COMPARATIVE PERFORMANCE EVALUATION OF KOEKOEK, UNIMPROVED LOCAL, COSMOPOLITAN, IMPROVED HORRO AND THEIR F1 CROSSBRED CHICKENS IN DRY AREA OF ETHIOPIA

Abstract

The main objective of this PhD study was to evaluate the performance of Cosmopolitan (C), Improved Horro (H), and reciprocal between them (HC vs. CH), in reference to Indigenous (L), and Koekoek (KK) genotypes and with equal replications set up for each genotypes. For the study, a total of 1800 eggs were set; and from the hatched chicks 1440 were used for reproductive, productive, and chick and meat quality studies. For chick quality 60 chicks per genotype were used and 1440 (240 per genotype) unsexed chicks were randomely distributed to 24 pens and reared to 8 weeks, during which mixed sex growth measurement was taken. At 8 weeks chicken in the pens were identified to male and female. Among the females, 25 per pen (100 female per genotype) were retained in the pen together with five males per pen (20 per genotype and 5female:1male ratio) for body weight change and egg production studies. The male chiken not selected for mating and the remaining females were moved to separate pens and used for meat quality and serum studies. A total of 144, equal number of female and male, were used for meat quality and serum studies, while samples of minced meat from randomly taken 36 (18 per sex; 6 per genotype) carcass were used for fatty acid profile study. A total of 96 and 60 meat samples were used for nutritional composition and sensory characteristics, respectively. A total of 108, 180, and 90 eggs were used for the sensory, nutritional composition, and egg quality tests, respectively. Crossbreeding estimation was exclusively considered for C, H, HC and CH genotypes with equal replication of each trait studied. Economic advantage evaluation was also made for all genotypes set used in the study (live bird, meat and egg). Completely randomized design was used for the study. All data were analyzed following the GLM model using SAS software. Body weight (BW), body weight change (BWC) and daily weight gain (ADG) varied across genotypes at 0, 8, 16 and 24 weeks. BW, BWC and ADG were the highest in KK but the lowest in L than others. Average feed intake (AFI) and feed conversion ratio (FCR) have been the highest in KK, whereas L has the xxi least AFI and FCR to others. Mortality rate (MR) was the lowest for L, while CH had the highest MR than others. Males had higher body weight change (BWC8-24), dailiy weight gain (ADG8-24) and feed intake (AFI8-24) but lower feed conversion ratio (FCR8-24) and mortality rate (MR8-24) compared to females between 8 and 24 weeks of age. Slaughter weight (SW), dressed weight (DW), eviscerated weight (EV), breast weight (BWT), thigh weight (TWT) and drumstick weight (DWT) were affected by genotypes and sexes. SW, DW and EV had been the highest for KK but the lowest for L than others. Males had significantly higher SW, DW and EV than females. Wing, back, Neck, Gizzard, Liver and hear weight varied among genotypes and between sexes. Abdominal fat (AFT) was the highest for KK and the lowest for L compared to HC, CH, C and H. Males had higher AFT than females. The Lightness (L* ), yellowness (b* ), redness (a* ), chroma (C* ), hue angle (h* ), shear force (WBSF) and drip loss (DL) of the meat varied between sexes and genotypes. The meat pH at 45 minutes and 24 hours (pH45 and pH24) had varied between the sexes and across genotypes. Water holding capacity (WHC) was highest for the L and H genotypes, then for HC, C, CH, and KK (P<0.001). The cooking loss (CL) of KK, CH, and C genotypes was considerably (P<0.01) higher than that of HC, H, and L genotypes. The meat WBSF had an inverse and significant correlation with a* and WHC, but a direct correlation with DL, CL, L* , b* , C* , and h * . The overall serum total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL) and high density lipoprotein (HDL) for the chicken genotypes were 156.58±1.93, 128.22±0.75, and 85.03±1.55 and 80.62±1.43 mg/dl, respectively. Male had higher TC, TG, and LDL but lower HDL than female. Unsaturated fatty acid (UFA) contents were higher than saturated fatty acid (SFA) across genotypes and sexes. The crude fat (Fat), crude ash (Ash), crude fiber (CF), and energy contents of the L, H, and HC genotypes were lower than those of the C, CH, and KK genotypes. In comparison to the C, CH, and KK genotypes, the L, H, and HC genotypes showed higher crude protein (CP) and moisture (Mo) levels. Male meats had more energy, fat, ash, and CF than female. Panelists noted that meat tenderness, flavor, appearance, juiciness, and acceptability scores varied by genotype and sex. In terms of tenderness, flavor, appearance, and general acceptability, the meat of the females received higher ratings than that of the males. The Mo, CP, flavor, appearance, and acceptance of chicken meat were positively correlated, whereas the juiciness, fat, energy, Ash, and CF levels were negatively correlated. For egg production performance, Age at first egg (AFE), age at xxii peak (APP), hen day egg production (HDEP), hen housed egg production (HHEP), egg mass (EM) and egg number (EN) varied across genotypes. KK had the highest egg production performance followed by CH, H, HC and C but L had the lowest egg production performance. KK had the highest weight and feed intake followed by HC, CH, and C, whereas L had the lowest followed by H. Feed conversion ratio varied among genotypes. In the panelist test, boiled and scrambled eggs from L, H and C were better preferred followed by CH, HC, and KK. Results showed that KK, HC, CH, and C eggs had higher moisture, crude fat, crude ash, and crude fiber; however, the H and L eggs had significantly lower values. A significantly highest crude protein content of eggs were observed in L, higher in H, intermediate in HC, C, and CH, However, eggs from KK had demonstrated significantly lowest crude protein. Egg quality was significantly affected by genotypes across all traits of eggs except eggshell indices (P>0.05). Among the reproduction traits, H genotype had the highest egg fertility followed by CH. Conversely, C, HC, L and KK genotypes had the least egg fertility. CH had the highest hatchability from fertile egg set, while L had shown the lowest hatchability followed by the intermediate KK, HC and C. Early, mid, late and pipeline embryonic mortality rate was significantly affected by genotypes. Furthermore, chicks hatched from KK had the highest weight and length, but chicks hatched from L had the least weight and length. The results demonstrated that egg production traits like egg mass, hen day egg production, and hen housed egg production, and egg number had positive heterosis. On the other hand, the egg production traits of age at first egg and age at peak egg production showed negative heterosis. From reproduction traits, egg fertility and hatchability from egg set showed negative heterosis, while hatchability from fertile egg set revealed positive heterosis. The estimates of heterosis values for the examined egg quality traits were generally positive, with the exception of the yolk. The estimated direct additive values were significant and positive for most egg quality traits. The estimated direct maternal values were significant and positive for most egg quality traits. H genotype registered the highest net return and cost-benefit ratio (NR1vs. TR1/TC1; NR3 vs.TR3/TC3) compared to other genotypes for live chicken and eggs. KK genotype demonstrated the highest net return and cost-benefit ratio (NR2 vs. TR2/TC2) followed by HC, CH, C and H, whereas L had the lowest NR2 and TR2/TC2 for meat. Generally, the study showed that meat quality was best in the L and H genotypes, then in the HC, C, CH, and KK genotypes. The genotype differences of hens substantially influenced egg xxiii production performance. The reproduction traits were differed across genotypes. L, H, and C had best favored eggs followed by CH and C, by contrast, the eggs from the KK hen genotype were found to be the least favored. Mortality rate (MR) was the lowest for L compared to others. The majority of egg traits favor CH crossbred chickens over HC crossbreds, whereas the majority of growth traits favor HC crossbreds over CH crossbreds. The net return and cost-benefit ratio for live genotypes, meat and egg were notably positive and feasible except L had (for egg case) negative net return and cost-benefit ratio. From the result of the current study, it can be suggested that an investigation of the effects of genotype and sex on fiber structure and composition of meat. Consumption meat and egg from genotypes with higher fat values might have human health problems. It could also be interesting topic for future genetic and dietary studies