The Effects of Fertilization and Water Management on Growth and Production of Nile Tilapia in Deep Ponds During the Dry Season

Fertilization guidelines developed for shallow ponds (1 m) with controlled depths were tested in deeper (2.5 m) ponds to determine effectiveness of these guidelines for culture of Nile tilapia Oreochromis niloticus . Twelve ponds of 2.5-m depth were used in four treatments: (A) weekly fertilization with water addition; (B) weekly fertilization without water addition; (C) one early fertilization without water addition; and (D) fertilization frequency dependent on nutrient concentrations, without water addition. Sex-reversed Nile tilapia were stocked at 2 fish/m 2 with an initial weight of 15 g, and harvested after 234 d. Depth of water declined from 2.4 m to 1.6 m over the experiment in ponds without water addition. Fish growth rate was significantly higher in treatments A and B (0.86 g/d), than in other treatments, as was yield (3,830 kg/ha). Treatment C was lowest in growth (0.086 g/d) and yield (168 kg/ha), with treatment D intermediate. Fish growth rates and yields were strongly correlated to manure input ( R 2 = 0.89 and 0.94, respectively), and residuals were not correlated to any physical or chemical variables. Growth and yield in these deep ponds were somewhat lower than those in previous experiments for shallow ponds with regular water inputs. However, stagnant ponds did not accumulate nutrients and metabolites at rates higher than ponds with controlled water depths.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73615/1/j.1749-7345.1998.tb00664.x.pd

Prevalence of rubella serum antibody in autoimmune diseases

INTRODUCTION: The association between infections and autoimmune diseases (AID) has been well described in the medical literature. Several infectious agents have been implicated as inducers of autoimmune responses, such as Parvovirus B19, Epstein-Barr virus, cytomegalovirus, and hepatitis viruses. PATIENTS AND METHODS: We examined 1,173 sera from patients with 14 different AID and 238 sera from geographically matched healthy controls, for evidence of prior infection with rubella. All samples were tested for the presence of serum antibodies against rubella using the Bio-Rad BioPlex 2200 system. RESULTS: As a group, patients with AID had a higher prevalence of IgM anti-rubella antibodies as compared to healthy controls (11.7% versus 5.4%; P = 0.001). The prevalence of IgM anti-rubella antibodies was significantly higher in 5/14 AID, namely in patients with giant cell arteritis (33.3%), primary biliary cirrhosis (24%), antiphospholipid syndrome (20.6%), polymyositis (16%), and inflammatory bowel disease (16%). A similar prevalence of IgM anti-rubella antibodies was detected among controls from different countries. A high prevalence of IgG anti-rubella antibodies was detected among patients with AID (89.9%) and controls. CONCLUSION: The increased prevalence of IgM anti-rubella antibodies in AID suggests a possible role for rubella in the etiopathogenesis of several AID