No abstract

The nutritional quality of the blue-green alga Spirulina platerisis has been evaluated on the basis of its chemical and amino acid compositions and feeding trials with rats.The protein content of the alga was 58.5%, lysine 4.34 g 100 g-l protein, sulphurcontaining amino acids (methionine and cystine) 2.77 g 100 g-1 protein, and nucleic acids 4%. The true protein digestibility of the alga was found to be 75.5 and its biological value (BV) 68. Supplementation of the alga with methionine (0.2 %) resulted in a significant improvement in the BV and net protein utilisation (NPU), but had no effect on true digestibility (TD). TD, BV and NPU were significantly improved when the alga was supplemented with barley (50% nitrogen from both). In Chad and Mexico the alga has been used for centuries as a food. This together with its low cost of production, makes it a suitable source of high quality protein for use as a feed supplement.

In experiments with growing pigs highly significant correlations between body weight and urinary creatinine (r= 0.98) or creatine (r= 0.95) excretion, were found. Furthermore, creatine made up of 20-25 % total urinary creatininet creatine excretion. Creatinine excreted (expressed as mg kg-1 body weight) was significantly (P< 0.001) higher in heavier pigs (approx. 75 kg) compared to pigs at 25 kg and urinary creatinine as a percentage of total urinary N-excretion was significantly (P < 0.001) lower for pigs of 25 kg than for pigs of 53 and 75 kg, respectively. There was a significant positive correlation (P < 0.001) between N-balance and creatine excretion in 25 kg pigs whereas the opposite was the case for 75 kg pigs.

The protein quality of newly evolved high-yielding Indian varieties of rice, namely, Improved Sabarmati, Pusa 2-21, Jaya and Padma has been evaluated and compared with an old existing popular variety i.e. Basmati-370. All the new varieties were found superior in their limiting amino acid content (lysine, tryptophan and methionine) and the ratio of various fractions of proteins. The animal feeding tests for biological value (BV), true digestibility (TD), net protein utilisation (NPU) and utilisable nitrogen (UN) also showed their superiority over Basmati-370.

The protein quality of common Indian pulses, namely soybean (Glycine max), red gram (Cujunus cujan), green gram (Phuseolus uureus) and black gram (Phuseolus mungo Roxb) has been evaluated with respect to their limiting amino acids (methionine and tryptophan) and the protein fractions. Feeding experiments conducted on wistar albino rats showed a significant improvement in the biological value (BV) on rice-pulse mixed diets as compared to rice alone. However, significant reduction in the true digestibility (TD) of rice-pulse diets was observed when rice was mixed with black gram and red gram.