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.     

Effects of all‐male,mixed‐sex and all‐female freshwater prawn in polyculture with major carps and molas in the fallow rice fields

This study was conducted to evaluate the effects of all‐male, mixed‐sex and all‐female freshwater prawn (Macrobrachium rosenbergii) in a polyculture with major carps (Catla catla and Labeo rohita) and self‐recruiting small fish molas (Amblypharyngodon mola) in the fallow rice fields of Bangladesh. There were three treatments with three replicates. All ponds were stocked with carps and molas plus either all‐male prawns (treatment MP), mixed‐sex prawns (MFP) or all‐female prawns (FP). Prawn, mola, catla and rohu were stocked 20 000, 20 000, 1750 and 750 ha^?1, respectively, in all treatments. The prawns were fed twice daily, starting at 8% body weight and gradually reduced to 3% body weight. The fish were fed in the morning with mustard oil cake and rice bran (1:2 ratios) at 3% body weight. Significantly higher production of prawns (697 kg ha^?1) was obtained in treatment MP, which yielded 34.7% and 56.2% more production than MFP and FP respectively. Significantly higher total production of 1620 kg ha^?1 and a higher benefit–cost ratio of 2.10:1 were also obtained in treatment MP. It can be concluded that an all‐male prawn culture is economically more viable than all‐female and mixed‐sex prawn cultures, along with other fish like major carps and the nutrient‐dense molas in the polyculture.     

Evaluation of freshwater prawn‐small fish culture concurrently with rice in Bangladesh

An integrated aquaculture of freshwater prawn (Macrobrachium rosenbergii) and self‐recruiting small fish mola (Amblypharyngodon mola) was conducted in farmers' rice fields at Mymensingh, Bangladesh. There were four treatments with three replications. Four stocking densities, 10 000, 15 000, 20 000 and 25 000 ha^?1, of freshwater prawn were applied. The stocking density of mola was the same (20 000 ha^?1) in all treatments. During land preparation, triple super phosphate (TSP) and murate of potash (MP) were applied at the rate of 150 and 75 kg ha^?1 respectively. Urea was applied at the rate of 200 kg ha^?1 in equally distributed three installments after 16, 45 and 65 days of rice plantation. Prawns were fed with commercial pelleted feed at 3–8% body weight. All water quality parameters were found to be within the suitable range for freshwater prawn culture. There was a homogenous abundance of plankton communities in all treatments. The results of a 4‐month culture period showed that the average production of prawn ranged from 222 to 388 kg ha^?1, mola 51 to 68 kg ha^?1 and rice 2 880 to 3 710 kg ha^?1. Significantly higher production of both prawn and mola was recorded in the plots where the freshwater prawn stocking density was 15 000 ha^?1. This treatment resulted in a net profit of USD 1100 ha^?1.     

Effects of including catla and tilapia in a freshwater prawn–mola polyculture in a rotational rice–fish culture systems

An on-farm trial was carried out from February to June 2006 to evaluate the growth and production performance of catla ( Catla catla ) and tilapia ( Oreochromis niloticus ) with freshwater prawn ( Macrobrachium rosenbergii ) and mola ( Amblypharyngodon mola ) in farmer's rice fields. In all treatments, 20 000 mola ha⁻¹ and 20 000 prawn ha⁻¹ were stocked. Besides, stocking included 2500 catla ha⁻¹ in treatment-I, 2500 tilapia ha⁻¹ in treatment-II and catla and tilapia at 1250 ha⁻¹ each in treatment-III . Prawns were fed in the evening with pellets at a feeding rate of 3–8% body weight (initially 8% and gradually decreased to 3%). Catla and tilapia were fed in the morning with a paste of mustard oil cake and rice bran at a feeding rate of 3% body weight. Significantly higher combined production of fish and prawn observed was 2142 kg ha⁻¹ in treatment-I. The benefit:cost ratio was found to be significantly higher in treatment-I than in treatment-II and there were no differences between treatments I and III. From the production and economic point of view, treatment-I was found to be the best proposition for the rotational rice–fish culture systems.     

Impact of boron fertilization on boron fractions at different crop growth stages in cauliflower_cowpea_okra sequence in an inceptisols of North East India

Abstract

A field experiment was conducted at Horticultural Experimental Farm, Assam Agricultural University, Jorhat during the year 2015–17 to assess the impact of boron fertilization on dynamics of boron fractions in soil and crop yields in cauliflower–cowpea–okra cropping sequence. Five levels of boron (0, 0.5, 1.0, 1.5 and 2.0?kg ha^?1) along with the recommended dose of NPK fertilizer were applied in soil in cauliflower once in each 2 years (2015–17) of experimentation to assess the direct effect of boron fertilization, while cowpea and okra were grown as a suceeding test crop to study the residual effects of boron fertilization in the cropping sequence. Among the different levels of boron, the highest content of all the boron fractions in soil was recorded at rate of 2?kg B ha^?1 at different crop growth stages for all the three crops. Progressive decrease in content of all the boron fractions with crop ageing was noticed. The content of different boron fractions in soil follows the order readily soluble boron (RSB)<oxide bound boron (OXB)<organic bound boron (ORBB)<specifically adsorbed boron (SAB) <residual boron, respectively. The boron level of 2?kg B ha^?1 was found to prominent in increasing the yield in all the crops. In respect of contributions of different boron fractions to yield of crops, oxide bound boron(2.10) was found to be the highest contributor of cauliflower yield, while the residual boron (1.10), contributed the highest to cowpea yield and organic bound boron fraction (1.24) was found to be most prominent contributor of boron in leveraging okra yield.     

Growth rate and conversion efficiency of the air-breathing catfish, Heteropneustes fossilis, in relation to ration size

Effects of different feeding rates (0–20% live body weight) on food intake, growth and conversion efficiency of Heteropneustes fossilis were studied using the oligochaete worm Tubifex tubifex as food. An amount of worm substance equivalent to 12.73% live body weight/fish day^?1 represents the maximum amount which a 4.015 ± 0.340-g H. fossilis can consume under laboratory conditions. Geometrically derived feeding rations of 12, 40 and 130 mg/g live fish day^?1 represent the maintenance, optimum and maximum levels for H. fossilis. The SDA (specific dynamic action) increased from 14 mg/g day^?1 at optimum to 70 mg/g day^?1 at maximum feeding rate.     

Fishing for health: Do the world’s national policies for fisheries and aquaculture align with those for nutrition?

Aquatic foods are rich in micronutrients essential to human health, and fisheries and aquaculture are increasingly recognized for their capacity to contribute to reducing global micronutrient deficiencies and diet-based health risks. Whether fisheries and aquaculture sector and public health nutrition policies align to meet this goal, however, is unclear. Do fisheries and aquaculture policies have explicit nutrition and public health objectives? Do public health nutrition policies recognize the contribution of aquatic foods? Using content analysis, we assessed the alignment of objectives in national fisheries and public health nutrition policies. We further determined conditions associated with varying levels of cohesion among policies in these sectors or domains. We found that 77 of 158 national fisheries policies identified nutrition as a key objective in the sector, and 68 of 165 public health nutrition policies identified the importance of fish and shellfish consumption as key objectives. More recent policies were associated with improved coherence among sectors. International organization presence in policy development was also associated with greater coherence. Countries with higher overweight prevalence had fisheries and public health nutrition policies that were not aligned. There has been a promising recent trend for improved alignment of objectives between fisheries and public health nutrition policies, but more targeted and systematic policy approaches are needed to realize the potential contribution of nutrient-rich fish and shellfish to healthier food systems.     

Isolation of Listeria monocytogenes from buffaloes with reproductive disorders and its confirmation by polymerase chain reaction

Listeria monocytogenes, a gram-positive, facultative intracellular pathogen was isolated from buffaloes with a history of reproductive disorders and polymerase chain reaction (PCR) analyses for the presence of virulence-associated genes were conducted. A total of 530 samples of faecal, nasal, vaginal swabs and blood samples from 135 buffaloes were screened. The prevalence of L. monocytogenes and other Listeria spp. was found to be 4.4 and 7.4%, respectively. All isolates were subjected to PCR for virulence-associated genes (prfA, plcA, hlyA, actA and iap) and to pathogenicity testing by the phosphatidylinositol phospholipase C (PI-PLC) assay and mice and chick-embryo inoculation. All L. monocytogenes isolates were hemolytic and positive for the hlyA gene. One L. monocytogenes isolate possessed all five virulence-associated genes and was also positive in the PI-PLC assay as well as in the in vivo pathogenicity tests. The remaining hemolytic L. monocytogenes isolates lacking the plcA gene and PI-PLC assay activity were, however, non-pathogenic via mice and chick-embryo inoculation tests, in spite of having the hlyA gene. The detection of multiple virulence-associated genes, in combination with in vitro pathogenicity tests, must be performed to identify pathogenic L. monocytogenes.     

Potential of mixed culture of freshwater prawn (Macrobrachium rosenbergii) and self-recruiting small species mola (Amblypharyngodon mola) in rotational rice–fish/prawn culture systems in Bangladesh

The effects of different stocking densities of freshwater prawn (Macrobrachium rosenbergii) on its growth and production in relation to the presence of small self‐recruiting species mola (Amblypharyngodon mola) were investigated in modified rice fields after rice harvest at Mymensingh, Bangladesh. Keeping the stocking density of mola fixed at 20 000 ha^?1 in each treatment, four densities of freshwater prawn (treatments) were maintained: 10 000, 15 000, 20 000 and 25 000 ha^?1 respectively. The rice plots were limed (CaCO₃) and fertilized with urea, triple super phosphate and cowdung regularly. The prawns were fed daily with commercial pellets. Water quality parameters such as temperature, dissolved oxygen, transparency, pH, total alkalinity, inorganic nitrogen (nitrate, nitrite and total ammonia), chlorophyll a and orthophosphate were determined fortnightly. Numerical analysis of plankton communities was performed monthly. All water quality parameters were found to be within the suitable range for freshwater prawn culture, except high temperature, in the peak summer months. There was a homogenous abundance of plankton communities in all treatments throughout the experimental period. Mola started to breed in the second month of the original stocking with partial harvesting after the second month and continued until the final harvest. The total production of mola ranged between 124 and 152 kg ha^?1 during the 4‐month culture period. The average prawn survival ranged from 49% to 57% without any significant difference among treatments. Freshwater prawn production ranged from 294 to 596 kg ha^?1 with significantly higher production in the treatment where 20 000 ha^?1 freshwater prawn were stocked. This treatment also resulted in a higher net profit margin (74%), indicating that stocking at a combination of 20 000 ha^?1 freshwater prawn and 20 000 ha^?1 mola could be the optimum proposition for prawn–mola culture in modified rain‐fed rice fields after rice cultivation.