High genetic variation in African indigenous chicken populations provides opportunities for long-term genetic improvement. This study estimated genetic parameters for economic traits based on data derived from a nucleus flock comprising two generations, derived from 40 sires and 200 dams in a line breeding program through mass selection. Body weight (BW) at different weeks was analyzed for 1370 chickens. Similarly, egg performance was evaluated on 473 hens kept for 44 weeks. Genetic parameters were estimated using a multi-trait animal model based on an average information-restricted maximum likelihood (AI-REML) algorithm in WOMBAT software. Body weight showed significant heritability (p < 0.001), ranging from 0.251 for body weight at 8 weeks of age (BW8) to 0.34 for body weight at 16 weeks of age (BW16), indicating a good genetic improvement potential. Egg production traits had low to moderate heritability (0.08–0.37). Positive genetic correlations among growth traits, particularly BW8 and body weight at 12 weeks of age, BW12 (rG = 0.94), suggest shared genetic influences and the possibility of improving multiple traits simultaneously. The genetic correlation between BW16 and the cumulative egg number varied from low and negative (−0.02) in the first two months to high (0.51) in the cumulative egg number over six months, suggesting that heavier birds lay more eggs over time. Our limited dataset based on two generations and pedigree demonstrates that BW16 with egg production has moderate heritability and strong genetic correlations that can lead to genetic progress toward the development of a dual-purpose breed, and this offers a scientific basis for breeders to develop selection indices to develop a dual-purpose breed for smallholder production systems.

This study aims to estimate the heterotic effects (H^e), general combining abilities (GCA), specific combining abilities (SCA), and reciprocal effects (RE) for body weight (BW) in a 4 × 4 full diallel cross involving Improved Horro (H), commercial Sasso (S), Potchefstroom Koekoek (K), and Dz-white feathered (D) chickens. A total of 960 purebred and F1 hybrid chickens were used in this study, comprising sixteen genetic groups. The birds were reared from hatch to 14 weeks (wk) of age in a deep litter floor house partitioned with wire mesh. Chickens of different genotypes were randomly assigned to three pens per genetic group in a completely randomized design. BW measurements were recorded at hatch, 2, 4, 6, 8, 10, 12, and 14 wk of age. Heterosis estimates indicated that crosses between S males with K and D females (including their reciprocal crosses) exhibited the strongest H^e for BW from early to late ages. In contrast, crosses between H males and K females (and their reciprocals) showed positive but low H^e, which increased slightly at later ages. Meanwhile, the cross between K males and D females displayed negative H^e across all ages, whereas its reciprocal cross had low but positive H^e. GCA effects were high (p < 0.0001) among purebreds, which shows the importance of additive gene effects on BW. SCA highly (p < 0.0001) influenced BW at hatch, wk 2, 4, and 10, highlighting the role of non-additive genetic variance at the early age of BW inheritance. RE was generally non-significant except at hatch (p = 0.002), wk 2 (p < 0.0001), and wk 10 (p = 0.036), indicating potential maternal or paternal contributions during these early developmental stages. In conclusion, the results indicated that breeding strategies should prioritize selecting parents with superior GCA to ensure consistent and predictable gains in BW. Furthermore, developing a broiler line from S sires crossed with the K and D dams and H sires with S dam lines should also be considered.

In the present study, effects of crossbreeding on egg production traits were evaluated using a 4 × 4 full diallel cross involving four chicken breeds: Improved Horro (H), Sasso (S), Potchefstroom Koekoek (K), and Dz-white feathered (D). The experiment included 800 chickens in a completely randomized design. Data on egg production traits were collected over 40 weeks (WK). Genotypes exhibited significant variations (P < 0.0001) in age at first egg (AFE), body weight at sexual maturity (BWSM), egg weight at first egg (EWAFE), egg number (EN), hen-housed egg production (HHEP), hen-day egg production (HDEP), and egg mass (EM). Heterosis effects (H^e) varied widely, with positive H^e for BWSM and EM in most crosses, while AFE consistently showed negative H^e. All reciprocal crosses showed positive H^e for EWAFE, while direct crosses had negative values except H × S and H × D. The K × H cross showed the highest H^e for HHEP (26.85 %), HDEP (29.44 %), EM (40.88 %), and EN (28.27 %). The cross D × H also exhibited strong H^e for HHEP (25.16 %) and EN (24.60 %), while K × S ranked second for HDEP (22.60 %) and EM (33.89 %). Reciprocal crosses showed positive H^e for BWSM, EWAFE, HHEP, HDEP, EM, and EN, except AFE. General combining ability (GCA) and specific combining ability (SCA) effects were highly significant (P < 0.0001) for all traits. Reciprocal effects (RE) and maternal effects (M^e) also influenced trait expression. GCA/SCA ratios indicated that non-additive effects influenced AFE, while additive effects influenced EWAFE. Moderate ratios for HHEP, HDEP, EM, and EN suggested a balance between additive and non-additive effects. Optimizing crossbreeding strategies, aligning with synthetic breed development, using a K sire with H and S dams, and a D sire with H dam, is recommended to improve egg production.

In chicken diet with dietary fat, adding plant polyphenols as a natural antioxidant is recommended to enhance the n-3 polyunsaturated fatty acid (n-3 PUFA) content and improve oxidative stability in meat and eggs. However, high plant polyphenol doses could act as a pro-oxidant and interfere with the absorption of n-3 PUFAs. The study aimed to determine the effects of Dodoneae angustifolia (D. angustifolia) polyphenol levels in flaxseed-enriched diets on fatty acid content and oxidative stability in the meat and eggs of Sasso chickens. Chickens received 0, 200, 500, or 800 mg of D. angustifolia extract/kg diet designated as DA0, DA2, DA5, and DA8 treatments, respectively. Results showed that the breast muscle content of docosahexaenoic acid (DHA, C22:6n-3) in 200 and 500 mg extract/kg diet and eicosapentaenoic acid (EPA, C20:5n-3) in 800 mg extract/kg diet increased (p < 0.05) compared to those who did not receive. Feeding D. angustifolia polyphenol levels had no significant effect on egg yolk n-3 PUFA content. However, a decrease (p < 0.05) in egg yolk n-6 PUFAs was observed in hens with an increase in the dose of D. angustifolia polyphenol extract. In breast muscle, feeding on a 500 mg extract/kg diet decreased lipid peroxidation (p < 0.05) compared to the control diet. However, feeding different doses of D. angustifolia extracts had no effect on egg yolk lipid peroxidation.

Ethiopia is a developing nation that could highly benefit from securing food via improved smallholder poultry farming. To support farmer and breeding decisions regarding which chicken strain to use in which Ethiopian environment, G*E analyses for body weight (BW) of growing male and female chickens were conducted. Research questions were (1) if a G*E is present for BW and (2) which strain performs best in which environment in terms of predicted BW. Analyses were performed using predicted BW at four different ages (90, 120, 150, and 180 days) of five strains (Horro, Koekoek, Kuroiler, Sasso-Rhode Island Red (S-RIR), and Sasso) tested in five Ethiopian regions (Addis Ababa, Amhara, Oromia, South Region, and Tigray) that are part of three Agro-Ecological Zones (AEZ) (cool humid, cool sub-humid, and warm semi-arid). The indigenous Horro strain was used as a control group to compare four other introduced tropically adapted strains. The dataset consisted of 999 female and 989 male farm-average BW measurements. G*E was strongly present (p < 0.001) for all combinations of strain and region analyzed. In line with previous research, Sasso was shown to have the highest predicted BW, especially at an early age, followed by Kuroiler. Horro had the lowest predicted BW at most ages and in most regions, potentially due to its young breeding program. The highest predicted BW were observed in Tigray, Oromia, and Amhara regions, which are in the main part of the cool sub-humid AEZ.