Algae in animal production

• In the context of threats to fragile environments, there is a need in animal production to identify alternative feed resources, which are environmentally friendly, but at the same time utilize natural resources efficiently. Algae are autotrophic organisms, which have potentia as food and feed for man and animals. They are rich in protein (50-60%), lipids (2-22%), vitamins and minerals. Amino acid composition of algae is comparable to that of egg protein. In the Bangladesh Livestock Research Institute (BLRI), a method has been developed for culturing algae in a batch operating system, using locally available ingredients. With a mixed algal culture (Chlorella and Scenedesmus), grown in shallow polytene basins, daily yield of algal suspension was 95 tones or 247 kg dry substances per hectare. The estimated cost is about $ 1.25 per ton of algal suspension. The possibility of using this protein rich unicellular algae (Chlorella and Scenedesmus) as cattle feed has been studied. Heifers of indigenous breed consumed algal suspension @ 10% of their liveweight. In comparison to oilcake (0.5 kg/d), algal suspension supplemented to a basal straw diet increased fibre digestibilities (76 v. 81%), growth rate (399 v. 458 g/d) and feed conversion efficiency (10.3 v. 8.6 g DOMI/g LWt. gain). Algal suspension also increased the in sacco 48 h DM degradability (49 v. 53%) and rate of degradation (3.8 v. 4.18%) of rice straw. In another trial with bull calves fed urea-molassesed-straw, supplementation with algal suspension in comparison with pure drinking water improved (p > 0.05) the total microbial N yield (21.67 vs. 18.18 g/d), the efficiency of microbial N production (13.4 vs. 10.7 g/kg DOMR) and reduced the live weight loss (-3 vs. -10 kg in 60 d). It appears that as a supplement to a straw diet, algal suspension somehow created a more favorable environment in the rumen for efficient microbial growth and thus increased nutrients availability to the host.