- W. Grünberg (1)
- M. Jawara (1)
- B.G.J. Knols (1)
- A.P. Koets (1)
- Michiel Korthals (1)
- J.J.A. Loon van (1)
- P. Milligan (1)
- Y.T. Qiu (1)
- L. Ravesloot (1)
- R.C. Smallegange (1)
- J. Spitzen (1)
- W. Takken (1)
Effect of dietary phosphorus deprivation on leukocyte function in transition cows
Eisenberg, S.W.F. ; Ravesloot, L. ; Koets, A.P. ; Grünberg, W. - \ 2019
Journal of Dairy Science 102 (2019)2. - ISSN 0022-0302 - p. 1559 - 1570.
hypophosphatemia - immune function - lymphoproliferation test - phagocytosis assay
Phosphorus depletion and hypophosphatemia have been described to hamper immune function in different species, an effect barely studied in dairy cows commonly developing hypophosphatemia in early lactation. Dietary P deprivation in mid lactating dairy cows was associated with a decline of the number of granulocytes and impaired granulocyte survival, whereas the phagocytic activity remained unaffected. The objective of the study reported here was to determine the effect of P deprivation on the leukocyte function of periparturient dairy cows. Eighteen multiparous and late pregnant dairy cows were randomly assigned to either a treatment group that was offered a markedly P-deficient diet or a control group receiving the same ration with adequate P content. The study consisted of a 2-wk acclimation period that was followed by a P deprivation period extending from 4 wk before to 4 wk after parturition and a P repletion period of 2 wk thereafter. Blood samples for leukocyte counts and leukocyte function analysis were obtained at the end of the acclimation period, after 2 wk of P deprivation, within the first week of lactation, at the end of the P depletion period and after 2 wk of dietary P supplementation. Blood samples for biochemical analysis were obtained weekly. Immune function was assessed by means of a phagocytosis assay and a lymphocyte stimulation test. Dietary P deprivation resulted in pronounced and sustained hypophosphatemia. Time effects were observed on the counts of different leukocyte fractions, the relative number of phagocytic granulocytes, the degree of phagocytosis, and the lymphocyte proliferation. Differences between P-deprived and control cows were only identified for the degree of phagocytosis that was lower in P-deprived cows compared with control cows. The correlation and regression analyses, however, revealed positive associations of the plasma phosphate concentration and the granulocyte count, the relative number of phagocytic granulocytes, and the degree of phagocytosis at the end of the dietary P deprivation when P depletion was most severe. The results of the study reported here indicate a mild negative effect of pronounced and sustained hypophosphatemia on the granulocyte count and the phagocytic activity of granulocytes in transition dairy cows. The clinical relevance of this effect for health and productivity of dairy cows remains to be determined.
Gartenbau in den Niederlanden
Balendonck, Jos - \ 2016
|Macht, onmacht, manipulatie
Korthals, Michiel - \ 2009
Attractiveness of MM-X traps baited with human or synthetic odor to mosquitoes (Diptera: Culicidae) in The Gambia
Qiu, Y.T. ; Smallegange, R.C. ; Braak, C.J.F. ter; Spitzen, J. ; Loon, J.J.A. van; Jawara, M. ; Milligan, P. ; Galimard, A.M.S. ; Beek, T.A. van; Knols, B.G.J. ; Takken, W. - \ 2007
Journal of Medical Entomology 44 (2007)6. - ISSN 0022-2585 - p. 970 - 983.
vector anopheles-gambiae - yellow-fever mosquito - aedes-aegypti diptera - host-seeking behavior - human skin emanations - l-lactic acid - carbon-dioxide - malaria mosquito - carboxylic-acids - human sweat
Chemical cues play an important role in the host-seeking behavior of blood-feeding mosquitoes (Diptera: Culicidae). A field study was carried out in The Gambia to investigate the effects of human odor or synthetic odor blends on the attraction of mosquitoes. MM-X traps baited with 16 odor blends to which carbon dioxide (CO2) was added were tested in four sets of experiments. In a second series of experiments, MM-X traps with 14 odor blends without CO2 were tested. A blend of ammonia and L-lactic acid with or without CO2 was used as control odor in series 1 and 2, respectively. Centers for Disease Control and Prevention (CDC) traps were placed in a traditional house and an experimental house to monitor mosquito densities during the experiments. The MM-X traps caught a total number of 196,756 mosquitoes, with the most abundant species belonging to the genera Mansonia (70.6%), Anopheles (17.5%), and Culex (11.5%). The most abundant mosquito species caught by the CDC traps (56,290 in total) belonged to the genera Mansonia (59.4%), Anopheles (16.0% An. gambiae s.l. Giles, and 11.3% An. ziemanni Grünberg), and Culex (11.6%). MM-X traps baited with synthetic blends were in many cases more attractive than MM-X traps baited with human odors. Addition of CO2 to synthetic odors substantially increased the catch of all mosquito species in the MM-X traps. A blend of ammonia + L-lactic acid + CO2 + 3-methylbutanoic acid was the most attractive odor for most mosquito species. The candidate odor blend shows the potential to enhance trap collections so that traps will provide better surveillance and possible control.