The effect of poultry litter biochar on pellet quality, one to 21 d broiler performance, digesta viscosity, bone mineralization, and apparent ileal amino acid digestibility

Feeding poultry litter biochar (PLB), a product resulting from litter gasification, could decrease diet cost, maintain broiler growth performance, and decrease land application of manure. Past research observed improved pellet quality and mineral availability with dietary inclusions of 6 to 7% PLB; however, broiler performance was decreased, likely due from toxic-heavy-metal content (e.g., 99 ppm arsenic) and increased digesta viscosity of the particular PLB. The objective of the current study was to assess lower dietary inclusions of PLB, with decreased toxic-heavy-metal content, on descriptive feed manufacture, broiler performance, digesta viscosity, bone mineralization, and apparent ileal amino acid digestibility (AIAAD). Treatments were arranged as a Diet Formulation x Phytase Addition factorial in a randomized complete block design with 8 replications per treatment. Four dietary formulations were produced: positive control (PC) with 0.45% non phytate phosphorus (nPP), negative control with 0.23% nPP, and 2 or 4% PLB with 0.45% nPP. Phytase was either included at 9,500 ftu/kg or withheld. There were 8 treatments total. Contrasts comparing PC and 2 or 4% PLB also were conducted. Diets were pelleted and crumbled prior to feeding. Positive and negative control formulations and phytase addition affected bird performance as expected. Birds fed 2% PLB had increased FCR and birds fed 4% PLB had decreased LWG when compared to PC (P < 0.05). However, these performance deficiencies were corrected with phytase inclusion. Birds fed diets with PLB had similar tibia measures compared to the PC. No significant main effects, interactions, or contrast comparisons were observed for viscosity data. The incorporation of PLB into formulations without phytase increased diet AIAAD of some amino acids relative to the corresponding PC (P < 0.05). A lower toxic-heavy-metal PLB product (e.g., 22 ppm arsenic) provided available minerals and amino acids to diets, but performance similar to PC necessitated the addition of phytase.