Owing to the wide use of feed additives in modern intensive poultry and livestock production, the major components and their concentrations of domestic animal manures may be greatly changed, as compared with those in traditional breeding. An investigation on the 61 samples of chicken, pig and pigeon manures from the intensive poultry and livestock farms of Guangdong Province showed that the concentrations of total N, P and K in chicken and pig manures were obviously higher than those of traditional breeding, and the P/N ratio of three test manures was greater than that of common crops. The concentrations of total soluble salts (TSS) of test manures averaged 49.0, 20.6 and 60.3 g x kg(-1) , respectively, which were mainly composed of the sulfate and chloride of potassium and sodium. The mean concentrations of Cu, Zn and As reached 107.5, 366.6 and 21.6 mg x kg (-1) in chicken manure, 765.1, 1128.0 and 89.3 mg x kg(-1) in pig manure, and 56.1, 210.9 and 2.9 mg x kg(-1) in pigeon manure, respectively. These manures were low in Pb, Cd and Cr contents, from non-detectable to 12.0 mg x kg(-1). According to the limiting criteria of heavy metals in fertilizers, the Cu, Zn and As in the three manures were the major elements exceeding the limits, especially for Zn.
"Increasing demands for products from animal origin have significant consequences on natural recourses like the availability and quality of water, soil, pastures as well as concomitant effects on biodiversity and environmental pollution. Intensive livestock production results in an increased recycling of the minerals N, P and K and heavy metals Cu, Zn and As via faeces back into the environment (Yao and Dang, 2006). These adverse effects of intensive feeding are becoming a worldwide dilemma. "
[Show abstract][Hide abstract] ABSTRACT: Commercialisation of animal agriculture changed the phenotype and production characteristics of livestock. The sigmoidal growth curve and sequence of physiological events remained virtually unchanged, but the rate and extent of these processes increased remarkably. Physiological limits to growth are apparent in species selected for accelerated growth and production, like stress sensitivity, PSE and DFD syndromes in livestock, double-muscled cattle, the callipage gene in sheep, ascites and associated metabolic defects in broilers, leg problems in layers, abortions in Angora goats, wet carcass syndrome in sheep, and other tissue defects as well as reproductive failure due to interactions between the growth hormone cascade, gonadotrophic axis and endocrine factors that regulate metabolism like thyroxin and leptin.Although, the physiology of animals is generally quite forgiving, there are warning lights on the horizon. The challenge in livestock production should shift towards synchronising the best genotypes in a specific environment with the most appropriate and environmentally acceptable technologies available to produce consistently high quality meat. Manipulation of the quality of animal products through feeding, breeding and physiology will become increasingly important, provided that these technologies are practical, economical and do not detract from the intrinsic and extrinsic attributes of animal products, or any other aspect relating to environmentally acceptable or ethical livestock production.
"Peptone is commonly used as nitrogen source for the growth of yeast. Poultry manure as a way of recycling environmental waste has been seen to be efficient as peptone, because of their similar level of yeast growth, and it can also be considered as a better and preferred source of nitrogen because of its abundant availability and the presence of mineral salts like phosphorus, potassium, calcium and magnesium which can as well aid in the growth and development of yeast (Albers et al., 1996; Yao et al., 2006). The optimal growth of yeast as shown by studies is best in the presence of carbon and nitrogen sources; hence, glucose stands as an important carbon source for the growth of yeast with a dual role in biosynthesis, and energy generation and for microbial fermentation processes (Stanbury et al., 1995; Dubai and Muhammad, 2005) which was also confirmed in this experimental design. "
[Show abstract][Hide abstract] ABSTRACT: Cassava is made up of starch as its major nutritive reserve. Starch which is one of the most important products synthesized by plants is consumed as food and can be used in industrial processes. This investigation seeks to explore the availability of cassava as a source of glucose as well as poultry manure as a source of nitrogen in the production of yeast. Cassava flour was hydrolyzed with 0.5% (v/v) concentrated H 2 SO 4 as carbon source for the production of yeast. It was found that pH 6.5 gave optimum yeast growth. Increased concentrations of acid-hydrolyzed cassava and poultry manure extracts led to significant (P < 0.05) increase in yeast biomass after 36 h culture. The residual glucose concentration was also determined and was found to be significantly (P < 0.05) increased with increase in the concentration of poultry manure extract. Therefore, yeast can be produced using acid hydrolyzed cassava flour as carbon source with poultry manure extract as nitrogen source. The methods described in this work can be used in the development of a rapid method of producing glucose and simple sugars from cassava through acid hydrolysis and combining this with poultry manure for yeast production.
[Show abstract][Hide abstract] ABSTRACT: Globally, besides human medicine, an increasing amount of antibiotics as veterinary drugs and feed additives are used annually in many countries with the rapid development of the breeding industry (livestock breeding and aquaculture). As a result, mostly ingested antibiotic doses (30–90%) and their metabolites to humans and animals, as emerging persistent contaminants, were excreted together with urine and feces, and subsequently disseminated into environmental compartments in forms of urban wastewater, biosolids, and manures. More importantly, significant amount of antibiotics and their bioactive metabolites or degradation products were introduced in agro-ecosystems through fertilization and irrigation with antibiotics-polluted manures, biosolids, sewage sludge, sediments, and water. Subsequently, accumulation and transport of antibiotics in soil–crop systems, particularly soil–vegetable systems, e.g., protected vegetable and organic vegetable production systems, poses great risks on crops, soil ecosystem, and quality of groundwater- and plant-based products. The aim of this review is to explore the sources, fates (degradation, adsorption, runoff, leaching, and crop uptake), and ecological risks of antibiotics in agro-ecosystems and possible food security and public health impacts. Three topics were discussed: (1) the occurrence, fates, and ecological impacts of antibiotics in agro-ecosystems, a global agro-ecological issue; (2) the potential ecological risks and public health threat of antibiotic pollution in soil–vegetable system, especially protected vegetable and organic vegetable production systems; and (3) the strategies of reducing the introduction, accumulation, and ecological risks of antibiotics in agro-ecosystems. To summarize, environmental contamination of antibiotics has become increasingly serious worldwide, which poses great risks in agro-ecosystems. Notably, protected vegetable and organic vegetable production systems, as public health closely related agro-ecosystems, are susceptible to antibiotic contamination. Occurrence, fate, and ecotoxicity of antibiotics in agro-ecosystems, therefore, have become most urgent issues among antibiotic environmental problems. Nowadays, source control, including reducing use and lowering environmental release through pretreatments of urban wastes and manures is a feasible way to alleviate negative impacts of antibiotics in agro-ecosystems.
Agronomy for Sustainable Development 04/2011; 32(2). DOI:10.1007/s13593-011-0062-9 · 3.99 Impact Factor
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