It is well established that PRRSV elimination is an effective strategy for PRRS control, but published reports concerning successful PRRSV elimination cases in farrow-to-finishing herds are rare. Here, we have reported a successful PRRSV elimination case in a farrow-to-finish herd by employing a “herd closure and rollover” approach with some modifications. Briefly, the introduction of pigs to the herd was stopped and normal production processes were maintained until the herd reached a PRRSV provisional negative status. During the herd closure, strict biosecurity protocols were implemented to prevent transmission between nursery pigs and sows. In the current case, introducing gilts before herd closure and live PRRSV exposure were skipped. In the 23rd week post-outbreak, the pre-weaning piglets started to show 100% PRRSV negativity in qPCR tests. In the 27th week, nursery and fattening barns fully launched depopulation. In the 28th week, nursery and fattening houses reopened and sentinel gilts were introduced into gestation barns. Sixty days post-sentinel gilt introduction, the sentinel pigs maintained being PRRSV antibody negative, manifesting that the herd matched the standard of the provisional negative status. The production performance of the herd took 5 months to bounce back to normal. Overall, the current study provided additional information for PRRSV elimination in farrow-to-finish pig herds.
High Ni 2+ levels are toxic to plant growth; however, being a micro-nutrient, its application and/or presence in low concentration may improve plant growth. Present study investigated the effects of exogenous Ni application on morpho-physiological attributes of two rice cultivars in China i.e., Yuxiangyouzhan and Meixiangzhan 2. Nickel was applied exogenously to 11 days old seedlings as Ni(NO3)2 in a solution form in the following concentrations: 0.1 mM (Ni1), 0.2 mM (Ni2) and 0.5 mM (Ni3). The seedlings without Ni 2+ application were taken as control. Results showed that exogenous Ni 2+ application improved the early growth of seedlings in terms of seedling length, basal diameter, biomass accumulation and seedling index. Substantial improvements were also observed regarding chl a, chl b, total chl contents and carotenoids in plants under Ni 2+ application compared to CK. Furthermore, all Ni 2+ treatments decreased the content of Malondialdehyde (MDA). Among all applied concentrations, Ni2 proved better regarding its promotive effects, however further research is needed to explore the molecular basis of Ni-induced modulations in seedlings of both rice cultivars.
a b s t r a c tOzone aeration may significantly change nitrogen form and availability in anaerobic swine wastewater, hence it is important to characterize the effect of ozone on nitrogen. In order to study the influences of ozone and aeration time on the nitrogen transformation and availability in anaerobic swine wastewater, an indoor experiment was conducted with self-designed ozone producer apparatus under five different durations of ozone aeration, 0, 10, 20, 40 and 60 min, respectively. Water samples were collected in different aeration time and different nitrogen forms were determined. The results showed that different durations of ozone aeration remarkably affected nitrogen contents and formations in wastewater system. Specifically, the content of total nitrogen, soluble Kjeldahl nitrogen, ammonium nitrogen, nitrite nitrogen and particulate organic nitrogen (PON) significantly declined by 10.11%, 6.75%, 17.90%, 98.81% and 89.33% (p < 0.05), respectively. On the contrary, the content of nitrate nitrogen and dissolved organic nitrogen increased by 613.85% and 459.85% at the end of 60 min (p < 0.05), respectively. The results suggested nitrogen form transformation and nutrient concentration change should be taken into consideration before reusing swine wastewater in irrigation.
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