sugar Beet (Beta vulgaris) Fruit Tissue

Cercospora leaf spot (CLS) is a globally important disease of sugar beet (Beta vulgaris) caused by the fungus Cercospora beticola. Long-distance movement of C. beticola has been indirectly evidenced in recent population genetic studies, suggesting potential dispersal via seed. Commercial sugar beet "seed" consists of the reproductive fruit (true seed surrounded by maternal pericarp tissue) coated in artificial pellet material. In this study, we confirmed the presence of viable C. beticola in sugar beet fruit for 10 of 37 tested seed lots. All isolates harbored the G143A mutation associated with quinone outside inhibitor resistance, and 32 of 38 isolates had reduced demethylation inhibitor sensitivity (EC50 > 1 µg/ml). Planting of commercial sugar beet seed demonstrated the ability of seedborne inoculum to initiate CLS in sugar beet. C. beticola DNA was detected in DNA isolated from xylem sap, suggesting the vascular system is used to systemically colonize the host. We established nuclear ribosomal internal transcribed spacer region amplicon sequencing using the MinION platform to detect fungi in sugar beet fruit. Fungal sequences from 19 different genera were identified from 11 different sugar beet seed lots, but Fusarium, Alternaria, and Cercospora were consistently the three most dominant taxa, comprising an average of 93% relative read abundance over 11 seed lots. We also present evidence that C. beticola resides in the pericarp of sugar beet fruit rather than the true seed. The presence of seedborne inoculum should be considered when implementing integrated disease management strategies for CLS of sugar beet in the future.

Motor behavior of mouse large intestine: A Minireview.

Mice with a recessive gene which reduces the number of ganglion cells of the distal colon and rectum and produces megacolon, imitating Hirschsprung disease, are discussed as a model for integrative control of the large intestinal smooth musculature by the enteric division of the autonomic nervous system (ie, the brain-in-the-gut). Investigative approaches, such as propulsion of artificial pellets in preparations of whole colon in organ baths in vitro and innovative approaches capitalizing on neurogenetic technologies (eg, optogenetics), are considered in view of potential application in the development of novel therapeutic mechanisms to selectively evoke and control gastrointestinal motility patterns, such as the small intestinal digestive motility pattern, interdigestive pattern, and reversed direction of powerful propulsive motility during emesis. This minireview relates to the paper titled: "Motor patterns in the proximal and distal mouse colon which underlie formation and propulsion of feces," appearing in this issue of Neurogastroenterology and Motility.

Induced breeding and larval rearing of vermiculated spinefoot, Siganus vermiculatus (Valenciennes, 1835) in indoor conditions

Vermiculated spinefoot, Siganus vermiculatus has been reported to be one of the fastest growing species among genus Siganus. Even though it breeds in captivity, commercial level hatchery production is yet to be achieved. In the present study, mature brooders of S. vermiculatus (female weighing 400 g and male weighing 385 g) were induced to breed in captivity and the larvae were reared to metamorphosis. Fishes (55 nos., 150 g–700 g) were collected from the wild and reared in marine cages using formulated floating pellets as feed. Among the mature fishes brought to the hatchery, a female having an average ova diameter of 440 μm and a running male were induced with two intramuscular injections of human chorionic gonadotropin (hCG) at the rate of 500 IU/ fish and 200 IU/ fish respectively in a spawning tank. Spawning occurred on the day after the full moon, between 20- and 21 h after the second injection. Fecundity was estimated as 1.85 lakhs with 68–71% of viable eggs and hatching rate of 73–85%. Green water systems with microalgae, Nannochloropsis salina and Isochrysis galbana at a concentration of 2–3 × 106 cells mL−1 and 2–3 × 105 cells mL−1 were used in tanks (1000L) for egg incubation and larval rearing respectively. Copepod, Parvocalanus crassirostris (T1) and enriched rotifer, Brachionus rotundiformis (S-type) (T2) were tested as first feed for newly hatched larvae. The fertilised eggs (0.57 ± 0.02 mm) hatched out between 24 and 25 h and the newly hatched larvae measured 1.92 ± 0.08 mm in total length with a transparent yolk sac (0.63 ± 0.04 mm) and an oil globule (0.23 ± 0.02 mm). Mouth gape of 89.03 ± 9.4 μm was observed after 42 h post hatch. The use of copepod, P. crassirostris as the first feed helped in successful rearing of the larvae to metamorphosis and an improved survival rate (4.5%–12%). Metamorphosis was completed within 35–37 dph, during which post larvae with vermiculated body pattern measured 25.2–28.4 mm in length and 0.28–0.30 g in weight. Enriched rotifers (5–37 dph), copepodites (10–20 dph), umbrella stage of Artemia (18–24 dph), artificial pellet feeds (21–37 dph) and enriched Artemia nauplii (29–37 dph) were also used during various stages of larviculture. The present study is the first report of induced breeding of S. vermiculatus during full moon phase of lunar cycle. The results of the present study also demonstrate a protocol for successful rearing of larvae to metamorphosis with P. crassirostris nauplii as first feed.

Motor patterns in the proximal and distal mouse colon which underlie formation and propulsion of feces

In herbivores, the proximal and distal colonic regions feature distinct motor patterns underlying formation and propulsion of fecal pellets, respectively. Omnivores, such as mice and humans, lack a similar clear anatomical transition between colonic regions. We investigated whether distinct processes form and propel content along the large intestine of a mouse (an omnivore). We recorded propulsive and non-propulsive neurogenic motor activity in mouse large intestine under six different stimulus conditions of varying viscosities. Gut wall movements were recorded by video and smooth muscle electrical behavior recorded with extracellular suction electrodes. Three major neurally mediated motor patterns contributed to pellet formation and propulsion. (1) Pellet-shaped boluses are pinched off near the ceco-colonic junction and slowly propelled distally to a transition located at 40% length along the colon. (2) At this functional colonic flexure, propulsion speed is significantly increased by self-sustaining neural peristalsis. Speed transition at this location also occurs with artificial pellets and with spontaneously formed boluses in the empty colon. (3) Periodic colonic motor complexes (CMCs) were present in all conditions reaching a maximal frequency of about 0.4cpm and extending across the proximal and distal colon with faster speed of propagation. The three motor patterns share a unique underlying fundamental property of the enteric circuits, which involve extended ensembles of enteric neurons firing at close to 2Hz. The demonstration of distinct functional differences between proximal and distal colon in rabbit, guinea pig, and now mouse raises the possibility that this may be an organizational principle in other mammalian species, including humans.

Predicting Impacts of Offshore Monoculture Farm Expansion in Ultra-Oligotrophic Waters of the Levantine Basin

The aim of this brief research report was to define the consequential shifts in biomass and trophic structure of an ecosystem surrounding an offshore monoculture fish farm in Israel. It attempts to clarify the impact of the industry expansion and input of artificial fish pellets on functional group biomasses. We account for the direct addition of artificial food pellets, as well as metabolic wastes from the caged fish in a mass-balance food web model (Ecopath), as well as the temporal expansion of the farm’s production capacity to 21,000 t over a 30-year period (Ecosim). In the former static mass-balance model of the food web, the addition of the fish cages at its current production size of 1000 t does not adversely affect the system, and trophic energy transfer is still dependent on primary production versus the detrital pathway. The model suggests a semi-stable ecosystem with low trophic interactions. With time, the increase in fish farming at the site is characterised by an increase of all functional group biomasses at the site over the 30-year period. The accumulation in detritus most notably correlates to greater biomass for all benthic functional niches and their secondary consumers. It is, therefore, apt to develop an indicator species list to indicate negative site disturbance. In summary, the sediment column condition will be the indicator for ecosystem stability, as well as large predator attraction to the cages from the input of artificial pellets and the accumulation of dead fish at the cage bottom.

Movement Technique During Jump-Landing Differs Between Sex Among Athletic Playing Surfaces.

Pryor, JL, Burbulys, ER, Root, HJ, and Pryor, RR. Movement technique during jump-landing differs between sex among athletic playing surfaces. J Strength Cond Res 36(3): 661-666, 2022-Whether athletic surface type affects movement technique, a causal factor for lower extremity injury, is unclear. This study evaluated the influence of 4 common athletic surfaces on movement technique using the Landing Error Scoring System (LESS). Secondarily, we aimed to evaluate differences in movement technique between men and women among surfaces. Recreationally active men and women (n = 38) completed jump-landing tests on 4 common athletic surfaces in a quasi-randomized crossover fashion. Vertical jump height, perceptual fatigue, and muscle soreness were evaluated before jump-landing movement analyses and were similar across testing sessions (p > 0.05). Men achieved higher LESS scores on hardwood and artificial pellet turf compared with women (p ≤ 0.037). Women exhibited lower LESS scores on grass and artificial turf vs. concrete (p ≤ 0.048). Data indicate differential lower extremity movement technique and therefore injury risk across athletic surface types and sex, challenging the generalizability of the LESS construct. Athletic playing surface should be considered during movement technique assessment and implementation of injury prevention programs.

Edukasi Usaha Budidaya Cacing Tubifex sebagai Salah Satu Peluang Ekonomi bagi Masyarakat Desa Lubuk Saban Kecamatan Pantai Cermin Kabupaten Serdang Bedagai

THE EDUCATION OF TUBIFEX WORM CULTIVATION BUSINESS AS ONE OF THE ECONOMIC OPPORTUNITIES FOR PEOPLE OF LUBUK SABAN VILLAGE, PANTAI CEMIN DITRICT, SERDANG BEDAGAI REGENCY. Lubuk Saban is one of the areas whose population is engaged in aquaculture businesses where a large supply of freshwater fish is needed. Most farmers use artificial pellets which are relatively expensive, while the production cost can be reduced using natural food. Besides being cheaper, natural feed such as Tubifex are environmentally friendly. The purpose of this community service activity is to enable freshwater fish farmers in Lubuk Saban Village gain knowledge of Tubifex worm cultivation as one of the natural feed substitutes. In addition, this activity is expected to help the community in opening new business opportunities, provide natural food, reduce production costs, and improve the community's economy. The implementation of service activities is carried out using counseling methods with material exposure activities and direct practice regarding the stages of this Tubifex cultivation, with questionnaires and interactive discussions between devotees and students. From the results of community service activities conducted, it is concluded that participants of the service received new knowledge on the cultivation of Tubifex worms as one of the very promising economic opportunities. Furthermore, the servants gained field knowledge and new experiences on how to approach the general public, especially freshwater fish farmers

Effects of Calcium Levels in Artificial Pellet Feed on the Growth and Survival Rate of Black Apple Snails (Pila polita)

The present study was conducted to evaluate the effects of different dietary calcium levels on the growth and survival rate of black apple snails (Pila polita) in the grow-out period. There were 3 replicates for each treatment and the snails were fed with five calcium levels (% dry matter) in diet as follows: 1% (Ca1), 3% (Ca3), 5% (Ca5), 7% (Ca7), and 9% (Ca9). Two-month-old juveniles with an average initial body weight of 2.13g, shell height of 21.71mm, and shell width of 16.35mm were reared in tarpaulin tanks (1 × 1 × 1m; 40cm water depth) at the density of 100 individuals per tank. After 4 months of the rearing period, the average body weight, shell height, and shell width of the snails reached the highest values in the Ca5 treatment (28.43 g, 54.97 mm, and 40.09mm, respectively) and these values were significantly different compared to the remaining calcium contents (Ca1, Ca3, Ca7, and Ca9). The survival rate of the snails in Ca3 (75.7%) was higher than in Ca1 and Ca7 (74.7%), Ca5 (73.7%), and Ca9 (71.7%). However, the survival rate was not significantly different among the treatments. Snails in Ca5 obtained the highest productivity (2.88 kg m-2) and this value was significantly different from Ca1 (2.55 kg m-2) and Ca9 (2.35 kg m-2). The results of this study showed that the growth rate and productivity of black apple snails were highest when they consumed a diet containing 5% calcium. The optimum requirement of calcium for the black apple snails in the grow-out period was 4.51%.

Inter-species differences of total mercury and methylmercury in farmed fish in Southern China: Does feed matter?

China is now the largest producer of marine farmed fish and there is a considerable concern of seafood safety due to potential mercury contamination. We analyzed both the total mercury (THg) and methylmercury (MeHg) concentrations in nine species of commercial fish from two marine-cage farms in Southern China. 13C and 15N stable isotopes were concurrently analyzed to identify the artificial feed sources and the trophic levels of farmed fish. Mercury concentrations of all species were much lower than the human health screening values and safety limits established by different countries. Mercury levels in artificial pellets were the main determinants of Hg accumulation in fish between two sites, while somatic growth dilution and size also played an important role. Among the different fish tissues, muscle was a major reservoir for Hg and contained the highest ratio of MeHg/THg, and liver was the second important organ for Hg accumulation in most fish species. Intestine was a critical organ for Hg biotransformation with its %MeHg differing greatly among different fish species. δ15N analysis could not be used to determine the trophic levels in culturing systems where artificial practices were involved. Based on the δ13C signatures, five species of fish were identified to solely feed on the artificial pellets, yet the Hg bioaccumulation differed significantly among these species. We therefore concluded that Hg bioaccumulation in different fish species may be dependent on their internal Hg biotransformation as well as their biokinetics.

Pengembangan Pakan Ikan untuk Menekan Biaya Produksi Budidaya Lele

DEVELOPING IN FISH FEED FOR SAVING PRODUCTION COSTS OF CATFISH CULTIVATION. Making catfish feed from waste raw materials and the surrounding environment in order to save production cost. The growth of fish depends on the feed intake, but this is not sufficiently well due to the increase in feed prices. Therefore, it is necessary to innovate the production of feed that utilizes the natural resources around the surrounding waste. Development of fish feed to reduce costs by 4 ways i.e. fish feed with organic fertilization, utilization of Azzola plants or mini water spikes, organic feed from growing and the surrounding waste and artificial pellet feed with appropriate technology. Feeding innovation is expected to reduce the production cost of 70% which designate is feed. This devotion partner is a group of Mulyo Tani 1 and Orphanage group of orphanage son of Muhammadiyah Setrorejo, Baturetno. This devotion activity successfully developed catfish farming business by doing continuous feed development.

Broodstock development, induced breeding and larval rearing of Indian pompano, Trachinotus mookalee, (Cuvier, 1832) – A new candidate species for aquaculture

The present study describes the first trial on broodstock development, induced breeding and larval rearing of Indian pompano, Trachinotus mookalee. Indian pompano fingerlings were collected from wild and raised to adults having an average size of 2.84 ± 0.10 kg weight and 47.6 ± 1.43 cm length. These adult fishes were stocked in 125 t capacity circular tank having re-circulatory facility for broodstock development. The fishes were fed with squid along with clam meat and matured in four months. Mature females with >500 μm ova and oozing males were selected in the ratio of 1:2 (female:male) and were induced with single dose of hCG at the rate of 350 IU /kg body weight. Three trials with same sex ratio and hormonal doses were tried. The fish spawned after 36–38 h of induction at a temperature 29 ± 1 °C. Eggs were collected and treated with iodophore and stocked in 1 t FRP tank for hatching. The eggs hatched out after 18–20 h of incubation at a temperature of 29 ± 1 °C. The overall fertilization and hatching rate was found to be 69 ± 1.55% and 87.67 ± 0.81%, respectively. Larval rearing was carried out in 2 t capacity fibre reinforced plastic (FRP) tanks using green water system. The newly hatched larvae was 2.12 ± 0.02 mm in total length, with an oval shaped yolk sac of 0.55 mm2 and an oil droplet of 0.06 mm2 in area. The mouth opening was formed 40–46 h post hatch with mouth gape measuring 228.10 ± 1.31 μm. A systematic and overlapping regime of live feed beginning from copepod nauplii, rotifer, Artemia nauplii and artificial pellet were utilized during larval rearing. Weaning of larvae to inert diet was started from 15th day post hatching (DPH) onwards. Larvae started metamorphosis by 17th DPH onwards and was completed by 21st DPH, when the larvae reached 27.33 ± 0.10 mm. The larval rearing protocol resulted in an average survival rate of 21.53 ± 1.45% till complete metamorphosis. The present study showed T. mookalee to mature in captive conditions. The potential for induced spawning in captivity and larval rearing with a survival rate of 21.53% makes Indian pompano an excellent candidate for mariculture. This forms the first report of broodstock development, induced breeding and larval rearing of this species in captivity. The results of this study would facilitate mass scale seed production of Indian pompano in captivity, which is essential for its aquaculture.

Domestication affects exploratory behaviour of pikeperch (Sander lucioperca L.) during the transition to pelleted food.

Genetic selection for body size during domestication of animal species can inadvertently affect a number of physiological and behavioural traits. The pace-of-life syndrome (POLS) hypothesis predicts that domestication in an artificial environment lacking predators and providing abundant resources prefers proactive individuals with strong feeding motivation, high levels of aggression and risk taking, with low hypothalamus–pituitary–adrenal (HPA) axis responsiveness. In the present experiment we weaned fingerling pike-perch from live feed and habituated them to formulated feed. We recorded the number of weeks needed for the fish to accept pellets, their body length at the age of 100 days, their boldness in a novel object test and their HPI axis responsiveness. Individuals accepting the artificial feed within the first week grew larger than fish habituating later; therefore early weaners would be kept and bred in routine aquaculture procedures. Contrary to predictions of POLS hypothesis, fish weaning earlier and thus growing faster were less bold and had higher HPI axis responsiveness than fish accepting the pellets later or never. As live feed is preferred to artificial pellets, less competitive individuals may switch to pellets earlier. Inadvertent selection for stress sensitive fish may have an effect on production in aquaculture as well as on natural population after intensive restocking.

Effects of Protein Levels in Artificial Pellet Feed on Growth and Survival Rate of Black Apple Snail (Pila Polita)

Effects of Protein Levels in Artificial Pellet Feed on Growth and Survival Rate of Black Apple Snail (Pila Polita)

Palatability of stereoisomers and other amino acid derivatives to fish

Using a behavioral approach, it was shown that stereoisomers and other derivatives of amino acids (Ala, Glu, Gln; 0.1–0.01 М) have different palatability to fish (three-spined stickleback Gasterosteus aculeatus). The palatability of L-α-Ala is higher than of D-α-Ala or L-β-Ala, however, L-Glu and D-Glu equally increase the uptake of agar-agar pellets. L-Glu-Na has no stimulatory effect, probably, due to carnivorous feeding type in the three-spined stickleback. Palatabilities of L-Gln and L-Gln-HCl differ considerably. It is assumed that the influence of the configuration and structure of molecules on the palatability of amino acids to fish, as well as their taste preferences, are species-specific. The diversity of taste properties not only of L-, but also D-isomers of amino acids may matter in choosing adequate food objects in fish. Fish feeding behavior during oral sensory testing of artificial pellets, containing amino acids or their derivatives, obeys two alternative stereotypes, differing in the number of repeated manipulations with pellets and duration of the pellet retention time.

Effects of Diet and Feeding Regime on Growth and Survival of the Red AbaloneHaliotis rufescensin Land-Based Tank Cultures in Southern Chile

ABSTRACT The effects of different diets on the survival, growth, food consumption, and conversion factor of juvenile red abalone (Haliotis rufescens) under tank culture conditions were investigated. The algae Macrocystis pyrifera, Gracilaria chilensis, and Sarcothalia crispata were administered as mixed diets, mono diets, or in rotation changing weekly. Additionally, an artificial pellet feed (ABfeed) was administered alone using a feeder or as part of a mixed diet. The experiment lasted 10 mo. The 100% S. crispata diet was suspended after 4mo due to low survival rates (92.1% ± 3.4%). Treatments had significant effects (P < 0.05) on survival, growth, food consumption, and conversion factor. The lowest survival rate was obtained using the artificial feed with a feeder (94.2% ± 4.3%) and the highest with a mix of M. pyrifera and artificial feed (99.0% ± 0.8%). The highest growth rates were obtained with the mix of M. pyrifera, G. chilensis, and artificial feed (0.044 ± 0.007 mm/day per 0.054 ± 0.005 g/day) ...

Microstructural and Mineralogical Characterization of Artificially Produced Pellets for Civil Engineering Applications

Most hazardous, industrial waste from thermal coal-fired power plants has found utilization opportunities in different civil engineering applications by various treatment operations in recent years. Such initiatives provide improvements in economy, environmental protection, and health safety. One of the techniques used in treatment of powdered wastes is to make pellets by pelletization discs. These artificial pellets are mainly used in many structural applications as aggregate in concrete, filling material for roads and foundations, drainage and infiltration material, and so on. In this study, artificially produced pellets from mixtures of fly ash, bentonite, and powdered window glass were sintered at different temperatures to obtain desirable properties. Microstructure of these sintered pellets were investigated in order to understand the changes due to the sintering agent type, content, and sintering temperature. For this purpose, thermal, mineralogical, and microstructural studies were performed. It was noted that sintering temperature and the type and amount of the sintering agent had a remarkable effect on the changes in the microstructure of the pellets. X-ray diffraction (XRD) patterns also showed that sintering produced new crystalline phases not found in the raw materials which was also detected in differential thermal analysis (DTA). Thus, the dissimilar sintering behavior is attributed to the combined effect of crystal structure, morphological characteristics, and oxide compositions of the powder materials used in the production of the pellets.

Fish farming status at Sreemangal upazila of Moulvibazar district, Bangladesh

The potential and prospect of fish farming of Sreemangal, Moulvibazar was carried out from January to December 2015 by interviewing of 90 fish farmers with a well-structured questionnaire. The survey revealed that 40% of the ponds were seasonal and 60% perennial, of which 85% with single ownership and 15% accompanied by multiple ownership. The average pond size was 0.13 ha and depth 2.6 m. The ponds were prepared using of lime, cow dung, urea and TSP at the rate of 250, 250, 40 and 20 kg/ha, respectively. Nearly all of the farmers practiced polyculture with Indian major carps and exotic carps. Fish was stocked from March to June and average stocking density was 15,500 fingerlings/ha. To sustain natural food production, farmers generally used cow dung, urea and TSP at the rate of 2,600, 300 and 150 kg/ha/yr, respectively. Healthy environmental condition was maintained by applying lime and salt at 600 and 60 kg/ha/yr, respectively. The fish were fed by supplementary feed (45% farm) e.g., rice bran and mustard oil-cake with an average quantity of 2,200 and 550 kg/ha/yr, respectively and artificial pellet feed (55% farm). The average fish production, production cost and profit were found 2,945 kg/ha/yr, 1,25,940 and 94,935 Tk./ha/yr, respectively. The major constraints for sustainable pond fish farming were non-availability of fish fingerlings during stocking period, insufficient water in dry season, high production cost, poor technical knowledge, lack of money etc. By establishing more hatcheries, arranging training at farm level, providing interest free or at lower interest loan to the farmers the existing fish production could be increased.Res. Agric., Livest. Fish.3(2): 361-368, August 2016