The effect of date pits (DP) in diet of broiler chickens on performance, carcass characteristics and blood parameters was studied. A total of 192 day-old commercial broiler chickens were assigned randomly to four experimental diets containing 0, 10, 20, and 30% of DP kg(1 dry matter. All diets were isonitrogenous and isocaloric, and formulated according to nutrient requirements of poultry. The birds and feed of each treatment were weighted weekly. At 6 weeks of age, bleeding from cardiac puncture performed for serum biochemical analyses. DP significantly decreased final weight, average daily gain and feed consumption (p B0.05). Additionally 20 and 30% of date fibre caused a significant increase in the feed conversion ratio. DP caused a significant decrease in thigh and increase in heart weight, as percent of dressed weight, but had no significant effect on dressed weight and kitchen carcass weight, and percentage of breast, gizzard and liver. However, there was significant difference (p B0.05) in heart and thigh percentage between treatments. The diets had no significant effect on blood parameters including cholesterol, triglycerides, high density lipoprotein, low density lipoprotein and very low density lipoprotein (p!0.05). Blood glucose of birds fed diet containing 20% DP was significantly more than control diet (p B 0.05), but there was no significant difference with diet containing 30% DP (p !0.05). DP could provide a cheap source of feed to birds and using 10% had no negative effects on performance, carcass characteristics and blood parameters.
This study compared four nonlinear models to describe growth parameters of broiler chicken fed on different levels of corn bran. Two experiments were designed for this purpose. In the first experiment, 80 chickens (308 Ross strain) that had been fed on the same diet and weighed separately were used to determine the best model. Indicators of R 2 , ACI and the number of circulation of the model were used to confirm the best model. In the second experiment, 300 one-day-old Ross 308 broiler chickens were used in a completely randomized design with four treatments and five replicates. The treatments included control and diets contained 2.5, 5 and 7.5% corn bran. Results showed that the Gompertz function had the highest R 2 and the lowest AIC and number of iterations. So, the Gompertz model best described the broiler growth curves. R 2 , AIC values and number of iterations of the Gompertz model were 0.9970, 648 and 5, respectively. Different levels of corn bran significantly affected mature body weight (W f ) and body weight at the inflection point (W i ) (P<0.05), but did not affect the initial body weight (W 0 ), inflection point (T i ) and coefficient of relative growth (b) (P>0.05). Additionally, corn bran significantly decreased the growth rate on days 21, 28, 35 and 42 (P<0.05), but had no significant effect on the growth rate on days 7 and 14 (P>0.05). Overall, the results showed that the Gompertz model described the biological curves of broiler fed on corn bran better than other models. Also, growth parameters were affected by corn bran.
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