In the current study, fennel essential oil was used as an antibiotic alternative compared to gentamycin for enhancing the expression of apoptosis genes and antioxidant enzymes in weaned rabbits as well as meat quality and growth performance. The gene expression of the cell lymphoma 2 (BAX and BCL2), caspase3 (CASP3), and glutathione peroxidase (GPX1) were estimated in the liver tissue using qRT-PCR. A total of 45 Moshtohor weaned male rabbits aged four weeks were randomly allocated to control, T1, and T2 treatment groups; each consisted of 15 weaned male rabbits with five replicates. Rabbits in the T1 and T2 groups were orally supplied with 1 mL fennel oil and 1 mL gentamycin, respectively. Weaned rabbits under different treatments showed increased body weight (BW) at 8 and 12 weeks of age and average daily gain (ADG) at 4–8 and 4–12 weeks of age compared to the control group. Compared to the controls, the weaned rabbits supplemented with fennel oil and gentamycin had lower total cholesterol, triglyceride, and MDA. In addition, villus length, mRNA of BAX, BCL2, Casp3, and GPX were increased in the different treatments compared to the control. Furthermore, the meat of these rabbits was less tender, had a lower aerobic plate count (APC), pH, and was brighter and redder in color than the control. Under the conditions of the present study, the supplementation of weaned Moshtohor rabbits with fennel oil as a natural alternative for gentamycin enhanced feed conversion and daily gain through enhancing villus length and mucus thickness. Additionally, fennel essential oil reduces oxidative stress by increasing the antioxidant enzymes.

The potential effects of anthocyanin-rich roselle, Hibiscus sabdariffa L. extract (ARRE) on the growth, carcass traits, intestinal histomorphology, breast muscle composition, blood biochemical parameters, antioxidant activity, and immune status of broiler chickens were evaluated. In the present study, Hibiscus acidified ethanolic extract was reported to have a total anthocyanin content of about 359.3 mg cyanidin 3-glucoside/100 g DW, total polyphenol concentration (TPC) of about 598 mg gallic acid equivalent (GAE)/100 g DW, and total flavonoids (TFs) of about 100 mg quercetin equivalent (QE)/100 g DW. Two-hundred-fifty one-day-old chicks (Ross 308 broiler) (87.85 gm ± 0.32) were randomly allotted to five experimental groups and fed on basal diets supplemented with five levels of ARRE: 0, 50, 100, 200, and 400 mg Kg⁻¹ for 35 days. Dietary ARRE addition did not improve the birds’ growth and carcass traits. Supplemental ARRE increased the n-3 polyunsaturated fatty acids (PUFA) (ω-3) percentage in the breast muscle. Dietary ARRE increased the villous height, and the ARRE100 group raised the villus height to crypt depth ratio. Dietary ARRE increased the immunoexpression of immunoglobulin G (IgG) in the spleen. The serum thyroxine hormone (T4) level was higher in the ARRE200 group. The serum growth hormone level was increased by ARRE addition in a level-dependent manner. According to the broken-line regression analysis, the optimum inclusion level of ARRE was 280 mg Kg⁻¹. All levels of supplemental ARRE decreased the serum triglyceride level. The serum total antioxidant capacity (TAC) was increased in the ARRE100-ARRE400 groups, the serum superoxide dismutase (SOD) level was increased in the ARRE200 group, and the serum malondialdehyde (MDA) level was decreased by increasing the ARRE level. Supplemental ARRE significantly increased the serum levels of lysozymes and IL10. The serum complement 3 (C3) level was increased in ARRE200 and ARRE400 groups. It can be concluded that dietary ARRE addition had many beneficial effects represented by the improvements in the bird’s metabolic functions, blood biochemistry, intestinal morphology, antioxidant activity, immune status, and higher ω-3 content in the breast muscles. However, it had no improving effect on the birds’ growth.

The effect of phenolic-rich onion extract (PROE), as a feed additive, was evaluated on the growth, carcass traits, behavior, welfare, intestinal histology, amino acid ileal digestibility “AID%,” and the immune status of broiler chicks for 35 days. A total number of 400, 1-day-old broiler chicks (45.38 g ± 1.35) were allocated to four different treatments with 10 replicates each (100 chicks/treatment) consisting of: T1, basal diet without additives (control treatment) (PROE0); T2, basal diet + phenolic-rich onion extract (1 g/kg diet) (PROE1); T3, basal diet + phenolic-rich onion extract (2 g/kg diet) (PROE2); and T4, basal diet + phenolic-rich onion extract (3 g/kg diet) (PROE3). An increase in the final body weight “FBW,” bodyweight gain “BWG,” and feed consumption was observed (P < 0.05) at different PROE levels. Also, the thymus and bursa percentages were increased in the PROE2 and PROE3 treatments (P < 0.05). The chicks fed on PROE supplemented diets had increased frequency of feeding and drinking and showed comfortable behavior (P < 0.05) with lesser aggression (P < 0.05). Additionally, an increase was observed in the antioxidant enzyme activity, phagocytic %, phagocytic index, and serum lysozyme activity in PROE supplemented treatments, with the best outcome reported in the PROE3 treatment (P < 0.01). IgM was increased in the birds fed with PROE2 and PROE3 diets (P < 0.01). PROE supplementation increased the AID% of lysine and methionine (P <0.01), PROE3 treatment increased the AID% of threonine (P < 0.05), and PROE2 and PROE3 treatments increased the AID% of leucine and isoleucine (P < 0.05). Besides, PROE2, and PROE3 treatments increased the villus height and width, mucosal thickness, and goblet cell count from the duodena, jejuna, and ilea (P < 0.05) compared to control treatment. Based on these results, we concluded that the dietary addition of phenolic-rich onion extracts can improve the growth rate of broiler chicken by improving the AID% of amino acids and intestinal histology. Also, it can improve the welfare, antioxidant enzymes activity, and immune status of the birds. Phenolic-rich onion extracts can be used as a natural growth promoter in the poultry feed for good health and improved performance.

The current study aimed to replace soybean oil in broiler diets with linseed oil, which is rich in omega-3 fatty acid supplemented with pomegranate peel extract (PPE) and measured its effect on broiler performance, carcass traits, lipid profile, as well as fatty acids composition, phenols and flavonoids content of broiler muscles and immunity of broiler chicks. A total of 300 1-day-old Cobb chicks were randomly allotted into six experimental groups, T1 fed on basal diet with soybean oil without any additives, T2 fed on basal diet with soybean oil with addition of 0.5 g/kg diet PPE, T3 fed on fed on basal diet with soybean oil with addition of 1 g/kg diet PPE, T4 fed on basal diet with linseed oil without any additives, T5 fed on basal diet with linseed oil with addition of 0.5 g/kg diet PPE and T6 fed on basal diet with linseed oil with addition of 1 g/kg diet PPE. The PPE supplementation with 0.05% improved final body weight with either soybean oil ration or linseed oil ration. The PPE improved carcass dressing percentage in comparison with the control groups. Body fat levels decreased with increasing PPE levels, especially with a linseed oil diet. Replacing soybean oil with linseed oil decreased the total cholesterol and triacylglycerol levels in broiler serum. The PPE supplementation decreased serum total cholesterol levels and increased high-density lipoprotein cholesterol levels. The content of the breast muscle alpha linolenic acid improved after replacement of soybean oil with linseed oil in broiler diets. PPE supplementation increased the phenol and flavonoid content in broiler meat and increased lysozyme activity. Replacing soybean oil with linseed oil in broiler diets with the addition of PPE enriched muscle meat with omega-3 fatty acids and antioxidants and improved broiler immunity and their serum lipid profile.