- - - Department of Animal Sciences, Faculty of Agriculture, Lorestan University, Khorramabad, Iran.
- - - Department of Animal Sciences, Faculty of Agriculture, Lorestan University, Khorramabad, Iran.
- - - Department of Animal Sciences, Faculty of Agriculture, Lorestan University, Khorramabad, Iran.

This ۲ × ۳ factorial experiment aimed to evaluate the single and interactive effects of feed form (pelleted, crumble and mash) and carbon tetrachloride (CCl۴) intoxication on liver function, blood parameters, and certain external body dimensions in broiler chicken up to day ۴۲ of age. The six experimental treatments were examined with a completely randomized block design in six replicates of ۱۳ birds each using ۴۶۸ ۱۰-day old female Arbor Acres (۳۲۰±۱۰g) chicks. For CCl۴ intoxication, birds were intraperitoneally injected with ۰.۵, ۰.۵, and ۰.۷۵ mL/kg body weight CCl۴ in olive oil at a ratio of ۱: ۱, v/v in days ۱۴, ۲۱, and ۲۸ of age. Results indicated that feeding the pelleted diet increased daily weight gain (DWG), liver fat percentage (LFP), and improved feed conversion ratio compared with those received crumble and mash diets (P < ۰.۰۵). The broilers receiving the pelleted diet had a greater breast angle (BrG) than those feeding with the mash diet (P < ۰.۰۵). Exposure to CCl۴ decreased breast width (BrW), breast girth (BrG), and BrA of the treated birds (P < ۰.۰۱). The best multivariate linear model for prediction of liver fat percentage achieved by the Forward modeling approach in SAS involving serum TC, LDL TP, TBIL, LDH, BrA, and ShL with R۲=۰.۳۰۱۱. It was concluded that feeding diets in pelleted form may cause a greater performance loss and liver dysfunction when broiler chickens are fed with contaminated feed resources. Moreover, prediction of LFP using multivariate linear models based on blood constituents and external body measurements could not be convincing as for no model R۲ exceeds ۰.۳۱ likely due to the lack of strong correlation between LFP and the considered predictors.

Fatty liver, Broiler chicken, Feed physical form, Liver fat prediction, Carbon tetrachloride