Structure—activity relationships for some organotin molluscicides

Bioassay data are reported for 12 organotin compounds, R₃SnX, against the adult snail, Biomphalaria glabrata, an intermediate host of schistosomiasis. The relationship between the molluscicidal activity and the nature of the R and X groups in the organotin compounds is discussed, as well as the possible mode of toxic action of these compounds.     

Comparative study of different surface decontaminants on chicken quality

(1) A comparative study on the effect of different surface decontaminants: hot water at 70 degrees C for one minute; 2% lactic acid for 30 s; 1200 p.p.m. acidified sodium chlorite (ASC) solution for 5 s and 50 p.p.m. chlorine solution for 5 min in the form of dips and sprays on the surface of dressed broilers for 0, 24 and 48 h of storage was conducted. (2) The variables studied were, total plate count (TPC), presumptive coliform count (PCC), pH and extract release volume (ERV). All treatments reduced TPC and PCC. (3) Lactic acid dip and hot water dip were the most effective for reducing TPC (1.36 and 1.28 log/cm2, respectively) with no significant difference between them. (4) ASC and hot water in dip could diminish PCC (1.37 and 1.34 log/cm2, respectively) and did not vary significantly. (5) No treatment affected muscle pH, water holding capacity (WHC), ERV, appearance, smell, tenderness and overall acceptability of treated broilers significantly. (6) Hot water treatment is the cheapest, most convenient and simplest decontamination technique for hygienic and wholesome poultry production.     

Detection of Pasteurella multocida isolates from local pigs of India by polymerase chain reaction and their antibiogram

Pasteurella multocida has been recognized as an important veterinary pathogen for over a century. Conventional methods for diagnosis of pasteurellosis rely on the detection of the organism by microscopy and its isolation and identification. However, as far as pasteurellosis is concerned, it is not just sufficient to know the identity of the organism. To constitute effective control measures, it is important to know the serotype of the organism. A study was undertaken to characterize the Pasteurella isolates from local pigs in India with clinical respiratory disease by determination of their capsule types and presence or absence of toxin gene. Pasteurella could be isolated from 66.70% of pigs with clinical respiratory disease. All the isolates were confirmed through biochemical characterization and P. multocida-specific polymerase chain reaction. It has also been observed that all the isolates belonged to capsular type D. All the isolates were sensitive to chloramphenicol, chlortetracycline, doxycycline, and enrofloxacin, while the rest of the antibiotics were less effective. It has also been observed that all isolates were resistant to cephalexin, penicillin G, and sulphadiazine. The study revealed the detection of P. multocida serotype D from clinical respiratory diseases of local pigs of India, which could be one of the important respiratory tract pathogens responsible for mortality of local pigs in India.     

Density and nitrogen effects on interference and economic threshold of common lambsquarters in wheat

Common lambsquarters (CL) constitutes about 50 % of the total weed population in many wheat fields of the northern and central India. It causes considerable wheat yield losses. Its interference is highly influenced by nitrogen (N). Information on its density effect in response to N, and economic threshold (ET) will be useful for its effective management. This experiment was designed to evaluate and compare the interference of CL in response to N with that of natural weed infestations; and to determine its ET in wheat. It was observed that the natural weed infestation including CL, and a pure stand of 128 CL plants/m² were more competitive, causing greater reductions in wheat growth and yield than other CL densities. In the absence of CL, the natural weed infestation was less competitive. The natural weed infestation including CL, and the pure stand densities of 128 and 64 CL/m² inflicted more yield losses at 120 than 60 kg N/ha. But, at lower densities up to 32 CL/m², increasing N levels favoured wheat more, resulting in greater crop-weed balance at 120 than at 60 kg N/ha. The ET, 6–7 CL/m², would help in making decisions for CL management and fitting models. It can be approximated for other similar locations. This ET takes several production factors into account and would be more economical than what was determined based on only yield losses. The ET-based control would reduce future CL/weed populations by preventing seed bank build-up in soil, and rationalize herbicide use through tailoring of doses.     

Feed consumption,diet digestibility and mineral utilization in captive blackbuck (Antelope cervicapra) fed different levels of concentrates

A feeding trial was conducted to know the level of concentrates in the diet of Antelope cervicapra at which diet digestibility and mineral utilization were optimum. Fifteen blackbucks (25–33 kg BW) were distributed into three groups of five each. Fresh oat (Avena sativa) and berseem (Trifolium alexandrinum) fodders were offered ad libitum to all the animals. In addition, animals in groups II and III received concentrate mixture at the rate of 0.5 and 1% of BW, whereas animals in group I received no concentrates. As the level of concentrates increased, consumption of fodder decreased resulting in decreased consumption of neutral detergent fibre (NDFom), acid detergent fibre (ADFom), hemicellulose and cellulose. However, overall total dry matter (DM) and organic matter (OM) intake was not significantly different between the groups. Digestibility of DM, OM and gross energy (GE) increased while that of NDFom and ADFom decreased with increased level of concentrates in the diet. Intake of P, Zn, Cu and Mn increased with increased level of concentrate supplementation; however, consumption of Ca and Fe followed the reverse trend. Absorption of P and Zn increased with increased level of concentrate supplementation. Serum concentration of Zn increased when concentrate was supplemented at the rate of 0.5% BW beyond which there was no further improvement. Increasing the level of concentrates in the diet was resulted in increased serum glucose and cholesterol levels. Forage‐only diet was inadequate in supply of energy, P and zinc. Supplementation of concentrates at the rate of 0.5% BW was able to meet the requirement of these nutrients. Supplementation at the rate of 1% BW supplied energy and P in excess of requirement. It was concluded that the feeding of concentrates to the captive blackbuck fed forage‐based diets should be restricted to 0.5% of BW.     

Effect of concentration and addition method of glycerol on the quality of cryopreserved mithun (Bos frontalis) spermatozoa

The effect of concentration and addition method of glycerol on the quality of cryopreserved mithun (Bos frontalis) spermatozoa was investigated. Semen samples were collected from five healthy mithun bulls through rectal massage method and cryopreserved in liquid nitrogen. The samples were diluted in Tris–egg yolk–glycerol extender, equilibrated for 4 h at 4 °C and loaded into 0.50‐ml straws. The straws were then frozen in liquid nitrogen vapour for 10 min and finally plunged into liquid nitrogen for storage. The required amount of glycerol was added into the diluted samples either in a single dose (3%, 4%, 5%, 6% or 7%; added at 37 °C immediately before equilibration) or in split doses (5%, 6% or 7%; the total amount was divided into four equal parts, and a part was added at 37 °C immediately before equilibration, and the remaining parts were added subsequently at 1, 2 and 3 h of equilibration at 4 °C). In the single‐dose addition method, following freeze‐thawing, greater (p < 0.05) motility (%) and proportion of live spermatozoa with intact acrosome (LSIA, %) in 5% glycerol (40.6 ± 1.7 and 43.4 ± 1.8 respectively) and lesser (p < 0.05) total morphological abnormalities (%) in 5% (14.1 ± 0.8) and 6% (13.7 ± 1.0) glycerol were observed compared to the other glycerol concentrations. In the split‐dose addition method, following freeze‐thawing, greater (p < 0.05) motility (%) and LSIA proportion (%) were found in 5% (50.2 ± 1.9 and 53.3 ± 1.8 respectively) compared to 6% or 7% glycerol, but the total morphological abnormalities were not different among the glycerol concentrations. In addition, in all the glycerol concentrations, better (p < 0.05) post‐freeze‐thaw motility and LSIA proportions were observed when glycerol was added in split doses compared to a single dose. In conclusion, Tris–egg yolk extender with 5% glycerol added in split doses was found most suitable for cryopreserving mithun sperm.     

Physiological responses of dietary tryptophan fed Labeo rohita to temperature and salinity stress

Two experiments were conducted to elucidate the possible effects of dietary L‐tryptophan (TRP) in Labeo rohita based on growth performance and physio‐biochemical responses. In the experiment I, a 60‐day feeding trial was carried out to elucidate the effects of dietary TRP enrichment on growth performance and physio‐biochemical responses. In the experiment II, the TRP pre‐fed L. rohita, from experiment I, was exposed to temperature and salinity stress to evaluate stress‐mitigating efficacy of TRP. In L. rohita, dietary supplementation of TRP showed significant effect on weight gain percentage and feed conversion ratio but not on blood glucose. A significant increase in RNA content and RNA/DNA ratio upon TRP supplementation was observed and was positively correlated with growth performance. The results of experiment II indicated that weight gain percentage, serum T3 and T4 levels were significantly reduced in groups that were exposed to temperature and salinity stress and fed diets without TRP supplementation. However, dietary supplementation of TRP significantly augmented weight gain percentage in stress‐exposed groups. Tryptophan supplementation helped in bringing back T3 and T4 levels comparable with control. A significant increase in superoxide dismutase, catalase, Adenosine triphosphatase, blood glucose and serum cortisol was observed in temperature‐ and salinity‐exposed groups fed without TRP‐supplemented diets. However, TRP supplementation was found to be effective in restoring the above parameters. The results of these experiments suggest that dietary TRP supplementation augments growth, lowers energy demand and helps in mitigating thermal and salinity stress in L. rohita.     

Studies on bacteriological quality of nainital lake water in different seasons

The total coliform and E. coli load of Nainital lake water in different seasons has been studied. The variation of these organisms with season, rainfall and human activities in the catchment area were observed.     

Effect of efficient pectinolytic bacterial isolates on retting and fibre quality of jute

Four bacterial strains with high balanced polygalacturonase (PG) and pectin lyase (PNL), and xylanase with minimal cellulase activity were used in jute retting. The 16S rDNA analysis revealed that the organisms were: Bacillus sp. L6 (GQ891097), Bacillus pumilus strain EK-17 (GQ891098), B. pumilus strain Geo-03-422 (GQ891103) and B. pumilus strain IK-MB12-518F (GQ891105). The microorganisms in different combinations of consortia showed synergistic effect resulting in increased PG (35.52-46.61 IU/g cell wet weight), PNL (39.79-72.12 U/ml), xylanase (0.705-0.840 μmol/ml/min) and little cellulase (0-0.153 μmol/ml/min) activities. The organisms in different combinations of consortia reduced the retting period from 11 to 13 days as compared to 19 days in the control. Microbial inoculation produced remarkable improvement in jute fibre strength (26.62-28.91 g/tex) and fineness (2.76-2.92 tex) over control. The pH of the post-retting water samples became acidic, and the electrical conductivity (Ec), chemical oxygen demand (COD) and hardness increased. The organisms could be adopted in industrial application for extraction of jute fibre.