Model 1261

For cumulative food intake, mice that received the same AAV were housed 4 mice/cage, and the amounts of diet consumed each week were recorded. Broken up food crumbs that fell onto the cage bottoms were recovered, weighed, and subtracted from the food intake calculation to increase accuracy of the measurement. In a separate experiment, after 5-week diet feeding, before differences in body weight appeared, mice were individually housed for 48 h during which body weights and food weights were recorded at time 0, 24, and 48 h. Broken up food crumbs were recovered and subtracted from the food consumption calculation. Feces were collected and weighed at the end of 48 h. Energy content of food and feces was determined using a bomb calorimeter (Model 1261, Parr Instruments, Moline, IL) as previously described^{112 (link)}. Samples were dried and the energy content of the dried samples were measured in duplicate and then averaged. Net energy intake of each mouse, expressed as kcal/day), was calculated as [daily food consumption (g/day)* energy content of diet (4.782 kcal/g)] − [fecal weight (g/day)* energy content of feces (kcal/g)].

Three birds per pen were transferred to metabolic cage to conduct the trial in nutrient digestibility. The chickens were fed diets with chromic oxide (0.25%) added for the last 10 days (adaptive and collective periods) of each phase to determine the apparent total tract digestibility of dry matter (DM), gross energy (GE), crude protein (CP) and Cu. The excreta samples per replicate were collected into stainless steel trays and then dried in a forced-air oven at 60°C for 72 hours, grounded in a Wiley Mill (Thomas Model 4 Wiley Mill; Thomas Scientific, Swedesboro, NJ, USA) using a 1-mm screen, and used for chemical analysis. Each sample was analyzed in triplicate for DM (Method 930.15) and CP (Method 990.03), according to the methods of AOAC [31 ]. The Cu in the feed, and excreta was determined by inductively coupled plasma emission spectroscopy (ICP) according to the methods of AOAC [31 ]. The GE of the diets and excreta were measured using a bomb calorimeter (Model 1261, Parr Instrument, Molin, IL, USA), and the chromium concentrations were determined with an automated spectrophotometer (Shimadzu, Japan) according to the procedure described by Fenton and Fenton [32 (link)].

Chromic oxide (0.25%) was added into each diet from day 104 to 112 of gestation as an inert indigestible indicator to measure the apparent total tract digestibility (ATTD) of nutrients. Fecal samples were harvested from the floor during the last four days of gestation to measure the ATTD of DM; GE; CP; NDF; and ADF. The samples were mixed within the pen and dried in a forced-air drying oven at 60 °C for 72 h, and ground in a Wiley mill (Thomas Model 4 Wiley Mill, Thomas Scientific, Swedesboro, NJ, USA) using a 1-mm screen and used for chemical analysis. Experimental diets and excreta samples were analyzed in triplicate for DM (Method 930.15), CP (Method 990.03), and ADF (Method 973.18) according to AOAC [50 ]. The gross energy of the diets and feces was measured by a bomb calorimeter (Model 1261, Parr Instrument Co., Moline, IL), and chromium concentrations were determined with an automated spectrophotometer (Jasco V-650, Jasco Corp., Tokyo, Japan) according to the procedure of Fenton and Fenton [51 (link)]. This is an improved method for chromic oxide determination in feed and feces. The NDF was determined gravimetrically with exposure of samples to neutral detergent, amylase, and sodium sulfite, then filtration of samples on a 1.5-µm glass filter.