| Four experiments were conducted to evaluate the nutritional values of corn DDGS in cockerels (Exp.1and2) and its optimum inclusion levels in corn-based or wheat-based layer diets (Exp.3and4). In Exp.1, this study was conducted to evaluate the apparent metabolizable energy (AME) and true metabolizable energy (TME) contents in30sources of corn distillers dried grains with solubles (DDGS) in adult roosters, and establish the prediction equations to estimate the AME and TME value based on its chemical composition and color score. The experiment was conducted with3periods. Ninety-five adult roosters were used in each period, with90being fed the DDGS samples (50g) and5being fasted to estimate basal endogenous energy losses. Results showed that the AME ranged from5.93to12.19MJ/kg, TME ranged from7.28to13.54MJ/kg. Correlations were found between ME and ash content (-0.64, P<0.01) and between ME and yellowness score (P<0.05) of the DDGS samples. Furthermore, the best-fit regression equation for AME content of DDGS based on chemical composition and color score was AME=6.57111+0.51475GE-0.10003NDF+0.13380ADF+0.07057fat-0.57029ash-0.02437L (R2=0.70). The best-fit regression equation for TME content of DDGS was TME=7.92283+0.51475GE-0.10003NDF+0.13380ADF+0.07057fat-0.57029ash-0.02437L (R2=0.70).In Exp.2, this study was conducted to evaluate the apparent amino acid digestibility (AAAD) and true amino acid digestibility (TAAD) contents in30sources of corn distillers dried grains with solubles (DDGS) in adult roosters. The experiment design was same as the experiment1. The results suggested that the bioavailability Lys ranged from0.31%to1.46%, the bioavailability Met ranged from0.32%to0.92%, the range of bioavailability TSAA was0.61%to1.96%. Correlations were found between bioavailability Lys and lightness score and yellowness score (P<0.05) of the DDGS samples. Furthermore, the best-fit regression equation for bioavailability Lys content of DDGS based on0.01142b (R2=0.66)(R2=0.66). The best-fit regression equation for Met content of DDGS was Met=chemical composition and color score was Lys=0.57592-0.04748EE+0.00993L-0.01939a+-0.53401+0.03929CP+0.02773EE+0.00458a-0.00373b (R2=0.44)(R2=0.44).The equation for TSAA was TSAA=-1.46055+0.08833CP+0.03299EE+0.01888NDF-0.04286ADF-0.00734L (R2=0.40). Exp.3was conducted to determine the effect of feeding corn distillers dried grains with solubles (DDGS) in wheat-based diets on egg production and the internal quality of eggs from laying hens. A total of six hundred and seventy-five45-wk-old Jing-hong laying hens (initial BW of1.80±0.1kg) were randomly allotted to3birds per cage with5consecutive cages representing an experimental unit. Five wheat-soybean diets were formulated to contain0,6.05,12.10,18.15or24.20%corn DDGS. The results suggested that no differences in egg production, egg mass, feed intake, feed conversion, body weight change and Haugh unit among DDGS treatments were found. The DDGS diets significantly (p<0.05) affected the egg weight, shell breaking strength, shell thickness and yolk color. A linear change in egg weight, shell breaking strength, shell thickness and yolk color as DDGS levels increased was observed. It was concluded that up to24.20%of DDGS could be included in the wheat-soybean diet without affecting on laying performance, and with no apparent adverse effects on egg quality. Exp.4was conducted to determine the effect of feeding corn distillers dried grains with solubles (DDGS) in corn-based diets on egg production and the internal quality of eggs from laying hens. A total of six hundred and seventy-five45-wk-old Jing-hong laying hens (initial BW of1.80±0.1kg) were randomly allotted to3birds per cage with5consecutive cages representing an experimental unit. Five corn-soybean diets were formulated to contain0,11.25,22.50,33.75or45.00%corn DDGS. The results suggested that, the45.00%DDGS diets significantly (p<0.05) decreased the egg production, egg mass, feed intake, body weight change and significantly (p<0.05) increased feed conversion. The11.25%and45.00%DDGS diets significantly (p<0.05) decreased the egg weight. A linear change in egg production, egg mass, feed conversion, body weight change, shell breaking strength and yolk color as DDGS levels increased was observed. It was concluded that up to33.75%of DDGS could be included in the corn-soybean diet without affecting on laying performance, and with no apparent adverse effects on egg quality. But corn-based diet was contain45.00%corn DDGS significantly decreased laying performance and increase shell breaking strength. |
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