Effects of enzyme treated palm kernel expeller on metabolizable energy, growth performance, villus height and digesta viscosity in broiler chickens.

This study examined whether pre-treating palm kernel expeller (PKE) with exogenous enzyme would degrade its fiber content; thus improving its metabolizable energy (ME), growth performance, villus height and digesta viscosity in broiler chickens fed diets containing PKE. Our results showed that enzyme treatment decreased (p<0.05) hemicellulose and cellulose contents of PKE by 26.26 and 32.62%, respectively; and improved true ME (TME) and its nitrogen corrected value (TMEn) by 38% and 33%, respectively, compared to the raw sample. Average daily gain (ADG), feed intake and feed conversion ratio (FCR) of chickens fed on different dietary treatments in the grower period were not significantly different. Although there was no difference in feed intake (p>0.05) among treatment groups in the finisher period, ADG of chickens in the control (PKE-free diet) was higher (p<0.05) than in all treatment groups fed either 20 or 30% PKE, irrespective of with or without enzyme treatment. However, ADG of birds fed with 20% PKE was higher than those fed with 30% PKE. The FCR of chickens in the control was the lowest (2.20) but not significantly different from those fed 20% PKE diets while birds in the 30% PKE diets recorded higher (p>0.05) FCR. The intestinal villus height and crypt depth (duodenum, jejunum and ileum) were not different (p>0.05) among treatments except for duodenal crypt depth. The villus height and crypt depth of birds in enzyme treated PKE diets were higher (p<0.05) than those in the raw PKE groups. Viscosity of the intestinal digesta was not different (p>0.05) among treatments. Results of this study suggest that exogenous enzyme is effective in hydrolyzing the fiber (hemicellulose and cellulose) component and improved the ME values of PKE, however, the above positive effects were not reflected in the growth performance in broiler chickens fed the enzyme treated PKE compared to those received raw PKE. The results suggest that PKE can be included up to 5% in the grower diet and 20% in the finisher diet without any significant negative effect on FCR in broiler chickens.

Evaluation of the activities of concentrated crude mannan-degrading enzymes produced by Aspergillus niger

The mannan-degrading enzymes produced by Aspergillus niger were concentrated and the activities were evaluated. The optimum pH for -mannanase, endoglucanase and -galactosidase were obtained at pH 3.5 while pH optimum for -mannosidase was occurred at pH 3.0. The -mannanase, endoglucanase, -mannosidase and -galactosidase was stable at pH 3.5 to 7, pH 3.5 to 6.5, pH 4 to 7 and pH 3.5 to 5.0, respectively. The enzymes obtained in this study were characterized and defined as acidic proteins. The -mannanases from A. niger had two optimum temperatures (at 50 °C and 60 °C) and its half-life was 6 h and 4 h at 60 °C and 70 °C, respectively. The -mannosidase, endoglucanase and -galactosidase displayed optimal activity at 70 °C, 60 °C and 50 – 60 °C, respectively. The -mannosidase had half-life of 1.5 h at 70 °C, while -galactosidase had a half-life of 2.5 h at 60 °C and endoglucanase had a half-life of 6 h at 60 °C and 45 min at 70 °C.

Biological treatment of fishery washing water using Bacillus sphaericus coupled with production of spores that are toxic to mosquito larvae.

Research was undertaken to investigate the treatment of fishery washing water using Bacillus sphaericus, and to recover the spores for subsequent use as bioinsecticide to control the population of mosquitoes. This treatment method could reduce pollution due to organic matter by decreasing the value of Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) by about 85% and 92%, respectively. The maximum concentration of spores (83.3 x 10(7) spores ml(-1)) using normal concentration of filtered fishery washing water was only about 27% lower than that obtained in fermentation using 0.25% (w/v) yeast extract. The larvicidal activity of the spores produced in fermentation using fishery washing water to Culex quinquefaciatus, as measured by LD50 after 48 h, was almost the same as the larvicidal activity of spores obtained from fermentation using yeast extract.

Kojic acid production by Aspergillus flavus using gelatinized and hydrolyzed sago starch as carbon sources.

Direct conversion of gelatinized sago starch into kojic acid by Aspergillus flavus strain having amylolytic enzymes was carried out at two different scales of submerged batch fermentation in a 250-mL shake flask and in a 50-L stirred-tank fermentor. For comparison, fermentations were also carried out using glucose and glucose hydrolyzate from enzymic hydrolysis of sago starch as carbon sources. During kojic acid fermentation of starch, starch was first hydrolyzed to glucose by the action of alpha-amylase and glucoamylase during active growth phase. The glucose remaining during the production phase (non-growing phase) was then converted to kojic acid. Kojic acid production (23.5 g/L) using 100 g/L sago starch in a shake flask was comparable to fermentation of glucose (31.5 g/L) and glucose hydrolyzate (27.9 g/L) but in the 50-L fermentor was greatly reduced due to non-optimal aeration conditions. Kojic acid production using glucose was higher in the 50-L fermentor than in the shake flask.