Digestibility of fungi-based protein products fed to broiler chickens

Abstract: Two fungal protein sources (X and Y) grown using wheat-DDGS were used in broiler chicken diet to evaluate the apparent ileal digestibility coefficient (AIDC) of crude (CP) and the amino acids (AA) cysteine, lysine, methionine, threonine as well as the apparent digestibility coefficient (ADC) of dry matter (DM), organic matter (OM) and gross energy (GE). Furthermore, the apparent metabolizable energy (AME), digestible CP and digestible AA in the two the fungal biomasses were evaluated. A total of 280 one-day old Ross 308 broiler chicks were obtained from a local hatchery and randomly allotted to 35 pens in a closed house with controlled climate. Birds were fed a commercial crumbled organic starter diet from day 1 to 10, which was followed by a pelleted growing diet from day 11 to 28. Day 28-35 the chickens were fed experimental diets. A total of seven experimental diets were formulated by replacing 0 %, 10 %, 20 % and 30 % of the finisher diet with one of the two fungi-based potential feedstuffs (X or Y). Each experimental diet was randomly allotted to 5 pens. An indigestible marker, TiO2 was supplemented to each diet at a level of 5g/kg to enable digestibility calculation. Body weight and feed intake were registered during the experiment. Faecal samples were collected on days 33 and 34 and ileal digesta samples were collected on day 35. Litter quality was assessed on day 33. Results showed that AIDCs of CP, cystine, lysine, methionine and threonine in the fungal biomass X were 0.74, 0.68, 0.61, 0.70 and 0.67 respectively and in the fungal biomass Y they were 0.72, 0.60, 0.72, 0.75 and 0.70 respectively. The ADCs of DM, OM and GE in the fungal biomass X were 0.94, 0.94 and 0.78 respectively whereas these values were 0.89, 0.91 and 0.66 respectively in the fungal biomass Y. Digestible CP (g kg−1 as is) in X and Y were 251 and 342 respectively. In the fungal biomass X, digestible cystine, lysine, methionine and threonine were 4.90, 5.01, 4.07 and 7.33 respectively and in Y corresponding values were 4.81, 11.79, 6.39 and 11.69 respectively. The calculated AME in the fungal biomasses X and Y was 14.7 and 16.1 MJ/kg DM respectively. Litter quality was good in all pens and no foot pad lesions were observed even for pens with high inclusion level of X and Y. Our findings suggest that both X and Y are potential sources of protein with good nutritional value and AME in broiler chicken diets.