Biochemical Changes in Freshwater Prawn Macrobrachium rosenbergii During Larval Development

Abstract.— Quantitative changes in the protein, lipid and carbohydrate were studied in the early larval stages of developing freshwater prawn Macrobrachium rosenbergii reared under fed and starved conditions to understand the relative importance of these nutrients in energy metabolism of the growing larvae. Larvae obtained from several females were stocked into three 250-L tanks at a density of 30 larvae/L. The feeding regime consisted of newly hatched Artemia nauplii. Protein was always the major organic constituent followed by lipids and then carbohydrates of both fed and starved larvae. Protein levels of both fed and starved larvae increased during development, suggesting an important role in morphogenesis. The decline of lipid during the larval growth that was more rapid for starved larvae, suggests a probable utilization of lipid as the major metabolic source of energy. Carbohydrates formed less than 5 and 2.4% of the larval dry weight of fed and starved larvae, respectively, suggesting their limited role in larval metabolism.     

Chitosan nanoparticles enhance developmental competence of in vitro-matured porcine oocytes

Oxidative stress is inevitable as it is derived from the handling, culturing, inherent metabolic activities and medium supplementation of embryos. This study was performed to investigate the protective effect of chitosan nanoparticles (CNPs) on oxidative damage in porcine oocytes. For this purpose, cumulus–oocyte complexes (COCs) derived from porcine slaughterhouse ovaries were exposed to different concentrations of CNPs (0, 10, 25 and 50 µg/ml) during in vitro maturation (IVM). Oocytes treated with 25 µg/ml CNPs showed significantly higher levels of GSH, along with a significant reduction in ROS levels compared to control, CNPs10 and CNPs50 groups. In parthenogenetic embryo production, the maturation rate was significantly higher in the CNPs25 group than that in the control and all other treated groups. In addition, when compared to the CNPs50 and control groups, CNPs25-treated oocytes showed significantly higher cleavage and blastocyst development rates. The highest concentration of CNPs reduced the total cell number and ratio of ICM: TE cells in parthenogenetic embryos, suggesting that there is a threshold where benefits are lost if exceeded. In cloned embryos, the CNPs25 group, as compared to all other treated groups, showed significantly higher maturation and cleavage rates. Furthermore, the blastocyst development rate in the CNPs25-treated group was significantly higher than that in the CNPs50-treated group, as was the total cell number. Moreover, we found that cloned embryos derived from the CNPs25-treated group showed significantly higher expression levels of Pou5f1, Dppa2, and Ndp52il genes, compared with those of the control and other treated groups. Our results demonstrated that 25 µg/ml CNPs treatment during IVM improves the developmental competence of porcine oocytes by reducing oxidative stress.     

Impacts of Institutional Reforms on Irrigated Agriculture in Pakistan

Poor functioning of theirrigation system in Pakistan has been asource of concern for the last few decades,during which time it has been the subject ofconsiderable external assistance andinternal policy reforms. Consequently, thegovernment of Pakistan introducedinstitutional restructuring in irrigationand drainage subsectors to impartnecessary improvements. Under thesereforms, management at secondary canallevel has recently been handed over to theFarmers Organizations (FOs) of selecteddistributaries in pilot areas. This studywas designed to evaluate a farmer-manageddistributary in southern Punjab. Fieldmeasurements revealed that hydraulicaspects of the irrigation service deliveredby the FO management has been significantlyimproved and as a result highlyproportionate and equitable waterdistribution was observed, particularly atthe tail reaches of the distributary. Dueto effective FO management farmers'interventions to increase the outletdischarge by illegal means has been almosteradicated. As a result of theseimprovements imparted by the FO in systemmanagement, the extent of irrigated area hasincreased on average by 6 to 7%, evenunder severe drought-like conditionsprevailing in the country during recentyears. Further cost recoveries haveincreased by an amount of 14% for summerand 23% for winter growing seasons,respectively, from the irrigated area of thedistributary. Thus experience from Hakra4-R distributary has shown that even underundesirable natural circumstancesIrrigation Management Transfer (IMT) wasquite effective in achieving the keytargets of the institutional reformslaunched at pilot scale in the country.     

A study of water distribution from a branch to distributary canals: A case study of Gugera Branch,Punjab, Pakistan

This study was conducted on Gugera Branch of Lower Chenab Canal, Punjab, Pakistan. Sample distributaries off taking from Gugera Branch were selected for the study. The existing conditions of water distribution among the distributaries were studied. Field data were collected during the whole of 1988. Field observations suggested that the variability at the head of distributaries is much greater than the variability in the Gugera Branch under existing operational practices. The distribution of water among the distributaries is rarely in accordance with design criteria. Some channels get priority over other channels. The annual closure period varied from 17 to 41 days for different channels. The discharge at the head of distributaries remained lower than the standard operational range for 69 to 183 days in a year. The data suggested that a regulating gate at the head of the distributary can reduce discharge variation up to 2.4 times compared with a Karrees System (wooden stop logs used for water regulation). The data indicated that the adjustments in the head gate of a distributary on daily basis can substantially improve discharge conditions at the head of distributary. Rotational schedules are not being followed as per design and need to be improved. Most of the existing head discharge relationships of discharge measuring structures are not reliable. A frequent calibration of these structures is recommended.     

Assessment of Bacterial and Fungal Aerosol in Different Residential Settings

The concentration and size distribution of bacterial and fungal aerosol was studied in 15 houses. The houses were categorized into three types, based on occupant density and number of rooms: single room in shared accommodation (type I), single bedroom flat in three storey buildings (type II) and two or three bedroomed houses (type III). Sampling was undertaken with an Anderson six-stage impactor during the summer of 2007 in the living rooms of all the residential settings. The maximum mean geometric concentration of bacterial (5,036 CFU/m³, ± 2.5, n?=?5) and fungal (2,124 CFU/m³, ± 1.38, n?=?5) aerosol were in housing type III. The minimum levels of indoor culturable bacteria (1,557 CFU/m³, ±1.5, n?=?5) and fungal (925 CFU/m³, ±2.9, n?=?5) spores were observed in housing type I. The differences in terms of total bacterial and fungal concentration were less obvious between housing types I and II as compared to type III. With reference to size distribution, the dominant stages for culturable bacteria in housing types I, II and III were stage 3 (3.3–4.7 μm), stage 1 (7 μm and above) and stage 5 (1.1–2.1 μm), respectively. Whereas the maximum numbers of culturable fungal spores were recovered from stage 2 (4.7–7 µm), in housing type I, and from stage 4 (2.1–3.3 μm) in both type II and III houses. The average geometric mean diameter of bacterial aerosol was largest in type I (4.7 μm), followed by type II (3.89 μm) and III (1.96 μm). Similarly, for fungal spores, type I houses had the highest average mean geometric diameter (4.5 μm), while in types II and III the mean geometric diameter was 3.57 and 3.92 μm, respectively. The results indicate a wide variation in total concentration and size of bioaerosols among different residential settings. The observed differences in the size distributions and concentrations reflect their variable airborne behaviour and, as a result, different risks of respiratory exposure of the occupants to bioaerosols in various residential settings.