I Higuera Ciapara | PubMed Health

PubMed1998

[Methods for extracting chitin from shrimp shell waste].

Shrimp shell waste obtained from several industrial freezing-purchasing plants of Guaymas, Sonora, Méx., was studied as a source of value-added chitin biopolymers. In part I, the effect of different isolation conditions on the chitin yield and chemical characteristic, was investigated. Protein and mineral matter were removed with alkali and acid treatment respectively. A 2x2x3 factorial a way of a completely randomized design was used in order to evaluate the effect of the process variables, namely, NaOH concentration (0.4 and 2%) during the deproteinization and HCl concentration (3 and 5%) carried out at 40, 50 and 60 degrees C. The best processing conditions were desproteinization with 2% NaOH, and demineralization with 5% HCl at 50 degrees C, in terms of final ash and chitin content and yield. In part II, a selection of methods of isolation of chitin and chitosan was studied in order to establish the best conditions for scaling up a process to pilot plant level. The processing conditions were selected from reported methods as well as from those defined in part I. Purity of chitin samples was determined in terms of residual protein, ash and chitin each one to produce high quality chitin (0.00% protein, 0.01% ash, 99.99% chitin) and standard grade chitin (0.00% protein, 0.09% ash, 99.13% chitin). Both products were considered as of adequate quality and their manufacture process could be scaled up by further optimization of the processing conditions.

Analysis of Variance↗

PubMed1992

Amoxycillin in the control of furunculosis in Atlantic salmon parr.

The efficacy of amoxycillin in the control of laboratory induced Aeromonas salmonicida infection in Atlantic salmon parr was investigated. When given in the diet at a dose rate of 80 mg per kg bodyweight it was effective against both a moderate and severe challenge (with mortality rates in untreated groups of 75 per cent and 45 per cent). At 40 mg per kg it was effective against the moderate challenge only. The plasma levels in these regimens were 1.25 micrograms per ml and 0.3 to 0.6 micrograms per ml and the minimum inhibitory concentration of the challenge strain of A salmonicida was 0.6 micrograms per ml. The potential of the Charm radiobioassay system in detecting antibiotic residues in fish tissue was studied. The level of amoxycillin in muscle and bone from fish in mid-treatment at 80 mg per kg was 0.32 micrograms per ml. After a 12 day withdrawal period at 18 degrees C no residue was detected within the 0.005 micrograms per ml limit of this test.

Aeromonas↗