Use of vitamin C as an immunostimulant. Effect on growth,nutritional quality,and immune response of <Emphasis Type="Italic">Labeo rohita</Emphasis> (Ham.)

Teleost fish lack the enzyme for endogenous synthesis of ascorbic acid (AA), an essential micronutrient for fish. The aim of this study was to examine the effect of higher levels of dietary vitamin C on growth, nutritional quality, and immunomodulation in the Indian major carp, rohu (Labeo rohita). Four groups of L. rohita were fed experimental diets containing either no vitamin C (control) or supplemented with vitamin C at 500 mg kg⁻¹ (Exp-1), 1000 mg kg⁻¹ (Exp-2), or 1500 mg kg⁻¹ (Exp-3) for 60 days. Growth parameters (NWG, ADG, and SGR), serological parameters (TSP, TSA, TSG, and A:G), haematological parameters (TLC, TEC, Hct, MCV, and MCH), and different non-specific immunological parameters (PR, PI, respiratory burst activity, and bactericidal activity) were evaluated during the experimental trial. Fish fed a vitamin C-supplemented diet showed higher specific growth rate (SGR) up to 1000 mg kg⁻¹ compared with control fish. Different haematological and serological parameters along with non-specific immune parameters were influenced by vitamin C supplementation. Among the non-specific immune parameters phagocytic activity (PR and PI) and respiratory burst activity (NBT cells) were significantly (P ≤ 0.05) enhanced by increasing doses of vitamin C supplementation. Higher levels of dietary vitamin C significantly (P ≤ 0.05) enhanced protection against Aeromonas hydrophila (AH1) infection compared with controls. Results from this study help to establish the beneficial effect of vitamin C on growth and immunmodulation in rohu (L. rohita).     

Tillage Effects on Crop Yield and Physicochemical Properties of Sodic Soils

Tillage modifies soil structure and has been suggested as a practice to improve physical, hydrological and chemical properties of compacted soils. But little is known about effect of long‐term tillage on physicochemical soil properties and crop yield on sodic soils in India. Our objective was to investigate the effect of different tillage regimes on crop yield (wheat and paddy rice) and physicochemical properties of sodic soils. Two sodic sites under conventional tillage for 5 (5‐YT; 5‐year tillage) and 9 (9‐YT; 9‐year tillage) years were selected for this study. Changes in crop yield and physicochemical soil properties were compared with a control, sodic land without any till history, that is, 0‐year tillage/untilled (0‐YT). Five replicated samples at 0‐ to 10‐cm and 10‐ to 20‐cm soils depths were analysed from each site. In the top, 0‐ to 10‐cm soil depth 5‐YT and 9‐YT sites had higher particle density (Pd), porosity, water holding capacity, hydraulic conductivity, organic carbon, total nitrogen (N_t), available nitrogen (N_avail), phosphorus (P_avail) and exchangeable calcium (Exch. Ca⁺⁺) than 0‐YT, whereas bulk density (Bd), C : N ratio and CaCO₃ were significantly lower. Bd, pH, EC and CaCO₃ increased significantly with depth in all the lands, whereas Pd, porosity, water holding capacity, hydraulic conductivity, organic carbon, N_t, N_avail, P_avail and Exch. Ca⁺⁺ decreased. We conclude that continuous tillage and cropping can be useful for physical and chemical restoration of sodic soils. Copyright © 2014 John Wiley & Sons, Ltd.     

Volatilization losses of surface-applied urea nitrogen from Vertisols in the Indian semi-arid tropics

The N loss from Vertisols was estimated by measuring the loss of ¹⁵N-labelled urea N under conditions that promote NH₃ volatilization. Urea granules were placed on the top of 150-mm deep soil columns (Vertisols) collected from three sites with a range in pH, electrical conductivity, and cation exchange capacity. There were two contrasting moisture treatments, one near field capacity (wet) and another with intermittent wetting of the soil surface before allowing the columns to dry (moist-dry). The results indicated that losses were influenced markedly by pH and moisture treatment, being 29.5, 33.5, and 33% from the wet soils and 37, 42, and 40.5% from the moistdry soils with pH values of 7.7, 8.2, and 9.3, respectively. These observations clearly indicate that broadcasting of urea on the surface of Vertisols may cause substantial N losses.     

Effect of nutrients and liming on changes in pH,redox potential,and uptake of iron and manganese by wetland rice in iron-toxic soil

In a greenhouse experiment, the nutrients NPK, NPK + lime, K, and Mn were applied to an iron-toxic soil (Typic Haplastulf). Soil pH and dry matter production were increased and Eh and available Fe in the soil were decreased. Though liming the soil decreased available Fe and Mn and increased pH to the greatest extent, the highest dry matter production was obtained with NPK application. NPK + lime produced a smaller yield than NPK without lime. Though the application of K or Mn alone produced much less dry matter than NPK or NPK + lime, no symptoms of Fe toxicity were observed. We conclude that Fe toxicity can be reduced with a balanced use of fertilizers (NPK or NPK + lime) and its occurrence was mostly due to nutrient stress.     

15N studies on the transfer of legume-fixed nitrogen to associated cereals in intercropping systems

Summary An attempt has been made to estimate quantitatively the amount of N fixed by legume and transferred to the cereal in association in intercropping systems of wheat (Triticum aestivum L.) — gram (Cicer arietinum L.) and maize (Zea mays L.) —cowpea (Vigna unguiculate L.) by labelling soil and fertilizer nitrogen with ¹⁵N. The intercropped legumes have been found to fix significantly higher amounts of N as compared with legumes in sole cropping if the intercropped cereal-legume received the same dose of fertilizer N as the sole cereal crop. But when half of the dose of the fertilizer N applied to sole cereal crop was received by intercropped plants, the amount of N fixed by legumes in association with cereals was significantly less than that fixed by sole legumes. Under field conditions 28% of the total N uptake by maize (21.2 kg N ha^–1) was of atmospheric origin and was obtained by transfer of fixed N by cowpea grown in association with maize. Under greenhouse conditions gram and summer and monsoon season cowpea have been found to contribute 14%–20%, 16% and 32% of the total N uptake by associated wheat and summer and monsoon maize crops, respectively. Inoculation of cowpea seeds with Rhizobium increased both the amount of N fixed by cowpea and transferred to maize in intercropping system.     

Growth potential and biocide tolerance of non-heterocystous filamentous cyanobacterial isolates from rice fields of Uttar Pradesh, India

Twenty-eight non-heterocystous filamentous cyanobacterial strains were isolated from different locations in the rice fields of Uttar Pradesh. These strains belonged to seven genera, namely Pseudanabaena, Limnothrix, Phormidium, Microcoleus, Plectonema, Lyngbya and Oscillatoria. A wide variation was observed in these strains with respect to dry weight, generation time and tolerance to biocides. Lyngbya palmarum and Oscillatoria acuminata showed maximum biomass (dry weight), while Pseudanabaena frigidum, Phormidium foveolarum, O. acuminata, Lyngbya palmarum and Lyngbya spiralis showed a significantly shorter generation time as compared to other strains studied. An interesting feature observed was that these non-heterocystous filamentous cyanobacteria possessed a remarkable tolerance to the biocides 2,4-dichlorophenoxyacetic acid, Malathion and Dimecron, at doses much higher than those recommended for rice crops.     

Immunization of neonatal bovines against Theileria annulata by an infection and treatment method

Sixty three cross-bred (Bos taurus X Bos indicus) 4-5-day-old calves were divided into 16 groups (A-P). Each calf in Groups A and B was given ground-up-tick supernate prepared from Theileria annulata-infected or non-infected Hyalomma anatolicum anatolicum (GUTS) equivalent to 5 ticks (50 infected acini). Groups D and E received infected GUTS equivalent to 2 ticks (20 infected acini) and Groups G and H were given infected GUTS equivalent to 1 tick (10 infected acini). Each calf in Groups J, K and L received infected GUTS equivalent to 5 infected acini (0.035 tick), and Group O was inoculated with non-infected GUTS equivalent to 5 ticks. Each calf in Groups A, D, G, J, K and O was also given a single intramuscular injection of long acting oxytetracycline, 20 mg kg-1 body weight just after inoculation of GUTS. Severe reactions resulted in the death of five of eight, three of eight, five of six, one of five and one of five calves in Groups A, D, G, J and K respectively and all of the calves in Groups B, E, H, and L. The surviving calves of Groups A, D, G, J, K and O were challenged on Day 45 post-immunization along with freshly introduced susceptible control calves of Groups C, F, I, M, N and P. All the calves of Groups A, G, J and K withstood the challenge dose; in Group D four of five and in Groups C, F, I, M, N, O, and P all the calves died of theileriosis. It is concluded that though the infection and treatment method of immunization may be used for neonatal bovines, the dose of immunogen should be based on actual counts of infected salivary acini of ticks instead of the number of ticks.     

The effect of inoculum size and betamethasone treatment on the course of infection with Dictyocaulus filaria in lambs

The effect of Betamethasone treatment on faecal larval production in lambs infected with Dictyocaulus filaria was studied. Four-to-six-month-old male lambs were infected with D. filaria at a dose of 75 larvae per kg body weight (L/kg) and subsequently treated with a total dose of 14 mg of Betamethasone, administered in divided doses, either during the early (day 5–15) or late (day 30–40) stages of infection. Faecal larval yields in treated animals during the period of patency were compared with those of un-treated controls and also with lambs infected with a dose of 150 L/kg.Higher worm establishment, as well as higher percentage survival of infected animals during patency, were associated with infections of 75 L/kg in comparison to 150 L/kg. Treatment with Betamethasone during the early stages of infection resulted in higher worm establishment but similar treatment given during the late stages of infection produced no such effects.The number of larvae per gram of faeces was higher in animals receiving infections of 150 L/kg in comparison to 75 L/kg. Treatment with Betamethasone, whether given during the early or late stages of infection, increased larval output in faeces of infected lambs. However, the output did not reach the levels shown by lambs given infections of 150 L/kg. The total estimated faecal larval yields for the period of patency were higher in the treated animals. The yields were much higher in animals treated during early stages of the infection.     

Echinococcus granulosus in animals in northern India

The prevalence of larval Echinococcus granulosus in buffaloes, sheep and goats and in adult stray and shepherd dogs was studied in northern India. A total of 48.1% of 754 buffaloes, 30.5% of 1215 sheep and 21.0% of 447 goats were found to be infected with this parasite. The prevalence of infection in buffaloes was higher in older animals than in younger animals. The lungs and livers appeared to be the sites of predilection. A high percentage of cysts from buffaloes (71.1%) were sterile, whereas a high percentage (90.0%) of cysts from sheep and goats were fertile. Shepherd dogs showed a higher prevalence of infection than stray dogs and the latter examined near the vicinity of slaughter houses had a higher prevalence of infection than those examined in other parts of the city.