Performance of Hybrids Produced from the Cross of Marandi with RIR, White PR and CR

This experiment was conducted to evaluate productivity of Iranian native Marandi (MA), White Plymouth Rock (PR), Cornish (CR) as meat types and Rhode Island Red (RIR) as dual purpose breeds and their crosses in 12 breeding combination. No crosses was considered between pure breeds. In meat type crossing, thirty chicks produced (in total 1680 chickens) in three successive hatches and were reared separately up to 56 days of age. Chickens were weighed at third, sixth and eighth week, and feed consumption was also measured. At the end of experiment, one cock and one hen were randomly chosen and slaughtered. In dual purpose type crossing, chicks from crosses were kept at 28 boxes in litter system up to four months of age separately. During this period eight pullets from each box were randomly selected and transferred to individual cages. Traits such as egg numbers and weights, Hugh unit, index and feed intake were measured for six months. The results showed that hybrids from MA with PR or CR had significantly higher body weight, carcass weight, most parts of carcass and feed intake, and lower FCR at the end of 21, 42 and 56 days of age in comparison to pure MA (P<0.05). Significant sex effect was observed for body weight and carcass weight and whole pieces except abdominal fat. The highest and lowest egg production (EP) was for RIR and pure MA, respectively, and EP in hybrids was about 29.84% higher than pure MA. Feed intake, Hugh unit, egg index differed signficaty among the different crosses. Heterosis in MA and PR crossing was negative for all traits except for feed intake in 42 days, percentage of carcass, breast, wing, back and neck and giblet. However, it was positive in MA and CR crossing for all traits except for percentage of breast, giblet and FCR. A negative heterosis was observed in crossing between MA and RIR for all traits except for mean egg weight and feed intake. Crosses MA♂ * PR♀, CR♂ * MA♀ and MA♂ * RIR♀ had superiority to their reciprocals MA♀ * PR♂, CR♀ * MA♂ and MA♀ * RIR♂, respectively.