Co-inoculation of potassium solubilizing and nitrogen fixing bacteria on solubilization of waste mica and their effect on growth promotion and nutrient acquisition by a forage crop

Waste mica, a potassium-bearing mineral, is a by-product of mica industry; however, its potassium (K)-supplying capacity for crop production is not well understood. A greenhouse trial was made to study the effect of co-inoculation of potassium solubilizing (Bacillus mucilaginosus) and nitrogen (N) fixing (Azotobacter chroococcum A-41) bacteria on solubilization of waste mica (a potassium-bearing mineral) and their effects on growth promotion and nutrient uptake by a forage crop of sudan grass (Sorghum vulgare Pers.) in a Typic Haplustalf. Results revealed that significantly higher biomass accumulation and nutrient acquisition were obtained in all the pots treated with mica and/or bacterial strain as compared to control. Data indicated that co-inoculation of waste mica with B. mucilaginosus and A. chroococcum A-41 resulted in highest biomass production and nutrient acquisition. Co-inoculation of bacterial strains maintained consistently highest amounts of available K and N in soils even at 150 days of crop growth than other treatments. B. mucilaginosus strain was more effective and potent K solubilizer than A. chroococcum A-41. Thus, co-inoculation of potassium solubilizing and nitrogen fixing bacteria to waste mica could be a promising and alternative option for utilizing this potent source as K fertilizer to crops and maintaining greater nutrients availability in soil. Further studies are necessary to see the effects of these bacterial strains on mobilization of potassium-bearing minerals under field conditions.     

Enhanced Erythrocytic Lipid Peroxides and Reduced Plasma Ascorbic Acid,and Alteration in Blood Trace Elements Level in Dairy Cows with Mastitis

Oxidative stress has been associated in several inflammatory conditions and incriminated in the pathogenesis of many diseases. However, little information is available on the status of plasma antioxidant levels, essential components of important antioxidant enzymes such as copper, zinc and selenium in blood, and the end product of oxidative damage to the erythrocytic polyunsaturated fatty acids in inflammatory udder conditions. Blood samples were collected from three groups of dairy cows, with 21 in each group: animals with healthy udder, clinical mastitis, and subclinical mastitis. These animals were randomly selected from a herd on the basis of the California mastitis test, somatic cell count and total bacterial count. The mean plasma ascorbic acid concentration was significantly lower in cows with subclinical (p = 0.004) and clinical mastitis (p = 0.000) and the erythrocytic lipid peroxide levels were significantly (p = 0.000) higher in clinical mastitis as compared to controls. There was a significant decrease in mean blood zinc concentration in subclinical (p = 0.005) and clinical mastitis (p = 0.000), but an increase in mean blood copper level in the clinical mastitis group. It was concluded that the blood antioxidant status declines in inflammatory udder conditions, suggesting that incorporation of antioxidants may help in better management of mastitis in dairy cows.     

Comparative fatty acid profiles of wild and farmed tropical freshwater fish rohu (<Emphasis Type="Italic">Labeo rohita</Emphasis>)

The proximate composition of the whole body and the fatty acid composition of the liver, muscle, eye and brain of wild and cultured rohu (Labeo rohita) were analyzed. The cultured species was found to have significantly (P < 0.05) higher lipid contents than its wild counterpart. The saturated (SFA) and monounsaturated (MUFA) fatty acid contents were significantly higher in the cultured species, whereas the n-6 and n-3 polyunsaturated fatty acid (PUFA) levels were higher in the wild species. Fatty acids C16:0 and C18:1 n-9 were the principal fatty acids of the SFAs and MUFAs, respectively, identified in the analyses. Docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid were the predominant PUFAs in both groups, and all three were found to be present at significantly (P < 0.05) higher levels in the wild species. Erucic acid (C22:1 n-9), which was the predominant fatty acid (30.76%) in the feed, was detected only at low levels in muscle (0.30%), liver (1.04%) and eye (1.28%) of cultured fish tissue.     

Yield characteristics and morphometric relationships of giant freshwater prawn,Macrobrachium rosenbergii (de Man, 1879)

Meat yield of 233 individuals of giant freshwater prawn, Macrobrachium rosenbergii (de Man, 1879), and their morphometric relationships were examined. Morphometric parameters of different length and weight measurements were recorded for both the sexes separately and subjected to analysis. The meat yield of prawns was size and sex dependent with females showing significantly greater (P < 0.05) tail meat yield than males. The tail meat as a body weight percentage ranges from 26.12 to 40.75 and 32.97 to 42.11 in males and females, respectively. Much of the differences in yield are related to the size and weight of the head and claws. The head weight of males was observed to be higher compared to females in all the size classes. Regression slopes of total length versus body weight and total length versus head weight were significantly higher than critical isometric value indicating high positive allometric growth in both the sexes, with males showing significantly higher (P < 0.05) slope than females. The relationship parameters of total length versus tail weight and total length versus tail meat showed a positive allometric growth in females, whereas it is isometry and negative allometry in males. The morphometric relationship of tail length versus all weight measurements showed positive allometry and negative allometry in females and males, respectively.     

Pharmacokinetic Profile of Erythromycin after Intramammary Administration in Lactating Dairy Cows with Specific Mastitis

The pharmacokinetics of erythromycin was studied in five lactating dairy cows following single intramammary infusion of 300 mg erythromycin in each of two quarters per cow with specific mastitis. Levels of erythromycin in plasma and quarter milk samples were measured by agar plate diffusion assay using Micrococcus luteus (ATCC 9341) as the test organism. Erythromycin level in plasma reached a peak concentration value (C _max) of 0.07 ± 0.01 μg/ml at 30 min; thereafter, levels declined gradually to reach 0.05 ± 0.00 μg/ml 12 h post drug administration. The pharmacokinetic profile of the drug revealed mean absorption half life (t _1/2ka) as 0.26 ± 0.05 h. The drug was eliminated slowly with elimination half-life (t _1/2β) of 13.75 ± 0.35 h and elimination rate constant (k _el) of 0.04 ± 0.00 h⁻¹. The volume of distribution based on the zero-time plasma concentration intercept of the least-squares regression line of the elimination phase (V _d(B)) was 0.032 L/kg. The drug crossed to untreated quarters also; mean drug levels of 0.20 ± 0.07, 0.23 ± 0.07, 0.17 ± 0.04, and 0.17 ± 0.04 μg/ml were found at 3, 6, 8 and 12 h, respectively. The mean drug concentration for treated quarters was measured as 22.97 ± 2.31 μg/ml milk at first milking (12 h) following drug infusion. No apparent adverse reaction was seen in cows administered erythromycin. It is concluded that following intramammary infusion erythromycin diffuses readily and extensively in various body fluids and tissues and adequate concentration is maintained in udder tissues for at least 12 h post intramammary administration. Thus, erythromycin may be recommended for local therapy of acute mastitis caused by Gram-positive bacteria in lactating dairy cows.     

Effects of acclimation on chilling tolerance in Asian cultivated and wild rice

Tolerance to low temperature can be enhanced by pre-exposure to low, non-harmful temperatures, a process known as acclimation. The effects of acclimation on chilling tolerance in species from tropical and subtropical regions are not well understood. Therefore, we investigated whether acclimation improved chilling tolerance at the plumule and seedling stages in Asian rice. A comparison of the effect of acclimation between chilling tolerance scores from a tolerant (A58) and a susceptible (W107) strain demonstrated that acclimation enhances chilling tolerance especially in the tolerant strain, indicating that considerable genetic variation in acclimation capacity exists. The genetic variation in chilling tolerance in acclimated plants was investigated using 57 strains derived from cultivated (Oryza sativa L. ssp. japonica and ssp. indica) and wild (O. rufipogon Griff.) rice. The genetic differentiation of the japonica and indica subspecies of cultivated rice with regard to chilling tolerance was more prominent in the presence than in the absence of acclimation. Furthermore, latitudinal clines for chilling tolerance were observed in both acclimated plumules and seedlings of wild rice, whereas without acclimation, a latitudinal cline was observed only at the plumule stage. This suggests that acclimation capacity, as well as intrinsic chilling tolerance, might contribute to local adaptation. QTLs involved in acclimated chilling tolerance at the plumule stage are different from those involved in intrinsic chilling tolerance. The present results indicate that the maximum genetic potential for chilling tolerance is achieved by acclimation, giving cautions for evaluation of genetic resources in rice.