Agricultural Wastes最新文献

Orange peels at 21·2% dry matter were ensiled in airtight containers for 92 days at 26°C. In one experiment in which there was release of gases and seepage, total DM losses reached 33·7 ± 1·98% (9·8% seepage, 23·9% gases). In another experiment, in which only gas was released, DM losses were 26·5 ± 0·04%. The dynamics of gas and seepage release and the chemical changes of stored seepage are described.

Rheological properties of sieved beef-cattle manure slurries having total solids concentrations (TS) ranging from 2.6% to 19.3%, temperatures ranging from 14 to 64°C, and shear rates ranging from about 0·1 to 200 s⁻¹ were measured using a rotational viscometer. A rheological model was proposed and used to describe the slurries' shear stress and shear rate relationship. Equations relating the rheological parameters to the temperature and solids concentration were also obtained.

Broiler poultry droppings (PD) were solid-state fermented with Fusarium and Pleurotus fungi under controlled and room temperature conditions. Fungal fermentation, as well as reducing the crude fibre and available carbohydrates, resulted in the reduction of uric acid from 7·0% in untreated PD to around 1·0%. The various levels (5% to 25%) of untreated (UT), autoclaved (AC) and Pleurotus and Fusarium treated PD were incorporated in isocaloric and isonitrogenous, semi-purified broiler mashes. The ash content in the PD mashes was kept low by reducing by 0·5 kg mineral supplement for each 5·0 kg addition of PD in 100 kg of mash. Compared with the control, semi-purified, diet, the 6-week growth rate was retarded when the UT, Pleurotus and Fusarium treated PD levels in the mashes were raised above 15% and 20%, respectively. The reduced growth rate with the increased levels of untreated PD was primarily attributed to high uric acid and crude fibre contents. The total protein efficiency, with respect to extracted groundnut cake, was 42·8%, 51·6% and 53·0% to 55·0% for UT, AC and Pleurotus and Fusarium treated PD. However, the metabbolizable energy (ME) content did not show any appreciable difference. With the practical type broiler mashes containing 15% and 20% UT, AC and Pleurotus and Fusarium treated PD, the 8-week growth rate was similar to that of the control when the ME content in the diets was adjusted to meet the requirement of broilers. However, with the untreated and Pleurotus treated PD mashes containing low ME, the increase in feed intake was associated with a significant (P < 0·05) reduction in the weight gain. It suggested that the PD cannot replace the energy sources in the practical broiler mashes. In conclusion, the results showed that the broiler PD can be recycled in their mashes provided the uric acid below 1% and the required level of ME is maintained in the ration formulations.

Protein-rich (approximately 84%–86%) keratins—epidermal derivatives—have not yet found a wide area of effective application as proteins. This is because of the disulphide bridges of cystine molecules, which make the proteins very rigid and strongly resistant to solubilization and normal enzymatic degradation. The present study was chiefly aimed at breaking up this resistance so as to explore the possibility of utilizing keratins, particularly hair-keratin, as a part of the protein component of animal feeds. The results were encouraging in the sense that human hair could be degraded either by physical or chemico-physical or chemico-enzymatic means and the protein so obtained was found to be good enough to serve as a partial, but effective, supplement supporting the growth of rats. The PER values ranged from 1·49 to 2·20 and the NPR values indicated that all the test diets were at par in maintaining the growth of either sex.

Rice straw was treated with 4% urea (w/w) dissolved in water to result in straw to water ratios of 1:1, 1:0·3 and 1:0·1. The methods of urea solution application were: uniform mixing of straw and solution, mixing of 10% of the straw with solution stacking the rest of the straw above this and adding urea solution on to straw after stacking. Assessments were based on the distribution of total nitrogen added, water-soluble and free ammonia nitrogen and IVOMD of the treated material.

When urea solution was uniformly mixed with straw the total nitrogen, water-soluble NH₃-N and IVOMD of the straw treated with a straw to water ratio of 1:1 or 1:0·3 were not significantly different (IVOMD values, 52% and 53%). Water at 1:0·1 resulted in significantly lower (P < 0·01) N contents and IVOMD values.

Addition of urea solution on to stacked straw or mixing of solution with a limited quantity of straw resulted in N and digestibility gradients within the stack.