Effect of differential duration of androgen treatment on growth of Nile tilapia under Indian condition

Little is known about the effect of differential duration of androgen treatment on growth performance of Oreochromis niloticus in India. In this study, 3 days old juveniles of tilapia were fed with 17α-methyltestosterone treated diet for three different duration regimes: 0 days (control), 30 days (30 days treatment) and 180 days (throughout treatment). After six months of culture, different growth parameters like body weight, length, depth, daily weight gain (DWG), specific growth rate (SGR) and proximate body composition were analyzed. The serum testosterone concentrations of the fish were measured from the 3rd month of culture. It was found that both the 30 days treated and throughout treated categories yielded significantly higher weight, length, depth, DWG, SGR and protein content compared to the control fish. But, there was no significant difference in growth parameters among the two hormone treated groups. Achievement of an optimum saturation level of hormone activity after the application of a particular titre of testosterone may attribute to such trend in growth pattern. The serum testosterone concentration of the 30 days treated fish at the end of culture period is similar to that of the control males. This can validate the human consumption of the 30 days treated tilapia rather than throughout treated ones that have ~2 times more testosterone concentration at the same time. Thus, dietary androgen treatment for the first month of culture followed by rearing with control diet can be regarded as the ideal method for sustainable augmented fish production in India

Comparative growth performance of mixed-sex and monosex Nile tilapia at various stocking densities during cage culture

Information related to impact of stocking density on growth performance of androgen-treated monosex Nile tilapia, Oreochromis niloticus during cage culture in West Bengal, India is limited. The aim of this study was to compare the growth potential of mixed-sex control and hormone-treated monosex tilapia at various stocking densities and to determine an ideal stocking density for cage culture of monosex fish. Mixed-sex control and 17α-methyltestosterone treated monosex tilapia were stocked separately in standing surface cages at different stocking densities (1, 5, 10, 15, 25, 50, 75 and 100 fish/m3). At the end of 5-month culture period, the highest growth was observed in the 50 fish/m3 groups for both the control and hormone treated categories. More over, the monosex androgen treated tilapia in each density class showed significantly higher (P-value < 0.05) weight, length and depth compared to mixed-sex fish in the corresponding density class. The survival rate of the fish did not alter significantly with hormone treatment but stocking density had significant effect (P-value < 0.05) on it. Thus, cage culture of hormone treated monosex tilapia at a density of 50 fish/m3 may be considered ideal for augmented production of the fish under Indian context

DIETARY ADMINISTRATION OF ETHANOL AND METHANOL EXTRACTS OF Withania somnifera ROOT STIMULATES INNATE IMMUNITY, PHYSIOLOGICAL PARAMETERS AND GROWTH IN NILE TILAPIA Oreochromis niloticus

U istraživanju je procijenjena učinkovitost etanola i metanolnih ekstrakata korijena ljekovite biljke Withania somnifera na imunostimulativna svojstva i rast Nilsketilapije Oreochromis niloticus. Korijeni Withanie ekstrahirani su vodom, etanolom, metanolom, metilenkloridom, heksanom i sukcesivnim metanolom. Izmjereni su sadržaji fenola i flavonoida te antiradikalna aktivnost svih ekstrakata. Nakon toga, izvršena je hranidba nilske tilapije (n=126) hranom koja je sadržavala različite koncentracije (0, 0,3, 0,5 i 0,7 g kg-1 hrane) etanola i metanolnih ekstrakata korijena W. somnifera tijekom 30 dana kroz 3 ponavljanja. Pri usporedbi s kontrolnom hranidbom, ribe hranjene hranom obogaćenom biljnim ekstraktom indicirale suznačajno bolje (P <0,05) imunološke, hematološke i biokemijske pokazatelje te parametre rasta. Riba hranjena hranom koja sadrži ekstrakt etanola u koncentraciji od 0,7g kg-1 imala je najveće imunološke (fagocitna aktivnost, aktivnost respiratornog praska, lizozim u serumu, ukupni protein, ukupni imunoglobulin), hematološke (ukupna crvena krvna zrnca, hemoglobin, hematokrit, ukupnobijelih krvnih zrnaca, limfocita) i biokemijske (smanjena aktivnost glutationa, glutation-reduktaza) pokazatelje te najviše parametre rasta (masa, prirast, specifičnu stopurasta). Prema rezultatima, istraživani biljni ekstrakt može djelovati kao sredstvo za uklanjanje slobodnih radikala u ribljim tkivima te posjeduje sposobnost zaštite tkiva,pritom povećavajući zdravlje riba.Efficacy of ethanol and methanol extracts of medicinal herb Withania somnifera roots was evaluated in Nile tilapia Oreochromis niloticus on immunostimulation and growth. Withania roots were extracted with water, ethanol, methanol, methylene chloride, hexane, successive methanol. Phenol, flavonoid content and antiradical activity of all the extracts weremeasured. Ethanol extract showed the highest phenol, flavonoid content and antiradical activity followed by methanol extract. Subsequently, Nile tilapia (n = 126) were fed diets containing different concentrations (0.0, 0.3, 0.5 and 0.7 g kg-1 feed) of ethanol and methanol extracts of W. somnifera roots for 30 days (3 replicates). Fish fed plant extract fortified diets showed significantly better (P<0.05) immunological, haematological, biochemical and growth parameters compared to the fish fed control diet. Fish fed dietcontaining ethanol extract at the concentration of 0.7 g kg-1 feed showed the highest immunological (phagocytotic activity, respiratory burst activity, serum lysozyme, total protein, total immunoglobulin), haematological (total red blood cells, haemoglobin, hematocrit, total white blood cells, lymphocyte), biochemical (reduced glutathione, glutathione reductase activity) and growth (final weight, weight gain, daily weight gain, specific growth rate) parameters. The plant extract might act as potent free radical scavenger in fish tissues and have tissue protecting ability, thus increasingfish health

Does fish price depend solely on weight? A market survey analysis from four districts of West Bengal, India

Fish is an important food item that contains perfect combination of essential nutrients. The main consumable fishes in West Bengal, India are various carps and other small indigenous fishes. The objective of the study was to find out whether fish weight was a crucial factor to decide pricing and what kind of fish was beneficial for consumer from economic perspective. Thirteen markets in four districts (Kolkata, North and South 24 Parganas, Howrah) of West Bengal were surveyed to collect information about price, weight and number of vendors selling a particular fish considering 22 fish species. Subsequent statistical analyses were performed to conclude about the relationship between fish weight and price. The study indicates that pricing of every fish species does not depend solely on their weight. Weight plays important role to determine the price of few fish species such as Liza persia, Lates calcarifer, Wallago attu, Ompok pabo and Mystus tengara. But, the price of small indigenous fishes like Chanda nama, Colisa fasciata, Harpadon nehereus, Monopterus cuchia, Rhingomugil corsula, Sperata aor and Puntius puntio does not depend on the weight of individual fish. Seasonal availability, taste, consumer’s personal preference have important role to determine fish price

Melatonin ameliorates H2O2-induced oxidative stress through modulation of Erk/Akt/NFkB pathway

Abstract Background Improper control on reactive oxygen species (ROS) elimination process and formation of free radicals causes tissue dysfunction. Pineal hormone melatonin is considered a potent regulator of such oxidative damage in different vertebrates. Aim of the current communication is to evaluate the levels of oxidative stress and ROS induced damage, and amelioration of oxidative status through melatonin induced activation of signaling pathways. Hepatocytes were isolated from adult Labeo rohita and exposed to H2O2 at three different doses (12.5, 25 and 50 µM) to observe peroxide induced damage in fish hepatocytes. Melatonin (25, 50 and 100 μg/ml) was administered against the highest dose of H2O2. Enzymatic and non-enzymatic antioxidants such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) was measured spectrophotometrically. Expression level of heat shock proteins (HSP70 and HSP90), HSPs-associated signaling molecules (Akt, ERK, cytosolic and nuclear NFkB), and melatonin receptor was also measured by western blotting analysis. Results H2O2 induced oxidative stress significantly altered (P < 0.05) MDA and GSH level, SOD and CAT activity, and up regulated HSP70 and HSP90 expression in carp hepatocytes. Signaling proteins exhibited differential modulation as revealed from their expression patterns in H2O2-exposed fish hepatocytes, in comparison with control hepatocytes. Melatonin treatment of H2O2-stressed fish hepatocytes restored basal cellular oxidative status in a dose dependent manner. Melatonin was observed to be inducer of signaling process by modulation of signaling molecules and melatonin receptor. Conclusions The results suggest that exogenous melatonin at the concentration of 100 µg/ml is required to improve oxidative status of the H2O2-stressed fish hepatocytes. In H2O2 exposed hepatocytes, melatonin modulates expression of HSP70 and HSP90 that enable the hepatocytes to become stress tolerant and survive by altering the actions of ERK, Akt, cytosolic and nuclear NFkB in the signal transduction pathways. Study also confirms that melatonin could act through melatonin receptor coupled to ERK/Akt signaling pathways. This understanding of the mechanism by which melatonin regulates oxidative status in the stressed hepatocytes may initiate the development of novel strategies for hepatic disease therapy in future