Substitution of live feed by formulated diet: effect on the growth and survival of Betta splendens (Regan) fry

The present work evaluates the effectiveness of partial or total replacement of live feed (LF) (Tubifex) together with formulated diet (FD) for Betta splendens. Three hundred Betta splendens fry of uniform size (mean weight 0.19±0.01g) were equally distributed in five treatment groups with three replicates in glass aquaria of 351itre capacity. Fishes were given diets at different ratio of LF and FD viz. T1(C) 100% LF; T2 75% LF, 25% FD; T3 50% LF, 50% FD; T4 25% LF, 75% FD and T5 100% FD and the experiment continued for 105 days. T2 group registered highest (P<0.05) % body weight gain (125.61±0.26) and specific growth rate (2.34±0.02), which was similar to T1 and T3 groups. Lowest FCR was recorded in T2 (2.40±0.11) group, which was similar to Tl, T3 and T4 groups. Highest (P<0.05) PER was observed in T4 (1.00±0.03) group, which was similar to T3 and T5 groups. At the end of experiment, highest % survival was recoded in T1, T2 and T3 groups (96.67±1.67), which was similar to T4 group. From the study, it is concluded that LF can be successfully replaced up to 75% by FD without any adverse effect on the growth and survival of Betta splendens

Ontogeny of the digestive tract in stinging catfish, Heteropneustes fossilis (Bloch) larvae

Heteropneustes fossilis (Bloch) is an important candidate species for diversification of freshwater aquaculture in India. However, high mortality rate during larval rearing is the most serious bottleneck in commercial production of this species. A proper understanding of the ontogenic development of digestive system provides the basis to understand the nutritional physiology of larvae and develop appropriate feeding strategies. In the present study, the ontogenical development of the digestive tract in H. fossilis larvae was studied from hatching until 30 day post-hatching (dph) at 29 °C. At hatching (2.8 ± 0.2 mm standard length, SL), the digestive tract was undifferentiated and attached dorsally to the yolk sac. At 1 dph (2.9 ± 0.2 mm SL), the mouth opened and oral valves were visible. At 2 dph (3.0 ± 0.3 mm SL), goblet cells were observed in the buccoparyngaeal cavity. At this age, exogenous feeding started and the intestine was differentiated into the anterior and posterior regions, and the rudimentary liver and pancreas were also seen. Small supranuclear vacuoles were observed in the enterocytes of the posterior intestine at 2 dph. Zymogen granules were observed in acinar cells of pancreas by 3 dph, and islets of Langerhans were visible at 4 dph (3.5 ± 0.1 mm SL). At the same age, most of the yolk sac reserves were consumed, whereas they were completely exhausted by 5 dph (3.9 ± 0.5 mm SL). Between 4 and 6 dph, the liver elongated in size and started to accumulate lipids in the hepatocytes. Gastric glands were detected at 4 dph, and the pyloric sphincter was completely differentiated at 9 dph (6.1 ± 0.4 mm SL) as an epithelial fold that separated stomach from the anterior intestine. By 13 dph (8.6 ± 0.2 mm SL), profuse gastric glands were visible inside longitudinal mucosal folds of the stomach. The formation of gastric glands and their development were noticed as the last events in the development of the digestive tract in H. fossilis. This indicated the end of the larval period and the commencement of the juvenile stage. Considering these observations, it is suggested that H. fossilis larvae have a morphologically complete digestive tract by 13 dph. The findings of the study on the development of the digestive system in H. fossilis may help in synchronising the larval stage of development and feeding strategies and would be helpful in improving larval rearing techniques for catfish species.info:eu-repo/semantics/acceptedVersio

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Not AvailableEffect of dietary zinc on growth, survival and physiological responses of Tor putitora fry was investigated. A 60-day experiment was conducted with 1,800 fry (avg. wt 54.35 ± 3.09 mg) of golden mahseer distributed randomly among six treatments in triplicate. Six isonitrogenous semi-purified diets were prepared with graded levels of zinc (0, 10, 20, 40, 60 and 80 mg/kg). Zinc sulphate was added as dietary zinc source to the basal diet. Zinc concentration in rearing water was monitored during feeding period and it was set from 0.01 to 0.03 mg/L. Growth parameters as average weight gain, percentage weight gain, feed efficiency ratio were higher (p < 0.05) in fish fed diets with 40 mg Zn/kg. Suppressed growth and higher mortality was observed in groups fed with 80 mg Zn/kg diet. RNA/DNA ratio and whole body zinc retention showed increasing trend with increasing dietary zinc up to 40 mg Zn/kg and plateaued thereafter. Analysis of digestive enzymes revealed that amylase activity increased with increase in dietary zinc levels however, lipase and protease showed rhythmic changes among treatment groups. There was an increasing trend of alkaline phosphatase (ALP) activity with increase in zinc supplementation and highest ALP activity was observed in 80 mg Zn/kg diet which was significantly different from that of control group. Polynomial regression analysis indicated that 44.62–46.73 mg Zn/kg diet is optimum requirement, which favoured enzymatic responses for optimal growth and survivality in T. putitora fry.Not Availabl

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Not AvailableThree hydroponic media crushed stones (T1), river stones (T2), and floating raft (T3) were compared in an aquaponic system with common carp (Cyprinus carpio) and mint (Mentha arvensis). Fish effluents were used as plant nutrients while plants filtered water by stripping off the nutrients before returning to the fish tank. Fish growth, plant growth, and water quality parameters were used to evaluate the suitability of three different media. Growth performance of common carp and mint followed the relationship of crushed stones > floating raft > river stones with significant difference observed among all treatments. Total ammonia nitrogen (TAN) removal varied significantly among different treatments. The maximum TAN removal was observed in T1 (77.13%) followed by T3 (69.65%), and the minimum removal was observed in T2 (48.82%). Nitrate removal varied significantly among different treatments. The highest removal was observed in T1 (82.95%) followed by T3 (68.04%) and T2 (59.51%). Removal of phosphate was significantly lower in T2 (50.12%) when compared to T1 (67.85%) and T3 (70.71%). Biofilter performance (g m−3 day−1 ) of T2 (4.80) was significantly lower compared to T1 (7.13) and T3 (7.37). Crushed stone and floating raft were significantly efficient when compared to river stone medium in terms of nutrient removal and water quality maintenance for the fish culture. Considering all growth parameters, crushed stone media proved to be better when compared to other two media. Thus, medium selection could be a considerable factor when designing an aquaponic system.Not Availabl

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Not AvailableThe present study was carried out to find the suitable salinity for growth performance and survival of Pangasianodonhypophthalmus (Sauvage, 1878) in inland saline water. P. hypophthalmus (0.41±0.03g) 225 fishes were stocked in five treatments in triplicate for 60 days. The experimental design consisted of freshwater as control and inland ground saline water with salinities 5,10,15, 20 and 25 ppt as treatment groups T1, T2, T3, T4 and T5 respectively .The results indicate that P. hypophthalmus can tolerate the salinities up to 15 ppt in inland saline water where as 100% mortality was observed treatments (20 ppt) and (25 ppt) after 48 hours and 18 hours respectively. Osmotic study using serum osmolality, water osmolality, and osmoregulatory capacity indicated that, P. hypophthalmus cannot survive at higher salinities. The stress level in the animals at higher salinities is indicated by higher blood urea level, reduction in total serum protein, variable calcium and magnesium concentration in serum and histological studies. Though P. hypophthalmus survived up to 15 ppt but the optimum salinity for culture is 10 ppt in inland saline water.Not Availabl

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Not AvailableThe present study evaluated the effect of stocking density on growth and survival of post larvae (PL) of Fenneropenaeus merguiensis (de Man, 1888), commonly known as banana shrimp. PL was stocked at four different densities i.e., 10, 20, 30 and 40/m2 (T10, T20, T30 and T40, respectively) and reared for a period of 60 days. Water quality and growth performance parameters of different treatments were compared during the experiment. A significant (p<0.05) decrease in dissolved oxygen (DO) concentration relative with the higher stocking density was observed. Though some of the parameters showed significant (p<0.05) difference among the treatments, the water quality remained within safe level, throughout the experiment. Increase in stocking density led to significant reduction (p<0.05) in BWG and SGR of PL. The highest value of FCR was in T40 and lowest in T10. Stocking density also showed an inverse relationship with survival percentage of shrimp. Results of the present study revealed that high stocking density (≥30/m2) can seriously impair the growth of F. merguiensis PLNot Availabl

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Marine sponges as biological indicator of oligotrophic Andaman waters

338-341Surveys on marine sponges conducted vide SCUBA at South Andaman (North Bay, Chidiyatapu, Havelock and Neil Island) at three different depth zones (5, 10 and 15m) using randomly placed quadrants(1x1m2). Marine sponge recorded in the surveys showed Carteriospongia foliascens, a phototrophic species, which mainly relies on the translocation of nutrients from their symbiotic cyanobacteria was observed in all depths and is well known as biological indicator of oligotrophic waters

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Not AvailableThe knowledge on the reproductive biology of fishOreochromis niloticus (Linnaeus, 1758) in riverine condition is meagre in the Indian sub-continent which is necessary for the development of an appropriate fishery management protocols for the rivers. In this context, the gonadal maturation profile and fecundity of O. niloticus was studied. Mature, spawning and spent females recorded in almost all the months of the year evidenced multiple and prolonged breeding behaviour. An overall sex ratio (M/F) of 1: 1.08 observed was statistically non-significant from expected 1:1 ratio (χ2=6.994219, p=0.8642) indicating that males and females were statistically equal in number. The absolute fecundity ranged from1192 to 4760 with mean of 2590 eggs from ovary weighing between1.91 g to 28.89 g. Monthly changes in gonado-somatic index (GSI) revealed that fish bred throughout the year except in July and August, but at peak between October- November and March-June. Size at first maturity of male was estimated as 229.6 mm with confidence limit of 235.9 and 223.6 mm and for female as 238.1 mm with confidence limit of 244.7 and 231.7 mm, respectively.Not Availabl