Standardized Ileal Digestibility of Protein and Amino Acids in Black Soldier Fly Larvae and Duckweed in Broiler Chickens

Black soldier fly larvae (BSFL) and duckweed are potential alternative feed ingredients for sustainable poultry production. This study aimed to determine the standardized ileal digestibility (SID) of amino acids (AAs) in BSFL, <i>Lemna</i>, and <i>Spirodela</i> compared with soybean meal and rapeseed meal. Six cages of eighteen broiler chickens were allocated to each treatment. The crude protein (CP) content was highest in soybean meal (511 g/kg dry matter; DM), intermediate in BSFL (391 g/kg), and rapeseed meal (335 g/kg DM) and lowest in <i>Lemna</i> (185 g/kg DM) and <i>Spirodela</i> (145 g/kg DM). Ether extract was highest in BSFL (95 g/kg DM), whereas crude fiber was highest in <i>Lemna</i> (109 g/kg DM) and <i>Spirodela</i> (171 g/kg DM). The SID of CP was higher (<i>p</i> < 0.05) in BSFL (89.0%) than in soybean meal (82.3%), rapeseed meal (71.3%), <i>Lemna</i> (70.2%), and <i>Spirodela</i> (44.9%). The SID of all essential amino acids (AAs) was higher (<i>p</i> < 0.05) in <i>Lemna</i> than in <i>Spirodela</i>, but it did not differ from that in rapeseed meal. In conclusion, the high fat content in BSFL can enhance AA digestibility, whereas the use of duckweed may be limited by its fiber fractions, which negatively impact the SID of CP and AAs in broiler chickens.