Soxtex system ht 1047 hydrolyzing unit

The tested NCG was determined by an Ion Chromatography, iChrom W5100, Xi'an Heb Biotech Co. Ltd, Shanxi, China). The mixing homogeneity of feed (CV) was determined following the method of ICCF Guidance #3 (ICCF, 2019 ). All chemical analyses of the diets were carried out in duplicate according to AOAC (2006) . The dry matter was analyzed by drying the samples to a constant weight at 105 °C. Crude protein (CP) was determined using a Kjelte 2300 Unit (Foss, Hillerød, Denmark) by the method of Kjeldahl, and the CP content was estimated by multiplying nitrogen by 6.25. Crude lipid was analyzed by acid hydrolysis with a Soxtex System HT 1047 Hydrolyzing Unit (Foss, Hillerød, Denmark), followed by Soxhlet extraction using a Soxtex System 1043 (Foss, Hillerød, Denmark). Ash was analyzed by combustion in a muffle furnace (CWF1100, Carbolite, Derbyshire, UK) at 550 °C for 16 h. Gross energy was determined using an IKAC2000 Calorimeter (IKA, Staufen, Germany). The amino acids of diets were determined by an amino acid analyzer Hitachi 8900 (Tokyo, Japan) after hydrolysis in 6 mol/L HCl for 22 to 24 h at 110 °C. The free amino-acid concentrations in the plasma were analyzed by an automatic amino acid analyzer (S-433D, Sykam, Germany).

All chemical analyses were conducted in duplicate according to AOAC (2006) . The dry matter was measured at 105 °C. Crude protein was analyzed by the method of Kjeldahl (KjeltecTM 2300 Unit, Foss, Hillerød, Denmark), and the crude protein content was calculated by multiplying nitrogen by 6.25. Crude lipid was measured by acid hydrolysis (Soxtex System HT 1047 Hydrolyzing Unit, Foss, Hillerød, Denmark) followed by Soxhlet extraction (Soxtex System 1043, Foss, Hillerød, Denmark). Ash was obtained by burning the samples in a muffle furnace (CWF1100, Carbolite, Derbyshire, UK) at 550 °C for 16 h. The amino acids of the diets and protein materials were measured by using an amino acid analyzer (Hitachi 8900, Tokyo, Japan). The nucleobases in ingredients and feed were both measured following the method of Mydland et al. (2008) with some modifications. The samples were hydrolyzed with perchloric acid (20%) for 60 min at 100 °C. Then, the 5 kinds of nucleobases in the samples were analyzed by a Hitachi Chromaster high-performance liquid chromatography (HPLC) system (Hitachi Co. Ltd., Japan). The total nucleotide content of the samples is calculated, assuming that the molar fraction of each nucleotide is equal to that of its respective nucleobase (Romarheim et al., 2013 ).