Anita Bhatnagar

Use of Additional Substrate to Enhance Growth Performance of Milkfish,Chanos chanos(Forsskal) in Inland Saline Groundwater Ponds

Abstract Milkfish, Chanos chanosfingerlings were cultured in inland saline groundwater ponds. Bamboo poles as additional substrate were used to increase the surface area of the ponds (Treated ponds). Controls, without the provision of additional substrate, were also maintained. After a culture period of 60 days, significantly (P < 0.05) higher growth was observed in treated ponds (mean fish wt. 86.6±2.4 g; SGR 1.5±0.01) as compared to controls (mean fish wt. 50.2±1.2 g; SGR 1.0±0.1). Length-weight relationship showed high exponential value (n) of length in treated ponds (n = 2.49) in comparison with controls (n = 1.63). Significant differences in most of the water quality parameters were not observed between the two treatments; however, turbidity, NH4-N, net primary productivity, chlorophyll apheophytin aand zooplankton population were significantly (P < 0.05) higher in controls. Significantly, (P < 0.05) high periphyton biomass in terms of dry matter (DM) (1.5±0.02 mg/cm2), chlorophyll a (13.5±1.1 μg/cm2), pheophytin a (8.3±1.2 μg/cm2) and mean periphyton productivity (1.4 mg C/m2/day) were observed at a depth of 50 cm in treated ponds. Autotrophic index was significantly (P < 0.05) low at 50 cm depth than at the other depths. Low values of epilithic periphyton density in ponds provided with additional substrate indicate the incorporation of planktonic flora and fauna in periphyton development. These investigations thus clearly suggest that the provision of additional substrate in culture ponds resulted in higher yield of milkfish.

Effect of Periphyton and Supplementary Feeding on Growth Performance and Nutritive Physiology of Nile Tilapia, Oreochromis niloticus, and Pearlspot, Etroplus suratensis, Under Polyculture

ABSTRACT Growth performance of Nile tilapia, Oreochromis niloticus, and pearlspot, Etroplus suratensis, under polyculture was studied in inland saline groundwater ponds. Three treatments (1–3) each in replicate of two were maintained: In Treatment 1 (substrate ponds), bamboo poles as additional substrate were provided for the development of periphyton, while in Treatment 2 (fed ponds), no additional substrate was provided; however, the fish were fed on supplementary diet (40% CP). Treatment 3 served as control, where neither the fish were fed on any supplementary diet, nor any substrate provided in the ponds. Irrespective of the treatment (duration 90 days), ponds were fertilized with cow-dung at 7,500 kg/ha/year. Results revealed significantly (P < 0.05) higher fish growth in Treatment 1 due to the provision of additional substrate compared with diet (39%) and control (102%) ponds. The exponential value of “n” for both the fish species was higher (n = 3.2) in ponds provided with additional substrate than fish fed a diet or fish in control ponds. Further, irrespective of treatment, growth performance of O. niloticus was significantly (P < 0.05) higher than E. suratensis. Significant differences in most of the water quality parameters were not observed among the three treatments; however, bicarbonate, pH, electrical conductivity, NH4-N, NO2-N, and o-PO4 were significantly (P < 0.05) lower, while NO3-N remained significantly (P < 0.05) higher in ponds having substrate (Treatment 1). Further, a review of data indicates that some of the productivity indicating parameters (viz, TDS, turbidity, and alkalinity), and BOD5 were significantly (P < 0.05) higher in Treatment 2 compared with Treatment 1 and control ponds. Net primary productivity (NPP), chlorophyll a, and sulphate concentration remained significantly lower (P < 0.05) in ponds with substrate (Treatment 1). No significant variations in carbonate concentration, gross primary productivity (GPP), plankton density, and plankton species diversity were observed among the three treatments. Significantly (P < 0.05) high periphyton biomass in terms of dry matter (1.6 ± 0.03 mg/m2), chlorophyll a (10.3 ± 0.69 μg/cm2), pheophytin a (3.5 ± 0.36 μg/cm2), and mean periphyton productivity (0.9 mg C/m2/day) were observed at a depth of 50 cm in ponds with substrate (Treatment 1). On the other hand, autotrophic index (AI) remained low at 50 cm depth. Epilithic periphyton density and chlorophyll a concentration in substrate ponds were significantly (P < 0.05) lower compared with the other two treatments. No significant variation in sediment quality among different treatments were observed; however, NO3-N and benthos were significantly (P < 0.05) higher in diet and control ponds compared with substrate ponds. Significantly (P < 0.05) higher values of digestive enzyme activity (protease, amylase, and cellulase), accumulation of high muscle protein, muscle, and liver glycogen, and also higher values of viscero-somatic index (VSI) and hepato-somatic index (HSI) were observed in fishes grown in ponds with substrate compared with other treatments. Proximate composition of periphyton indicates high protein (35.0–41.1%) and energy contents (13.3–15.5). These investigations suggest that provision of additional substrate for the enhancement of periphyton production has a greater importance in growth enhancement of Nile tilapia and pearlspot when stocked at the densities used in this study (10,000 fish/ha).

Antimicrobial ability and growth promoting effects of feed supplemented with probiotic bacterium isolated from gut microflora of Cirrhinus mrigala

The present studies were conducted to isolate, select, identify and characterize gut bacteria as antimicrobial and growth promoting agent for the feed of economically important fish Cirrhinus mrigala. Intestinal microflora were isolated, counted, and identified, and their in vitro antibacterial properties were determined. The results have revealed that occurrence of Gram-negative rods was around 75% and of Gram-positive rods was 25%. Among the isolates Gram-positive were maintained in nutrient agar slants at 4°C. Of these, eight strains were replica-plated on agar seeded with Aeromonas hydrophila and only one strain CM2 (C. mrigala 2) exhibited antibacterial properties in vitro showing inhibition against fish pathogen by well diffusion assay. This isolated strain was identified as Bacillus cereus. This bacterium was mass cultured and incorporated in the pelleted diet (40% protein and 18 kJ g−1 gross energy) of C. mrigala to investigate its effect on growth performance, digestibility, nutrient retention and activities of digestive enzymes. The results of feeding trial revealed significantly (P<0.05) high growth performance in terms of specific growth rate, growth percent gain in body weight (BD) (272.4±1.5)%, high apparent protein digestibility ((79.9±0.30)%) and low food conversion ratio in the group of fishes fed on diet containing B. cereus in comparison to the fishes fed on diet without probiotics. The carcass composition also revealed high accumulation of proteins ((15.28±0.15) g 100 g−1) in fishes fed on diet containing probiotics. Intestinal enzyme activities of protease, amylase and cellulase were also significantly (P<0.05) high in the group of fishes fed on diet supplemented with probiotics indicating the extracellular enzyme production by B. cereus. These results indicate that probiotics stimulate the digestion through the supply of digestive enzyme and certain essential nutrients to animals. Also significantly (P<0.05) low excretion of metabolites, i.e., ammonia excretion and phosphate production (mg kg−1 BW d−1) was observed in the fishes fed with probiotic based diets. Thus, B. cereus appears to be a promising candidate for ptobiotic applications which can enhance growth performance and nutrient retention in C. mrigala.

Nutritive Evaluation of Lysine- and Methionine-Supplemented Raw Vs Heat-Processed Soybean to Replace Fishmeal as a Dietary Protein Source for Grey Mullet, Mugil cephalus, and Milkfish, Chanos chanos

Two experiments were conducted to study the effect of methionine- and lysine-supplemented raw and hydrothermically processed full-fat soybean as a dietary protein source on growth performance, digestibility, and digestive enzyme activity in grey mullet, Mugil cephalus (mean BW 0.55 g), and milkfish, Chanos chanos (mean BW 3.83 g). Eight isocaloric (gross energy about 18.27 kj g−1) and isonitrogenous (crude protein about 40%) diets (1–4 = raw soybean based; 5–8 = processed full-fat soybean based) were formulated. A fishmeal-based diet was used as the reference/control diet. Growth performance, nutrient retention, feed conversion ratio (FCR), and protein digestibility in fishes correlated well with the trypsin inhibitor activity levels of the diets. Carcass phosphorous levels were significantly (P < 0.05) higher in fish fed the fishmeal control diet. Irrespective of the fish species, significantly (P < 0.05) lower levels of total ammonia excretion and reactive phosphate production (mg kg−1 BW d−1) were recorded where the fish were fed processed full-fat soybean diets compared with the fish fed fishmeal or raw soybean diets. Among these diets, the best growth performance and the lowest levels of metabolic waste were obtained in fishes fed the methionine- and lysine-supplemented processed soybean-based diets containing no fishmeal.

Genotoxic Effects of Chlorpyrifos in Freshwater Fish Cirrhinus mrigala Using Micronucleus Assay

The genotoxicity of pesticides is an issue of worldwide concern and chlorpyrifos is one of the largest selling organophosphate agrochemicals that has been widely detected in surface waters of India. The studies on long term genotoxic biomarkers are limited; therefore, present study was carried out to analyze the incidence of nuclear anomalies in the blood cells of fresh water fish Cirrhinus mrigala using micronucleus (MN) assay as a potential tool for assessment of genotoxicity. Acute toxicity of chlorpyrifos was evaluated by exposing fingerlings to different doses of chlorpyrifos (1/20, 1/10, and 1/5 of LC 50 ) and LC 50 was calculated as 0.44mg L -1 using probit analysis. Blood samples were taken on days 2, 4, 8, 12, 21, 28, and 35. In general, significant effects for both concentration and duration of exposure were observed in treated fish. It was found that MN induction was highest on day 14 at 0.08mg L -1 concentration of chlorpyrifos. It was concluded that chlorpyrifos is genotoxic pesticide causing nuclear anomalies in Cirrhinus mrigala .

Studies on Sediment Chemistry of River Yamuna with Special Reference to Industrial Effluents in Yamunanagar, India

A study on sediment chemistry and water quality index of river Yamuna was conducted to understand the overall quality of river. Three sampling stations were selected: Station Y1 at the upstream of the river before the influx of effluents, Station Y2 at the point of influx and Station Y3 at 5 kilometres downstream from station Y2. The results showed the increasing values of pH, alkalinity, chloride and organic matter from station Y1 to Y2. Calculation of water quality index also categories station Y2 in bad or severely polluted zone.The correlation statisticsshowed the significant positive correlation between chloride and pH whereas significant negative correlation between organic matter and water quality index. The present work revealed the effect of Maskaranala’s effluents on the overall chemistry of sediments of river Yamuna.

Karyomorphological studies from mitotic metaphases in three carp species

Karyological analysis of three carp species viz. Ctenopharyngodon idella, Hypophthalmichthyes molitrix, and Cyprinus carpio communis belonging to family Cyprinidae was carried out. The study samples of these species were collected from local fish farm in Haryana. The diploid chromosome number in C. idella was found to be 2n = 48, with 13 pairs of metacentric, 3 pairs of submetacentric and 8 pairs of acrocentric chromosomes. Chromosomal studies on the H. molitrix revealed the diploid chromosome number to be 2n = 48, with 6 pairs of metacentric, 6 pairs of submetacentric and 12 pairs of acrocentric chromosomes. The diploid chromosome number in C. c. communis was found to be 2n = 100, with 17 pairs of metacentric, 3 pairs of submetacentric, 1 pair of subtelocentric and 29 pairs of acrocentric chromosomes. Arm ratio, centromeric index and fundamental number of arms was also determined. The study reveals that diversification in these carp species of cyprinidae family is related to structural changes in chromosomes. Habitat conditions and anthropogenic activities might be responsible for incidence of pericentric inversions causing karyomorphological changes and thereby variation in karytype formulae vis-à-vis earlier reports.

Molecular Characterization and Dosage Application ofAutochthonous Potential Probiotic Bacteria in Cirrhinus mrigala

The present communication deal with the identification of probiotic strain isolated from the intestine of Cirrhinus mrigala (Mrigal) on the basis of phylogenetic analysis and nucleotide homology and was found similar to Bacillus cereus strain SL1. The strain was further investigated for its probiotic abilities; acid and bile tolerance, autoaggregation, coaggregation and hydrophobicity. A dietary experiment of 90 days was carried out to examine its effect on the growth, digestive enzyme activity and survival of C. mrigala. Four isonitrogenous and isocaloric diets were prepared and B. cereus was incorporated in the experimental diets; T1, T2 and T3 at three different levels in the proportion of 2 × 104, 2 × 105 and 2 × 106 cells 100 g-1 of feed respectively, along with a control diet TC without probiotic. After 90 days, the group of mrigal fed on probiotic supplemented diets showed significantly (P<0.05) better growth, specific growth rate (SGR), feed conversion ratio (FCR) than those fed with basal diet (control) with best result for diet T2 (P<0.05). Values of digestive enzyme activities (protease, amylase and cellulose) and carcass protein were also significantly (P<0.05) higher and excretion of metabolites (ammonia and phosphate) were lower in groups fed with diet T2. When probiotic supplemented diet fed fish were challenged with pathogenic Aeromonas hydrophila by immersion for 10 days, all probiotic fed groups showed high survival in comparison to group fed on control diet without probiotic supplementation indicating immunostimulating effect

Immunostimulating and Growth Promoting Activity of Dietary Levamisole on Cirrhinus mrigala Fingerlings

The effects of supplementing diets with levamisole on growth, immune response and resistance against pathogenic Aeromonas hydrophila were determined. Fish were assigned to three treatments with different level of levamisole(125, 250 and 500 mg kg¯¹ diet) and the control diet was prepared without levamisole. Cirrhinus mrigala were fed at 4% of their body mass for 60 days. Growth performance, enzyme activities and immunological parameters were analyzed among groups. The total erythrocyte count, total leucocyte count, phagocytic activity and NBT reduction were significantly (P<0.05) enhanced in levamisole treated group when compared to control. The relative percentage survival, A. hydrophila post-challenge was significantly higher in fishes fed on 250 mg kg¯¹ of levamisole supplemented diet. The same dose also resulted in significantly high specific growth rate (SGR), feed conversion ratio (FCR), apparent protein digestibility (APD) and elevated intestinal enzyme activities compared to other groups. Thus, administration of 250 mg of levamisole kg¯¹diet is recommended for enhancement of immunity, growth and survival of C. mrigala hence acting as a potent immunostimulant agent.

Effect of various dietary fats supplementation on the liver glycogen, protein and digestive enzymes activities in striped murrel, Channa striatus

A 84-days experiment was conducted to observe the effects of different feeds rich with different types of fats on selected biochemical parameters of Channa striatus grow-outs. There were seven treatments (F1, L3HUF; F2, H3HUF; F3, MUSOL; F4, LINOL; F5, MIXOL; F6, SATOL and F7, NATFO), fed to fish (avg. wt., 27.36 ± 0.09 to 32.54 ± 0.41 g). Results showed that the variation in liver glycogen content was recorded on addition of different fat content in the diet. Activity of intestine protease recorded significantly (p