Cultivation ofSpirulina in sewage for poultry feed

Abstract

Summary.A method for cultivating Spirulina platensis in domestic raw sewage, coupled with pisciculture and water reclamation in an integrated recycling system, has been standardized. The alga is grown in an indigenously designed open-air pilot production unit consisting of 4 concrete basins with a total surface area of 450 m 2. The harvesting and processing methods are based on simple filtration and sun drying. Extensive bench and field experiments have made it possible to produce pure blooms of African Spirulina in sewage, using sodium bicarbonate and nitrate, and employing a fertilizing schedule which replenishes nitrogen withdrawn from the medium by the alga. Although urea and several ammoniacal nitrogen sources have been tried, the best source of protein-inducing nitrogen for mass cultivation of Spirulina appears to be nitric nitrogen.Maximum long-term yields of 7.3-9.5 g m-2day -1 have been attained during the summer months, but they decrease to about 5 g m-Zday -1 during the winter.The chemical analysis of sewage-grown Spirulina revealed a high content of protein (50-55%) with a well-balanced amino acid spectrum, moderate quantities of carbohydrates and lipids, considerable amounts of pigments and low amounts of nucleic acids, nitrite and nitrosamines. Microbiological analysis of the product has shown that the flora consists mainly of gram-positive, sporeforming bacilli and faecal streptococci; occasionally very low numbers of coliforms are detected. Pathogens, such as Salmonella, Shigella and Vibrio are absent. The material has also been found to be free from pathogenic amoebae, enteroviruses and worm cysts. The results of the chick-feeding tests demonstrate that Spirulina protein can totally replace groundnut cake, the chief source of vegetable protein supplement in starter poultry feeds. In laying hens the alga shows better pigmentation effect on egg yolks than conventional oxycarotenoid sources and can be used as the sole pigmenter to obtain adequately colored yolks for table use or for the bakery industry. The diluted effluent is fed at various flow rates into a 260 m 2 fish pond in which attempts are being made to rear valuable carp. The water from the fish pond shows moderate amounts of dissolved solids and low values of sodium adsorption ratio and can, therefore, be safely utilized for irrigation purposes.

Effect of dietary supplementation of spirulina (Arthrospira platensis) and thyme (Thymus vulgaris) on apparent digestibility and productive performance of growing rabbits

“…In poultry, sewage-grown spirulina was first tested as a replacement for ground nut cake (Saxena et al, 1983) and results were promising because the 6-week weight gain and FI were improved by increasing the level of dietary spirulina inclusion. In another study in weanling pigs (Grinstead et al, 2000), dietary supplementation with 0.2, 0.5 and 2% spirulina (in substitution of soybean meal) showed slight improvements in growth performance and feed efficiency, but only if considering certain phases of the cycle.…”

A Prominent Superfood: Spirulina platensis

“…S. platensis grows naturally in shallow bodies of water and in the presence of an alkaline medium of high salinity [40,41]. The primary component for growing this microalgae is sodium bicarbonate.…”

Influencia de la proporción agua de mar y bicarbonato en la producción de biomasa de Spirulina sp. con iluminación de diodo emisor de luz

“…Medio de Zarrouk ha servido con éxito como medio estándar (ME) para el cultivo de Spirulina durante muchos años (Zarrouk, 1966). En consecuencia, muchos medios han sido desarrollados utilizando agua de mar (Faucher et al, 1979), aguas servidas (Saxena et al, 1982) y efluentes industriales (Tanticharoen et al, 1993). La Spirulina se cultiva mayormente utilizando medios químicamente definidos (Belay y Ota, 1994).…”