In Situ Protein Degradability, In Vitro Ammonia Release and N Solubility of some Feed Ingredients

Nine feed ingredients, viz, rapeseed cake, groundnut cake, sunflower seed cake, cotton seed cake, soybean meal, wheat bran, rice polish, maize gluten and tamarind seed cake were subjected to in situ protein degradability, in vitro ammonia release and N solubility determination. The effective protein degradability was lowest for maize gluten (28.2%) followedby tamarind seed cake (55.1 %) and highest for GN cake (85.8%). The values for soybean meal, cotton seed cake and rapeseed cake were 60.1, 61.9 and 82.5 per cent, respectively. Accordingly, the umdegraded dietary protein (UDP) value of feeds was highest in maize gluten (35.5%) followed by soybean meal (19.84%), cotton seed cake (14.5%), sunflower cake (8.9%), tamarind seed cake (8.72%), G.N. Cake (6.86%), rapeseed cake (6.39%), wheat bran (6.11%) and rice polish (4.0%), on DM basis. However, N solubility in phosphate buffer was highest in rice polish (54.28%) and lowest in tamarind seed cake (12.5%). In vitro ammonia release as tng/100 ml SRL was highest on cotton seed cake (17.0 mg) and lowest on tamarind seed cake (3.62 mg). TSie correlation coefficient between in vitro N solubility and effective protein degradability by in situ technique was found to be poor (r = 0.41, r 2 = 0.16). Similarly, the correlation between in vitro ammonia release and in situ protein degradability was also not high (r=0.56, r 2 =0.31).