Estimation of crossbreeding parameters for growth and feed efficiency traits in exotic chicken breed crosses with Fayoumi under reciprocal mating

A better understanding of genetic parameters is required to evaluate the combining abilities of different genotypes. The current experiment aimed to estimate crossbreeding parameters for body weight (BW), body weight gain (BWG), and feed conversion ratio (FCR) in genetic groups generated through reciprocal mating between Fayoumi (FM) and three other exotic breeds, namely, Koekoek (KK), Sasso (SS), and White Leghorn (WL) at different growth stages. Birds were weighed individually at hatch and every four weeks until 20 weeks, and BWG was determined. The FCR was estimated based on the feed intake of each genetic group. Purebred effect (PE), general combining ability (GCA), maternal effect (ME), specific combining ability (SCA), and heterosis were highly significant for BW, BWG, and FCR at different ages. Purebred SS had the highest PE and GCA for BW and BWG but the lowest estimate for FCR; in some instances, KK showed values slightly closer to SS's. Closely followed by KK, purebred SS had the highest ME for BW. Crosses of FM with WL and KK exhibited the highest SCA for BW and BWG and the lowest value for FCR, whereas reciprocal crosses between FM and KK had positive heterosis for BW and BWG but negative heterosis for FCR. The results generally suggest the importance of additive (PE, GCA, and ME) and non-additive (SCA and heterosis) genetic effects for the inheritance of growth and feed efficiency traits. In crossbreeding programs involving these genetic groups, synthetic breeds with different breed combinations could be developed using genotypes showing the highest additive effects (SS and KK) as male parents and those having the highest non-additive effects (FM x KK, KK x FM, and FM x WL) as female parents

Evaluation of growth performance and feed efficiency in exotic chicken breed crosses involving Fayoumi

This is a preprint article, it offers immediate access but has not been peer reviewed.The present study aimed to investigate the relative performance of crossbreds generated through reciprocal mating of Fayoumi (FM) with Koekoek (KK), Sasso (SS), and White Leghorn (WL), and the purebred parents for growth and feed efficiency traits. Birds were weighed individually at hatch and every four weeks to 20 weeks to determine body weight (BW) and body weight gain (BWG). Feed intake for each genetic group was used to estimate feed conversion ratio (FCR). Results revealed that significant differences (p < 0.001) existed among the genotypes in BW, BWG, and FCR. For these genotypes, SS outperformed all other genotypes throughout the study period. Reciprocal crosses of FM and SS performed better than the remaining seven genotypes, with KK and reciprocal crosses of KK and FM showing intermediate performance, while FM and WL and reciprocal crosses involving them performed least. Mating FM males with SS, KK, and WL produce crossbreds that outperformed their reciprocal crosses, suggesting that FM has a higher combining ability. Thus, females of these genotypes could be crossed with the third breed to generate crossbreds having higher feed efficiency and growth rates. The results also revealed that crossbreds had higher performance than FM and sometimes their other exotic parents. In most instances, reciprocal crosses of FM with KK and WL outperformed both of their parents in the growth and feed efficiency traits. Therefore, these genotypes could be used in any crossbreeding system to exploit the heterotic effects that existed in them, thereby improving the growth and feed efficiency traits