Veterinary Research Communications - Avian polyomavirus (APV) infection, also called as budgerigar fledgling disease (BFD) causes various health problems in many psittacine species which may cause... 相似文献
A 6‐week feeding trial was conducted to determine the effects of varying dietary electrolyte balance (DEB) on growth performance and physiological responses in broiler chicks reared during hot summer months (26.1–37.5 °C). The average minimum and maximum room temperatures recorded from 14 to 42 days of age were 26.1 and 37.5 °C, respectively, with relative humidity ranging from 51% to 55%. Five DEB treatments supplying 0, 50, 150, 250 and 350 (Na++K+–Cl?) mEq/kg of diet were prepared by adding NaHCO3 and/or NH4Cl to basal diet that contained 185 mEq/kg from 1 to 28 days and 172 mEq/kg from 29 to 42 days. These DEB diets were randomly offered to six experimental units of 20 chicks each. Improved 42‐day body weight gain (BWG), feed:gain (F:G) and reduced mortality was noted with DEB 50, 150 and 250 mEq/kg compared to DEB 0 and 350 mEq/kg. A quadratic effect of increasing DEB level was observed on BWG and F:G, whereas the effect was linear for feed intake, water intake and litter moisture. The DEB 50, 150 and 250 maintained better blood pH, pCO2 and HCO3 concentrations during acute heat stress periods than that of 0 and 350. The blood heterophil and lymphocyte percent as well as heterophil:lymphocyte were remained unaffected. The lowest DEB (0 mEq/kg) diet reduced the feed intake and promoted metabolic acidosis. At 350 mEq/kg DEB, water intake and metabolic alkalosis were promoted probably due to high levels of dietary NaHCO3. The study concluded that overall better performance was recorded with DEB 50, 150 and 250 mEq/kg. These results indicated that single optimal DEB value could not be recommended to combat heat stress in broilers. 相似文献
1. The present study investigated the effects of encapsulated benzoic acid (BA) supplementation in broiler feed on performance and gastrointestinal microbiota.
2. Eighty broilers were randomly divided into two groups. Birds in the control group were fed on maize–soybean-based diets. Birds in the treatment group were provided the same diet supplemented with 2 g/kg BA encapsulated in a vegetable oil matrix.
3. At the end of the trial (d 35), pH, bacterial composition and metabolites were determined in the crop, jejunum, ileum and caecum.
4. Growth performance variables and pH were not significantly different.
5. BA concentration decreased rapidly in the proximal gut. However, the treatment diet showed higher BA in the crop, jejunum, ileum and caecum.
6. Total lactate in the crop and D-lactate in the jejunum was higher in the BA treated group. Caecal total and branched chain fatty acids were decreased due to the treatment.
7. Lactobacilli populations were significantly altered by BA supplementation. A trend for increased lactobacilli was observed in the crop, while it became significant in the jejunum and ileum. Lactobacillus species responded differently to the treatment. Four of 5 measured Lactobacillus species, particularly in the ileum, followed the course observed for total lactobacilli; only Lactobacillussalivarius was not modified.
8. Correlation analysis showed that BA modified the intestinal microbiota. Lactobacilli correlated negatively to all studied clostridial clusters and enterobacteria. Clostridial clusters IV and XIVa were significantly increased in the jejunum, whereas only clostridial cluster XIVa was increased in the caecum.
9. Encapsulated BA modified the intestinal microbiota which can lead to the conclusion, that the main beneficial mode of action of BA in the gut appears to be the enhancement of lactic acid bacteria, which in turn may act as a vanguard against pathogens. 相似文献
Journal of Plant Diseases and Protection - The fall armyworm (FAW), an invasive pest of maize, is an emerging threat in Southern Asia after America and Europe. Recently, this notorious pest has... 相似文献
Glycine betaine (GB) is an important organic compound mediating plant responses to environmental stresses. However, despite ample research on this biomolecule, the potential of GB in mitigating the effects of waterlogging in plants has not been established. Therefore, we studied the influence of GB on growth and physiology of tomato plants under waterlogged conditions. Waterlogging reduced plant growth, degraded chlorophyll, and increased concentration of malondialdehyde and hydrogen peroxide that deteriorated membrane integrity. Waterlogging increased catalase and peroxidase activities. Waterlogging increased the concentration of Na and reduced concentrations of K. Reductions in root Ca were also recorded. GB enhanced growth, concentration of chlorophyll and activities of superoxide dismutase, catalase, and peroxidase that in turn protected the plants from oxidative damage. GB decreased Na while increasing leaf and root K and stem and fruit Ca under waterlogging. Waterlogging reduced fruit quality. There was decrease in protein, fat, and total dissolved solids and an increase in fruit moisture, P, and Na in plants under waterlogging. GB enhanced fruit quality largely by improving fruit protein, ash, fat, TDS, and Ca, while it decreased fruit Na. The results of this study suggest the use of GB for commercial production of tomato where waterlogging is likely. 相似文献
Thyroid hormones (THs) are involved in the development of lymphoid organs and regulation of immune function in birds. However, their role as an immune‐modulator in the hyperthyroid state is still debatable. To explore the interrelationship of thyroxine (T4) and the immune system, chicks were divided into three groups. Group I was comprised of control birds, who received the basal diet while group II and III were given diets supplemented with 5 μg and 10 μg thyroxine/kg feed, respectively, from 15 to 28 days of age. Cell‐mediated immune response was evaluated through in vitro abdominal macrophage phagocytosis assay, macrophage nitric oxide (NO) production, heterophil‐to‐lymphocyte (H:L) ratio and delayed‐type hypersensitivity response against phytohemagglutinin (PHA). Humoural immune response was assessed through serum IgG and IgM antibody production against sheep red blood cells (SRBCs) and antibody production against infectious bronchitis virus (IBV). Sampling was carried out at 7, 14 and 21 days of treatment. Results have shown higher levels (p < .001) of circulating T4 in both treatment groups compared to the control group. There was a lower (p< .05) macrophage engulfment percentage, an increase in H:L ratio (p< .001) in treated birds, while their NO production remained higher (p< .05) in thyroxine supplemented groups after bacterial lipopolysaccharide stimulation. The humoural immune response revealed a significant decline (p < .001) in IgG, IgM antibody production against SRBCs but IBV circulating antibodies increased with age. In conclusion, hyperthyroidism has a strong co‐relation with decreased immune performance of birds. 相似文献
A number of 252, 70 week old, single comb white leghorn hens at the end of their first production cycle were divided into two groups: group‐I; molted by fasting and group‐II; by high dietary zinc to obtain the second and third production cycle. Sampling was carried out at 5%, peak and end of the second production cycle and at 5% and peak of the third production cycle. Serum zinc decreased at the peak of the second production cycle, while increased at the 5% of the third production cycle in zinc‐molted group. Serum copper and manganese increased at the 5% and peak of the second production cycle in zinc‐molted group. Egg albumin zinc and copper increased at the 5% and peak of the second as well as third production cycles in zinc‐molted group. Egg albumin manganese increased at 5% during the second production cycle in fasting molted group. Egg yolk zinc increased at the peak of the second production cycle in zinc‐molted group. Egg yolk copper increased at the 5% of second production cycle but decreased during the third production cycle in zinc‐molted group. Egg yolk manganese increased at the 5% and at the end of the second production cycle in zinc molted group. Egg yolk manganese and iron decreased during the third production cycle in zinc‐molted group. Eggshell zinc decreased at the end of the second production cycle in the zinc‐molted group, while eggshell copper increased at the peak of the second as well as third production cycles in fasting molted group. 相似文献
With the aim to select powerful microbial strains to be used for the enhancement of maize yield and resistance to abiotic and biotic stresses, we tested five endophytic bacterial strains previously isolated from maize roots. A range of different laboratory assays in regard to potential plant growth promotion was performed and strains were further evaluated for improving growth of five maize cultivars under axenic and natural soil conditions. Endophytic colonization was an additional component in our selection process as it is of high importance for an inoculant strain to efficiently colonize the plant environment. All strains had the potential to improve maize seedling growth under axenic conditions. Enterobacter sp. strain FD17 showed both the highest growth-promoting activity under axenic conditions as well as colonization capacity. FD17 was therefore selected for further plant tests in a net house, in which two different maize cultivars were grown in large pots until ripening and subjected to outdoor climatic conditions. Results showed that inoculation significantly increased plant biomass, number of leaves plant?1, leaf area, and grain yield up to 39 %, 14 %, 20 %, and 42 %, respectively, as compared to the un-inoculated control. Similarly, inoculation also improved the photochemical efficiency of photosystem II (PSII) of maize plant and reduced the time needed for flowering. We also confirmed that strain FD17 is able to colonize the rhizosphere, roots and stems. Based on rigorous testing, Enterobacter sp. strain FD17 showed the highest potential to promote growth and health of maize grown under natural conditions. This study suggested that in vitro plant growth-promoting traits and potential of maize seedling growth promotion by bacterial endophytes could be used for the selection of potential inoculant strains subjected for further testing as bio-inoculant under field conditions. 相似文献
The performance of seven mutants of mungbean along with parental types was studied at 41 different sites in three summer crop seasons from 1980 to 1982. The performance of mutants was also studied in spring in the fallow period preceding cotton, and in early summer in the fallow period between wheat harvest and rice/maize planting, to assess their suitability of growing as a catch-crop in these fallows.
The mutants yielded significantly higher and matured 2–4 weeks earlier than parental types, leaving sufficient time to sow the succeeding crops. The mutants were characteristically short-statured, and superior to their parents with respect to number of pods per plant, seed weight, harvest index and productivity per day, but similar in numbers of seeds per pod and seed protein content.
The stability of yield was estimated through regression analysis. Significant genotypic differences were observed among mutants and varieties. Some mutants were widely adapted whereas others performed better in favourable environments. The parental types tended to respond well under poor environments.
Owing to their higher yield potential, early and uniform maturity, and wide adaptability, four mutants were approved as commercial varieties in 1986. These mutants yield 30–50% higher than the parents, mature in 55–70 days, and are suited to both summer and spring crop seasons. Of these four mutants, two can be grown in the fallow period between wheat harvest and rice/maize planting. Because of their determinate plant type, non-shattering pod and top fruit-bearing habit, these mutants are also amenable to intercropping practices and mechanised harvesting operations.
The role of induced mutations for the improvement of mungbean is discussed. 相似文献
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